Terminal equipment, base station equipment, and communication method

Abstract

To enable low-latency communication.SOLUTION: A terminal device for communicating with a base station device or another terminal device includes: a transmitting unit that transmits a radio frame; a receiving unit that receives carrier sense and a radio frame; and a control unit that controls transmission and reception of the radio frames. The control unit transmits a radio frame containing priority right usage condition information and priority right request information to the base station device.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present invention relates to a terminal device, a base station device, and a communication method.

Background Art

[0002] IEEE (The Institute of Electrical and Electronics Engineers Inc.) has been continuously working on updating the specifications of IEEE802.11, which is a wireless LAN standard, in order to achieve higher speed and more efficient frequency utilization in wireless LAN communication. In wireless LAN, wireless communication can be performed using an unlicensed band that can be used without permission (license) from a country or region. For personal use such as in homes, a wireless LAN access point function is included in a line termination device for connecting to a WAN (Wide Area Network) line such as the Internet, or a wireless LAN access point device (AP) is connected to the line termination device, etc., so that Internet access from within a residence has been wirelessized. That is, a wireless LAN station device (STA) such as a smartphone or a PC can connect to a wireless LAN access point device and access the Internet.

[0003] In February 2021, the specifications of IEEE802.11ax were finalized, and communication devices such as wireless LAN devices compliant with the specifications, smartphones, and PCs (Personal Computers) equipped with the wireless LAN devices have appeared on the market as Wi-Fi6 (a registered trademark, a name for products compliant with IEEE-802.11ax that have received Wi-Fi Alliance certification). And currently, as a successor standard to IEEE802.11ax, the standardization activity of IEEE802.11be has been started. With the rapid spread of wireless LAN devices, in the IEEE802.11be standardization, further improvement of throughput per user in an overcrowded environment of wireless LAN devices is being considered.

[0004] The IEEE 802.11 standard introduces error control as a technique to increase throughput. Error control is broadly divided into Forward Error Correction (FEC) and Automatic Repeat Request (ARQ). Forward Error Correction is a method in which errors occurring in the transmission path are corrected at the receiving end using error correction codes, and if the codeword block is recovered correctly, a retransmission request to the transmitting end is unnecessary. Error correction capability can be improved by increasing the proportion of redundant bits in the codeword, but this is in a trade-off relationship with increased decoding processing and decreased transmission efficiency. On the other hand, ARQ is a method in which the receiving end requests the transmitting end to retransmit codeword blocks that were not correctly decoded. Errors in codeword blocks during decoding are detected by the receiving end's Medium Access Control (MAC) and discarded without being accumulated in the buffer. If a codeword block is successfully decoded, an acknowledgment (ACK) is sent to the transmitter; if an error is detected in the codeword block, a negative acknowledgment (NACK) is sent. Codeword block retransmission is performed by ARQ if a NACK is sent to the transmitter or if an ACK is not sent to the transmitter within a certain period. In addition to the error control in the IEEE 802.11 standard described above, the IEEE 802.11be standardization activities are considering a hybrid ARQ (HARQ) that combines forward error correction codes and ARQ. HARQ widely explores chase synthesis, which improves the signal-to-noise power ratio (SNR) of the received signal by sending the same codeword block during retransmission and synthesizing the codeword block at the receiver, and incremental redundancy (IR) synthesis, which enhances the receiver's error correction and decoding capability by sending a redundant signal (parity signal) during retransmission.

[0005] Standards from IEEE 802.11n onward introduce frame aggregation as a technology to increase throughput by reducing overhead. Frame aggregation is broadly classified into A-MSDU (Aggregated MAC Service Data Unit) and A-MPDU (Aggregated MAC Protocol Data Unit). While frame aggregation improves transmission efficiency by allowing a large amount of data to be transmitted at once, it also increases the possibility of transmission errors. For this reason, in standards from IEEE 802.11ax onward, in addition to the improvement of transmission efficiency through frame aggregation, efficient error control for each MPDU is expected to be a key element in increasing throughput. Therefore, in the standardization activities for IEEE 802.11be, it is expected that transmission quality will be improved by obtaining time diversity using HARQ. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] IEEE 802.11-20 / 1046-08-0be, July.2020 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] In the IEEE 802.11be standardization efforts, the application of wireless LAN communication technology to applications requiring high reliability and low latency, such as TSNs (Time Sensitive Networks), is also considered within the scope of standardization. The Restricted TWT technology proposed in Non-Patent Literature 1 is based on the TWT (Target Wake Time) technology of IEEE 802.11ax and is scheduled to be introduced in IEEE 802.11be Release 1. In conventional TWT technology, the start of the TWT SP (Service Period) is determined by NAV (Network Allocation Vector) Protection using RTS / CTS (Request To Send / Clear To Send) or self-CTS mechanisms. Therefore, if the wireless medium is being used by other communications, the start time of the TWT SP is subject to delays and jitter and cannot be accurately predicted. Restricted TWT minimizes the delays and jitter experienced by the start time of the TWT SP by adjusting the system to terminate the transmission opportunity (TXOP: Transmission OPportunity) of other communications before the start of the TWT SP, thereby improving low latency. However, in this system, the station device secures the TXOP based on the TWT SP determined by the access point device. This means that there is a time lag between when the station device is actually able to transmit data and when the TXOP SP begins. This time lag cannot be eliminated, and it is not sufficient to achieve low latency.

[0008] This invention has been made in view of these circumstances, and discloses a communication device and communication method that enables higher performance and lower latency communication by having the station device take the lead in preferentially securing a TXOP for its own data transmission, rather than having the station device use or share a TXOP secured by the access point device. [Means for solving the problem]

[0009] The communication device and communication method according to the present invention, which solve the above-mentioned problems, are as follows.

[0010] (1) That is, a communication device according to one aspect of the present invention is a terminal device that communicates with a base station device or another terminal device, comprising: a transmitting unit that transmits a radio frame; a receiving unit that receives carrier sense and a radio frame; and a control unit that controls the transmission and reception of radio frames, wherein the control unit transmits a radio frame to the base station device that includes priority usage condition information and information requesting priority.

[0011] (2) A communication device according to one aspect of the present invention is a terminal device that communicates with a base station device or another terminal device, comprising: a transmitting unit that transmits a radio frame; a receiving unit that receives carrier sense and a radio frame; and a control unit that controls the transmission and reception of radio frames, wherein the control unit receives a radio frame from the base station device that includes priority usage condition information and information that grants priority.

[0012] (3) Furthermore, a communication device according to one aspect of the present invention is described in (1) or (2) above, and the priority right is a priority right relating to low-latency transmission after carrier sensing.

[0013] (4) A communication device according to one aspect of the present invention is described in any of (1) to (3) above, wherein the priority right usage condition information includes a threshold that restricts the transmission of the terminal device using the priority right, and the threshold includes an upper limit threshold for the wireless medium occupancy rate of the wireless frame transmitted by the terminal device exercising the priority right.

[0014] (5) A communication device according to one aspect of the present invention is described in any of (1) to (3) above, wherein the priority right usage condition information includes a threshold that restricts the transmission of the terminal device using the priority right, and the threshold includes an upper limit threshold for the wireless medium occupancy time of the wireless frame transmitted by the terminal device exercising the priority right.

[0015] (6) A communication device according to one aspect of the present invention is described in any of (1) to (3) above, wherein the priority right usage condition information includes a threshold that restricts the transmission of the terminal device using the priority right, and the threshold includes an upper limit threshold for the number of wireless frames that the terminal device transmits by exercising the priority right.

[0016] (7) Furthermore, a communication device according to one aspect of the present invention is described in any of (1) to (6) above, and the priority right relates to the acquisition of wireless resources.

[0017] (8) Furthermore, a communication device according to one aspect of the present invention is described in any of (1) to (7) above, and when transmitting by exercising the priority right, the exercise of the priority right is indicated by the priority right identification information included in the PHY header of the wireless frame.

[0018] (9) Furthermore, a communication device according to one aspect of the present invention is described in any of (1) to (7) above, and when transmitting by exercising the priority right, the exercise of the priority right is indicated by the priority right identification information included in the MAC header of the wireless frame.

[0019] (10) A communication device according to one aspect of the present invention comprises a transmitting unit that transmits wireless frames, a receiving unit that receives carrier sense and wireless frames, a control unit that controls the transmission and reception of wireless frames, and an evaluation unit that confirms the received wireless frames, wherein the control unit receives wireless frames that include priority right usage condition information and information requesting priority transmitted from the terminal device.

[0020] (11) Furthermore, a communication device according to one aspect of the present invention comprises a transmitting unit that transmits a wireless frame, a receiving unit that receives carrier sense and a wireless frame, a control unit that controls the transmission and reception of wireless frames, and an evaluation unit that confirms the received wireless frame, wherein the control unit transmits a wireless frame to the terminal device that includes priority right usage condition information and information that grants priority right.

[0021] (12) Further, the communication device according to one aspect of the present invention is as described in the above (10) or (11), and the priority is a priority related to low-latency transmission after performing the carrier sense.

[0022] (13) Further, the communication device according to one aspect of the present invention is as described in any one of (10) to (12) above, and the priority usage condition information includes a threshold for restricting transmission using the priority of the terminal device, and the threshold includes an upper limit threshold of the radio medium occupancy rate of the radio frame transmitted by the terminal device exercising the priority.

[0023] (14) Further, the communication device according to one aspect of the present invention is as described in any one of (10) to (12) above, and the priority usage condition information includes a threshold for restricting transmission using the priority of the terminal device, and the threshold includes an upper limit threshold of the radio medium occupancy time of the radio frame transmitted by the terminal device exercising the priority.

[0024] (15) Further, the communication device according to one aspect of the present invention is as described in any one of (10) to (12) above, and the priority usage condition information includes a threshold for restricting transmission using the priority of the terminal device, and the threshold includes an upper limit threshold of the number of radio frames transmitted by the terminal device exercising the priority.

[0025] (16) Further, the communication device according to one aspect of the present invention is as described in any one of (10) to (15) above, and the evaluation unit determines whether the priority is applied to the radio frame received from the terminal device.

[0026] (17) Further, the communication device according to one aspect of the present invention is as described in (16) above, and the determination of whether the priority is applied is performed using the priority identification information included in the PHY header of the radio frame received from the terminal device.

[0027] (18) In addition, a communication device according to one aspect of the present invention is as described in (16) above, and the determination of whether or not the priority right applies is made by the priority right identification information contained in the MAC header of the wireless frame received from the terminal device.

[0028] (19) Another method according to one aspect of the present invention is a communication method used in a communication system comprising a base station device and a terminal device that communicates with the base station device, wherein the terminal device indicates the exercise of priority rights by priority right identification information included in the PHY header of a radio frame transmitted by exercising priority rights when priority rights are valid, and the base station device determines whether or not priority rights have been exercised from the priority right identification information of the radio frame received from the terminal device.

[0029] (20) Another method according to one aspect of the present invention is a communication method used in a communication system comprising a base station device and a terminal device that communicates with the base station device, wherein the terminal device indicates the exercise of priority rights by priority right identification information included in the MAC header of a radio frame transmitted by exercising priority rights when priority rights are valid, and the base station device determines whether or not priority rights have been exercised from the priority right identification information of the radio frame received from the terminal device. [Effects of the Invention]

[0030] According to the present invention, it is possible to contribute to improving highly reliable and low-latency communication in accordance with the IEEE 802.11 standard. [Brief explanation of the drawing]

[0031] [Figure 1] This is a schematic diagram showing an example of wireless resource partitioning according to one aspect of the present invention. [Figure 2] This figure shows an example of a frame configuration according to one aspect of the present invention. [Figure 3] This figure shows an example of a frame configuration according to one aspect of the present invention. [Figure 4] This figure shows an example of communication according to one aspect of the present invention. [Figure 5]This figure shows an example configuration of a communication system according to one aspect of the present invention. [Figure 6] A block diagram showing an example configuration of a wireless communication device according to one aspect of the present invention. [Figure 7] A block diagram showing an example configuration of a wireless communication device according to one aspect of the present invention. [Figure 8] This is a schematic diagram showing an example of an encoding scheme according to one aspect of the present invention. [Figure 9] This is a schematic diagram showing an example of a frame format according to one aspect of the present invention. [Figure 10] This is a schematic diagram of wireless frame transmission according to one aspect of the present invention. [Figure 11] This is a control sequence diagram between wireless communication devices according to one aspect of the present invention. [Figure 12] This is a priority table relating to the positional aspects of the present invention. [Figure 13] This is a control sequence diagram between wireless communication devices according to one aspect of the invention. [Modes for carrying out the invention]

[0032] The communication system in this embodiment comprises an access point device (also referred to as a base station device) and a plurality of station devices (also referred to as terminal devices). The communication system and network composed of the access point device and station devices are referred to as a basic service set (BSS: Basic service set, management range, cell). Furthermore, the station devices in this embodiment may have the functions of an access point device. Similarly, the access point device in this embodiment may have the functions of a station device. Therefore, in the following, when simply referring to a communication device, it can refer to both a station device and an access point device.

[0033] The base station equipment and terminal equipment within the BSS shall communicate based on CSMA / CA (Carrier sense multiple access with collision avoidance). In this embodiment, the infrastructure mode in which the base station equipment communicates with multiple terminal equipment is targeted, but the method of this embodiment can also be implemented in ad-hoc mode in which terminal equipment communicates directly with each other. In ad-hoc mode, terminal equipment takes the place of the base station equipment and forms the BSS. The BSS in ad-hoc mode is also called IBSS (Independent Basic Service Set). Hereinafter, terminal equipment that forms the IBSS in ad-hoc mode can also be considered as base station equipment. The method of this embodiment can also be implemented in P2P (Peer to Peer) communication in which terminal equipment communicates directly with each other. One method of implementing P2P communication is TDLS (Tunneled Direct Link Setup). In TDLS, traffic flowing between terminal equipment connected to the base station equipment is transmitted and received directly between terminal equipment without passing through the base station equipment. The method of this embodiment can also be implemented with WiFi Direct®. In WiFi Direct, terminal devices act as base station devices and form groups. In the following, a terminal device that is the group owner forming a group in WiFi Direct can also be considered a base station device.

[0034] In an IEEE 802.11 system, each device can transmit multiple frame types of transmit frames that share a common frame format. The transmit frame is defined by three layers: the Physical (PHY) layer, the Medium Access Control (MAC) layer, and the Logical Link Control (LLC) layer. The Physical layer is also referred to as the PHY layer, and the MAC layer as the MAC layer, respectively.

[0035] The transmission frame of the PHY layer is called a Physical Protocol Data Unit (PPDU: PHY protocol data unit, physical layer frame). A PPDU consists of a Physical Layer Header (PHY header) which contains header information for signal processing at the physical layer, and a Physical Service Data Unit (PSDU: PHY service data unit, MAC layer frame), which is a data unit processed at the physical layer. A PSDU can be composed of an Aggregated MPDU (A-MPDU), which is an aggregate of multiple MAC Protocol Data Units (MPDUs: MAC protocol data units) that serve as retransmission units in the wireless section.

[0036] The PHY header contains reference signals such as the Short Training Field (STF), used for signal detection and synchronization, and the Long Training Field (LTF), used to acquire channel information for data demodulation, as well as control signals such as the Signal (SIG), which contains control information for data demodulation. Furthermore, STFs are classified according to the corresponding standard into categories such as Legacy STF (L-STF), High-throughput STF (HT-STF), Very High-throughput STF (VHT-STF), High-efficiency STF (HE-STF), and Extremely High-throughput STF (EHT-STF). Similarly, LTFs and SIGs are classified into L-LTF, HT-LTF, VHT-LTF, HE-LTF, L-SIG, HT-SIG, VHT-SIG, HE-SIG, and EHT-SIG. VHT-SIG is further classified into VHT-SIG-A1, VHT-SIG-A2, and VHT-SIG-B. Similarly, HE-SIG is classified into HE-SIG-A1 to HE-SIG-A4 and HE-SIG-B. In addition, a Universal SIGNAL (U-SIG) field containing additional control information may be included to accommodate technical updates within the same standard.

[0037] Furthermore, the PHY header may include information that identifies the BSS that originated from the transmitted frame (hereinafter also referred to as BSS identification information). This BSS identification information may be, for example, the SSID (Service Set Identifier) ​​of the BSS or the MAC address of the base station device of the BSS. Alternatively, the BSS identification information may be a value unique to the BSS other than the SSID or MAC address (for example, the BSS Color).

[0038] PPDU is modulated according to the corresponding standard. For example, under the IEEE 802.11n standard, it is modulated into an orthogonal frequency division multiplexing (OFDM) signal.

[0039] An MPDU consists of a MAC layer header (MAC header) containing header information for signal processing at the MAC layer, a MAC service data unit (MSDU) or frame body which is a data unit processed at the MAC layer, and a frame check sequence (FCS) which checks whether the frame is error-free. Multiple MSDUs can also be aggregated into an aggregated MSDU (A-MSDU).

[0040] MAC layer transmission frames are broadly classified into three types: management frames, which manage the connection status between devices; control frames, which manage the communication status between devices; and data frames, which contain the actual transmission data. Each of these is further classified into multiple subframe types. Control frames include Acknowledge (Ack) frames, Request to send (RTS) frames, and Clear to send (CTS) frames. Management frames include Beacon frames, Probe request frames, Probe response frames, Authentication frames, Association request frames, and Association response frames. Data frames include Data frames and CF-poll frames. Each device can determine the frame type and subframe type of a received frame by reading the contents of the frame control field included in the MAC header.

[0041] Furthermore, Ack may include Block Ack. Block Ack can send reception completion notifications to multiple MPDUs. Additionally, Ack may include Multi STA Block Ack (M-BA), which includes reception completion notifications to multiple communication devices.

[0042] A beacon frame contains fields that indicate the beacon transmission interval and the SSID. Base station equipment can periodically broadcast beacon frames within the Base Station Service Station (BSS), and terminal equipment can identify nearby base station equipment by receiving these beacon frames. When terminal equipment identifies base station equipment based on beacon frames broadcast by base station equipment, this is called passive scanning. On the other hand, when terminal equipment searches for base station equipment by broadcasting a probe request frame within the BSS, this is called active scanning. Base station equipment can transmit a probe response frame in response to the probe request frame, and the contents of the probe response frame are equivalent to those of the beacon frame.

[0043] After recognizing the base station device, the terminal device initiates a connection process to the base station device. The connection process is classified into authentication and association procedures. The terminal device sends an authentication frame (authentication request) to the base station device it wishes to connect to. Upon receiving the authentication frame, the base station device sends an authentication frame (authentication response) to the terminal device, which includes a status code indicating whether or not authentication was granted to the terminal device. By reading the status code in the authentication frame, the terminal device can determine whether or not it has been authorized to authenticate by the base station device. Note that the base station device and the terminal device can exchange authentication frames multiple times.

[0044] Following the authentication procedure, the terminal device sends a connection request frame to the base station device to initiate the connection procedure. Upon receiving the connection request frame, the base station device determines whether to allow the connection from the terminal device and sends a connection response frame to notify the terminal device of this decision. The connection response frame contains a status code indicating whether the connection process was successful or not, as well as an Association Identifier (AID) to identify the terminal device. The base station device can manage multiple terminal devices by assigning a different AID to each terminal device for which it has granted connection permission.

[0045] After the connection process is completed, the base station equipment and terminal equipment perform actual data transmission. The IEEE 802.11 system defines a Distributed Coordination Function (DCF), a Point Coordination Function (PCF), and extended mechanisms such as Enhanced Distributed Channel Access (EDCA) and Hybrid Coordination Function (HCF). The following explanation uses the example of a base station equipment transmitting a signal to a terminal equipment using DCF, but the same applies when a terminal equipment transmits a signal to a base station equipment using DCF.

[0046] In DCF, base station and terminal equipment perform carrier sense (CS) to check the usage status of radio channels around their devices prior to communication. For example, if a base station (transmitting station) receives a signal higher than a predetermined clear channel assessment level (CCA level) on a radio channel, it will postpone the transmission of the transmission frame on that radio channel. In the following, the state in which a signal of CCA level or higher is detected on the radio channel will be called the busy state, and the state in which no signal of CCA level or higher is detected will be called the idle state. This CS, performed by each device based on the power of the signal actually received (received power level), is called physical carrier sense (physical CS). The CCA level is also called the carrier sense level (CS level) or CCA threshold (CCAT). When base station and terminal equipment detect a signal of CCA level or higher, they will begin the operation of demodulating the signal at least at the PHY layer.

[0047] Base station equipment performs carrier sensing on transmitted frames for a frame interval (IFS: Inter frame space) appropriate to the type of frame to determine whether the radio channel is busy or idle. The duration of carrier sensing by the base station equipment varies depending on the frame type and subframe type of the transmitted frame that the base station equipment will transmit. In the IEEE 802.11 system, multiple IFSs with different durations are defined, including the short frame interval (SIFS: Short IFS) used for the highest priority transmitted frames, the polling frame interval (PCF IFS: PIFS) used for relatively high priority transmitted frames, and the distributed control frame interval (DCF IFS: DIFS) used for the lowest priority transmitted frames. When base station equipment transmits data frames using DCF, the base station equipment uses DIFS.

[0048] After waiting for DIFS, the base station equipment waits for an additional random backoff time to prevent frame collisions. In IEEE 802.11 systems, a random backoff time called the Contention window (CW) is used. CSMA / CA assumes that a transmission frame sent by one transmitting station is received by a receiving station without interference from other transmitting stations. Therefore, if transmitting stations send transmission frames at the same time, the frames will collide, and the receiving station will not be able to receive them correctly. To avoid this, each transmitting station waits for a randomly set time before starting to transmit, thus preventing frame collisions. When the base station equipment determines through carrier sense that the radio channel is idle, it starts a CW countdown, and only when the CW countdown reaches 0 does it acquire the right to transmit and send a transmission frame to the terminal device. If the base station equipment determines through carrier sense that the radio channel is busy during the CW countdown, it stops the CW countdown. Then, when the radio channel becomes idle, following the IFS, the base station equipment resumes the remaining CW countdown.

[0049] Next, we will explain the details of frame reception. The receiving terminal device receives the transmitted frame, reads the PHY header of the transmitted frame, and demodulates the received transmitted frame. The terminal device can then determine whether the transmitted frame is addressed to itself by reading the MAC header of the demodulated signal. The terminal device can also determine the destination of the transmitted frame based on the information contained in the PHY header (for example, the group identifier (GID) listed in VHT-SIG-A).

[0050] If a terminal device determines that a received transmission frame is intended for itself and has successfully demodulated the frame without error, it must send an ACK frame to the base station (the transmitting station) to indicate that the frame was received correctly. The ACK frame is one of the highest-priority transmission frames and is sent only during the SIFS period (without any random backoff time). The base station terminates the communication series upon receiving the ACK frame from the terminal device. If the terminal device fails to receive the frame correctly, it will not send an ACK. Therefore, if the base station does not receive an ACK frame from the receiving station within a certain period (SIFS + ACK frame length) after transmitting the frame, it considers the communication to have failed and terminates the communication. Thus, the termination of a single communication (also called a burst) in an IEEE 802.11 system is always determined by the presence or absence of an ACK frame, except in special cases such as the transmission of broadcast signals like beacon frames or when fragmentation is used to divide the transmitted data.

[0051] If a terminal device determines that a received transmission frame is not intended for itself, it sets a Network Allocation Vector (NAV) based on the length of the transmission frame as described in the PHY header, etc. The terminal device does not attempt communication for the period set in the NAV. In other words, the terminal device performs the same action as if the physical CS had determined that the wireless channel was busy for the period set in the NAV, so communication control by NAV is also called virtual carrier sense (virtual CS). In addition to being set based on the information described in the PHY header, the NAV is also set by Request to Send (RTS) frames and Clear to Send (CTS) frames, which are introduced to resolve the hidden terminal problem.

[0052] In DCF, each device performs carrier sensing and autonomously acquires transmission rights, whereas in PCF, a control station called a Point Coordinator (PC) controls the transmission rights of each device within the BSS. Generally, the base station device acts as the PC and acquires the transmission rights of the terminal devices within the BSS.

[0053] The PCF communication period includes a Contention-Free Period (CFP) and a Contention Period (CP). During the CP, communication is conducted based on the DCF described above, and the PC controls the transmission right only during the CFP. The base station equipment, which is the PC, broadcasts a beacon frame containing the CFP duration (CFP Max duration), etc., into the BSS prior to PCF communication. PIFS is used to transmit the beacon frame broadcast at the start of PCF transmission, and it is transmitted without waiting for CW. Upon receiving the beacon frame, the terminal equipment sets the CFP duration described in the beacon frame to the NAV. Thereafter, until the NAV has elapsed or a signal (e.g., a data frame containing CF-end) broadcasting the end of the CFP into the BSS is received, the terminal equipment can only acquire transmission right if it receives a signal (e.g., a data frame containing CF-poll) from the PC signaling the acquisition of transmission right. Furthermore, since no frame collisions occur within the same BSS during the CFP period, each terminal device does not take the random backoff time used in DCF.

[0054] A wireless medium can be divided into multiple resource units (RUs). Figure 1 is a schematic diagram showing one example of a wireless medium division state. For example, in resource division example 1, the wireless communication device can divide the frequency resource (subcarrier), which is the wireless medium, into nine RUs. Similarly, in resource division example 2, the wireless communication device can divide the subcarrier, which is the wireless medium, into five RUs. Of course, the resource division examples shown in Figure 1 are just examples, and for example, multiple RUs can be composed of different numbers of subcarriers. In addition, the wireless medium divided into RUs can include not only frequency resources but also spatial resources. A wireless communication device (e.g., an access point device) can transmit frames to multiple terminal devices (e.g., multiple station devices) simultaneously by placing frames destined for different terminal devices in each RU. The access point device can include information indicating the division state of the wireless medium (resource allocation information) as common control information in the PHY header of the frames it transmits. Furthermore, the access point device can include resource unit assignment information (RU) indicating the RU to which each frame destined for a station device is located, as unique control information, in the PHY header of the frame it transmits.

[0055] Furthermore, multiple terminal devices (e.g., multiple station devices) can simultaneously transmit frames by placing and transmitting frames on their respective assigned RUs. After receiving a frame containing trigger information (Trigger frame: TF) transmitted from an access point device, multiple station devices can wait for a predetermined period before transmitting frames. Each station device can determine the RU assigned to it based on the information contained in the TF. In addition, each station device can acquire an RU through random access based on the TF.

[0056] An access point device can simultaneously assign multiple RUs to a single station device. These multiple RUs may consist of consecutive subcarriers or discontinuous subcarriers. The access point device can transmit a single frame using the multiple RUs assigned to a single station device, or it can transmit multiple frames, each assigned to a different RU. At least one of these multiple frames may be a frame containing common control information for multiple terminal devices transmitting resource allocation information.

[0057] A single station device can be assigned multiple RUs (Units of Transmission) from an access point device. The station device can transmit a single frame using the assigned RUs. Alternatively, the station device can assign multiple frames to different RUs and transmit them. These multiple frames may each be of a different frame type.

[0058] An access point device can assign multiple AIDs to a single station device. The access point device can assign a RU to each of the multiple AIDs assigned to a single station device. The access point device can transmit different frames to each of the multiple AIDs assigned to a single station device using the assigned RUs. These different frames may be of different frame types.

[0059] A single station device can be assigned multiple AIDs by an access point device. A single station device can be assigned a RU (Routing Unit) to each of the multiple AIDs it has been assigned. The station device recognizes all the RUs assigned to each of the multiple AIDs assigned to it as RUs assigned to itself, and can transmit a single frame using these assigned RUs. Furthermore, the station device can transmit multiple frames using these assigned RUs. In this case, each of these frames can contain information indicating the AID associated with its assigned RU. An access point device can transmit different frames to each of the multiple AIDs assigned to a single station device using the RUs it has assigned to each. These different frames can be frames of different frame types.

[0060] Hereafter, base station equipment and terminal equipment will be collectively referred to as wireless communication equipment or communication equipment. Furthermore, the information exchanged when one wireless communication device communicates with another will be referred to as data. In other words, wireless communication equipment includes both base station equipment and terminal equipment.

[0061] A wireless communication device has either the function to transmit PPDUs, the function to receive them, or both. Figure 2 shows an example of the configuration of a PPDU transmitted by a wireless communication device. A PPDU compliant with the IEEE 802.11a / b / g standard has a configuration that includes L-STF, L-LTF, L-SIG, and a Data frame (MAC Frame, MAC frame, payload, data section, data, information bits, etc.). A PPDU compliant with the IEEE 802.11n standard has a configuration that includes L-STF, L-LTF, L-SIG, HT-SIG, HT-STF, HT-LTF, and a Data frame. A PPDU compliant with the IEEE 802.11ac standard has a configuration that includes L-STF, L-LTF, L-SIG, VHT-SIG-A, VHT-STF, VHT-LTF, VHT-SIG-B, and some or all of the MAC frame. In the IEEE 802.11ax standard, the PPDU consists of L-STF, L-LTF, L-SIG, RL-SIG (a temporally repeated L-SIG), HE-SIG-A, HE-STF, HE-LTF, HE-SIG-B, and some or all of the Data frames. In the IEEE 802.11be standard, the PPDU consists of L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-SIG, EHT-STF, EHT-LTF, and some or all of the Data frames.

[0062] The L-STF, L-LTF, and L-SIG enclosed by the dotted lines in Figure 2 are configurations commonly used in the IEEE 802.11 standard (hereinafter, L-STF, L-LTF, and L-SIG will be collectively referred to as L-headers). For example, a wireless communication device compliant with the IEEE 802.11a / b / g standard can properly receive the L-header in a PPDU compliant with the IEEE 802.11n / ac standard. A wireless communication device compliant with the IEEE 802.11a / b / g standard can receive a PPDU compliant with the IEEE 802.11n / ac standard as if it were a PPDU compliant with the IEEE 802.11a / b / g standard.

[0063] However, wireless communication devices compliant with the IEEE 802.11a / b / g standards cannot demodulate the PPDU compliant with the IEEE 802.11n / ac standards that follows the L-header. Therefore, they cannot demodulate information related to the Transmission Address (TA), Receiver Address (RA), and the Duration / ID field used for NAV settings.

[0064] IEEE 802.11 specifies a method for inserting Duration information into the L-SIG as a way for wireless communication devices compliant with the IEEE 802.11a / b / g standards to properly set NAV (or perform receiving operations for a predetermined period). The transmission speed information (RATE field, L-RATE field, L-RATE, L_DATARATE, L_DATARATE field) and transmission period information (LENGTH field, L-LENGTH field, L-LENGTH) within the L-SIG are used by wireless communication devices compliant with the IEEE 802.11a / b / g standards to properly set NAV.

[0065] Figure 3 shows an example of how Duration information is inserted into the L-SIG. While Figure 3 shows a PPDU configuration corresponding to the IEEE 802.11ac standard as an example, the PPDU configuration is not limited to this. PPDU configurations corresponding to the IEEE 802.11n standard and IEEE 802.11ax standard are also acceptable. TXTIME contains information about the length of the PPDU, aPreambleLength contains information about the length of the preamble (L-STF + L-LTF), and aPLCPHeaderLength contains information about the length of the PLCP header (L-SIG). L_LENGTH is a virtual period set to maintain compatibility with the IEEE 802.11 standard, and is related to Signal Extension and L_RATE. opsIt is calculated based on aSymbolLength, which is information about the duration of one symbol (symbol, OFDM symbol, etc.), aPLCPServiceLength, which indicates the number of bits contained in the PLCP Service field, and aPLCPConvolutionalTailLength, which indicates the number of tail bits of the convolutional code. The radio communication device can calculate L_LENGTH and insert it into L-SIG. The radio communication device can also calculate L-SIG Duration. L-SIG Duration indicates information about the duration of the PPDU containing L_LENGTH and the sum of the duration of the Ack and SIFS that are expected to be transmitted from the destination radio communication device in response.

[0066] Figure 9 shows an example of the MAC Frame format. Here, MAC Frame refers to the Data Frame (MAC Frame, MAC Frame, Payload, Data Section, Data, Information Bits, etc.) in Figure 2 and the MAC Frame in Figure 3. The MAC Frame includes Frame Control, Duration / ID, Address1, Address2, Address3, Sequence Control, Address4, QoS Control, HT Control, Frame Body, and FCS.

[0067] Figure 4 shows an example of L-SIG Duration in L-SIG TXOP Protection. DATA (frame, payload, data, etc.) consists of the MAC frame and part or both of the PLCP header. BA is either Block Ack or Ack. PPDU includes L-STF, L-LTF, and L-SIG, and can also include DATA, BA, RTS, or CTS, or one or more of them. The example shown in Figure 4 illustrates L-SIG TXOP Protection using RTS / CTS, but CTS-to-Self may also be used. Here, MAC Duration is the period indicated by the value in the Duration / ID field. The Initiator can also send a CF_End frame to notify of the end of the L-SIG TXOP Protection period.

[0068] Next, a method for identifying the BSS from a frame received by a wireless communication device will be described. In order for a wireless communication device to identify the BSS from a frame received, it is preferable for the wireless communication device transmitting the PPDU to insert information for identifying the BSS (BSS color, BSS identification information, and a value unique to the BSS) into the PPDU, and the information indicating the BSS color can be described in HE-SIG-A.

[0069] A wireless communication device can transmit an L-SIG multiple times (L-SIG Repetition). For example, a receiving wireless communication device can improve the demodulation accuracy of the L-SIG by receiving multiple L-SIGs using MRC (Maximum Ratio Combining). Furthermore, if the wireless communication device successfully receives the L-SIG using MRC, it can interpret the PPDU containing the L-SIG as a PPDU compliant with the IEEE 802.11ax standard.

[0070] A wireless communication device can receive parts of a PPDU other than the PPDU itself (for example, the preamble, L-STF, L-LTF, PLCP header, etc. as defined by IEEE 802.11) even while receiving a PPDU (this is also called dual reception). If the wireless communication device detects parts of a PPDU other than the PPDU while receiving a PPDU, it can update some or all of the destination address, source address, and information regarding the PPDU or DATA period.

[0071] Ack and BA can also be referred to as responses (response frames). Furthermore, probe responses, authentication responses, and connection responses can also be referred to as responses. [1. First Embodiment]

[0072] Figure 5 shows an example of a wireless communication system according to this embodiment. Wireless communication system 3-1 includes wireless communication device 1-1 and wireless communication devices 2-1 to 2-3. Wireless communication device 1-1 is also referred to as base station device 1-1, and wireless communication devices 2-1 to 2-3 are also referred to as terminal devices 2-1 to 2-3. Wireless communication devices 2-1 to 2-3 and terminal devices 2-1 to 2-3 are also referred to as wireless communication device 2A and terminal device 2A, respectively, as devices connected to wireless communication device 1-1. Wireless communication device 1-1 and wireless communication device 2A are wirelessly connected and are in a state where they can send and receive PPDU to and from each other. In addition to wireless communication system 3-1, the wireless communication system according to this embodiment may also include wireless communication system 3-2. Wireless communication system 3-2 includes wireless communication device 1-2 and wireless communication devices 2-4 to 2-6. Wireless communication device 1-2 is also referred to as base station device 1-2, and wireless communication devices 2-4 to 2-6 are also referred to as terminal devices 2-4 to 2-6. Furthermore, wireless communication devices 2-4 to 2-6 and terminal devices 2-4 to 2-6 are also referred to as wireless communication device 2B and terminal device 2B, respectively, as devices connected to wireless communication device 1-2. Although wireless communication systems 3-1 and 3-2 form different BSSs, this does not necessarily mean that they have different ESSs (Extended Service Sets). An ESS represents a service set that forms a LAN (Local Area Network). In other words, wireless communication devices belonging to the same ESS can be considered to belong to the same network from the upper layer. Also, BSSs are combined via a DS (Distribution System) to form an ESS. Note that each of wireless communication systems 3-1 and 3-2 may also be equipped with multiple wireless communication devices.

[0073] In Figure 5, for the following explanation, it is assumed that the signal transmitted by wireless communication device 2A reaches wireless communication devices 1-1 and 2B, but does not reach wireless communication device 1-2. That is, when wireless communication device 2A transmits a signal using a certain channel, wireless communication devices 1-1 and 2B determine that the channel is busy, while wireless communication device 1-2 determines that the channel is idle. Also, it is assumed that the signal transmitted by wireless communication device 2B reaches wireless transmitters 1-2 and 2A, but does not reach wireless communication device 1-1. That is, when wireless communication device 2B transmits a signal using a certain channel, wireless communication devices 1-2 and 2A determine that the channel is busy, while wireless communication device 1-1 determines that the channel is idle.

[0074] Figure 6 shows an example of the device configuration of wireless communication devices 1-1, 1-2, 2A, and 2B (hereinafter collectively referred to as wireless communication device 10-1, station device 10-1, or simply station device). Wireless communication device 10-1 includes a higher layer section (higher layer processing step) 10001-1, an autonomous distributed control section (autonomous distributed control step) 10002-1, a transmitting section (transmitting step) 10003-1, a receiving section (receiving step) 10004-1, and an antenna section 10005-1.

[0075] The upper layer processing unit 10001-1 processes information handled within its own wireless communication device (such as information related to transmitted frames and MIB (Management Information Base)) and frames received from other wireless communication devices at layers higher than the physical layer, such as the MAC layer and LLC layer.

[0076] The upper layer 10001-1 can notify the autonomous distributed control unit 10002-1 of information regarding frames and traffic being transmitted on the wireless medium. This information regarding frames and traffic may include, for example, control information contained in management frames such as beacons, or measurement information reported by other wireless communication devices to the wireless communication device itself. Furthermore, it may include control information contained in management frames or control frames, without limiting the destination (it may be addressed to the device itself, to other devices, or it may be broadcast or multicast).

[0077] Figure 7 shows an example of the device configuration of the autonomous distributed control unit 10002-1. The autonomous distributed control unit 10002-1 is also called the control unit 10002-1, and its configuration includes a CCA unit (CCA step) 10002a-1, a backoff unit (backoff step) 10002b-1, and a transmission decision unit (transmission decision step) 10002c-1.

[0078] The CCA unit 10002a-1 can determine the state of the radio resource (including whether it is busy or idle) using either or both of the information regarding the received signal power received via the radio resource and the information regarding the received signal (including the decoded information), which are notified by the receiving unit 10004-1. The CCA unit 10002a-1 can notify the backoff unit 10002b-1 and the transmission determination unit 10002c-1 of the status determination information of the radio resource.

[0079] The backoff unit 10002b-1 can perform backoff using status determination information for the radio resource. The backoff unit 10002b-1 generates CW and has a countdown function. For example, it can execute a CW countdown when the status determination information for the radio resource indicates an idle state, and stop the CW countdown when the status determination information for the radio resource indicates a busy state. The backoff unit 10002b-1 can notify the transmission determination unit 10002c-1 of the value of the CW.

[0080] The transmission decision unit 10002c-1 makes a transmission decision using either the status determination information of the radio resource, the CW value, or both. For example, when the status determination information of the radio resource indicates idle and the CW value is 0, it can notify the transmission unit 10003-1 of the transmission decision information. Also, when the status determination information of the radio resource indicates idle, it can notify the transmission unit 10003-1 of the transmission decision information.

[0081] The transmission unit 10003-1 includes a physical layer frame generation unit (physical layer frame generation step) 10003a-1 and a wireless transmission unit (wireless transmission step) 10003b-1. The physical layer frame generation unit (physical layer frame generation step) may also be referred to as the frame generation unit (frame generation step). The physical layer frame generation unit 10003a-1 has the function of generating a physical layer frame (hereinafter also referred to as a frame or PPDU) based on transmission decision information notified from the transmission decision unit 10002c-1. The physical layer frame generation unit 10003a-1 includes an encoding unit that generates encoded blocks by performing error correction encoding processing on the data received from the upper layer. The physical layer frame generation unit 10003a-1 also has the function of performing modulation, pre-recording filter multiplication, etc. The physical layer frame generation unit 10003a-1 sends the generated physical layer frame to the wireless transmission unit 10003b-1.

[0082] Figure 8 shows an example of error correction coding according to this embodiment. As shown in Figure 8, the shaded area contains the information bit (systematic bit) sequence, and the white area contains the redundant bit sequence (parity bit sequence). Bit interleavers are appropriately applied to both the information bits and the redundant bits. The physical layer frame generation unit 10003a-1 can read the required number of bits from the arranged bit sequence as the starting position determined according to the Redundancy Version (RV) value. By adjusting the number of bits, flexible changes in the coding rate, i.e., puncturing, become possible. In Figure 8, there are four possible RV values, but in the error correction coding according to this embodiment, the RV selection is not limited to a specific value. The RV position needs to be shared among the station devices. Needless to say, the error correction coding method according to this embodiment is not limited to the example in Figure 8, and any method that allows the coding rate to be changed and achieves decoding on the receiving side is acceptable.

[0083] For example, RV may indicate the parity block number. A parity block is a division of the parity bit sequence into one or more blocks. If there are four parity blocks, and each parity block is designated RV1 through RV4, then different parity bits will be transmitted depending on the value of RV.

[0084] Furthermore, the frame generated by the physical layer frame generation unit 10003a-1 includes a trigger frame that instructs the destination terminal, which is a wireless communication device, to transmit the frame. This trigger frame includes information indicating the RU (Ruler Unit) that the wireless communication device, which has been instructed to transmit the frame, will use when transmitting the frame.

[0085] The wireless transmitter 10003b-1 converts the physical layer frame generated by the physical layer frame generation unit 10003a-1 into a radio frequency (RF) band signal to generate a radio frequency signal. The processing performed by the wireless transmitter 10003b-1 includes digital-to-analog conversion, filtering, and frequency conversion from the baseband band to the RF band.

[0086] The receiving unit 10004-1 includes a wireless receiving unit (wireless receiving step) 10004a-1 and a signal demodulation unit (signal demodulation step) 10004b-1. The receiving unit 10004-1 generates information regarding the received signal power from the RF band signal received by the antenna unit 10005-1. The receiving unit 10004-1 can notify the CCA unit 10002a-1 of the information regarding the received signal power and the information regarding the received signal.

[0087] The wireless receiver unit 10004a-1 has the function of converting the RF band signal received by the antenna unit 10005-1 into a baseband signal and generating a physical layer signal (e.g., a physical layer frame). The processing performed by the wireless receiver unit 10004a-1 includes frequency conversion from the RF band to the baseband band, filtering, and analog-to-digital conversion.

[0088] The signal demodulation unit 10004b-1 has the function of demodulating the physical layer signal generated by the wireless receiver unit 10004a-1. The processing performed by the signal demodulation unit 10004b-1 includes channel equalization, demapping, error correction decoding, etc. The signal demodulation unit 10004b-1 can extract from the physical layer signal, for example, information contained in the PHY header, information contained in the MAC header, and information contained in the transmission frame. The signal demodulation unit 10004b-1 can notify the higher layer unit 10001-1 of the extracted information. The signal demodulation unit 10004b-1 can extract any or all of the information contained in the PHY header, MAC header, and transmission frame. The evaluation unit (evaluation step) (10004c-1) performs a predetermined evaluation on the information contained in the extracted PHY header, MAC header, etc., and notifies the higher layer unit of the content according to the evaluation.

[0089] The antenna unit 10005-1 has the function of transmitting the radio frequency signal generated by the radio transmission unit 10003b-1 into wireless space. The antenna unit 10005-1 also has the function of receiving the radio frequency signal and passing it to the radio receiving unit 10004a-1.

[0090] The wireless communication device 10-1 can cause surrounding wireless communication devices to set NAV for a specified period by including information indicating the period during which the wireless communication device will use the wireless medium in the PHY header or MAC header of the frame it transmits. For example, the wireless communication device 10-1 can include information indicating the period in the Duration / ID field or Length field of the frame it transmits. The NAV period set in surrounding wireless communication devices will be called the TXOP period (or simply TXOP) acquired by the wireless communication device 10-1. The wireless communication device 10-1 that acquired the TXOP will be called the TXOP holder. The frame type of the frame that the wireless communication device 10-1 transmits to acquire the TXOP is not limited to any particular type; it may be a control frame (e.g., an RTS frame or a CTS-to-self frame) or a data frame.

[0091] A wireless communication device 10-1, which is a TXOP holder, can transmit frames to wireless communication devices other than itself within the TXOP. If wireless communication device 1-1 is a TXOP holder, it can transmit frames to wireless communication device 2A within the TXOP period. Also, wireless communication device 1-1 can instruct wireless communication device 2A to transmit frames addressed to wireless communication device 1-1 within the TXOP period. Wireless communication device 1-1 can transmit a trigger frame to wireless communication device 2A within the TXOP period that includes information instructing wireless communication device 2A to transmit frames addressed to wireless communication device 1-1.

[0092] The wireless communication device 1-1 may reserve a TXOP for the entire communication band where frame transmission may occur (e.g., Operation bandwidth), or it may reserve a TXOP for a specific communication band (Band), such as the communication band on which frames are actually transmitted (e.g., Transmission bandwidth).

[0093] The radio communication device that issues a frame transmission instruction within the TXOP period acquired by radio communication device 1-1 is not necessarily limited to a radio communication device connected to itself. For example, a radio communication device can instruct a radio communication device not connected to itself to transmit a frame in order to have radio communication devices in its vicinity transmit management frames such as Reassociation frames or control frames such as RTS / CTS frames.

[0094] Furthermore, we will also explain TXOP in EDCA, a data transmission method different from DCF. The IEEE 802.11e standard relates to EDCA and specifies TXOP from the perspective of ensuring QoS (Quality of Service) for various services such as video transmission and VoIP. Services are broadly classified into four access categories: VO (Voice), VI (Video), BE (Best Effort), and BK (Background). Generally, the order of priority from highest to lowest is VO, VI, BE, and BK. Each access category has parameters such as the minimum CW value CWmin, the maximum CW value CWmax, AIFS (Arbitration IFS), a type of IFS, and the TXOP limit, which is the upper limit of transmission opportunities, and these values ​​are set to create differences in priority. For example, by setting CWmin, CWmax, and AIFS for VO, the highest priority category for voice transmission, to relatively smaller values ​​compared to other access categories, it becomes possible to prioritize data transmission over other access categories. For example, in VIs where the amount of data transmitted is relatively large for video transmission, setting a larger TXOP limit allows for longer transmission opportunities compared to other access categories. In this way, the values ​​of the four parameters for each access category are adjusted to ensure QoS according to the type of service.

[0095] The following embodiments mainly describe a case where a wireless communication device 2A (terminal device 2A), including a wireless communication device 2-1 (terminal device 2-1), acquires priority from a wireless communication device 1-1 (base station device 1-1) and transmits frames according to the acquired priority. However, the present invention is not limited to this case and can also be applied to a case where a wireless communication device 1-1 (base station device 1-1) acquires priority from a wireless communication device 2A (terminal device 2A) and transmits frames according to the acquired priority. Furthermore, in these embodiments, the priority is mainly described as a priority for low-latency transmission (low-latency transmission priority), but it is also applicable to other types of priority. Examples include priority for securing a wireless channel and priority for securing wireless resources (resource units), but are not limited to these. Unless otherwise specified, the device configurations of wireless communication devices 1-1 and 2A are the same as the device configuration examples described using Figures 6 and 7. In a wireless communication system, there may be no limit to the number of wireless communication devices that can acquire priority, but it may be limited to an upper limit specified in the operational policy of the wireless communication system.

[0096] The wireless communication system according to this embodiment is based on DCF, in which the control unit of each wireless communication device performs carrier sensing, autonomously acquires transmission rights, and controls frame transmission. In other words, basically, each wireless communication device acquires transmission rights and becomes capable of frame transmission when it determines that it is in an idle state after carrier sensing has elapsed in addition to DIFS and a random time backoff time has elapsed. On the other hand, in this embodiment, the wireless communication device acquires low-latency transmission priority rights on the premise that it complies with specific conditions (conditions for using low-latency transmission priority rights). As an example of a method for realizing low-latency transmission, the control unit acquires transmission rights (acquisition of transmission rights at PIFS) when it determines that it is in an idle state after carrier sensing has elapsed in a time PIFS which is shorter than DIFS, and transmits frames. By shortening the waiting time (backoff time), it is possible to preferentially acquire the wireless medium (acquisition of TXOP), and frame transmission becomes possible with low latency. Hereafter, frame transmission by acquiring transmission rights at PIFS will be mainly described as an example of realizing low-latency transmission, but it is not limited to PIFS and other IFS may be used. Furthermore, the method for realizing low-latency transmission is not limited to changing the IFS, but any method that can preferentially transmit frames with low latency is acceptable.

[0097] For devices intended for specific fields, such as IoT devices and control signal devices for robots, where the transmitted frame size is expected to be small and the transmission frequency is low, frame transmission may be performed by acquiring transmission rights via PIFS (Prior Indication Frame System) with low latency transmission priority rights exercised for all data frames transmitted by the wireless communication device.

[0098] On the other hand, general wireless communication devices transmit traffic (data, frames) for various applications (or services) with diverse requirements defined by delay, jitter, etc., so it is not necessary to exercise low-latency transmission rights for all frame transmissions. In other words, a wireless communication device that has acquired low-latency transmission priority rights does not necessarily exercise low-latency transmission priority rights to transmit all frames by acquiring transmission rights via PIFS. For example, traffic (data, frames) with higher delay and jitter requirements than the traffic and frames classified into access categories defined in the aforementioned IEEE 802.11e standard are defined as very high-priority traffic (VHPT), and all other traffic is defined as non-very high-priority traffic (non-VHPT). The control unit allocates only very high-priority traffic so that it is transmitted using the low-latency transmission priority rights in this embodiment.

[0099] Whether traffic in a lower layer is ultra-high priority or not may be determined by the requirements specifications for communication traffic from an application (or service) located in the upper layer, through inter-layer communication with the upper layer. The requirements specifications for communication traffic may be defined by acceptable latency, acceptable jitter, data size, data generation frequency, etc. Depending on these requirements, for example, traffic with a small data size and low data generation frequency may be classified as ultra-high priority traffic if the acceptable latency and jitter are small, and the low-latency transmission priority described in this embodiment may be granted. Alternatively, congestion information from the physical layer may be transmitted to the upper layer, allowing the upper layer or application to determine the requirements specifications for communication traffic.

[0100] Provided that the low-latency transmission priority usage conditions are observed, the wireless communication device 2A can acquire low-latency transmission priority. The low-latency transmission priority usage conditions may include, for example, setting thresholds for the number of frames transmitted per unit of time, the wireless medium occupancy time per unit of time, and the wireless medium occupancy rate for frames transmitted by the wireless communication device 2A when exercising low-latency transmission priority. For example, the set thresholds can be set as upper thresholds, and rules (regulations) can be established that the wireless communication device can exercise low-latency transmission priority and transmit frames as long as the thresholds are not exceeded. This helps to suppress the number of transmitted frames, medium occupancy time, and medium occupancy rate resulting from acquiring transmission rights in PIFS by exercising low-latency transmission priority, and balances the normal DIFS frame transmission in this DCF-based wireless communication system so as not to be significantly disrupted.

[0101] When the wireless communication device 2A transmits a frame by exercising the acquired low-latency transmission priority right, it may embed information that can determine whether or not the right has been exercised (low-latency transmission priority right identification information) into the frame in question. The low-latency transmission priority right identification information can be placed in the PHY header. For example, the low-latency transmission priority right identification information may be assigned to a specific field in the U-SIG included in the PHY header. Here, the aforementioned specific field will be referred to as the low-latency transmission priority right identification field. If the number of bits in the low-latency transmission priority right identification field is 1, a value of "0" in the field indicates transmission on a DIFS basis, while a value of "1" indicates frame transmission due to acquisition of transmission rights on a PIFS basis by exercising the low-latency transmission priority right. The case where the low-latency transmission priority right identification field is assigned 1 bit to the U-SIG in the PHY header has been described, but it may be another field in the PHY header, and the number of bits assigned is arbitrary. Furthermore, it is not always necessary to use the PHY header; the presence or absence of the exercise of the low-latency transmission priority right may be distinguished using a specific bit in a field included in a higher layer such as the MAC header. For example, the low-latency transmit priority identification field may be assigned to a part of the QoS control field in the MAC header, or it may be assigned to a field other than the QoS control field.

[0102] The wireless communication device 1-1 can determine whether the wireless frame received from the wireless communication device 2A was transmitted on a DIFS basis or as a frame transmitted by acquiring transmission rights on a PIFS basis by exercising low-latency transmission priority, by checking the low-latency transmission priority identification field of the received wireless frame. The evaluation unit of the wireless communication device 1-1 can count the number of frames in which low-latency transmission priority was exercised among the received frames, and can also calculate the wireless media occupancy time of the frame using the Duration information contained in the L-SIG of the PHY header and the Duration information contained in the MAC header. Therefore, the wireless communication device 1-1 can also calculate the wireless media occupancy rate of frames transmitted by each of the wireless communication devices 2A exercising low-latency transmission priority. Using the values ​​calculated in this way, the evaluation unit can check whether the low-latency transmission priority usage conditions are being complied with.

[0103] The wireless communication device 1-1 can distinguish wireless communication devices from the source MAC address included in the MAC header of the received frame, and can calculate the number of frames transmitted using the low-latency transmission priority, the wireless medium occupancy time, and the wireless medium occupancy rate for each wireless communication device 2A. An AID may be used to distinguish each of the wireless communication devices 2A. If information that can distinguish each of the wireless communication devices 2A is transmitted in the PHY header of the frame transmitted by the wireless communication device 2A, then the wireless communication device 1-1 can use the information contained only in the PHY header to calculate the number of frames transmitted using the low-latency transmission priority, the wireless medium occupancy time, and the wireless medium occupancy rate for each of the wireless communication devices 2A. Information shortened by a hash function or the like may be used to reduce the amount of identification information in the PHY header.

[0104] If, as confirmed by the aforementioned radio communication device 1-1, radio communication device 2A is found to be failing to comply with the conditions for using low-latency transmission priority, it may be penalized by radio communication device 1-1. For example, radio communication device 2A may receive control information from radio communication device 1-1 indicating the invalidation of low-latency transmission priority and may have its low-latency transmission priority invalidated. This invalidation may be temporary and may be re-enabled after a certain period of time. For example, radio communication device 2A may receive control information from radio communication device 1-1 indicating a change in low-latency transmission priority and have its priority lowered. One example of how priority may be lowered is the application of a change from TXOP acquisition with PIFS to TXOP acquisition with DIFS without backoff time. In this case, the priority is lower than PIFS but higher than normal DIFS + random backoff time, allowing radio medium acquisition (TXOP acquisition) and frame transmission. The application of such DIFS without backoff time may be temporary, and the priority of PIFS transmission may be re-enabled after a certain period of time. Thus, the application of penalties may be temporary and may be lifted after a certain period of time has elapsed.

[0105] Figure 10 shows an example of wireless communication device 2-1 transmitting frames for ultra-high priority traffic and non-ultra-high priority traffic (non-VHPT). Assume that VHPT is accumulated in the transmission queue of wireless communication device 2-1. When the busy state of the wireless medium (100-1) ends, the procedure moves to transmitting the VHPT present in the transmission queue by exercising the low-latency transmission right; that is, if the wireless medium is idle after PIFS, the transmission right is acquired and transmitted as frame 100-2. Next, assume that non-VHPT is accumulated in the transmission queue. When the busy state of the wireless medium (100-3) ends, normal DFS-based transmission is performed; that is, in addition to DIFS, if the wireless medium is idle after random backoff (100-4), the transmission right is acquired and transmitted as frame 100-5. If multiple transmission queues can be prepared, a transmission queue for ultra-high priority traffic may be prepared, and if there is data in the transmission queue for ultra-high priority traffic, it may be given priority over other queues.

[0106] In Figure 10, it is assumed that during time t1, radio communication device 2-1 is allowed to transmit frames twice by exercising its low-latency transmission right. This is an example of the low-latency transmission priority usage conditions mentioned earlier. In Figure 10, the radio frames transmitted by exercising the low-latency transmission right are frame 100-2 and frame 100-10. If the low-latency transmission priority usage conditions are not observed, for example, if VHPT frames are transmitted three times during time t1, the low-latency transmission priority acquired by radio communication device 2-1 will be invalidated. The invalidation of low-latency transmission priority was explained using the number of frame transmissions as an example, but the same applies to radio medium occupancy time. For VHPT frames 100-2 and 100-10, the radio medium occupancy times are t2 and t3, respectively. If the low-latency transmission priority usage conditions are set to a radio medium occupancy time of t4, the sum of t2 and t3 must be less than or equal to t4. If t4 exceeds this value, the low-latency transmission priority acquired by radio communication device 2-1 will be invalidated for failing to comply with the conditions for using the low-latency transmission priority right.

[0107] Figure 11 shows a sequence diagram relating to low-latency transmission priority in this embodiment. Wireless communication device 2-1 can transmit a low-latency transmission priority request (11-1) to wireless communication device 1-1. The low-latency transmission priority request includes information relating to the low-latency transmission priority requested by wireless communication device 2-1, information relating to the conditions for using the low-latency transmission priority (low-latency transmission priority usage condition information), etc. The low-latency transmission priority usage condition information may include, for example, values ​​related to calculating the wireless media occupancy rate, such as the number of transmissions per unit of time of frames transmitted by exercising the low-latency transmission priority, or the wireless media occupancy time per unit of time. In addition, it may include information on the field to which the application (or service) requesting the low-latency transmission priority belongs (e.g., IoT, robot control, etc.). Furthermore, the low-latency transmission priority usage condition information may be set by protocols used in higher layers, such as class information used in DiffServe used in the IP layer.

[0108] The wireless communication device 1-1 compares its own low-latency transmission priority usage conditions with the requested values ​​of the low-latency transmission priority usage conditions included in the low-latency transmission priority request of the wireless communication device 2-1, determines whether to accept the request of the wireless communication device 2-1, and transmits a low-latency transmission priority response (11-2) to the wireless communication device 2-1. The low-latency transmission priority response includes low-latency transmission priority acquisition information indicating whether or not it is permitted for the wireless communication device 2-1 to transmit a frame exercising low-latency transmission priority, and may also include low-latency transmission priority usage condition information permitted to the wireless communication device 2-1. The low-latency transmission priority usage condition information may be calculated and determined based on the low-latency transmission priority usage conditions requested by the wireless communication device 2-1 and the low-latency transmission priority usage conditions held by the wireless communication device 1-1. As for the calculation method, the conditions requested by the wireless communication device 2-1 may be accepted as they are, or the conditions held by the wireless communication device 1-1 may be enforced on the wireless communication device 2-1. Specifically, the conditions for using the low-latency transmission priority right may be determined according to the current media occupancy measurement result measured by the wireless communication device 1-1. For example, if the media occupancy measurement result falls below a predetermined threshold, the request of the wireless communication device 2-1 may be accepted, and if it exceeds the threshold, the conditions held by the wireless communication device 1-1 may be enforced on the wireless communication device 2-1.

[0109] As explained in the previous paragraph, negotiating the conditions for using low-latency transmission priority by signaling a low-latency transmission priority request (11-1) and a low-latency transmission priority response (11-2) has the advantage of allowing the conditions to be flexibly determined according to the radio environment. On the other hand, there is overhead for negotiation, so it is also possible to omit the negotiation and use the low-latency transmission priority conditions broadcast by radio communication device 1-1, or the low-latency transmission priority conditions individually determined by radio communication device 2-1, as they are. This eliminates the need for signaling for negotiation between radio communication device 1-1 and radio communication device 2-1. The presence or absence of the aforementioned negotiation may be determined according to the operational policy of the radio communication system.

[0110] The wireless communication device 2-1 checks the low-latency transmission priority acquisition information included in the low-latency transmission priority response (11-2). If "permission" is notified, it is possible to transmit a frame exercising the low-latency transmission priority; if "prohibition" is notified, it is not possible to transmit a frame exercising the low-latency transmission priority. In addition to "prohibition," it is also possible that frame transmission exercising the low-latency transmission priority is not possible in states such as "stopped" or "paused," which indicate an unauthorized state.

[0111] A low-latency transmission priority request may be included in the Association Request transmitted by radio communication device 2-1 when connecting to radio communication device 1-1, and a low-latency transmission priority response may be included in the Association Response. Furthermore, the conditions for using low-latency transmission priority by radio communication device 1-1 that receives the low-latency transmission priority request may be described in the MIB, and the conditions for using low-latency transmission priority by radio communication device 2-1 that transmits the low-latency transmission priority request may also be described in the MIB.

[0112] The radio communication device 2-1 may send a request to change the low-latency transmission priority (11-3) to the radio communication device 1-1 and change the information related to the low-latency transmission priority. The radio communication device 1-1 will decide whether or not to accept the request from the radio communication device 2-1 and will send a response to change the low-latency transmission priority (11-4) to the radio communication device 2-1. The response to change the low-latency transmission priority includes information indicating whether or not the radio communication device 2-1 is permitted to exercise its low-latency transmission priority under the conditions requested by the radio communication device 2-1.

[0113] The radio communication device 1-1 checks the low-latency transmission priority identification field of the frame received from the radio communication device 2-1 and monitors whether the previously agreed-upon low-latency transmission priority usage conditions are met. If the radio communication device 2-1 is determined not to be complying with the low-latency transmission priority usage conditions, it may be penalized by the radio communication device 1-1. The radio communication device 1-1 sends a low-latency transmission priority change notice (11-5) to the radio communication device 2-1, which includes control information indicating a change in low-latency transmission priority.

[0114] Even if radio communication device 2-1 is complying with the conditions for using low-latency transmission priority, radio communication device 1-1 may send a low-latency transmission priority change notice (11-5). For example, if it determines that it cannot tolerate low-latency transmission priority due to a dramatic increase in the number of frames transmitted and received within its own radio communication system or the number of frames transmitted and received by other nearby radio communication systems, it may send a low-latency transmission priority change notice (11-5). In addition, radio communication device 1-1 may periodically send information to radio communication device 2-1 to confirm whether it will use low-latency transmission priority. If the response to this information to confirm whether it will use low-latency transmission priority does not include information indicating that it will use low-latency transmission priority, radio communication device 1-1 may send a low-latency transmission priority change notice and revoke the low-latency transmission priority.

[0115] The control information included in the low-latency transmission priority change notification (11-5) may be an instruction to disable the low-latency transmission priority, and radio communication device 2-1, upon receiving the notification from radio communication device 1-1, may disable the low-latency transmission priority. The disabling may be temporary and may be re-enabled after a certain period of time. Alternatively, the low-latency transmission priority may be re-enabled by receiving a low-latency transmission priority change notification (11-5) that includes control information for enabling the low-latency transmission priority. As another example, the control information included in the low-latency transmission priority change notification (11-5) may indicate a change in the low-latency transmission priority method. The priority can also be changed by changing the method, specifically by applying a change to transmission with DIFS without backoff time to lower the priority. In this case, the priority is lower than PIFS but higher than normal DIFS + random backoff time, allowing for radio medium acquisition (TXOP acquisition) and frame transmission. The application of such DIFS without backoff time may be temporary, and the priority for PIFS transmission may be re-enabled after a certain period of time. Alternatively, priority for PIFS transmission may be reactivated by receiving a notification of change of priority for low-latency transmission (11-5) which includes control information indicating transmission via PIFS as a method for prioritizing low-latency transmission. Thus, the application of penalties may be temporary and may be lifted after a certain period of time.

[0116] If the acquired low-latency transmission priority right is no longer needed, the wireless communication device 2-1 may proactively declare that it will not use the low-latency transmission priority right by sending a low-latency transmission priority right cancellation notice to the wireless communication device 1-1.

[0117] The information relating to low-latency transmission priority included in the low-latency transmission priority request (11-1) transmitted by the wireless communication device 2-1 may be the number of frames that the wireless communication device 2-1 transmits after exercising the low-latency transmission priority response (11-2), or the radio medium occupancy time. In this case, after consuming the approved number of frames or radio medium occupancy time, the wireless communication device 2-1 automatically invalidates (suspends, revoks) the low-latency transmission priority.

[0118] Up to this point, we have specifically described priority rights for low-latency transmission, referring to them as low-latency transmission priority rights. However, the sequence described using Figure 11 is not limited to low-latency transmission priority rights, but may also relate to other priority rights. For example, there are priority rights for securing radio channels, priority rights for securing radio resources (resource units), etc. [2. Second Embodiment]

[0119] The configuration of the wireless communication system, access point device (also referred to as base station device), and station device (also referred to as terminal device) in the second embodiment is the same as in the first embodiment. In the first embodiment, one example of a low-latency transmission priority method was frame transmission by acquiring transmission rights in PIFS. In the second embodiment, several types of priority orders (priority sequences) may be provided for low-latency transmission priority, and which priority order to use may be determined by negotiation between the base station device and the terminal device. Furthermore, a procedure for changing the priority order in response to changes in the wireless communication environment in the wireless communication system may also be included.

[0120] Furthermore, the sequence diagram relating to low-latency transmission priority in the second embodiment is the same as in the first embodiment. As shown in Figure 11, it may include a low-latency transmission priority request (11-1), a low-latency transmission priority response (11-2), a low-latency transmission priority change request (11-3), a low-latency transmission priority change response (11-4), and a low-latency transmission priority change notification (11-5). In addition, the second embodiment is characterized by the fact that each of the wireless communication devices 2A requests and obtains different priority orders and transmits with low latency, which will be described later using Figure 13.

[0121] The second embodiment may be implemented based on all of the first embodiment, or based on (or in combination with) parts of the first embodiment. For example, it may be implemented in combination with the low-latency transmission priority usage conditions described in the first embodiment (conditions that limit the wireless media occupancy rate, such as the number of transmissions per unit time or the wireless media occupancy time per unit time of frames transmitted using the low-latency transmission priority), or it may be implemented without using the low-latency transmission priority usage conditions.

[0122] The priority orders may be pre-organized into a predetermined table. Figure 12 shows an example of a priority table when there are 5 priority orders, in which case priority order 1 has the highest priority and priority order 5 has the lowest priority. In this example, priority orders are characterized by three priority parameters: IFS (frame interval), the minimum contention window value CWmin, and the maximum contention window value CWmax. The smaller each value, the higher the probability of acquiring the radio medium, resulting in a higher priority. In this example, there are 5 priority orders, from 1 to 5, and the priority parameters characterizing each priority order are IFS, the minimum contention window value CWmin, and the maximum contention window value CWmax. However, the number of priority orders can be arbitrary, the priority parameters can be combinations other than IFS, CWmin, and CWmax, and other factors that affect priority can be added.

[0123] Figure 13 shows a sequence diagram related to the low-latency transmission priority right in this embodiment. In Figure 13, two wireless communication devices, wireless communication device 2-1 and wireless communication device 2-2, are used as examples for the explanation. However, the number of wireless communication devices 2A that perform the low-latency transmission priority right procedure for wireless communication device 1-1 is not limited to two, but may be any number, or it may be limited to the upper limit specified in the wireless communication system's operational policy.

[0124] The wireless communication device 2-1 may transmit a low-latency transmission priority request (13-1) to the wireless communication device 1-1. The low-latency transmission priority request may include information relating to the low-latency transmission priority requested by the wireless communication device 2-1, such as information relating to the priority order shown in Figure 12. The priority order number may be stored in the low-latency transmission priority request, in which case the number of bits to be allocated can be reduced. Alternatively, the values ​​of the priority parameters (IFS, CWmin, CWmax, etc.) that characterize the priority order may be stored, in which case the number of bits to be allocated will increase, but a wide variety of priority rankings that can be implemented with low-latency transmission priority can be provided.

[0125] The radio communication device 1-1 determines whether to accept the request from the radio communication device 2-1 and transmits a low-delay transmission priority response (13-2) to the radio communication device 2-1. The low-delay transmission priority response includes low-delay transmission priority acquisition information indicating whether or not it is permitted for the radio communication device 2-1 to transmit a frame exercising the low-delay transmission priority, and may also include low-delay transmission priority usage conditions information permitted to the radio communication device 2-1.

[0126] As explained in the previous paragraph, priority orders and priority parameters may be determined by signaling low-latency transmission priority requests (13-1) and low-latency transmission priority responses (13-2). However, to reduce the overhead of negotiation, low-latency transmission priority may initially be implemented using the priority orders and priority parameters determined individually by the radio communication device 2-1. Whether or not such negotiation takes place may be determined according to the operational policy of the radio communication system.

[0127] The wireless communication device 2-1 checks the low-latency transmission priority acquisition information contained in the low-latency transmission priority response (13-2). If "permission" is notified, it is possible to transmit a frame exercising the low-latency transmission priority; if "prohibition" is notified, it is not possible to transmit a frame exercising the low-latency transmission priority. The low-latency transmission priority response (13-2) may also contain information relating to the permitted (or prohibited) priority order and priority parameters.

[0128] A low-latency transmission priority request may be included in the Association Request transmitted by radio communication device 2-1 when connecting to radio communication device 1-1, and a low-latency transmission priority response may be included in the Association Response. Furthermore, the conditions for using low-latency transmission priority by radio communication device 1-1 that receives the low-latency transmission priority request may be described in the MIB, and the conditions for using low-latency transmission priority by radio communication device 2-1 that transmits the low-latency transmission priority request may also be described in the MIB.

[0129] The wireless communication device 2-1 may send a low-latency transmission priority change request (13-3) to the wireless communication device 1-1 to change information related to low-latency transmission priority, such as priority order and priority parameters. The low-latency transmission priority change request may store the priority order number, or it may store the values ​​of the priority parameters (IFS, CWmin, CWmax, etc.) that characterize the priority order.

[0130] When priority order numbers are used, the information included in a low-latency transmission priority change request may indicate how much the priority order will be increased or decreased relative to the currently implemented priority order number. For example, if wireless communication device 2-1 is implementing priority order "3" as shown in Figure 12, and the low-latency transmission priority change request contains "plus 1" as information indicating an increase in the priority order, it means a request to change the priority order from "3" to "4". Conversely, for example, if the low-latency transmission priority change request contains "minus 1" as information indicating a decrease in the priority order, the priority order will be changed from "3" to "2". In this way, the priority order may also be changed by specifying a relative value based on the currently implemented priority order.

[0131] The radio communication device 1-1 determines whether to accept the change request from the radio communication device 2-1 and transmits a low-delay transmission priority change response (13-4) to the radio communication device 2-1. The low-delay transmission priority change response may include low-delay transmission priority acquisition information indicating whether or not to permit the exercise of low-delay transmission priority by the radio communication device 2-1 under the conditions requested by the radio communication device 2-1.

[0132] Similarly to wireless communication device 2-1, wireless communication device 2-2 may exchange low-latency transmission priority requests (13-5), low-latency transmission priority responses (13-6), low-latency transmission priority change requests (13-7), and low-latency transmission priority change responses (13-8) with wireless communication device 1-1, as shown in Figure 13. The priority order implemented by wireless communication device 2-2 may differ from the priority order implemented by wireless communication device 2-1. When using the priority order table shown in Figure 12, for example, wireless communication device 2-1 may be granted priority order "1" in its low-latency transmission priority response (13-2), while wireless communication device 2-2 may be granted priority order "5" in its low-latency transmission priority response (13-6). In this way, each wireless communication device 2A implementing low-latency transmission priority may differentiate the priority order. Of course, priority parameters may also be specified instead of priority orders to differentiate the priority order.

[0133] Wireless communication device 1-1 may send a low-latency transmission priority change notification to wireless communication device 2A. Figure 13 shows an example where wireless communication device 2-1 receives a low-latency transmission priority change notification (13-9) and wireless communication device 2-2 receives a low-latency transmission priority change notification (13-10). For example, if it is determined that low-latency transmission priority cannot be tolerated due to reasons such as an increase in the number of frames transmitted and received within its own wireless communication system or the number of frames transmitted and received by other nearby wireless communication systems, it may send a low-latency transmission priority change notification (13-9, 13-10).

[0134] The control information included in the low-latency transmission priority change notification (13-9, 13-10) may be an instruction to invalidate the low-latency transmission priority, and radio communication devices 2-1 and 2-2, upon receiving the notification from radio communication device 1-1, may invalidate the low-latency transmission priority. Such invalidation may be temporary and may be re-enabled after a certain period of time has elapsed. Alternatively, the low-latency transmission priority may be re-enabled by receiving a low-latency transmission priority change notification that includes control information for enabling the low-latency transmission priority. As another example, the control information included in the low-latency transmission priority change notification may indicate a change in the priority ranking of the low-latency transmission priority. Similar to the low-latency transmission priority change request (13-3, 13-7) described above, the change in low-latency transmission priority may be notified to radio communication devices 2-1 and 2-2 by including information related to the low-latency transmission priority, priority order, and priority parameters in the low-latency transmission priority change notification (13-9, 13-10). The low-latency transmission priority change notification may store the priority order number, or it may store the values ​​of the priority parameters (IFS, CWmin, CWmax, etc.) that characterize the priority order.

[0135] If the acquired low-latency transmission priority is no longer needed, wireless communication devices 2-1 and 2-2 may proactively declare that they will not use the low-latency transmission priority by sending a low-latency transmission priority cancellation notice to wireless communication device 1-1. [3. Common to all embodiments]

[0136] The communication device according to the present invention can communicate in frequency bands (frequency spectrums) known as unlicensed bands, which do not require permission from a country or region for use, but the usable frequency bands are not limited to these. The communication device according to the present invention can also be effective in frequency bands known as white bands, which are not actually used for purposes such as preventing interference between frequencies, even though permission for use for specific services has been granted by a country or region (for example, frequency bands allocated for television broadcasting but not used in some regions), and in shared spectrums (shared frequency bands) that are expected to be shared by multiple operators.

[0137] The program that operates in the wireless communication device according to the present invention is a program that controls the CPU and the like (a program that makes the computer function) in order to realize the functions of the above-described embodiment related to the present invention. The information handled by these devices is temporarily stored in RAM during processing, and then stored in various ROMs or HDDs, and read, modified, and written by the CPU as needed. The recording medium for storing the program may be any of the following: semiconductor media (e.g., ROM, non-volatile memory card, etc.), optical recording medium (e.g., DVD, MO, MD, CD, BD, etc.), magnetic recording medium (e.g., magnetic tape, flexible disk, etc.). Furthermore, in addition to realizing the functions of the above-described embodiment by executing the loaded program, the functions of the present invention may also be realized by processing in cooperation with the operating system or other application programs based on the instructions of the program.

[0138] Furthermore, when distributing the program to the market, it can be stored on a portable recording medium and distributed, or transferred to a server computer connected via a network such as the Internet. In this case, the storage device of the server computer is also included in the present invention. In addition, some or all of the communication device in the above-described embodiment may be realized as an LSI, which is typically an integrated circuit. Each functional block of the communication device may be individually chipped, or some or all of them may be integrated into a single chip. When each functional block is made into an integrated circuit, an integrated circuit control unit is added to control them.

[0139] Furthermore, the method of implementing integrated circuits is not limited to LSIs; it may also be implemented using dedicated circuits or general-purpose processors. Additionally, if advancements in semiconductor technology lead to the emergence of integrated circuit technologies that can replace LSIs, it is possible to use integrated circuits based on those technologies.

[0140] Furthermore, the present invention is not limited to the embodiments described above. The wireless communication device of the present invention is not limited to application to mobile station equipment, but can also be applied to stationary or non-movable electronic devices installed indoors or outdoors, such as AV equipment, kitchen equipment, cleaning and washing machines, air conditioning equipment, office equipment, vending machines, and other household appliances.

[0141] While embodiments of this invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and designs and the like that do not depart from the spirit of this invention are also included in the scope of the claims. [Industrial applicability]

[0142] The present invention is suitable for use in communication devices and communication methods. [Explanation of Symbols]

[0143] 1-1, 1-2, 2-1~2-6, 2A, 2B Wireless communication equipment 3-1, 3-2 Scope of Management 10-1 Wireless communication equipment 10001-1 Upper layer section 10002-1 (Autonomous Distributed) Control Unit 10002a-1 CCA Department 10002b-1 Back-off section 10002c-1 Transmission determination unit 10003-1 Transmitter 10003a-1 Physical layer frame generation unit 10003b-1 Wireless Transmitter 10004-1 Receiving Unit 10004a-1 Wireless Receiver 10004b-1 Signal demodulation section 10004c-1 Evaluation Department 10005-1 Antenna section 100-1, 100-3, 100-6, 100-11 are busy. 100-4, 100-7 Random Backoff 100-2, 100-5, 100-8, 100-10 Wireless Frames

Claims

1. A terminal device, It comprises a transmitting unit and a receiving unit, The transmitting unit transmits a request frame requesting priority for communicating high-priority traffic. The receiving unit receives a response frame addressed only to the terminal device as a response to the request frame. The receiving unit further receives notification frames addressed only to the terminal device, When the aforementioned response frame is received, the parameters are set according to the information contained in the response frame. Upon receiving the notification frame, the terminal device updates its parameters according to the information contained in the notification frame so that it has an even higher priority. The terminal device is characterized in that the parameters include information indicating the frame interval (AIFS), the minimum contention window value (CWmin), and the maximum contention window value (CWmax).

2. The response frame includes information indicating either permission or denial. The terminal device according to feature 1.

3. The notification frame is not a response to the request frame. The terminal device according to feature 1.

4. Base station equipment, It comprises a transmitting unit and a receiving unit, The receiving unit receives a request frame from the terminal device requesting priority for the terminal device to communicate high-priority traffic. The transmitting unit, in response to the request frame, transmits a response frame for setting parameters to the terminal device only, and the response frame includes information for the terminal device to set the parameters. The transmitting unit further transmits a notification frame addressed only to the terminal device to update the parameters so that the terminal device has an even higher priority, and the notification frame includes information for the terminal device to update the parameters. The base station device is characterized in that the parameters include information indicating the frame interval (AIFS), the minimum contention window value (CWmin), and the maximum contention window value (CWmax).

5. The response frame includes information indicating either permission or denial. The base station device according to feature 4.

6. The notification frame is not a response to the request frame. The base station device according to feature 4.

7. Communicating with two or more terminal devices, The transmitting unit transmits the response frame to the two or more terminal devices individually. The base station device according to feature 4.

8. Communicating with two or more terminal devices, The transmitting unit transmits the notification frame to the two or more terminal devices individually. The base station device according to feature 4.

9. A communication method used in a communication system comprising a base station device and a terminal device that communicates with the base station device, The terminal device transmits a request frame to the base station device requesting priority for communicating high-priority traffic. The base station device transmits a response frame addressed only to the terminal device as a response to the request frame. When the terminal device receives the response frame, it sets the parameters according to the information contained in the response frame. The base station device further transmits a notification frame addressed only to the terminal device. When the terminal device receives the notification frame, it updates the parameters according to the information contained in the notification frame so that the terminal device has an even higher priority. A communication method characterized in that the parameters include information indicating the frame interval (AIFS), the minimum contention window value (CWmin), and the maximum contention window value (CWmax).

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