JP2023114923A - Communication device and communication method - Google Patents

Abstract

To provide a communication device and a communication method that control lower layers in consideration of applications.SOLUTION: A communication device for communicating with a plurality of communication devices includes: an upper layer unit that allocates the plurality of communication devices to radio resources based on priority; a physical layer frame generation unit that generates a physical layer frame based on the radio resource allocation; and a transmitting unit that transmits the physical layer frame. The priority is calculated based on requirements instantaneously required by applications executed by at least the plurality of communication devices.SELECTED DRAWING: Figure 6

Description

The present invention relates to a communication device and communication method.

IEEE (The Institute of Electrical and Electronics Engineers Inc.) continues to update IEEE 802.11, a wireless LAN standard, in order to increase the speed and efficiency of wireless LAN (Local Area Network) communication. I am working on it. In recent years, with the rapid spread of wireless LAN devices, it is expected that the use of real-time applications such as telemedicine and VR/AR will expand. The standardization of IEEE802.11be, which realizes standardization, is underway. Also, discussions on the next-generation standard of IEEE802.11be have started. IEEE802.11be and next-generation standards of IEEE802.11be are described in Non-Patent Document 1 and Non-Patent Document 2.

IEEE802.11-18/1231-06, March 2019. IEEE802.11-22/0032-00, January 2022.

IEEE802.11be or the next-generation standard of IEEE802.11be envisions various applications with advanced requirements as use cases. In order to implement such diverse applications, it is important to consider applications in lower layers such as the physical layer and the MAC layer.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and its object is to provide a communication apparatus and a communication method for controlling lower layers in consideration of applications.

A communication device and a communication method according to the present invention for solving the above problems are as follows.

A communication device according to an aspect of the present invention is a communication device that communicates with a plurality of communication devices, comprising: an upper layer unit that allocates radio resources to the plurality of communication devices based on priority; , a physical layer frame generation unit that generates a physical layer frame; and a transmission unit that transmits the physical layer frame, wherein the priority is at least a request instantaneously requested in an application executed by the plurality of communication devices. Calculated based on conditions.

Further, in the communication device according to an aspect of the present invention, the priority is calculated by a ratio of an instantaneous requirement to an average requirement in an application executed by each of the plurality of communication devices.

Further, in the communication device according to an aspect of the present invention, the transmission unit transmits a QoS packet, which is a packet in which QoS (Quality of Service) is set, and the priority is set to satisfy a predetermined requirement. It is determined based on the QoS throughput calculated from the received QoS packets.

Further, in the communication device according to an aspect of the present invention, a request condition instantaneously requested in an application executed by each of the plurality of communication devices is calculated based on the number of bits included in the QoS packet.

Further, a communication method according to an aspect of the present invention is a communication method in a communication device that communicates with a plurality of communication devices, comprising: allocating radio resources to the plurality of communication devices based on priority; and transmitting the physical layer frame, wherein the priority is at least based on instantaneous requirements of an application performed by the plurality of communication devices. calculated as

According to the present invention, by considering the application, it is possible to effectively control the lower layer for realizing the application.

1 is a schematic diagram showing an example of division of radio resources according to one aspect of the present invention; FIG. FIG. 4 is a diagram showing an example of a frame structure according to one aspect of the present invention; FIG. 4 is a diagram showing an example of a frame structure according to one aspect of the present invention; FIG. 3 is a diagram illustrating an example of communication according to one aspect of the present invention; 1 is a diagram showing one configuration example of a communication system according to one aspect of the present invention; FIG. 1 is a block diagram showing one configuration example of a wireless communication device according to one aspect of the present invention; FIG. 1 is a block diagram showing one configuration example of a wireless communication device according to one aspect of the present invention; FIG.

A communication system according to the present embodiment includes an access point device (also called a base station device) and a plurality of station devices (also called terminal devices). Also, a communication system or network composed of access point devices and station devices is called a basic service set (BSS: Basic service set, management range, cell). Also, the station device according to this embodiment can have the function of an access point device. Similarly, the access point device according to this embodiment can have the functions of the station device. Therefore, hereinafter, when simply referring to a communication device, the communication device can indicate both a station device and an access point device.

It is assumed that the base station apparatus and the terminal apparatus within the BSS each perform communication based on CSMA/CA (Carrier sense multiple access with collision avoidance). This embodiment targets the infrastructure mode in which the base station apparatus communicates with a plurality of terminal apparatuses, but the method of this embodiment can also be implemented in the ad-hoc mode in which the terminal apparatuses directly communicate with each other. In ad-hoc mode, the terminal device forms a BSS on behalf of the base station device. A BSS in ad-hoc mode is also called an IBSS (Independent Basic Service Set). In the following, a terminal device forming an IBSS in ad-hoc mode can also be regarded as a base station device. The method of this embodiment can also be implemented in WiFi Direct (registered trademark) in which terminal devices directly communicate with each other. In WiFi Direct, a terminal device forms a group instead of a base station device. In the following description, a terminal device of a group owner that forms a group in WiFi Direct can also be regarded as a base station device.

In the IEEE 802.11 system, each device can transmit transmission frames of multiple frame types with a common frame format. A transmission frame is defined in a physical (PHY) layer, a medium access control (MAC) layer, and a logical link control (LLC) layer, respectively. The physical layer is also called a PHY layer, and the MAC layer is also called a MAC layer.

A PHY layer transmission frame is called a physical protocol data unit (PPDU: PHY protocol data unit, physical layer frame). The PPDU consists of a physical layer header (PHY header) containing header information for performing signal processing in the physical layer, and a physical service data unit (PSDU: PHY service data unit, which is a data unit processed in the physical layer). MAC layer frame) and the like. A PSDU can be composed of an Aggregated MPDU (A-MPDU) in which a plurality of MAC protocol data units (MPDU), which are retransmission units in a wireless section, are aggregated.

The PHY header includes a short training field (STF) used for signal detection and synchronization, a long training field (LTF) used to acquire channel information for data demodulation, and the like. and a control signal such as a signal (Signal: SIG) containing control information for data demodulation. In addition, the STF is a legacy STF (L-STF: Legacy-STF), a high throughput STF (HT-STF: High throughput-STF), or a very high throughput STF (VHT-STF: Very high throughput-STF), high efficiency STF (HE-STF), ultra-high throughput STF (EHT-STF: Extremely High Throughput-STF), etc. LTF and SIG are also L- It is classified into 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 4 and HE-SIG-B. Also, a Universal SIGNAL (U-SIG) field may be included, which anticipates technology updates in the same standard and contains additional control information.

Furthermore, the PHY header can include information identifying the BSS that is the transmission source of the transmission frame (hereinafter also referred to as BSS identification information). The information identifying the BSS can be, for example, the SSID (Service Set Identifier) of the BSS or the MAC address of the base station device of the BSS. Also, information for identifying a BSS can be a value unique to the BSS (for example, BSS Color, etc.) other than the SSID and MAC address.

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

MPDU is a MAC layer header containing header information etc. for performing signal processing in the MAC layer, and a MAC service data unit (MSDU: MAC service data unit) which is a data unit processed in the MAC layer or It consists of a frame body and a frame check sequence (FCS) for checking whether the frame has any errors. Also, multiple MSDUs can be aggregated as an aggregated MSDU (A-MSDU: Aggregated MSDU).

The frame type of the transmission frame of the MAC layer is roughly classified into three types: a management frame that manages the connection state between devices, a control frame that manages the communication state between devices, and a data frame that contains actual transmission data. Each is further classified into a plurality of types of subframe types. The control frame includes a reception completion notification (ACK: Acknowledge) frame, a transmission request (RTS: Request to send) frame, a reception preparation completion (CTS: Clear to send) frame, and the like. Management frames include beacon frames, probe request frames, probe response frames, authentication frames, association request frames, and association response frames. included. The data frame includes a data (Data) frame, a polling (CF-poll) frame, and the like. Each device can recognize the frame type and subframe type of the received frame by reading the contents of the frame control field included in the MAC header.

Note that ACK may include Block ACK. Block ACK can implement reception completion notification for multiple MPDUs. Also, the ACK may include a Multi STA Block ACK including reception completion notifications for a plurality of communication devices.

The beacon frame includes a field describing a beacon interval and an SSID. The base station apparatus can periodically broadcast a beacon frame within the BSS, and the terminal apparatus can recognize base station apparatuses around the terminal apparatus by receiving the beacon frame. It is called passive scanning that a terminal device recognizes a base station device based on a beacon frame broadcast from the base station device. On the other hand, searching for a base station device by notifying a probe request frame in the BSS by a terminal device is called active scanning. The base station apparatus can transmit a probe response frame as a response to the probe request frame, and the description content of the probe response frame is equivalent to that of the beacon frame.

After recognizing the base station apparatus, the terminal apparatus performs connection processing to the base station apparatus. Connection processing is classified into an authentication procedure and an association procedure. A terminal device transmits an authentication frame (authentication request) to a base station device that desires connection. Upon receiving the authentication frame, the base station apparatus transmits to the terminal apparatus an authentication frame (authentication response) including a status code indicating whether or not the terminal apparatus can be authenticated. By reading the status code described in the authentication frame, the terminal device can determine whether or not the terminal device is permitted to be authenticated by the base station device. Note that the base station apparatus and the terminal apparatus can exchange authentication frames multiple times.

Following the authentication procedure, the terminal device transmits a connection request frame to the base station device to perform the connection procedure. Upon receiving the connection request frame, the base station apparatus determines whether or not to permit the connection of the terminal apparatus, and transmits a connection response frame to notify that effect. The connection response frame contains an association identifier (AID) for identifying the terminal device in addition to a status code indicating whether connection processing is possible. The base station apparatus can manage a plurality of terminal apparatuses by setting different AIDs for the terminal apparatuses that have issued connection permission.

After connection processing is performed, the base station apparatus and the terminal apparatus perform actual data transmission. In the IEEE 802.11 system, a distributed control mechanism (DCF: Distributed Coordination Function), a centralized control mechanism (PCF: Point Coordination Function), and an enhanced mechanism of these (enhanced distributed channel access (EDCA: Enhanced distributed channel access), A hybrid control mechanism (HCF: Hybrid coordination function, etc.) is defined. In the following, a case where the base station apparatus transmits a signal to the terminal apparatus using DCF will be described as an example, but the same applies to the case where the terminal apparatus transmits a signal to the base station apparatus using DCF.

In DCF, a base station apparatus and a terminal apparatus perform carrier sense (CS) to check the usage status of radio channels around the apparatus prior to communication. For example, when a base station apparatus, which is a transmitting station, receives a signal higher than a predetermined clear channel assessment level (CCA level: Clear channel assessment level) on the radio channel, it does not transmit a transmission frame on the radio channel. put off. Hereinafter, a state in which a signal of the CCA level or higher is detected in the radio channel is called a busy state, and a state in which a signal of the CCA level or higher is not detected is called an idle state. Thus, CS performed based on the power (reception power level) of the signal actually received by each device is called physical carrier sense (physical CS). The CCA level is also called a carrier sense level (CS level) or a CCA threshold (CCA threshold: CCAT). When the base station apparatus and the terminal apparatus detect a signal of the CCA level or higher, they start the operation of demodulating at least the PHY layer signal.

The base station apparatus performs carrier sensing for a frame interval (IFS: Inter frame space) corresponding to the type of transmission frame to be transmitted, and determines whether the radio channel is busy or idle. The period during which the base station apparatus performs carrier sensing differs depending on the frame type and subframe type of the transmission frame to be transmitted by the base station apparatus. In the IEEE 802.11 system, multiple IFSs with different periods are defined, a short frame interval (SIFS: Short IFS) used for transmission frames given the highest priority, and a short frame interval (SIFS) for transmission frames with relatively high priority. There is a polling frame interval (PCF IFS: PIFS) used, a distribution control frame interval (DCF IFS: DIFS) used for transmission frames with the lowest priority, and the like. When the base station apparatus transmits data frames in DCF, the base station apparatus uses DIFS.

After waiting for DIFS, the base station apparatus further waits for a random backoff time to prevent frame collision. In the IEEE 802.11 system, a random backoff time called contention window (CW) is used. CSMA/CA assumes that a transmission frame transmitted by a certain transmitting station is received by a receiving station without interference from other transmitting stations. Therefore, if the transmitting stations transmit transmission frames at the same timing, the frames collide with each other and the receiving stations cannot receive the frames correctly. Therefore, each transmitting station waits for a randomly set time before starting transmission, thereby avoiding frame collision. When the base station apparatus determines that the radio channel is in an idle state by carrier sense, it starts counting down the CW and acquires the transmission right only when the CW becomes 0, and can transmit the transmission frame to the terminal apparatus. If the base station apparatus determines that the radio channel is busy by carrier sensing during the CW countdown, the CW countdown is stopped. Then, when the radio channel becomes idle, following the previous IFS, the base station apparatus resumes counting down remaining CWs.

Next, the details of frame reception will be described. A terminal device, which is a receiving station, receives the transmission frame, reads the PHY header of the transmission frame, and demodulates the received transmission frame. By reading the MAC header of the demodulated signal, the terminal device can recognize whether or not the transmission frame is addressed to itself. The terminal device may also determine the destination of the transmission frame based on the information described in the PHY header (for example, the group identification number (GID: Group identifier, Group ID) described in VHT-SIG-A). It is possible.

When the terminal device determines that the received transmission frame is addressed to itself and demodulates the transmission frame without error, the terminal device transmits an ACK frame indicating that the frame has been correctly received to the base station device, which is the transmitting station. Must. The ACK frame is one of the highest priority transmission frames that is transmitted only waiting for the SIFS period (no random backoff time). The base station apparatus terminates a series of communications upon receiving the ACK frame transmitted from the terminal apparatus. In addition, when the terminal device cannot receive the frame correctly, the terminal device does not transmit ACK. Therefore, if the base station apparatus does not receive an ACK frame from the receiving station for a certain period of time (SIFS+ACK frame length) after frame transmission, the communication ends as failure. As described above, the end of one communication (also called a burst) in the IEEE 802.11 system is limited to special cases such as the transmission of a notification signal such as a beacon frame, or the use of fragmentation to divide transmission data. Except for this, the determination is always based on whether or not an ACK frame has been received.

When the terminal device determines that the received transmission frame is not addressed to itself, the terminal device uses a network allocation vector (NAV) based on the length of the transmission frame described in the PHY header or the like. vector). The terminal device does not attempt communication during the period set in NAV. In other words, the terminal device performs the same operation as when the physical CS determines that the radio channel is busy during the period set in the NAV. Therefore, communication control based on the NAV is also called virtual carrier sense (virtual CS). In addition to being set based on the information described in the PHY header, NAV is a request to send (RTS: Request to send) frame introduced to solve the hidden terminal problem, and a reception ready (CTS: Clear to send) frame.

In contrast to the DCF in which each device performs carrier sense and acquires the transmission right autonomously, in the PCF, a control station called a point coordinator (PC) controls the transmission right of each device within the BSS. In general, the base station apparatus becomes a PC and acquires the transmission right of the terminal apparatus within the BSS.

The communication period by PCF includes a non-period (CFP: Contention free period) and a contention period (CP: Contention period). During the CP, communication is performed based on the DCF described above, and it is during the CFP that the PC controls the transmission right. A base station apparatus, which is a PC, notifies a beacon frame in which a CFP duration (CFP Max duration) and the like are described within the BSS prior to PCF communication. It should be noted that PIFS is used to transmit the beacon frame notified at the start of PCF transmission, and is transmitted without waiting for the CW. A terminal device that receives the beacon frame sets the period of the CFP described in the beacon frame to NAV. Thereafter, until the NAV elapses or until a signal announcing the end of the CFP within the BSS (for example, a data frame containing CF-end) is received, the terminal equipment signals acquisition of the transmission right transmitted from the PC. The right to transmit can only be obtained when a signal (eg a data frame containing a CF-poll) is received. Note that during the CFP period, packet collisions do not occur within the same BSS, so each terminal device does not take the random backoff time used in DCF.

The wireless medium can be partitioned into multiple resource units (RUs). FIG. 1 is a schematic diagram showing an example of a division state of a wireless medium. For example, in resource division example 1, the wireless communication device can divide frequency resources (subcarriers), which are wireless media, into nine RUs. Similarly, in resource division example 2, the wireless communication device can divide subcarriers, which are wireless media, into five RUs. Of course, the example of resource division shown in FIG. 1 is only an example, and for example, a plurality of RUs can be configured with different numbers of subcarriers. Also, the wireless medium divided as RUs can include spatial resources as well as frequency resources. A wireless communication device (for example, an AP) can simultaneously transmit frames to a plurality of terminal devices (for example, a plurality of STAs) by arranging frames addressed to different terminal devices in each RU. The AP can describe the information (resource allocation information) indicating the division state of the wireless medium in the PHY header of the frame transmitted by the AP as common control information. Furthermore, the AP can describe information (resource unit assignment information) indicating the RU in which the frame addressed to each STA is allocated in the PHY header of the frame transmitted by the AP as unique control information.

Also, a plurality of terminal devices (for example, a plurality of STAs) can transmit frames simultaneously by arranging frames in assigned RUs and transmitting the frames. A plurality of STAs can transmit a frame after waiting for a predetermined period of time after receiving a frame (Trigger frame: TF) containing trigger information transmitted from the AP. Each STA can grasp the RU assigned to itself based on the information described in the TF. Also, each STA can acquire RUs through random access based on the TF.

The AP can allocate multiple RUs to one STA at the same time. The plurality of RUs can be composed of continuous subcarriers or discontinuous subcarriers. The AP can transmit one frame using multiple RUs assigned to one STA, or can transmit multiple frames by assigning them to different RUs. At least one of the plurality of frames may be a frame containing common control information for a plurality of terminal devices transmitting resource allocation information.

One STA can be assigned multiple RUs by the AP. A STA can transmit one frame using multiple assigned RUs. Also, the STA can use the assigned multiple RUs to assign multiple frames to different RUs and transmit them. The plurality of frames can be frames of different frame types.

The AP can assign multiple AIDs to one STA. The AP can assign RUs to multiple AIDs assigned to one STA. The AP can transmit different frames to multiple AIDs assigned to one STA using the assigned RUs. The different frames can be frames of different frame types.

One STA can be assigned multiple AIDs by the AP. One STA can be assigned RUs for each of the assigned AIDs. One STA recognizes all RUs assigned to multiple AIDs assigned to itself as RUs assigned to itself, and uses the assigned multiple RUs to transmit one frame. can do. Also, one STA can transmit multiple frames using the multiple assigned RUs. At this time, information indicating the AID associated with each assigned RU can be described in the plurality of frames and transmitted. The AP can transmit different frames to multiple AIDs assigned to one STA using the assigned RUs. The different frames can be frames of different frame types.

Below, the base station apparatus and the terminal apparatus are also collectively referred to as a wireless communication apparatus or a communication apparatus. Information exchanged when one wireless communication device communicates with another wireless communication device is also called data. That is, a wireless communication device includes a base station device and a terminal device.

A wireless communication device has either or both of a function to transmit and a function to receive PPDU. FIG. 2 is a diagram showing an example of the configuration of a PPDU transmitted by a wireless communication device. The PPDU corresponding to the IEEE802.11a/b/g standard has a configuration including L-STF, L-LTF, L-SIG and Data frames (MAC Frame, MAC frame, payload, data part, data, information bits, etc.). be. A PPDU conforming to the IEEE802.11n standard has a configuration including L-STF, L-LTF, L-SIG, HT-SIG, HT-STF, HT-LTF and Data frames. The PPDU corresponding to the IEEE802.11ac standard includes part or all of L-STF, L-LTF, L-SIG, VHT-SIG-A, VHT-STF, VHT-LTF, VHT-SIG-B and MAC frames. configuration. PPDU in the IEEE802.11ax standard is L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, HE-STF, HE-LTF, HE- This configuration includes part or all of SIG-B and Data frames. The PPDU considered in the IEEE802.11be standard is L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-SIG, EHT-STF, EHT-LTF and a part of Data frame or It is an all-inclusive configuration.

L-STF, L-LTF and L-SIG surrounded by dotted lines in FIG. collectively referred to as the L-header). For example, a wireless communication device compatible with the IEEE 802.11a/b/g standard can properly receive an L-header in a PPDU compatible with the IEEE 802.11n/ac standard. A wireless communication device conforming to the IEEE802.11a/b/g standard can receive a PPDU conforming to the IEEE802.11n/ac standard as a PPDU conforming to the IEEE802.11a/b/g standard.

However, since the wireless communication device compatible with the IEEE802.11a/b/g standard cannot demodulate the PPDU compatible with the IEEE802.11n/ac standard following the L-header, the transmission address (TA: Transmitter Address) , receiver address (RA), and information on the Duration/ID field used for NAV setting cannot be demodulated.

IEEE 802.11 inserts Duration information into L-SIG as a method for a wireless communication device compatible with IEEE 802.11a/b/g standards to appropriately set NAV (or perform reception operation for a predetermined period). stipulates the method. Information about the transmission rate in L-SIG (RATE field, L-RATE field, L-RATE, L_DATARATE, L_DATARATE field), information about the transmission period (LENGTH field, L-LENGTH field, L-LENGTH) is IEEE802.11a A wireless communication device supporting the /b/g standard is used to properly set the NAV.

FIG. 3 is a diagram showing an example of how Duration information is inserted into L-SIG. Although FIG. 3 shows a PPDU configuration corresponding to the IEEE802.11ac standard as an example, the PPDU configuration is not limited to this. A PPDU configuration compatible with the IEEE802.11n standard and a PPDU configuration compatible with the IEEE802.11ax standard may be used. TXTIME comprises information on the length of the PPDU, aPreambleLength comprises information on the length of the preamble (L-STF+L-LTF), and aPLCPHeaderLength comprises information on the length of the PLCP header (L-SIG). L_LENGTH is Signal Extension, which is a virtual period set for compatibility with the IEEE 802.11 standard; _Nops related to L_RATE; It is calculated based on aPLCPServiceLength indicating the number of bits included in the PLCP Service field and aPLCPConvolutionalTailLength indicating the number of tail bits of the convolutional code. The wireless communication device can calculate L_LENGTH and insert it into L-SIG. Also, the wireless communication device can calculate the L-SIG Duration. L-SIG Duration indicates information on the total duration of the PPDU including L_LENGTH and the duration of ACK and SIFS expected to be transmitted from the destination wireless communication device as a response.

FIG. 4 is a diagram showing an example of L-SIG Duration in L-SIG TXOP Protection. DATA (frame, payload, data, etc.) consists of part or both of the MAC frame and the PLCP header. BA is Block ACK or ACK. The PPDU includes L-STF, L-LTF, L-SIG, and may further include any or more of DATA, BA, RTS or CTS. Although the example shown in FIG. 4 shows L-SIG TXOP Protection using RTS/CTS, CTS-to-Self may be used. Here, MAC Duration is the duration indicated by the value of Duration/ID field. Also, the Initiator can transmit a CF_End frame to signal the end of the L-SIG TXOP Protection period.

Next, a method for identifying a BSS from a frame received by the wireless communication device will be described. In order for a wireless communication device to identify a BSS from a received frame, a wireless communication device that transmits a PPDU should include information for identifying the BSS (BSS color, BSS identification information, value unique to the BSS) in the PPDU. It is preferable to insert, and information indicating the BSS color can be included in HE-SIG-A.

The wireless communication device can transmit L-SIG multiple times (L-SIG Repetition). For example, the radio communication apparatus on the receiving side receives the L-SIG transmitted multiple times using MRC (Maximum Ratio Combining), thereby improving the demodulation accuracy of the L-SIG. Furthermore, when the L-SIG is correctly received by the MRC, the wireless communication device can interpret that the PPDU including the L-SIG is a PPDU conforming to the IEEE802.11ax standard.

The wireless communication device shall perform the reception operation of a part of the PPDU other than the PPDU (for example, the preamble, L-STF, L-LTF, PLCP header, etc. specified by IEEE 802.11) even during the reception operation of the PPDU. (also called double receive operation). When a wireless communication device detects part of a PPDU other than the relevant PPDU during a PPDU reception operation, the wireless communication device updates part or all of the information on the destination address, the source address, the PPDU, or the DATA period. can be done.

ACKs and BAs can also be referred to as responses (response frames). Also, probe responses, authentication responses, and connection responses can be referred to as responses.

FIG. 5 is a diagram showing an example of a wireless communication system according to this embodiment. The radio communication system 3-1 includes a radio communication device 1-1 and radio communication devices 2-1 to 2-3. The wireless communication device 1-1 is also called the base station device 1-1, and the wireless communication devices 2-1 to 2-3 are also called terminal devices 2-1 to 2-3. The wireless communication devices 2-1 to 2-3 and the terminal devices 2-1 to 2-3 are also referred to as a wireless communication device 2A and a terminal device 2A as devices connected to the wireless communication device 1-1. The wireless communication device 1-1 and the wireless communication device 2A are wirelessly connected and are in a state of being able to transmit and receive PPDUs to and from each other. Also, the radio communication system according to this embodiment may include a radio communication system 3-2 in addition to the radio communication system 3-1. The radio communication system 3-2 includes a radio communication device 1-2 and radio communication devices 2-4 to 2-6. The wireless communication device 1-2 is also called the base station device 1-2, and the wireless communication devices 2-4 to 2-6 are also called terminal devices 2-4 to 2-6. The wireless communication devices 2-4 to 2-6 and the terminal devices 2-4 to 2-6 are also referred to as a wireless communication device 2B and a terminal device 2B as devices connected to the wireless communication device 1-2. Although the radio communication system 3-1 and the radio communication system 3-2 form different BSSs, this does not necessarily mean that they have different ESSs (Extended Service Sets). ESS indicates a service set forming a LAN (Local Area Network). That is, wireless communication devices belonging to the same ESS can be regarded as belonging to the same network from higher layers. In addition, BSSs are combined via a DS (Distribution System) to form an ESS. Each of the radio communication systems 3-1 and 3-2 can further include a plurality of radio communication devices.

In FIG. 5, in the following description, it is assumed that the signal transmitted by the radio communication device 2A reaches the radio communication devices 1-1 and 2B, but does not reach the radio communication device 1-2. do. That is, when the radio communication device 2A transmits a signal using a certain channel, the radio communication device 1-1 and the radio communication device 2B determine that the channel is busy, while the radio communication device 1-2 The channel is determined to be idle. It is also assumed that the signal transmitted by the radio communication device 2B reaches the radio transmission device 1-2 and the radio communication device 2A, but does not reach the radio communication device 1-1. That is, when radio communication device 2B transmits a signal using a certain channel, radio communication device 1-2 and radio communication device 2A determine that the channel is busy, while radio communication device 1-1 The channel is determined to be idle.

FIG. 6 shows an example of the device configuration of radio communication devices 1-1, 1-2, 2A and 2B (hereinafter collectively referred to as radio communication device 10-1, station device 10-1, or simply station device). It is a diagram. The wireless communication device 10-1 includes an upper layer section (upper layer processing step) 10001-1, an autonomous distributed control section (autonomous distributed control step) 10002-1, a transmitting section (transmitting step) 10003-1, and a receiving section. (Receiving step) This configuration includes 10004-1 and antenna section 10005-1.

The upper layer section 10001-1 is connected to another network and can notify the autonomous distributed control section 10002-1 of information on traffic. Information about traffic may be, for example, control information included in a management frame such as a beacon, or may be measurement information reported by another wireless communication device addressed to the wireless communication device itself. Furthermore, the destination is not limited (it may be addressed to its own device, may be addressed to another device, or may be broadcast or multicast), even if it is control information included in a management frame or control frame. good.

FIG. 7 is a diagram showing an example of the configuration of the autonomous decentralized control section 10002-1. The control section 10002-1 includes a CCA section (CCA step) 10002a-1, a backoff section (backoff step) 10002b-1, and a transmission determination section (transmission determination step) 10002c-1.

CCA section 10002a-1 receives one or both of information about received signal power received via radio resources and information about received signals (including information after decoding) notified from receiving section 10004-1. can be used to determine the state of the radio resource (including busy or idle determination). The CCA section 10002a-1 can notify the back-off section 10002b-1 and the transmission decision section 10002c-1 of the radio resource state determination information.

The back-off unit 10002b-1 can perform back-off using radio resource state determination information. The backoff unit 10002b-1 generates CW and has a countdown function. For example, when the radio resource state determination information indicates idle, the CW countdown can be executed, and when the radio resource state determination information indicates busy, the CW countdown can be stopped. The backoff unit 10002b-1 can notify the transmission decision unit 10002c-1 of the CW value.

The transmission decision section 10002c-1 makes a transmission decision using either one or both of the radio resource status decision information and the CW value. For example, when the radio resource state determination information indicates idle and the value of CW is 0, the transmission determination information can be notified to the transmitting section 10003-1. Further, when the radio resource state determination information indicates idle, the transmission determination information can be notified to the transmitting section 10003-1.

The transmission section 10003-1 includes a physical layer frame generation section (physical layer frame generation step) 10003a-1 and a radio transmission section (radio transmission step) 10003b-1. The physical layer frame generation unit 10003a-1 has a function of generating a physical layer frame (hereinafter also referred to as PPDU) based on transmission determination information notified from the transmission determination unit 10002c-1. Physical layer frame generation section 10003a-1 performs error correction coding, modulation, precoding filter multiplication, and the like on a transmission frame sent from an upper layer. The physical layer frame generator 10003a-1 notifies the radio transmitter 10003b-1 of the generated physical layer frame.

A frame generated by the physical layer frame generator 10003a-1 includes control information. The control information includes information indicating in which RU (here, RU includes both frequency resources and space resources) data addressed to each wireless communication device is allocated. Also, the frame generated by the physical layer frame generation unit 10003a-1 includes a trigger frame that instructs the wireless communication device, which is the destination terminal, to transmit the frame. The trigger frame contains information indicating the RU used when the wireless communication device instructed to transmit the frame transmits the frame.

The radio transmission section 10003b-1 converts the physical layer frame generated by the physical layer frame generation section 10003a-1 into a radio frequency (RF) band signal to generate a radio frequency signal. Processing performed by the radio transmission unit 10003b-1 includes digital/analog conversion, filtering, frequency conversion from the baseband band to the RF band, and the like.

The receiving section 10004-1 includes a radio receiving section (radio receiving step) 10004a-1 and a signal demodulating section (signal demodulating step) 10004b-1. Receiving section 10004-1 generates information about received signal power from the RF band signal received by antenna section 10005-1. Receiving section 10004-1 can report information on received signal power and information on received signals to CCA section 10002a-1.

The radio receiving section 10004a-1 has a function of converting an RF band signal received by the antenna section 10005-1 into a baseband signal and generating a physical layer signal (for example, a physical layer frame). The processing performed by the radio reception unit 10004a-1 includes frequency conversion processing from the RF band to the baseband band, filtering, and analog/digital conversion.

The signal demodulator 10004b-1 has a function of demodulating the physical layer signal generated by the radio receiver 10004a-1. Processing performed by the signal demodulator 10004b-1 includes channel equalization, demapping, error correction decoding, and the like. The signal demodulator 10004b-1 can extract, for example, information contained in the physical layer header, information contained in the MAC header, and information contained in the transmission frame from the physical layer signal. The signal demodulation section 10004b-1 can notify the extracted information to the upper layer section 10001-1. The signal demodulator 10004b-1 can extract any or all of the information included in the physical layer header, the information included in the MAC header, and the information included in the transmission frame.

Antenna section 10005-1 has a function of transmitting a radio frequency signal generated by radio transmission section 10003b-1 to radio space. Also, the antenna section 10005-1 has a function of receiving a radio frequency signal and passing it to the radio receiving section 10004a-1.

The wireless communication device 10-1 writes information indicating the period during which the wireless communication device uses the wireless medium in the PHY header or MAC header of the frame to be transmitted, thereby notifying wireless communication devices around the wireless communication device 10-1 of the period. NAV can be set only for a period of time. For example, wireless communication device 10-1 can write information indicating the duration in the Duration/ID field or Length field of the frame to be transmitted. The NAV period set in the wireless communication devices around the own wireless communication device is called the TXOP period (or simply TXOP) acquired by the wireless communication device 10-1. Then, the wireless communication device 10-1 that has acquired the TXOP is called a TXOP holder. The frame type of the frame that is transmitted by the wireless communication device 10-1 to acquire the TXOP is not limited to anything, and may be a control frame (for example, an RTS frame or a CTS-to-self frame) or a data frame. But it's okay.

The wireless communication device 10-1, which is a TXOP holder, can transmit frames to wireless communication devices other than its own wireless communication device during the TXOP. If the radio communication device 1-1 is a TXOP holder, the radio communication device 1-1 can transmit frames to the radio communication device 2A within the period of the TXOP. Further, the radio communication device 1-1 can instruct the radio communication device 2A to transmit a frame addressed to the radio communication device 1-1 within the TXOP period. Within the TXOP period, the radio communication device 1-1 can transmit to the radio communication device 2A a trigger frame containing information instructing frame transmission addressed to the radio communication device 1-1.

The wireless communication device 1-1 may secure TXOP for all communication bands (for example, operation bandwidth) in which frame transmission may be performed, or may secure a communication band for actually transmitting frames (for example, transmission bandwidth). may be reserved for a specific communication band (Band).

The radio communication device that instructs the frame transmission within the period of the TXOP acquired by the radio communication device 1-1 is not necessarily limited to the radio communication device connected to the own radio communication device. For example, a wireless communication device is not connected to its own wireless communication device in order to transmit a management frame such as a Reassociation frame or a control frame such as an RTS/CTS frame to wireless communication devices around itself. A wireless communication device can be instructed to transmit a frame.

Furthermore, TXOP in EDCA, which is a data transmission method different from DCF, will also be described. The IEEE802.11e standard is related to EDCA, and defines TXOP from the viewpoint of guaranteeing QoS (Quality of Service) for various services such as video transmission and VoIP. Services are roughly classified into four access categories: VO (VOice), VI (VIdeo), BE (Best Effort), and BK (Back ground). Generally, the order of priority is VO, VI, BE, and BK. In each access category, there are parameters of CW minimum value CWmin, maximum value CWmax, AIFS (Arbitration IFS) which is a type of IFS, and TXOP limit which is the upper limit of transmission opportunities, and the priority is given a difference. Value is set. For example, CWmin, CWmax, and AIFS of the VO with the highest priority for voice transmission are set to relatively small values compared to other access categories, thereby giving priority to other access categories. Transmission becomes possible. For example, for a VI in which the amount of data to be transmitted is relatively large due to video transmission, setting a large TXOP limit makes it possible to secure a longer transmission opportunity than in other access categories. Thus, the values of the four parameters of each access category are adjusted for the purpose of guaranteeing QoS according to various services.

In the following embodiment, a case will be described in which the wireless communication device 1-1 (base station device 1-1) transmits and the wireless communication device 2-1 (terminal device 2-1) receives. However, it also includes the case where the wireless communication device 2-1 (terminal device 2-1) transmits and the wireless communication device 1-1 (base station device 1-1) receives. The device configurations of the wireless communication device 1-1 and the wireless communication device 2-1 are the same as the device configuration examples described with reference to FIGS. 6 and 7 unless otherwise specified.

The upper layer section 10001-1 of the wireless communication device 1-1 according to the present embodiment is a MAC layer payload A- MPDU is transferred to the transmitting section 10003-1. Also, one MPDU is a unit for determining ACK.

The physical layer frame generator 10003a-1 of the wireless communication device 1-1 according to this embodiment first generates a PSDU, which is the payload of the PHY layer, from the A-MPDU transferred by the upper layer 10001-1. The PSDU is appended with a PHY header to generate the PPDU of the transmission frame. The PHY header includes a PLCP preamble for synchronization detection, a PLCP header for determining a modulation and coding scheme according to the received signal strength, and control information notified by the MAC layer of the upper layer section 10001-1. , and when an MPDU-length information field is added to the control information, it includes an information field of a predetermined information bit length (encoding block length) for performing error correction coding corresponding to each information field. If the MAC layer of the upper layer section 10001-1 does not set MPDU aggregation, the PHY header may store the predetermined information bit length in the information field.

For application realization, in addition to the bit throughput improvement calculated from the bits correctly received, it is calculated from the packets (frames, slots, blocks, bits) received that meet the requirements of the application. Improving throughput is important. There are various conditions required by applications, but the minimum required round-trip time, average bit rate (e.g. bit rate per 10 seconds), instantaneous (e.g. It may be defined by bit rate per 500 milliseconds), momentary interruption time (maximum time during which data is interrupted), and the like.

As an example of an application, consider video transmission that requires real-time transmission such as streaming. Video data is generally divided into a plurality of packets and transmitted. One packet obtained by dividing video data is also called a QoS packet (video packet, application packet). A QoS packet is a packet associated with an application. In order to watch video without interruption, it is necessary to satisfy the requirements and continue to receive QoS packets. The throughput calculated from the received QoS packets satisfying the required conditions is also called QoS throughput (video throughput, application throughput).

It is desirable for the transmitting device to know the QoS throughput in order to be able to determine whether the video transmission is being performed satisfying the required conditions. In the following description, the AP is a transmitting device and the STA is a receiving device, but the present invention is not limited to this, and the present invention also includes the case where the STA is a transmitting device and the AP is a receiving device. When the AP calculates the QoS throughput, it can use the ACK regarding the QoS throughput from the STA. A signal (frame, information) to be reported to the AP to indicate that the STA has satisfied the requirements and correctly received the QoS packet is also called QoS ACK (video ACK, application ACK). To distinguish from QoS ACK, an ACK indicating that the MPDU has been correctly received is also called a bit ACK.

The number of bits carried in a QoS packet (QoS packet size) varies depending on instantaneous video content, video data rate, allowable delay time of video packets, and the like. Therefore, the QoS packet size may vary greatly depending on the type of application and video quality.

For example, if the QoS packet size is equal to or smaller than the A-MPDU size, QoS ACK is determined at the timing of bit ACK determination. In this case, the terminal device transmits bit ACK and QoS ACK for one MPDU. The QoS ACK also includes QoS BA (Block ACK), which is QoS ACK for a plurality of QoS packets.

If the QoS packet size is larger than the A-MPDU size, QoS ACK cannot be determined at the same timing as bit ACK is determined, so the terminal device transmits QoS ACK at a timing different from bit ACK. For example, when the last bit of a QoS packet is included in an A-MPDU, the terminal device can transmit QoS ACK at the most recent bit ACK transmission timing from the timing at which all QoS packets are received.

Note that the transmission timing of the QoS ACK may be different from the transmission timing of the bit ACK. For example, when the base station apparatus instructs a QoS ACK transmission cycle, the terminal apparatus transmits QoS ACKs in the period instructed by the base station apparatus regardless of the QoS packet reception timing. When a plurality of QoS packets are transmitted within the QoS ACK transmission period instructed by the base station apparatus, the terminal apparatus transmits QoS BA or QoS BLER (Block Error Rate), which is the error rate of the QoS packets. can be

In order to determine the QoS ACK, the terminal device needs information on the QoS packet size and the bits included in the QoS packet. The QoS packet size is indicated by control information from the base station apparatus to the terminal apparatus. The bits included in the QoS packet can be determined in advance in order to reduce the amount of information, although the base station apparatus can indicate the bits corresponding to the QoS packet in the A-MPDU to the terminal apparatus. For example, a QoS packet starts from the leading bit of A-MPDU and is continuously transmitted in A-MPDU until the size of the QoS packet is reached. In other words, the terminal device can receive the A-MPDU including the first bit of the QoS packet and the QoS packet size as control information and determine QoS ACK. The base station apparatus can also indicate the position of the first bit of the QoS packet. In this case, information indicating which bit of the A-MPDU the first bit of the QoS packet is is instructed from the base station apparatus to the terminal apparatus.

When transmitting QoS ACK, setting information is transmitted from the base station apparatus to the terminal apparatus. The configuration information includes QoS ACK transmission cycle and/or QoS information. The QoS information is part or all of the bit rate, delay time, and jitter indicated by the QoS, and the terminal device can determine QoS ACK when receiving the QoS packet satisfying the values included in the QoS information. The terminal device may transmit, as the QoS ACK, an index consisting of multiple levels indicating the degree of achievement of the value included in the QoS information. For example, the QoS ACK may be transmitted as an index indicating how much delay time is required for correct reception with respect to the allowable delay time, how much jitter is used for reception, and the like.

When the terminal device on the receiving side calculates the QoS throughput, the terminal device reports the QoS throughput or QoS BLER to the base station device. The reporting timing may be periodically reported, or may be reported based on a trigger from the AP. If QoS sets a time unit such as round-trip time or instantaneous throughput, the report period may be set based on this QoS setting. For example, if the instantaneous throughput defines a throughput per 10 milliseconds, the report period may be 10 milliseconds.

Also, the upper layer section 10001-1 allocates wireless resources to terminal devices that communicate with the wireless communication device 1-1. The physical layer frame generator 10003a-1 generates a physical layer frame based on the radio resource allocation result. Note that radio resources represent part or all of time resources, frequency resources, and space resources. A time resource is a resource that is temporally divided, and corresponds to, for example, a frame, slot, MPDU, and the like. A frequency resource is a resource divided in the frequency domain, and corresponds to a subband, resource unit, resource block, subcarrier, and the like. Spatial resources are resources divided spatially, and correspond to streams (ranks) of MIMO (Multiple Input Multiple Output), for example.

When a plurality of terminal devices communicate with the radio communication device 1-1, the upper layer section 10001-1 needs to determine which terminal devices are to be allocated to radio resources, that is, the priority (or metric) of radio resource allocation. be. For example, conventional schemes include MAX CIR (Carrier to Interference power Ratio), which allocates terminal equipment with the best radio quality to radio resources, and Proportional Fairness (PF), which considers both fairness between terminal equipment and average throughput. be. However, MAX CIR and PF consider radio quality but do not consider applications. Therefore, from the viewpoint of realizing the application, the priority of radio resource allocation is calculated. Let A be the average requirement in the application and B be the instantaneous requirement. There are three possible priorities for radio resource allocation. (1) Decide based on A to preferentially assign users with high average requirements in the application, (2) Decide based on B to preferentially assign users with high instantaneous requirements in the application. (3) Consider fairness between applications and decide based on B/A.

For example, considering video transmission as an application, A is the average requested video bitrate, eg 40 Mbps or 80 Mbps. Also, B can be calculated from the QoS packet size and the allowable delay time. Also, when the application performs a handshake such as flow control between the sending side and the receiving side, this handshake interval may be used.

It is also possible to consider application requirements and radio quality. If the QoS throughput is C and the priority of user allocation is B/C, fairness between applications is taken into consideration in terms of QoS throughput.

The communication device according to the present invention can communicate in a frequency band (frequency spectrum) called a so-called unlicensed band that does not require permission from a country or region, but the usable frequency band is not limited to this. The communication device according to the present invention is, for example, a white band that is not actually used for the purpose of preventing interference between frequencies, even though the country or region has given permission to use it for a specific service. Also in the frequency band called (for example, the frequency band allocated for television broadcasting but not used in some areas) and the shared spectrum (shared frequency band) that is expected to be shared by multiple operators It is possible to exert an effect.

A program that operates in the wireless communication device according to the present invention is a program that controls a CPU or the like (a program that causes a computer to function) so as to implement the functions of the above-described embodiments related to the present invention. Information handled by these devices is temporarily stored in RAM during processing, then stored in various ROMs and HDDs, and read, corrected, and written by the CPU as necessary. Recording media for storing programs include semiconductor media (eg, ROM, nonvolatile memory cards, etc.), optical recording media (eg, DVD, MO, MD, CD, BD, etc.), magnetic recording media (eg, magnetic tapes, flexible disk, etc.). By executing the loaded program, the functions of the above-described embodiments are realized. In some cases, inventive features are realized.

When distributed to the market, the program can be stored in a portable recording medium for distribution, 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. Also, part or all of the communication device in the above-described embodiments may be typically implemented as an LSI, which is an integrated circuit. Each functional block of the communication device may be individually chipped, or part or all of them may be integrated and chipped. When each functional block is integrated, an integrated circuit control unit for controlling them is added.

Also, the method of circuit integration is not limited to LSI, but may be realized by a dedicated circuit or a general-purpose processor. Also, if a technology for integrating circuits to replace LSIs emerges due to advances in semiconductor technology, it is possible to use an integrated circuit based on this technology.

In addition, this invention is not limited to the above-mentioned embodiment. The wireless communication device of the present invention is not limited to application to mobile station devices, but can be applied to stationary or non-movable electronic devices installed indoors and outdoors, such as AV equipment, kitchen equipment, cleaning/washing equipment, etc. Needless to say, it can be applied to equipment, air conditioners, office equipment, vending machines, and other household equipment.

Although the embodiments of the present 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 within the scope of the scope of the present invention can be applied within the scope of claims. Included in scope.

INDUSTRIAL APPLICABILITY The present invention is suitable for use in communication devices and communication methods.

1-1, 1-2, 2-1 to 6, 2A, 2B Wireless communication devices 3-1, 3-2 Control range 10-1 Wireless communication device 10001-1 Upper layer unit 10002-1 Control unit 10002a-1 CCA Unit 10002b-1 Backoff unit 10002c-1 Transmission judgment unit 10003-1 Transmission unit 10003a-1 Physical layer frame generation unit 10003b-1 Radio transmission unit 10004-1 Reception unit 10004a-1 Radio reception unit 10004b-1 Signal demodulation unit 10005 -1 Antenna part

Claims (5)

A communication device that communicates with a plurality of communication devices,
an upper layer unit that allocates the plurality of communication devices to radio resources based on priority;
a physical layer frame generator that generates a physical layer frame based on the radio resource allocation;
a transmission unit that transmits the physical layer frame,
The priority is calculated based on requirements instantaneously requested at least in applications executed by the plurality of communication devices,
Communication device. The priority is calculated by a ratio of an instantaneous request to an average request in an application executed by each of the plurality of communication devices,
A communication device according to claim 1 . The transmitting unit transmits a QoS packet, which is a packet in which QoS (Quality of Service) is set,
The priority is determined based on the QoS throughput calculated from the QoS packets received satisfying predetermined requirements,
A communication device according to claim 1 . A request condition instantaneously requested in an application executed by each of the plurality of communication devices is calculated based on the number of bits included in the QoS packet,
4. A communication device according to claim 3. A communication method in a communication device that communicates with a plurality of communication devices,
allocating the plurality of communication devices to radio resources based on priority;
generating a physical layer frame based on the radio resource allocation;
transmitting said physical layer frame;
The priority is calculated based on requirements instantaneously requested at least in applications executed by the plurality of communication devices,
Communication method.

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