Communication device, control method, and program

Abstract

This communication device, which operates as an access point (AP) that performs communication compliant with the IEEE 802.11 standard series, transmits, to a partner device that operates as a station (STA), a prescribed frame for causing the state of the partner device to transition from a first state in which a first communication parameter can be used for performing communication with the AP to a second state in which communication with the AP is possible at a higher communication rate than in the case of the first communication parameter and in which second communication parameter that is not included in the first communication parameter can be used. The communication device uses the second communication parameter to communicate with the partner device that has transitioned to the second state. The prescribed frame includes padding that corresponds to the time of the transition by the partner device to the second state from the first state, a first frame control sequence (FCS) that is disposed at the end of the prescribed frame, a second FCS that is disposed before the padding, and information that is disposed before the second FCS and that indicates the presence of the second FCS.

Description

Communication device, control method, and program

[0001] The present disclosure relates to power saving control technology in a wireless LAN.

[0002] Currently, wireless Local Area Networks (LANs) represented by the IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard series are widely used. The IEEE 802.11 standard series includes standards such as IEEE 802.11a / b / g / n / ac / ax / be, etc. And, in order to further improve the reliability of communication, the development of the IEEE 802.11bn standard is underway as a successor standard to the IEEE 802.11be standard.

[0003] As one of the candidate technologies defined in the IEEE 802.11bn standard, a technology for suppressing the power consumption of a communication device has been attracting attention (see Non-Patent Document 1). As such a technology, a function called DPS, which enables power saving in communication by dynamically changing wireless communication parameters, has been studied. Note that DPS is an abbreviation for Dynamic Power Save. A communication device corresponding to DPS can operate while switching between two states: a high-capability state that consumes more power but has high communication quality such as a communication rate, and a low-capability state that suppresses power consumption while reducing communication quality.

[0004] Laurent Carion et al., "Client power save (IEEE 802.11-23 / 2003r1)", IEEE 802.11, 2023

[0005] In DPS, an access point (AP) may transmit a trigger signal to transition a communication device operating as a low-capacity station (STA) to a high-capacity state. Hereafter, this trigger signal will be referred to as the ICF (Initial Control Frame). Upon receiving the ICF, the STA modifies its communication parameters. Such parameter changes involve modifications to parameters in areas such as the antenna and transmitting / receiving electrical circuits, requiring a certain amount of time for the changes to complete. Therefore, to ensure that high-capacity communication becomes possible immediately after this period, the ICF includes padding equal to or greater than this period. However, conventional radio frames have a Frame Control Sequence (FCS) at their end, and the device receiving the radio frame uses the FCS to determine whether it was successfully received. In contrast, if the STA transitions from a low-capacity state to a high-capacity state after receiving data up to the FCS, even if padding is set, it cannot process the state transition during that padding period.

[0006] This disclosure provides a technology that enables a station with Dynamic Power Save (DPS) functionality to transition from a low-capacity state to a high-capacity state while the reception of a trigger frame is still incomplete.

[0007] A communication device according to one aspect of the present disclosure is a communication device that operates as an access point (AP) performing communication in accordance with the IEEE 802.11 standard series, and includes a communication means for transmitting a predetermined frame to a remote device operating as a station (STA) to transition the state of the remote device from a first state in which a first communication parameter is available for communication with the AP to a second state in which communication with the AP is possible at a higher communication rate than the first communication parameter and a second communication parameter not included in the first communication parameter is available, and for communicating with the remote device that has transitioned to the second state using the second communication parameter, wherein the predetermined frame includes a padding corresponding to the time it takes for the remote device to transition from the first state to the second state, a first Frame Control Sequence (FCS) placed at the end of the predetermined frame and a second FCS placed before the padding, and information indicating the existence of a second FCS placed before the second FCS.

[0008] According to this disclosure, a station with Dynamic Power Save (DPS) functionality can transition from a low-capacity state to a high-capacity state while the reception of the trigger frame is still incomplete.

[0009] Other features and advantages of the technical ideas derived from this disclosure will become apparent from the following description with reference to the attached drawings. In the attached drawings, the same or similar components are given the same reference numeral.

[0010] The attached drawings are included in the specification and constitute part thereof, illustrating embodiments in this disclosure and used to explain the technical ideas derived from this disclosure together with their descriptions. Figure 1 is a diagram showing an example configuration of a wireless communication system. Figure 2 is a diagram showing an example hardware configuration of AP and STA. Figure 3 is a diagram showing the functional configuration of AP and STA. Figure 4 is a diagram showing an example of the communication flow performed in the wireless communication system. Figure 5 is a diagram showing an example of the ICF frame format. Figure 6 is a diagram showing an example configuration of the ICF Common Info field. Figure 7 is a diagram showing an example of the ICF frame format. Figure 8A is a diagram showing an example of the ICF frame format. Figure 8B is a diagram showing an example of the ICF frame format. Figure 9 is a diagram showing an example of the ICF frame format. Figure 10 is a diagram showing an example of the ICF frame format. Figure 11 is a diagram showing an example of the processing flow performed by AP. Figure 12 is a diagram showing an example of the processing flow performed by STA.

[0011] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the scope of the claims. While the embodiments describe multiple features, not all of these features are necessary, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0012] (System Configuration) Figure 1 shows an example of the configuration of a wireless communication system according to this embodiment. The wireless communication system is composed of communication devices that perform communication in accordance with the IEEE 802.11 standard series. Figure 1 shows a state in which there is one access point (AP102) and three stations (STA103, STA104, STA105) as communication devices, but this is just one example. That is, the number of APs may be two or more, and the number of STAs may be two or less or four or more. AP102 forms a network 101 and can transmit signals to STAs (STA103, STA104, STA105) within the range of the network 101 and can also receive signals from those STAs.

[0013] In this embodiment, AP102 and STA103 to STA105 are configured to perform wireless communication using a communication method compliant with the IEEE 802.11bn standard. The IEEE 802.11bn standard is the successor to the IEEE 802.11be standard, and its main features include the realization of functions such as highly reliable communication, low latency communication, improved throughput when communication traffic is congested, and power saving. The wireless frame used in the communication method compliant with this standard may be called a UHR (Ultra High Reliability) PPDU. PPDU is an abbreviation for PLCP Protocol Data Unit, and PLCP is an abbreviation for Physical Layer Convergence Protocol. Note that names such as UHR and IEEE 802.11bn may be changed to different names once the standards are finalized. Furthermore, the technologies described herein and in the claims attached herein are applicable to communication devices using all successor standards to IEEE 802.11be.

[0014] Furthermore, AP102 and STA103-STA105 may support at least one legacy standard that predates the IEEE 802.11bn standard and be configured to perform wireless communication compliant with that standard. Legacy standards include, for example, the IEEE 802.11a / b / g / n / ac / ax / be standards. AP102 and STA103-STA105 may also support other communication standards such as Bluetooth®, NFC, Bluetooth® LE (Low Energy), UWB, ZigBee, and MBOA. UWB stands for Ultra Wide Band, and MBOA stands for Multi Band OFDM Alliance. NFC stands for Near Field Communication. UWB includes wireless USB, wireless 1394, WiNET, etc. AP102 and STA103 to STA105 may also be configured to support wired communication using Ethernet cables or optical fibers. AP102 and STA103 to STA105 may also be configured to support wireless communication compliant with cellular communication standards such as fifth generation (5G) and LTE (Long Term Evolution). AP102 may be, but is not limited to, a wireless LAN router or a personal computer (PC). For example, the functions of AP102 described below may be implemented in an information processing device such as a wireless chip capable of performing wireless communication (e.g., transmission and reception of PPDUs) compliant with wireless communication standards such as the IEEE 802.11 standard series, including the IEEE 802.11bn standard. Furthermore, STA (STA103 to STA105) may be, but are not limited to, wearable devices such as cameras, tablets, smartphones, PCs, mobile phones, video cameras, smart glasses, and HMDs (head-mounted displays). For example, the functions of STA described below may be implemented in an information processing device such as a wireless chip that can perform wireless communication (e.g., transmission and reception of PPDUs) compliant with wireless communication standards such as the IEEE 802.11 standard series, including the IEEE 802.11bn standard.When functions are implemented in an information processing device (wireless chip), the device may be configured so that various controls are performed by internal hardware circuits. Alternatively, the wireless chip may be configured so that various processes are performed through the cooperation of a processor such as an ASIP, memory, and hardware circuits within the chip. ASIP stands for Application-Specific Instruction set Processor.

[0015] AP102 and STA103-STA105 can communicate using radio signals in frequency bands such as the 2.4 GHz band, 3.6 GHz band, 5 GHz band, 6 GHz band, and millimeter wave bands such as the 45 GHz band and 60 GHz band. The frequency bands used by AP102 and STA103-STA105 are not limited to these, and may also be the Sub1 GHz band, for example.

[0016] Furthermore, AP102 and STA103-STA105 can communicate using bandwidths (frequency bands) of 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, 540 MHz, 640 MHz, 1080 MHz, and 2160 MHz. The bandwidths used by AP102 and STA103-STA105 are not limited to these; for example, bandwidths such as 240 MHz or 4 MHz may be used. Note that the IEEE 802.11 series standard specifies frequency channels using a bandwidth of 20 MHz as basic channels in frequency bands such as the 2.4 GHz, 5 GHz, and 6 GHz bands. In addition, this standard defines multiple usable channels in each frequency band of the 2.4 GHz, 5 GHz, and 6 GHz bands. Furthermore, in this standard, a certain channel may be used in combination with other adjacent channels. A bundle of channels formed by one or two or more adjacent channels may be called a communication link (link). That is, in a link formed by two channels with a bandwidth of 20 MHz, a bandwidth of 40 MHz is used. AP102 and STA103 to STA105 may be AP MLDs (Multi-Link Devices) and STA MLDs that support Multi-Link, which establishes multiple links simultaneously for communication.

[0017] AP102 and STA103-STA105 establish one or more links with a peer device in order to communicate data with that peer device. For example, STA103-STA105 perform a predetermined connection procedure with AP102 in order to establish a link with AP102. A link is established between the devices once the predetermined connection procedure between STA103-STA105 and AP102 is completed. Once the link is established, AP102 and STA103-STA105 can access the wireless medium and communicate data and other information with the peer communication device. For example, if one link using a 160 MHz bandwidth is established between the devices, AP102 and STA103-STA105 communicate using all or some of the channels that make up that link. A link using a 160 MHz bandwidth may be composed of eight channels with a 20 MHz bandwidth bundled together.

[0018] As mentioned above, one of the candidate technologies specified in the IEEE 802.11bn standard is a function called DPS, which enables power saving in communication by dynamically changing communication parameters. DPS stands for Dynamic Power Save. In this embodiment, AP102 and STA103 to STA105 are assumed to have the DPS function. Communication parameters changed by DPS include, for example, the frequency bandwidth used for communication, the number of spatial streams, and MCS (Modulation and Coding Scheme). A wireless communication device with the DPS function can operate by switching between two states: a high-capacity state that consumes more power but has higher communication quality such as communication rate, and a low-capacity state that reduces power consumption while lowering communication quality. In this embodiment, AP102 can transmit an Initial Control Frame (ICF) as a trigger frame to an STA in a low-capacity state, causing the STA to transition to a high-capacity state. An ICF is a predetermined frame that can be transmitted to one or more STAs. By transmitting one ICF to multiple STAs, AP102 can simultaneously (in parallel) transition multiple STAs to a high-capacity state. When an STA receives an ICF, it changes the relevant communication parameters as described above in order to transition to a high-capacity state. Note that an STA may be configured to determine whether to maintain the low-capacity state or transition to a high-capacity state when it receives an ICF. The ICF may include information about the changed values ​​of the communication parameters, and the STA may be configured to change the communication parameters according to that information.

[0019] Changes to communication parameters in STA involve changes to parameters such as antennas and electrical circuits for transmitting and receiving radio signals. Therefore, a predetermined amount of time is required for these changes to be completed. If other communication devices begin communicating on the frequency channel used by AP102 and STA during this predetermined time, it is conceivable that STA may not be able to communicate even if it enters a high-capacity state. For this reason, the ICF includes padding of the same length as or longer than the predetermined time required for the communication parameter changes, so that STA can immediately perform high-capacity communication after the predetermined time has elapsed. In a frame with normal padding, the Frame Control Sequence (FCS) is placed after the Padding field. The FCS is a sequence used to confirm that the frame has been received correctly. On the other hand, in DPS, padding is used that corresponds to the time it takes for STA to transition from a low-capacity state to a high-capacity state, but if STA starts the state transition after receiving up to the FCS, the padding becomes meaningless. On the other hand, if STA initiates a state transition in the middle of a frame to effectively utilize padding, it will not be able to receive the frame during the state transition period, nor will it be able to receive the FCS of the ICF, making it impossible to confirm that the frame has been received correctly. Therefore, in this embodiment, in order to enable STA to receive the FCS while initiating a state transition early, an FCS called an intermediate FCS is placed before the padding. STA initiates a state transition after confirming the intermediate FCS contained within the ICF, that is, before receiving the subsequent padding.

[0020] On the other hand, intermediate FCS are not automatically included in wireless frames such as ICF, and it is assumed that STA cannot determine whether or not an intermediate FCS is present in that wireless frame and therefore cannot process the ICF properly. For this reason, this embodiment provides a mechanism to enable STA to properly process ICFs of DPS that include intermediate FCS.

[0021] (Device Configuration) Figure 2 shows an example of the hardware configuration of the communication device (AP102 and STA103 to STA105) in this embodiment. As an example of its hardware configuration, the communication device includes, for example, a storage unit 201, a control unit 202, a function unit 203, an input unit 204, an output unit 205, a communication unit 206, and an antenna 207. Note that these are just examples, and the communication device may have further configurations not shown in Figure 2, or some or all of the configurations shown in Figure 2 may be replaced by other configurations having similar functions.

[0022] The storage unit 201 is configured to include one or more memories such as ROM and RAM. The storage unit 201 stores various information such as computer programs for performing the various operations described later, and communication parameters for wireless communication. ROM stands for Read Only Memory, and RAM stands for Random Access Memory. In addition to memories such as ROM and RAM, the storage unit 201 may also be configured to include storage media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, and DVDs. Furthermore, the storage unit 201 may be configured to include multiple storage media such as memories.

[0023] The control unit 202 is configured to include, for example, one or more processors such as a CPU and an MPU. CPU stands for Central Processing Unit, and MPU stands for Micro Processing Unit. The control unit 202 controls the entire communication device by executing a computer program stored in the storage unit 201. Alternatively, the control unit 202 may control the entire device through cooperation between the computer program stored in the storage unit 201 and the operating system. The control unit 202 also generates data and signals (wireless frames) to be transmitted in communication with other communication devices. Furthermore, the control unit 202 may be equipped with multiple processors, such as a multi-core processor, and various controls may be performed by multiple processors. The control unit 202 may also be configured to include, for example, an ASIC (Application-Specific Integrated Circuit), a DSP (Digital Signal Processor), or an FPGA (Field-Programmable Gate Array).

[0024] Furthermore, the control unit 202 controls the functional unit 203 to perform predetermined processes such as wireless communication, imaging, printing, and projection. The functional unit 203 is configured to include hardware for the communication device to perform predetermined processes. If the communication device is a printer, the functional unit 203 is a printing device and prints, for example, image data acquired via the communication unit 206. If the communication device is a scanner, the functional unit 203 is a reading device and outputs the scanned image data to the outside, for example, via the communication unit 206. If the communication device is a camera, the functional unit 203 is configured to include an image sensor and a lens and outputs the image data captured by the camera to the outside, for example, via the communication unit 206. The functional unit 203 may also include configurations for realizing AP functions and STA functions.

[0025] The input unit 204 is configured to include, for example, a touch panel, hard keys, buttons, etc., and accepts various operations from the user. The output unit 205 is configured to include a display, speaker, etc., and provides various outputs to the user. Here, the output from the output unit 205 can be a screen display output on the display or an audio output from the speaker. The output unit 205 may also include a vibrator and output information by vibration output. Note that both the input unit 204 and the output unit 205 may be implemented in a single module, such as a touch panel display. The input unit 204 and the output unit 205 may be built into the communication device or implemented by an external input / output device. In this case, the communication device has an input / output interface for connecting to the input / output device.

[0026] The communication unit 206 performs control for wireless communication compliant with the IEEE 802.11 series standard. The communication unit 206 can perform control of wireless communication compliant with, for example, the IEEE 802.11bn standard, its successor standards, or earlier legacy standards, as well as control of wired communication such as wired LAN. The communication unit 206 controls the antenna 207 to send and receive signals for wireless communication generated by the control unit 202. For example, a communication device communicates data such as image data, document data, and video data with a partner device via the communication unit 206. If the communication device supports standards other than the IEEE 802.11 series standard, such as NFC or Bluetooth®, the communication unit 206 may perform control of wireless communication compliant with these communication standards. Furthermore, if the communication device is capable of performing wireless communication compliant with multiple communication standards, separate communication units and antennas corresponding to those communication standards may be provided.

[0027] Antenna 207 is, for example, an antenna capable of detecting and radiating radio waves in the 2.4 GHz band, the 5 GHz band, and the 6 GHz band, respectively. Antenna 207 may also be configured to enable communication in the same frequency band. In this case, antenna 207 may be, for example, a multiband antenna capable of communication in multiple frequency bands. Figure 2 shows an example where the communication device has only one antenna, but multiple antennas may be used, for example, depending on the number of available spatial streams. If the communication device has multiple antennas, it may have a communication unit 206 corresponding to each antenna. Antenna 207 may be provided separately from the communication unit 206, or it may be configured as a single module together with the communication unit 206.

[0028] Figure 3 shows an example of the functional (software) configuration of the communication device (AP102 and STA103 to STA105) of this embodiment. The communication device is configured to include, for example, a wireless LAN control unit 301, a frame generation unit 302, a frame analysis unit 303, a UI control unit 304, a storage control unit 305, and a DPS control unit 306. Note that this functional configuration is just an example, and other functions may be added or the shown functions may be modified. For example, one functional block shown in Figure 3 may be divided into multiple units, or multiple functional blocks may be combined into one. Also, some functions may be omitted, or functions not shown may be added. In one example, at least some of the functions shown in Figure 3 may be realized by the control unit 202 executing a program stored in the storage unit 201. Also, at least some of the functions shown in Figure 3 may be realized using dedicated hardware.

[0029] The wireless LAN control unit 301 controls wireless LAN (Local Area Network) communication. The wireless LAN control unit 301 controls the communication unit 206 and antenna 207 in order to send and receive wireless signals with other communication devices that are capable of wireless LAN communication. For example, the wireless LAN control unit 301 works in cooperation with the frame generation unit 302 and the frame analysis unit 303 to perform wireless frame communication control in accordance with the IEEE 802.11 standard series.

[0030] The frame generation unit 302 generates wireless frames that include MAC frames such as management frames, control frames, and data frames. MAC stands for Medium Access Control. MAC frames are also called MAC Protocol Data Units (MPDUs) or Aggregate MAC Protocol Data Units (A-MPDUs). Wireless frames consist of a preamble field and a data field. MAC frames such as management frames, control frames, and data frames are stored in the data field. Wireless control can be performed by each MAC frame generated by the frame generation unit 302. Here, the content of the wireless control may be constrained by the settings stored in the storage unit 201 by the storage control unit 305. The frame generation unit 302 can also accept settings from the user via the UI control unit 304. The wireless frames generated by the frame generation unit 302 are supplied to the wireless LAN control unit 301 and can be transmitted externally using the communication unit 206 and antenna 207 under the control of the wireless LAN control unit 301. The frame analysis unit 303 analyzes the wireless frames received via the communication unit 206 and antenna 207 under the control of the wireless LAN control unit 301. When analyzing wireless frames, the frame analysis unit 303 can determine the analysis method based on settings stored in the storage unit 201 by the storage control unit 305.

[0031] The UI control unit 304 controls the input unit 204 to accept input to a user interface (UI), such as a touch panel or buttons, for receiving operations on the communication device by a user (not shown). The UI control unit 304 can also control the output unit 205, for example, to perform controls to present information to the user, such as displaying images or outputting sound. The UI control unit 304 can also control the input unit 204 and the output unit 205 to display a graphical UI (GUI) on a display and accept operations on that GUI. The storage control unit 305 controls the storage unit 201 to perform various information storage controls, such as saving, searching, and extracting programs and data on which the communication device operates. The DPS control unit 306 performs controls related to DPS. For example, the DPS control units 306 of STA103 to STA105 perform DPS state changes based on the received ICF and the state of the device itself. The DPS control units 306 of STA103 to STA105 may, for example, determine whether or not to change the DPS state in response to the reception of an ICF. Furthermore, when the DPS control units 306 of STA103 to STA105 change the DPS state, they notify the wireless LAN control unit 301 and the frame generation unit 302 of the change. This causes the wireless frame generated by the frame generation unit 302 to be modified. The wireless LAN control unit 301 also modifies the settings of the communication unit 206 and the antenna 207. As a result, wireless frames corresponding to the modified communication parameters are transmitted using the modified communication parameters. Additionally, the DPS control unit 306 of AP102 controls STA103 to STA105 to generate and transmit an ICF frame in order to perform a state change. The DPS control unit 306 of AP102 can also perform control related to state transitions from a low-capacity state to a high-capacity state.

[0032] (Processing Flow) Next, an example of the communication flow performed in a wireless communication system will be explained using Figure 4. In the example in Figure 4, AP102 transmits ICF401 to STA103 to STA105, which are compatible with the DPS function, to transition from a low-capacity state to a high-capacity state. ICF401 may also be transmitted to an STA that is in a high-capacity state. In that case, the STA in a high-capacity state can maintain that state. ICF401 can be transmitted at various timings. For example, the timing at which ICF401 is transmitted between AP102 and each STA may be predetermined. Also, AP102 may transmit ICF401 when it determines that the STA it is communicating with needs to be in a high-capacity state, that is, when it determines that it should communicate with an STA in a high-capacity state.

[0033] Here, an example of the ICF401 frame format will be explained using Figure 5. The ICF401 includes a Frame Control field 501, a Duration field 502, an RA field 503, and a TA field 504. The ICF401 further includes a Common Info field 505, User Info fields 506-508, a Padding1 field 509, and an FCS field 510. The fields that are particularly relevant to this embodiment will be described below. Fields that are not specifically described serve the same roles as the fields included in conventional wireless frames, and therefore their descriptions will be omitted here.

[0034] The Common Info field 505 is a field that contains control information common to one or more STAs. The Common Info field 505 includes at least a Trigger Type subfield 511 and an Intermediate FCS mode subfield 512. An example of the correspondence between the value of the Trigger Type subfield 511 and the type of ICF that the value indicates is shown in the table below. In this embodiment, setting the value of the Trigger Type subfield 511 to 9 indicates that it is an ICF for DPS. The Intermediate FCS mode subfield 512 stores a value indicating whether or not an intermediate FCS is included in the Padding1 field 509. For example, storing "1" in the Intermediate FCS mode subfield 512 indicates that an intermediate FCS exists in the Padding1 field 509. Conversely, storing "0" in the Intermediate FCS mode subfield 512 indicates that an intermediate FCS does not exist in the Padding1 field 509. Note that this is just an example, and the Intermediate FCS mode subfield 512 may be set to "1" when an intermediate FCS exists in the Padding1 field 509, and to "0" when an intermediate FCS does not exist.

[0035] The Padding1 field 509 is located after the User Info fields 506-508, which store control information for each of the one or more STAs, and is set with padding bits. The Padding1 field 509 is set with padding bits of a length corresponding to the time required for the STA to transition from a low-capacity state to a high-capacity state. In this embodiment, the Padding1 field 509 includes a subfield 513 consisting of two octets of ones, an Intermediate FCS subfield 514, and a Padding2 subfield 515. The first 12 bits of the Padding1 field being 1 indicate that the User Info field 508 is the last User Info field and the next field is the Padding1 field 509. The length of the subfield 513 may be other than two octets. The Intermediate FCS subfield 514 may be 32 bits long, but may be of other lengths. The STA corresponding to the DPS confirms that the radio frame has been successfully received by receiving the Intermediate FCS subfield 514, provided that the ICF 401 contains a User Info field corresponding to its own device. Once the STA confirms that the radio frame has been successfully received, it starts the transition process from the low-capacity state to the high-capacity state. In this case, the STA does not need to interpret the Padding2 subfield 515 and the FCS field 510. The Padding2 subfield 515 is set with padding bits of a length corresponding to the time required for the STA to transition from the low-capacity state to the high-capacity state. For example, the padding length is set so that the time from the transmission timing of the Intermediate FCS subfield 514 to the transmission timing of the FCS field 510 corresponds to the time required for the STA to transition from a low-capacity state to a high-capacity state. If there are multiple STAs that need to transition to a high-capacity state, the padding length may be set based on the longest time required for each of the multiple STAs to transition from a low-capacity state to a high-capacity state.As a result, it is expected that all target STAs will be in a high-capacity state when the ICF transmission is completed. The length of the Padding2 subfield 515 (the bit length of the padding bits) may be specified, for example, in the Common Info field 505 or before the Padding2 subfield 515 of the Padding1 field 509.

[0036] ICF401 may be a frame defined prior to the IEEE 802.11bn standard, in which the value of the Trigger Type subfield 511 included in the Common Info field 505 is between 0 and 8. Details of the Common Info field 505 in this case are shown in Figure 6. The Common Info field 505 includes the subfields Trigger Type 601, UL Length 602, More TF 603, CS Required 604, and UL BW 605. The Common Info field 505 also includes GI And HE / EHT / UHR-LTF Type / Triggered TXOP Sharing Mode 606 and Reserved 607. Furthermore, Common Info field 505 includes Number Of HE / EHT / UHR-LTF Symbols 608, Reserved 609, LDPC Extra Symbol Segment 610, and AP Tx Power 611. Also, Common Info field 505 includes Pre-FEC Padding Factor 612, PE Disambiguity 613, UL Spatial Reuse 614, and Reserved 615. Furthermore, the Common Info field 505 includes HE / EHT / UHR P160 616 and Special User Info Field Flag 617. The Common Info field 505 also includes Intermediate FCS mode 618 and Trigger Dependent Common Info 619. Here, Intermediate FCS mode 618 is a subfield indicating whether or not the Padding1 field 509 contains an intermediate FCS, similar to the Intermediate FCS mode subfield 512 described above. It may also be indicated that this ICF is a DPS ICF using one of the Reserved fields. For example, setting the value of Reserved615 to "1" may indicate that this ICF is the ICF of DPS.

[0037] When STA103 to STA105 receive ICF401, they transition from a low-capacity state to a high-capacity state before AP102 completes the transmission of the FCS field 510. Once STA103 to STA105 have completed the state transition, they send response frames 402 to 404 to AP102 to notify the state transition. These response frames may, for example, be called Initial Control Response (ICR) frames. Note that AP102 may be notified of the completion of the state transition by a frame other than the ICR frame. Note that if STA does not transition to the high-capacity state, it is not necessary to send an ICR frame. For example, Ack frames or RTS frames may be used as response frames 402 to 404. Alternatively, frames containing communication parameters after the transition to the high-capacity state may be used as response frames 402 to 404. Communication parameters that become available after transitioning to a high-capacity state may be shared in advance between AP102 and STA103 to STA105, for example.

[0038] After receiving response frames 402-404, AP102 transmits PPDU 405 to STA103-STA105. AP102 determines the communication parameters to use for each STA according to the communication parameters in the high-capacity state. AP102 can use communication parameters with a higher communication rate than those used for STAs in the low-capacity state when communicating with STAs in the high-capacity state. Upon receiving PPDU 405, STA103-STA105 transmit Ack frames 406-408 to AP102 as response frames. After transmitting the Ack frames, STA103-STA105 return to the low-capacity state.

[0039] The time 409 from when STA transitions to the high-capacity state until it returns to the low-capacity state may be pre-set, or this time may be shared between AP102 and STA in advance. Information regarding the time 409 from the high-capacity state to the low-capacity state may also be included in the ICF. Furthermore, the time 409 from the high-capacity state to the low-capacity state may be determined, for example, based on TXOP (Transmission Opportunity). TXOP is set for each access category, and its upper limit is defined as TXOP limit. For example, the set TXOP or the maximum value of TXOP limit may be used as the time 409 from the high-capacity state to the low-capacity state. Additionally, STA may transition to the low-capacity state if it does not receive a signal for a certain period of time after Ack frames 406-408 are transmitted (i.e., if it determines that there are no data frames to receive).

[0040] Information indicating the presence of an intermediate FCS may be included in the Padding1 field 509 instead of the Common Info field 505. The structure of the ICF in this case is shown in Figure 7. This ICF, as in the case of Figure 6, may also be of a type defined prior to the IEEE 802.11bn standard, where the value of the Trigger Type subfield 511 is between 0 and 8. Alternatively, an ICF of a type not defined prior to the IEEE 802.11bn standard may be used, for example, an ICF where the value of the Trigger Type subfield 511 is set to 9. In the ICF of Figure 7, the Padding1 field 509 includes the Intermediate FCS mode subfield 702 and the Intermediate FCS subfield 703. Furthermore, the Padding1 field 509 includes a subfield 701 consisting of two octets of ones, and a Padding2 subfield 704. The length of subfield 701 does not have to be two octets. The lengths of subfield 701 and the Intermediate FCS mode subfield 702 can be predetermined. For example, a combination of subfield 701 being two octets and the Intermediate FCS mode subfield 702 being one bit can be used. Alternatively, a combination of subfield 701 being 12 bits and the Intermediate FCS mode subfield 702 being 4 bits can be used. In this way, by predetermining the combinations of lengths for each subfield, the STA can specify which bit position to interpret as the Intermediate FCS mode subfield 702. The Intermediate FCS mode subfield 702 is the same as the Intermediate FCS mode subfield 512. That is, the presence of a specific value in the Intermediate FCS mode subfield 702 indicates that the Intermediate FCS subfield 703 is located after it. Otherwise, it indicates that the Intermediate FCS subfield 703 does not exist.In this case, it may be indicated that the Padding2 subfield 704 is located immediately after subfield 701. That is, if a specific value is not stored at the location of the Intermediate FCS mode subfield 702, the Intermediate FCS mode subfield 702 may also be treated as not existing.

[0041] When STA receives this ICF, it interprets the fields after subfield 701 and determines that the Intermediate FCS mode subfield 702 exists if a predetermined specific value is stored there. Otherwise, STA may determine that neither the Intermediate FCS mode subfield 702 nor the Intermediate FCS subfield 703 exists. Note that the Intermediate FCS mode subfield 702 may always be present. Furthermore, if AP102 does not include the Intermediate FCS subfield 703 in the ICF, it may store a value different from the predetermined value in the Intermediate FCS mode subfield 702. In these cases, STA can determine that the Padding2 subfield 704 is located immediately after the subfield 701 (or the Intermediate FCS mode subfield 702).

[0042] Furthermore, while the above example described a case where ICF401 includes only one intermediate FCS, multiple intermediate FCSs may be included in ICF401. Examples of the configuration of ICF401 in this case are shown in Figures 8A and 8B. Note that the ICF401 in Figures 8A and 8B may be configured so that the Common Info field 505 does not include the Intermediate FCS mode subfield 512. Therefore, strictly speaking, the configuration of the Common Info field 505 may differ, but since it is the same in other respects, the same reference numerals are used and the explanation is omitted. Another difference is that a normal padding field 804 is used instead of the padding1 field 509, but since the configuration of the padding field 804 is prior art, the explanation is omitted here. On the other hand, in ICF401, the User Info fields 801-803 differ significantly from the User Info fields 506-508 in Figure 5, so their characteristics will be explained below.

[0043] In the ICF401 shown in Figure 8A, each of the User Info fields 801 to 803 contains an AID12 subfield 811. Furthermore, one or more of the User Info fields 801 to 803 contain an Intermediate FCS mode subfield 812. The AID12 subfield 811 stores the Association ID (AID) assigned to the STA that is to interpret that User Info field. That is, when the STA receives the ICF401, it interprets the User Info field where the value stored in the AID12 subfield matches the AID assigned to its device. On the other hand, the STA does not interpret (for example, ignores) User Info fields where the value stored in the AID12 subfield does not match the AID assigned to its device. The Intermediate FCS mode subfield 812 is configured similarly to the Intermediate FCS mode subfield 512. For example, if "1" is stored in the Intermediate FCS mode subfield 812, the User Info field includes the Intermediate FCS subfield 813. On the other hand, if "0" is stored in the Intermediate FCS mode subfield 812, the Intermediate FCS subfield 813 does not exist. The Padding subfield 814 may be configured to exist, for example, only when the Intermediate FCS subfield 813 exists. However, this is just one example, and the Padding subfield 814 may be set solely for adjusting the size of the User Info field, regardless of the presence or absence of the Intermediate FCS subfield 813. In this case, padding corresponding to the state transition time of the STA may be set in the Padding field 804. In this case, the Padding field 804 may be set so that the time from the end of the last set Intermediate FCS subfield 813 to the end of the frame corresponds to the state transition time.Also, the length of the Padding subfield 814 may be adjusted according to the difference in the time of state transition in each STA. Also, for example, the length of the padding bits of the Padding subfield 814 immediately after the Intermediate FCS subfield 813 set at the rearmost may be set to correspond to the time of state transition.

[0044] In the ICF 401 of FIG. 8B, the User Info fields 801 to 803 further include subfields of a Padding length subfield 815, a Request BW subfield 816, a Request Nss subfield 817, and a Request MCS subfield 818. A value indicating the length of the Padding subfield 814 is stored in the Padding length subfield 815. For example, a value obtained by integrating 1 microsecond with the value stored in the Padding length subfield 815 can be specified as the length of the Padding subfield 814. Also, a value obtained by integrating another length (for example, 32 microseconds) with the value stored in the Padding length subfield 815 may be specified as the length of the Padding subfield 814. Also, the length of the Padding subfield 814 may be made selectable from, for example, four specified values, and the 2-bit Padding length subfield 815 may selectively indicate the length from the specified values. The type of the specified value may be other than four, and the bit length of the Padding length subfield 815 may be other than 2 bits.

[0045] The Request BW subfield 816 stores information regarding the requested frequency bandwidth to be available for communication in the high-performance state after the transition. The Request Nss subfield 817 stores information regarding the requested number of spatial streams to be available for communication in the high-performance state after the transition. The Request MCS subfield 818 stores information regarding the requested MCS (Modulation and Coding Scheme) to be available for communication in the high-performance state after the transition. Information regarding other communication parameter requests may also be included in the ICF401. Upon receiving the ICF401, the STA can set the communication parameters to be available for communication in the high-performance state after the transition based on the Request BW subfield 816, Request Nss subfield 817, and Request MCS subfield 818. Furthermore, STA may set communication parameters in a high-capacity state without considering the requests from AP.

[0046] In the configurations shown in Figures 8A and 8B, the intermediate FCS can be flexibly set or not set for each user. For example, the Intermediate FCS mode subfield 812 to Padding subfield 814 can be set to exist for STA 103, but not for STA 104 and STA 105. If the Intermediate FCS mode subfield 812 to Padding subfield 814 does not exist in the User Info field corresponding to the device, the STA may not transition to the high-capacity state. This makes it possible to transition STAs that require high-capacity communication to the high-capacity state, while maintaining STAs that do not require high-capacity communication in the low-capacity state. In this case, for example, by transmitting an ICF401 (basic trigger frame) in which the Trigger Type subfield 511 is set to "0", it is possible to activate communication between both the high-capacity STA and the low-capacity STA in parallel.

[0047] In FIGS. 8A and 8B, an example in which each of the User Info fields 801 to 803 can include Intermediate FCS mode sub-fields 812 to Padding sub-fields 814 has been described. On the other hand, instead of storing the Intermediate FCS mode sub-field 812 in each of the User Info fields 801 to 803, it may be indicated in another field whether the intermediate FCS is stored in each of these fields. This example is shown in FIG. 9. In this example, an example in which whether the intermediate FCS is included in each of one or more User Info fields is indicated in the Common Info field 901 is shown.

[0048] The Common Info field 901 includes the Trigger Type subfield 511, as well as the Bitmap size subfield 911 and the Intermediate FCS Bitmap subfield 912. In this example, the value of the Trigger Type subfield 511 may be set to "9", for example, but it may also be set to any value from "0" to "8". The Bitmap size subfield 911 stores a value indicating the bit length of the Intermediate FCS Bitmap subfield 912. In this example, the bit length of the Intermediate FCS Bitmap subfield 912 matches the number of subsequent User Info fields. Each bit in the bitmap contained in the Intermediate FCS Bitmap subfield 912 indicates whether each subsequent User Info field contains an intermediate FCS. For example, if the nth bit from the beginning of the Intermediate FCS Bitmap subfield 912 is "1", it indicates that the nth User Info field contains an intermediate FCS. On the other hand, if the nth bit from the beginning of the Intermediate FCS Bitmap subfield 912 is "0", it indicates that the nth User Info field does not contain an intermediate FCS. Note that the meanings of "0" and "1" may be reversed. That is, the value "0" may indicate that the corresponding User Info field contains an intermediate FCS. Furthermore, the order of the values ​​in the Intermediate FCS Bitmap subfield 912 may differ from that in the example above. For example, the nth bit from the end may indicate whether the intermediate FCS is included in the nth User Info field from the beginning.

[0049] Among the User Info fields 902 to 904, the Intermediate FCS Bitmap subfield 912 specifies, for example, that the intermediate FCS is included in User Info field 902. In this case, User Info field 902 includes the AID12 subfield 811, the Intermediate FCS subfield 913, the Padding length subfield 914, and the Padding subfield 915. The Intermediate FCS subfield 913 stores a value for the intermediate FCS. The Padding length subfield 914 stores a value indicating the length of the Padding subfield 915. The Padding subfield 915 stores padding bits of the bit length indicated by the Padding length subfield 914. Similar to the Padding subfield 814 described above, the length of the padding bits can be set for the Padding subfield 915.

[0050] Furthermore, an ICF401 with a significantly different configuration from the one described above may be used. An example of the configuration of ICF401 in this case is shown in Figure 10. The ICF401 in Figure 10 is configured such that the User Info field includes a Next padding subfield 1011. This Next padding subfield 1011 stores information that makes it possible to determine whether or not a Padding field containing an intermediate FCS is set immediately after the User Info field containing that subfield. For example, in the example in Figure 10, the Next padding subfield 1011 of the User Info field 1002 stores a specific value that indicates that the Padding field 1003 is placed immediately after the User Info field 1002. This specific value may be, for example, "1". In other words, the setting of the Next padding subfield 1011 of the User Info field 1002 to "1" indicates that the Padding field 1003 will be placed immediately after the User Info field 1002. Similarly, the Next padding subfield 1011 of the User Info field 1004 stores a value that indicates that the Padding field 1005 will be placed immediately after the User Info field 1004. On the other hand, the Next padding subfield 1011 of the User Info field 1001 stores a value different from the value that indicates that the Padding field will be placed immediately after the User Info field 1001. For example, the Next padding subfield 1011 of the User Info field 1001 is set to "0", indicating that a padding field is not placed immediately after the User Info field 1001. In this way, no padding field is placed immediately after the User Info field 1001, while padding fields are placed immediately after the User Info fields 1002 and 1004.

[0051] Padding fields 1003 and 1005 include a Padding length subfield 1012, an Intermediate FCS subfield 1013, and a Padding subfield 1014. The Intermediate FCS subfield 1013 stores a value for the intermediate FCS. The Padding length subfield 1012 stores information indicating the bit length of the padding in the Padding subfield 1014. The Padding subfield 1014 has padding bits of the length indicated in the Padding length subfield 1012 inserted into it. The Padding length subfield 1012 may be placed after the Intermediate FCS subfield 1013. As shown in the example in Figure 10, the Next padding subfield indicates whether the Padding field is placed immediately after the User Info field, and the intermediate FCS is set in the Padding field. On the other hand, if the Padding field is not placed, the intermediate FCS is not set. This makes it possible to control the communication between STAs that require a transition from a low-capacity state to a high-capacity state and STAs that do not require such a state transition using a single ICF. For example, it is sufficient for the User Info field to specify whether or not a predetermined field where the intermediate FCS is stored is placed immediately after the User Info field, and it does not have to be the Next padding subfield 1011. Also, the Padding length subfield 1012 and the Padding subfield 1014 may be omitted. For example, in the last Padding field 1005, a padding bit of a length corresponding to the state transition time of STA may be set, and Padding field 1003 may be omitted. In another example, Padding field 1005 may be set including, for example, Padding length subfield 1012 and Padding subfield 1014, regardless of the contents of the last User Info field.

[0052] Furthermore, a common AID may be assigned to a group of STAs composed of multiple STAs. In this case, an intermediate FCS may be set in a single User Info field where the value corresponding to the AID of the STAs belonging to that group is stored in the AID12 subfield. This allows multiple STAs belonging to that group to be efficiently transitioned to a high-capacity state. In one example, AP102 may store the User Info fields corresponding to the STAs that should transition to a high-capacity state in order in ICF401. That is, for example, in Figure 10, User Info fields 1002 and 1004, where the subsequent Padding field containing the intermediate FCS is placed, may be placed before User Info field 1001. In other words, the order in which User Info fields are placed may be determined so that STAs that require a state transition can start the state transition early. With this arrangement, for STAs that require a state transition, all information after the intermediate FCS is not interpreted, so the information in the User Info field for STAs that do not require a state transition can be treated as equivalent to padding simply for occupying the wireless medium. As a result, for example, by placing the User Info field 1001 later, the length of at least one of the Padding field 1003 and Padding field 1005 can be shortened. Note that if the intermediate FCS is included in the User Info field, the last Padding field of ICF 401 is set to a length corresponding to the time from the intermediate FCS of the last User Info field until the STA completes its transition to the high-capacity state.

[0053] Furthermore, if all STAs receiving ICF401 transition to a high-capacity state, the FCS510 may be omitted. That is, since these STAs transition to a high-capacity state when they interpret the intermediate FCS, they operate without interpreting the subsequent portion of the frame. For this reason, if there are no STAs that interpret the FCS510, for example, padding bits may be set in the portion of the FCS510.

[0054] Next, the processing flow performed by AP102 in this embodiment will be explained using Figure 11. This processing is started, for example, when AP102 completes the connection process with STA.

[0055] First, AP102 determines whether the STA has DPS capability (S1101). AP102 may share relevant information with the STA before data communication. For example, management frames such as Association request frames and Authentication request frames sent from the STA during connection processing may include elements related to DPS capability information. Additionally, Probe request frames and Reauthentication request frames may include elements related to DPS capability information and be sent from the STA to AP. Furthermore, AP102's capability information may be sent from AP102 to surrounding STAs from time to time via Beacon frames. Furthermore, elements related to the DPS capability information of AP102 may be included in management frames such as Association Response frames and Authentication Response frames and transmitted to STA. Also, elements related to the DPS capability information of AP102 may be included in Probe Response frames and Authentication Response frames and transmitted to STA.

[0056] If AP102 determines that STA does not have DPS capability (NO in S1101), it communicates with STA using the conventional procedure (S1102). On the other hand, if AP102 determines that STA does have DPS capability (YES in S1101), it determines whether or not to transition STA to a high-capacity state and perform communication (S1103). AP102 determines, for example, that if the communication parameters required for communication with STA are usable even in the low-capacity state, then transitioning to a high-capacity state is unnecessary, and if they are not usable in the low-capacity state, then transitioning to a high-capacity state is necessary. If AP102 determines that it will not perform communication in the high-capacity state (NO in S1103), it communicates with STA using the conventional procedure without performing communication for transitioning to a high-capacity state (S1109). On the other hand, if AP102 determines to perform communication in a high-capacity state (YES in S1103), it sends an ICF to STA that includes an intermediate FCS and is intended to cause a state transition to the high-capacity state as described above (S1104). If AP102 does not receive a response (e.g., an ICR frame) from STA after sending the ICF (NO in S1105), it determines that STA is not in a high-capacity state and communicates with STA using the conventional procedure (S1109). On the other hand, if AP102 receives a response (e.g., an ICR frame) from STA after sending the ICF (YES in S1105), it confirms that STA is in a high-capacity state and performs communication in a high-capacity state. AP102 sends a PPDU to STA using communication parameters that are available to the STA in a high-capacity state (e.g., high communication rate) (S1106). Subsequently, AP102 determines whether or not it has received an Ack frame (e.g., a BlockAck frame) from STA (S1107). If AP102 has not received an Ack (NO in S1107), it retransmits the PPDU until the number of PPDU transmissions reaches a predetermined number that sets the upper limit for the number of retransmissions (NO in S1108, S1106). On the other hand, if AP102 has received an Ack (YES in S1107), it does not retransmit the PPDU or stops it and returns processing to S1103.Furthermore, if AP102 does not receive an Ack after transmitting a PPDU a predetermined number of times (NO in S1107, YES in S1108), it terminates the transmission of that PPDU and returns the process to S1103.

[0057] Next, the processing flow performed by STA (at least one of STA103 to STA105) in this embodiment will be explained with reference to Figure 12. This processing is started, for example, when STA completes the connection process with AP102.

[0058] If STA receives an ICF from AP102 (YES in S1201), it sends a response (e.g., an ICR frame) to AP102 (S1202). Then, upon confirming the intermediate FCS, STA begins the transition to the high-capacity state and completes the state transition (S1203). If STA successfully receives a PPDU from AP102 (YES in S1204), it sends an Ack frame (e.g., a BlockAck frame) to AP102 (S1205). After that, STA returns to the low-capacity state (S1206) and the process returns to S1201. Also, if STA does not receive a PPDU from AP and a predetermined time has elapsed after transitioning to the high-capacity state (NO in S1204, YES in S1207), it returns to the low-capacity state (S1206) and the process returns to S1201.

[0059] As described above, according to this embodiment, AP102 transmits an ICF including an intermediate FCS to an STA that supports the DPS function, causing the STA to transition from a low-capacity state to a high-capacity state. This allows AP102 to transition the STA to the high-capacity state only when it wants to perform communication at a high communication rate, and to maintain the STA in the low-capacity state during other periods, thereby suppressing power consumption. Furthermore, by maintaining the STA in the lowest possible capacity state and dynamically setting the minimum necessary communication parameters, the power consumption of the AP can also be suppressed. In addition, by using an intermediate FCS, the STA can start the state transition before receiving the ICF to the end. On the other hand, by continuing the ICF even after the start of the state transition in the STA, it is prevented from other communication devices using the frequency channel, and communication can be performed immediately after the STA transitions to the high-capacity state. As a result, communication performed by the STA in the high-capacity state can be terminated early, the STA can be returned to the low-capacity state early, and power consumption can be suppressed.

[0060] The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (for example, an ASIC) that implements one or more functions.

[0061] The technical ideas derived from this disclosure are not limited to the exemplary embodiments disclosed, but are intended to encompass various modifications of the exemplary embodiments, or substitutions with equivalent structures or functions. The scope of the following claims should be interpreted in the broadest way to encompass all such modifications and equivalent structures and functions.

[0062] This application claims priority based on Japanese Patent Application No. 2025-004948, filed on January 14, 2025, and all of its contents are incorporated herein by reference.

Claims

1. A communication device that operates as an access point (AP) performing communication in accordance with the IEEE 802.11 standard series, wherein the communication device transmits a predetermined frame to the remote device that operates as a station (STA) to transition the state of the remote device from a first state in which a first communication parameter is available for communication with the AP to a second state in which communication with the AP is possible at a higher communication rate than the first communication parameter and a second communication parameter not included in the first communication parameter is available, and the communication device has communication means for communicating with the remote device that has transitioned to the second state using the second communication parameter, wherein the predetermined frame includes a padding corresponding to the time it takes for the remote device to transition from the first state to the second state, a first Frame Control Sequence (FCS) placed at the end of the predetermined frame and a second FCS placed before the padding, and information indicating the existence of a second FCS placed before the second FCS.

2. The communication device according to claim 1, wherein the communication means includes the information indicating the existence of the second FCS in a Common Info field where information common to one or more of the other devices is stored, and places the second FCS after the Common Info field, where information for each of the one or more of the other devices is stored.

3. The communication device according to claim 2, wherein the communication means includes information indicating the length of the padding in the Common Info field.

4. The communication device according to claim 1, wherein the communication means includes the information indicating the existence of the second FCS and the second FCS in a predetermined field located after one or more User Info fields in which information for each of the one or more counterpart devices is stored.

5. The communication device according to claim 4, wherein the first 12 bits of the predetermined field are set to 1.

6. The communication device according to claim 1, wherein the communication means includes the information indicating the existence of the second FCS and the second FCS in at least one of one or more User Info fields in which information for each of the one or more counterpart devices is stored.

7. The communication device according to claim 6, wherein the communication means includes in the User Info field corresponding to the device that should communicate in the second state among the one or more of the other devices, the information indicating the existence of the second FCS and the second FCS, and the User Info field corresponding to the device that should communicate in the first state does not include in the information indicating the existence of the second FCS and the second FCS.

8. The communication device according to claim 6 or 7, wherein the communication means includes in the User Info field, which includes the information indicating the presence of the second FCS and the second FCS, a second padding and information indicating the length of the second padding positioned in front of the second padding.

9. The communication device according to any one of claims 6 to 8, wherein the communication means includes information relating to the second communication parameter in the User Info field which includes the information indicating the existence of the second FCS and the second FCS.

10. The communication device according to claim 1, wherein the communication means includes the information indicating the existence of the second FCS in a Common Info field where information common to one or more of the other devices is stored, and includes the second FCS in at least one of one or more User Info fields where information for each of the one or more of the other devices is stored, which are located after the Common Info field.

11. The communication device according to claim 10, wherein the information indicating the existence of the second FCS includes a bitmap indicating which of the one or more User Info fields contains the second FCS.

12. The communication means includes the information indicating the existence of the second FCS in at least one of one or more User Info fields in which information for each of one or more of the other devices is stored, and places a predetermined field containing the second FCS immediately after the User Info field containing the information indicating the existence of the second FCS.

13. The communication device according to claim 12, wherein the predetermined field includes a second padding positioned after the second FCS and information indicating the length of the second padding positioned before the second padding.

14. A communication device operating as a station (STA) performing communications in accordance with the IEEE 802.11 standard series, comprising: communication means for communicating with a partner device functioning as an access point (AP); and control means for controlling the communication device to communicate with the partner device in the second state, based on the reception of a predetermined frame from the partner device causing the communication device to transition from a first state in which a first communication parameter is available for communication with the AP to a second state in which communication with the AP at a higher communication rate than the first communication parameter is possible and a second communication parameter not included in the first communication parameter is available, wherein the predetermined frame includes: padding corresponding to the time it takes for the communication device to transition from the first state to the second state; a first Frame Control Sequence (FCS) placed at the end of the predetermined frame and a second FCS placed before the padding; and information indicating the existence of a second FCS placed before the second FCS. The control means, when operating in the first state, initiates a state transition to the second state when the interpretation of the second FCS is completed, before the Padding and the first FCS are received.

15. The communication device according to claim 14, wherein in the predetermined frame, a Common Info field, which stores information common to one or more of the other devices, includes the information indicating the existence of the second FCS, and the second FCS is located after the Common Info field, which stores information for each of the one or more of the other devices.

16. The communication device according to claim 15, wherein the Common Info field includes information indicating the length of the padding.

17. The communication device according to claim 14, wherein in the predetermined frame, a predetermined field located after one or more User Info fields in which information of one or more of the other devices is stored includes the information indicating the existence of the second FCS and the second FCS.

18. The communication device according to claim 17, wherein the first 12 bits of the predetermined field are set to 1.

19. The communication device according to claim 14, wherein in the predetermined frame, at least one of one or more User Info fields, each storing information of one or more of the other devices, includes the information indicating the existence of the second FCS and the second FCS.

20. The communication device according to claim 19, wherein in the predetermined frame, the User Info field corresponding to the device among the one or more of the other devices that should communicate in the second state includes the information indicating the existence of the second FCS and the second FCS, and the User Info field corresponding to the device that should communicate in the first state does not include the information indicating the existence of the second FCS and the second FCS.

21. The communication device according to claim 19 or 20, wherein in the predetermined frame, the User Info field including the information indicating the presence of the second FCS and the second FCS includes a second padding and information indicating the length of the second padding positioned in front of the second padding.

22. The communication device according to any one of claims 19 to 21, wherein in the predetermined frame, the User Info field, which includes the information indicating the presence of the second FCS and the second FCS, includes information relating to the second communication parameter.

23. The communication device according to claim 14, wherein in the predetermined frame, a Common Info field storing information common to one or more of the other devices includes the information indicating the existence of the second FCS, and at least one of the one or more User Info fields, which are located after the Common Info field and store information for each of the one or more of the other devices, includes the second FCS.

24. The communication device according to claim 23, wherein the information indicating the existence of the second FCS includes a bitmap indicating which of the one or more User Info fields contains the second FCS.

25. The communication device according to claim 14, wherein in the predetermined frame, at least one of one or more User Info fields, each storing information of one or more of the other devices, includes the information indicating the existence of the second FCS, and a predetermined field including the second FCS is placed immediately after the User Info field containing the information indicating the existence of the second FCS.

26. The communication device according to claim 25, wherein the predetermined field includes a second padding positioned after the second FCS and information indicating the length of the second padding positioned before the second padding.

27. A communication method performed by a communication device operating as an access point (AP) that performs communication in accordance with the IEEE 802.11 standard series, comprising: transmitting a predetermined frame to a remote device operating as a station (STA) to transition the state of the remote device from a first state in which a first communication parameter is available for communication with the AP to a second state in which communication with the AP at a higher communication rate than the first communication parameter is possible and a second communication parameter not included in the first communication parameter is available; and communicating with the remote device that has transitioned to the second state using the second communication parameter, wherein the predetermined frame includes a padding corresponding to the time it takes for the remote device to transition from the first state to the second state, a first Frame Control Sequence (FCS) placed at the end of the predetermined frame, a second FCS placed before the padding, and information indicating the existence of a second FCS placed before the second FCS. Communication method.

28. A communication method performed by a communication device that operates as a station (STA) performing communication in accordance with the IEEE 802.11 standard series and communicates with a remote device that functions as an access point (AP), comprising: receiving a predetermined frame from the remote device to transition the state of the communication device from a first state in which a first communication parameter is available for communication with the AP to a second state in which communication with the AP at a higher communication rate than the first communication parameter is possible and a second communication parameter not included in the first communication parameter is available; and controlling the communication device to communicate with the remote device in the second state based on the receipt of the predetermined frame, wherein the predetermined frame comprises a padding corresponding to the time it takes for the communication device to transition from the first state to the second state, and a first Frame Control placed at the end of the predetermined frame. A communication method comprising a Sequence (FCS) and a second FCS positioned before the Padding, and information indicating the existence of the second FCS positioned before the second FCS, wherein, when operating in the first state, the communication method includes initiating a state transition to the second state when the interpretation of the second FCS is completed, before the Padding and the first FCS are received.

29. A program for causing a computer to function as each of the means of the communication device described in any one of claims 1 to 13.

30. A program for causing a computer to function as one of the means of a communication device according to any one of claims 14 to 26.

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