Communication device and communication method

Abstract

To provide a communication device that observes channel conditions on a plurality of links.SOLUTION: A communication device that performs wireless communication using a plurality of links includes a first transmitting unit that transmits a first signal including information regarding the start of observation of channel conditions on some of the plurality of links, and a second transmitting unit that transmits a second signal that induces a signal including information regarding observation of channel conditions on one or more of the plurality of links. The first signal includes information regarding the links on which the observation is to be performed, or the first signal includes information regarding a third signal for another communication device to observe the channel conditions.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The technology disclosed in this specification (hereinafter referred to as "the present disclosure") relates to a communication device and a communication method that perform multi-link operation. [Background technology]

[0002] In recent years, standardization of wireless communication using multiple frequency bands (links) (Multi-Link Operation: MLO) has been progressing as a method to meet high transmission speed requirements such as XR and 8K video transmission. In MLO, it is assumed that MLO-compatible terminals (STAs: STAs) connect to an MLO-compatible access point (AP) using multiple links. Furthermore, in wireless communication, uplink user multiplexing (Uplink Multi-User: UL MU) and downlink user multiplexing (Downlink Multi-User: DL MU) are generally performed to efficiently perform uplink and downlink communications between an AP and multiple STAs. In other words, in MLO, it is assumed that an AP and STAs connected via multiple links will perform MU communications via multiple links.

[0003] When STAs with good channel characteristics and poor channel characteristics are multiplexed in MU communications, the AP's RSSI (Received Signal Strength Indicator) is limited to that of the STA with poor channel characteristics. Therefore, in MLO, it is desirable to allocate multiplexing resources for UL and DL MU communications, taking into account the channel characteristics between the AP and STAs for all links observed under highly time-correlated conditions. However, when observing multiple links, there is a problem in that time correlation cannot be guaranteed due to differences in observation timing, etc.

[0004] For example, a method has been proposed for optimizing the signal-to-interference plus noise ratio (SINR) on the receiving side in DL (Down Link) OFDMA (Orthogonal Frequency Division Multiple Access) as a communication method assuming a wireless local area network (LAN) using multiple bands (see Patent Document 1). However, even if this method optimizes transmission in DL OFDMA, it cannot be applied to UL MU communications with other multiple terminals.

[0005] Furthermore, the IEEE802.11 public contribution (19 / 1542r2) (Non-Patent Document 1) describes the issues that arise when a terminal supporting MLO receives a broadcast signal and the setting of a link (Configured Link) that performs reception processing of the broadcast signal. However, when an AP in MLO performs UL and DL MU communication with STAs connected via multiple links, it is necessary to consider both cases where a Configured Link is set and where it is not set. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-157535 [Non-patent literature]

[0007] [Non-Patent Document 1] IEEE802.11 Public Contribution (19 / 1542r2) Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present disclosure is to provide a communication device and a communication method for observing channel conditions in multiple links. [Means for solving the problem]

[0009] The present disclosure has been made in consideration of the above-described problems, and a first aspect thereof provides a communication device that performs wireless communication using a plurality of links, a first transmitter configured to transmit a first signal including information regarding a start of observation of channel conditions on some of the plurality of links; a second transmitter configured to transmit a second signal inducing a signal including information regarding observation of channel conditions on one or more of the plurality of links; The communication device is provided with:

[0010] The first signal includes information about the link on which the observation is performed, or information about a third signal for another communication device to observe the channel state.

[0011] The second signal is a signal that induces a fourth signal for the communication device itself to observe a channel state. In this case, the communication device according to the first aspect determines resource allocation for multi-user communication based on information regarding the channel state observed by the communication device itself from the fourth signal transmitted from another communication device in response to the second signal.

[0012] Alternatively, the second signal is a signal that induces a fifth signal including information on a channel state observed by another communication device, in which case the communication device according to the first aspect determines resource allocation for multi-user communication based on information on a channel state collected from the fifth signal transmitted by the other communication device in response to the second signal.

[0013] A second aspect of the present disclosure is a communication method for performing wireless communication using a plurality of links, comprising: a first transmitting step of transmitting a first signal including information regarding a start of observation of a channel state on a part of the plurality of links; a second transmitting step of transmitting a second signal that induces a signal containing information regarding observation of channel conditions on one or more of the plurality of links; It is a communication method having the following.

[0014] A third aspect of the present disclosure is a communication device that performs wireless communication using a plurality of links, transmitting a signal containing information regarding the observation of channel conditions on one or more of the plurality of links; It is a communication device.

[0015] The signal containing information regarding the observation of the channel state may be a fourth signal for other communication devices to observe the channel state, or a fifth signal containing information regarding the channel state observed by the communication device itself, and may include information regarding the transmission power of the signal.

[0016] A fourth aspect of the present disclosure is a communication method for performing wireless communication using a plurality of links, comprising: A method of communication comprising transmitting a signal containing information relating to observation of channel conditions on one or more of the plurality of links. [Effects of the Invention]

[0017] According to the present disclosure, it is possible to provide a communication device and a communication method that observe channel conditions to acquire channel characteristics with high time correlation over multiple links.

[0018] It should be noted that the effects described in this specification are merely examples, and the effects brought about by the present disclosure are not limited to these. Furthermore, the present disclosure may also bring about additional effects in addition to the effects described above.

[0019] Further objects, features, and advantages of the present disclosure will become apparent from the following detailed description based on the embodiments and accompanying drawings. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a communication system. [Figure 2] FIG. 2 is a diagram showing an example of the internal configuration of the communication device 200. As shown in FIG. [Figure 3] FIG. 3 is a diagram showing an example of a communication sequence (case (1)) for performing uplink sounding. [Figure 4] FIG. 4 is a diagram showing an example of a communication sequence (case (2)) for performing uplink sounding. [Figure 5] FIG. 5 is a diagram showing an example of a communication sequence (case (3)) for performing uplink sounding. [Figure 6] FIG. 6 is a diagram showing an example of a frame format of a Sounding Announcement signal. [Figure 7] FIG. 7 is a diagram showing an example of a frame format of a Sounding Trigger signal. [Figure 8] FIG. 8 is a diagram showing an example of a frame format of a test signal. [Figure 9] FIG. 9 is a flowchart showing the processing procedure executed by the AP MLD when uplink sounding is performed. [Figure 10] FIG. 10 is a flowchart showing the processing procedure executed by Non-AP MLD when uplink sounding is performed. [Figure 11] FIG. 11 is a flowchart showing the processing procedure executed by Single RF Non-AP MLD when uplink sounding is performed. [Figure 12] FIG. 12 is a diagram showing an example of a communication sequence (case (1)) for performing downlink sounding. [Figure 13] FIG. 13 is a diagram showing an example of a communication sequence (case (2)) for performing downlink sounding. [Figure 14] FIG. 14 is a diagram showing an example of a communication sequence (case (3)) for performing downlink sounding. [Figure 15] FIG. 15 is a diagram showing an example of a frame format of a Sounding Announcement signal. [Figure 16] FIG. 16 is a flowchart showing the processing procedure executed by the AP MLD when performing downlink sounding. [Figure 17] FIG. 17 is a flowchart showing the processing procedure executed by the AP MLD when performing downlink sounding. [Figure 18] FIG. 18 is a flowchart showing the processing procedure executed by Non-AP MLD when performing downlink sounding. [Figure 19] FIG. 19 is a flowchart showing the processing procedure executed by Single RF non-AP MLD when performing downlink sounding. DETAILED DESCRIPTION OF THE INVENTION

[0021] The technology according to the present disclosure will be described below in the following order with reference to the drawings. A. Overview B. System Configuration C. Equipment configuration D. Sounding Examples D-1. Sounding of the uplink D-2. Frame format of the signal used for sounding D-3. Operation of communication equipment during uplink sounding D-4. Down Ring Sounding D-5. Frame format of the signal used for downlink sounding D-6. Downlink Sounding Communication Sequence D-7. Operation of communication equipment during downlink sounding

[0022] A. Overview The present disclosure provides a channel state observation method for acquiring channel characteristics with high time correlation across multiple links. This disclosure makes it possible to observe the channel state of each link with high time correlation by aligning the transmission timing of a test signal (UL Sounding) and a null data packet (NDP) signal (DL Sounding) for channel state observation, i.e., sounding, closer together. This disclosure also provides a sounding method for when an MLO-enabled STA with a single RF (Radio Frequency) block is connected to an MLO-enabled AP. This disclosure also provides a sounding method for when an MLO-enabled AP is configured to receive and process broadcast-destined signals only on a specific link (Configured Link).

[0023] According to the present disclosure, it is possible to collect information necessary for setting resource parameters when performing UL and DL MU communications over multiple links while ensuring high time correlation. Furthermore, according to the present disclosure, it is possible to configure resources for UL and DL MU communications taking into account the channel characteristics of all links and improve spectrum efficiency. Furthermore, according to the present disclosure, it is possible to reduce the number of STAs and reception results for each link managed by the AP, thereby reducing memory requirements. Furthermore, according to the present disclosure, it is possible to prevent an increase in the number of links assigned to STAs and reduce the number of RF chain requests from the AP performing UL and DL MU communications.

[0024] B. System Configuration 1 is a schematic diagram illustrating an example of the configuration of an MLO-compatible communication system to which the present disclosure is applied. The illustrated communication system is configured with an AP MLD (Multi Link Device), Non-AP MLD1 and Non-AP MLD2, and a Single RF Non-AP MLD.

[0025] AP MLD is a communications device equivalent to a base station that supports MLO. Non-AP MLD is a communications device equivalent to a terminal that supports MLO. Non-AP MLD processes broadcast signals for reception using a configured link. The configured link is switchable. Single RF Non-AP MLD is a wireless device equivalent to a terminal that supports MLO, equipped with a single RF block (antenna, wireless interface, etc.) and communicating over a single link. The link that Single RF Non-AP MLD enables for sending and receiving is an enabled link. The enabled link is switchable.

[0026] Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD are each connected to the AP MLD. In addition, in Figure 1, the solid lines and dashed lines connecting Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD to the AP MLD indicate that they are connected by different links.

[0027] In this specification, a "link" refers to a wireless transmission path over which data can be transmitted between two communication devices. Each link is selected from a plurality of mutually independent wireless transmission paths (channels) divided, for example, in the frequency domain. The two links used in the communication system shown in FIG. 1 each use a channel selected from a plurality of channels included in one of frequency bands, such as the 2.4 GHz band, the 5 GHz band, the 6 GHz band, or the 920 GHz band. The two links used in the communication system shown in FIG. 1 may be two channels selected from the same frequency band or two channels selected from different frequency bands. Furthermore, the frequency band including the channel selected by at least one of the two links used in the communication system shown in FIG. 1 may be a frequency band whose use is permitted by database access such as a Spectrum Access System (SAS).

[0028] C. Equipment configuration Fig. 2 shows an example of the internal configuration of communication device 200. Communication device 200 is a communication device that supports MLO, and is assumed to operate as AP MLD or Non-AP MLD in the communication system shown in Fig. 1. Communication device 200 is mainly composed of a communication unit 210, a control unit 220, a storage unit 230, and an antenna 240. Furthermore, communication unit 210 includes a communication control unit 211, a communication storage unit 212, a data processing unit consisting of a common data processing unit 213 and an individual data processing unit 214, a signal processing unit 215, a wireless interface (IF) unit 216, and an amplifier 217.

[0029] The individual data processing unit 214, signal processing unit 215, wireless interface (IF) unit 216, amplifier unit 217, and antenna 240 are provided for each link. The communication device 200 is assumed to perform MLO using two links, a first link and a second link. For example, the individual data processing unit 214-1, signal processing unit 215-1, wireless interface unit 216-1, amplifier unit 217-1, and antenna 240-1 are configured as one set for transmission and reception processing in the first link, and the individual data processing unit 214-2, signal processing unit 215-2, wireless interface unit 216-2, amplifier unit 217-2, and antenna 240-2 are configured as another set for transmission and reception processing in the second link.

[0030] The communication control unit 211 controls the operation of each unit in the communication unit 210 and the transmission of information between each unit. The communication control unit 211 also controls the transfer of control information and management information to be notified to other communication devices to the data processing units (common data processing unit 213, individual data processing unit 214-1, and individual data processing unit 214-2).

[0031] In the present disclosure, communication control unit 211 controls the operation of each unit in communication unit 210 to transmit signals related to sounding in multiple links. Furthermore, communication control unit 211 controls the configuration of resources for UL MU communication or DL ​​MU communication in multiple links based on the sounding results.

[0032] The communication storage unit 212 stores information used by the communication control unit 211. The communication storage unit 212 also stores data transmitted by the communication device 200 and data received by the communication device 200.

[0033] The data processing unit is made up of a common data processing unit 213 and an individual data processing unit 214. The individual data processing unit 214 is made up of an individual data processing unit 214-1 and an individual data processing unit 214-2 for each link.

[0034] During transmission, the common data processing unit 213 performs sequence management of the data stored in the communication storage unit 212 and the control information and management information received from the communication control unit 211, performs encryption processing and the like to generate data units, and allocates them to the individual data processing units 214-1 and 214-2. During reception, the common data processing unit 213 performs decryption processing and reordering processing of the data units.

[0035] During transmission, the individual data processing units 214-1 and 214-2 perform channel access operations based on carrier sense on the corresponding link, add a MAC (Media Access Control) header and an error detection code to the data to be transmitted, and perform concatenation of multiple data units. During reception, the individual data processing units 214-1 and 214-2 perform concatenation release processing of the MAC header of the received data unit, analysis and error detection, and retransmission request operations.

[0036] The operations of the common data processing unit 213 and the individual data processing units 214-1 and 214-2 are not limited to those described above, and one may perform the operation of the other, for example.

[0037] During transmission, signal processing units 215-1 and 215-1-2 perform encoding, interleaving, modulation, etc. on data units, add physical headers, and generate symbol streams. During reception, signal processing units 215-1 and 215-2 analyze the physical headers and perform demodulation, deinterleaving, decoding, etc. on the symbol streams to generate data units. Furthermore, signal processing units 215-1 and 215-2 estimate complex channel characteristics and perform spatial separation processing as necessary.

[0038] During transmission, the radio interface units 216-1 and 216-2 perform digital-to-analog signal conversion, filtering, up-conversion, and phase control on the symbol stream to generate a transmission signal, and during reception, the radio interface units 216-1 and 216-2 perform down-conversion, filtering, and analog-to-digital signal conversion on the received signal to generate a symbol stream.

[0039] During transmission, amplifiers 217-1 and 217-2 amplify signals input from wireless interface units 216-1 and 216-2. During reception, amplifiers 217-1 and 217-2 amplify signals input from antennas 240-1 and 240-2. Some of amplifiers 217-1 and 217-2 may be components outside communication unit 210. Some of amplifiers 217-1 and 217-2 may be included in wireless interface units 216-1 and 216-2.

[0040] The control unit 220 controls the communication unit 210 and the communication control unit 211. The control unit 220 may also perform some of the operations of the communication control unit 211. The communication control unit 211 and the control unit 220 may also be configured as a single block.

[0041] The storage unit 230 holds information used by the communication unit 210 and the control unit 220. The storage unit 230 may also perform part of the operations of the communication storage unit 212. The storage unit 230 and the communication storage unit 212 may also be configured as a single block.

[0042] The individual data processing unit 214-1, signal processing unit 215-1, wireless interface unit 216-1, amplifier unit 217-1, and antenna 240-1 form one group, and perform wireless communication over a first link. The individual data processing unit 214-2, signal processing unit 215-2, wireless interface unit 216-2, amplifier unit 217-2, and antenna 240-2 form another group, and perform wireless communication over a second link. While only two groups are shown in FIG. 2, the communication device 200 may be configured to include three or more groups, each of which performs wireless communication over a respective link. The storage unit 230 or the communication storage unit 212 may be included in each group.

[0043] A link is a wireless transmission path that allows data transmission between two communication devices, and each link is selected from, for example, a plurality of mutually independent wireless transmission paths (channels) divided in the frequency domain. The links used by each of the above pairs may be two channels selected from the same frequency band, or two channels selected from different frequency bands. Furthermore, the individual data processing unit 214 and the signal processing unit 215 may be configured as one pair, and two or more pairs may be connected to one wireless interface unit 216.

[0044] The wireless interface unit 216, the amplifier unit 217, and the antenna 240 may be grouped together, and two or more groups may be components of the communication device 200.

[0045] The communication unit 210 can also be configured by one or more LSIs (Large Scale Integration).

[0046] The common data processing unit 213 is also referred to as an Upper MAC or a Higher MAC, and the individual data processing unit 214 is also referred to as a Lower MAC. The set of the individual data processing unit 214 and the signal processing unit 215 is also referred to as an AP entity or a Non-AP entity. The communication control unit 211 is also referred to as an MLD management entity.

[0047] D. Sounding Examples In this section, examples of sounding methods in communication systems to which the present disclosure is applied will be described, divided into uplink sounding and downlink sounding. In each example, the following cases (1) to (3) are shown.

[0048] (1) Case where Non-AP MLD connects to AP MLD (2) Case where Non-AP MLD and Single RF Non-AP MLD are connected to AP MLD (3) Cases where a Configured Link is set

[0049] In both the uplink and downlink sounding embodiments, the AP MLD, Non-AP MLD, and Single RF Non-AP MLD communicate using a first link (Link 1) and a second link (Link 2). At least one of the two link frequency bands may be a frequency band whose use is permitted by database access such as SAS.

[0050] D-1. Uplink Sounding First, an embodiment relating to uplink sounding will be explained for the above cases (1) to (3).

[0051] Figure 3 shows an example of a communication sequence for performing uplink sounding in case (1) where a Non-AP MLD connects to an AP MLD. This assumes the communication system shown in Figure 1, where Non-AP MLD1 and Non-AP MLD2, which support MLO, are both connected to the AP MLD via Link 1 and Link 2.

[0052] The horizontal axis in Figure 3 is the time axis, and shows the communication operations over time on each link: AP MLD, Non-AP MLD1, and Non-AP MLD2. Square blocks drawn with solid lines indicate the corresponding communication device, link, and transmitted frame at that time, and vertical solid arrows indicate the transmission of frames to their destinations.

[0053] Before starting this communication sequence, it is confirmed that the AP MLD, Non-AP MLD1, and Non-AP MLD2 support MLO and the sounding method shown in FIG.

[0054] When the AP MLD acquires the transmission right on Link1, it transmits a Sounding Announcement signal on Link1 that includes information about the start of uplink sounding.

[0055] Although not shown in FIG. 3, the AP MLD may transmit a signal to acquire the transmission right before the Sounding Announcement signal. This signal may be an RTS (Request To Send) frame or a CTS (Clear To Send) frame specified in IEEE 802.11. The CTS frame may be a CTS-to-self frame sent to the AP itself. The signal to acquire the transmission right causes surrounding communication terminals to suppress communication.

[0056] The AP MLD transmits a Sounding Announcement signal to the broadcast destination. The Sounding Announcement signal used in uplink sounding may include information about the sounding identifier, information about the transmission link of the subsequent Sounding Trigger signal or Sounding Announcement signal transmitted by the AP MLD, information about the timeout period during which the AP MLD waits for acquisition of the transmission right on another link and terminates sounding if the timeout period is exceeded, information about the identifier of the Non-AP MLD to be sounded, and information about the resource allocation of the Test signal transmitted by the Non-AP MLD to be sounded on the link on which the Sounding Announcement signal is transmitted. Details of the Sounding Announcement signal used in uplink sounding will be described later.

[0057] When Non-AP MLD1 and Non-AP MLD2 receive a Sounding Announcement signal from the AP MLD on Link 1, they suppress transmissions other than this sounding.

[0058] Next, the AP MLD acquires the transmission right in Link 2 and transmits a Sounding Trigger signal that induces the transmission of a Test signal for sounding on Link 2. Although not shown in Fig. 3, the AP MLD may transmit a signal (described above) that acquires the transmission right before the Sounding Trigger signal.

[0059] The AP MLD transmits a Sounding Trigger signal to the broadcast destination. The Sounding Trigger signal may include information about the sounding identifier, information about a request for transmission of a Test signal by the Non-AP MLD to be sounded on a link other than the link to which the Sounding Trigger signal is transmitted, information about the identifier of the Non-AP MLD to be sounded, and information about resource allocation for the Test signal to be transmitted by the Non-AP MLD to be sounded. Details of the Sounding Trigger signal will be described later.

[0060] If there are three or more links available for MLO in the assumed communication system, the AP MLD may transmit the Sounding Announcement signal over multiple links and transmit the Sounding Trigger signal over the last link.

[0061] In addition, if the AP MLD can acquire transmission rights simultaneously on multiple links, the AP MLD may transmit one or more Sounding Announcement signals and NDP Announcement signals simultaneously on each link. The NDP Announcement signal is a signal that contains information about the start of downlink sounding and notifies the AP MLD that it will transmit an NDP signal for monitoring the channel state.

[0062] When Non-AP MLD1 and Non-AP MLD2 receive a Sounding Trigger signal from the AP MLD on Link 2, they transmit Test signals on Link 1 and Link 2 at the same time based on the information in the Sounding Announcement signal and Sounding Trigger signal. Non-AP MLD1 and Non-AP MLD2 may transmit Test signals after a fixed time has elapsed since the completion of reception of the Sounding Trigger signal, or after a SIFS (Short Inter Frame Space) interval as defined by IEEE 802.11. Non-AP MLD1 and Non-AP MLD2 may also include information about transmission power in the Test signal. Details of the Test signal will be described later.

[0063] When the AP MLD receives the test signals simultaneously transmitted from Non-AP MLD1 and Non-AP MLD2, it calculates information about the uplink propagation loss with each of Non-AP MLD1 and Non-AP MLD2 from information about the received signal strength and transmission power. Before starting this communication sequence, the AP MLD and Non-AP MLD1 and Non-AP MLD2 may perform calibration to correct for errors in their transmission and reception circuits. The AP MLD may calculate weight information to be used when implementing DL MU Multiple Input Multiple Output (MU-MIMO) from this calibration information and information about the test signals.

[0064] The AP MLD then determines resource allocation for UL MU communication based on information about the calculated uplink path loss with each of the Non-AP MLD1 and Non-AP MLD2.

[0065] The communication sequence shown in Figure 3 enables AP MLD to collect path loss data for multiple link bands while maintaining time correlation, and also enables UL MU communication resource allocation that takes into account the path loss data for all links.

[0066] Figure 4 shows an example of a communication sequence for performing uplink sounding in case (2) where a Non-AP MLD and a Single RF Non-AP MLD are connected to an AP MLD. This assumes the communication system shown in Figure 1, with MLO-compatible Non-AP MLD1 and Non-AP MLD2 both connected to the AP MLD via Link 1 and Link 2. Additionally, the Single RF Non-AP MLD connects to the AP MLD by switching the Enabled Link, which is the link that enables signal transmission and reception, between Link 1 and Link 2 as needed.

[0067] The horizontal axis in Figure 4 is the time axis, and shows the communication operation over time on each link for AP MLD, Non-AP MLD1 and Non-AP MLD2, and Single RF Non-AP MLD. The square blocks drawn with solid lines indicate the corresponding communication device, link, and transmitted frame at that time, and the vertical solid arrows indicate the transmission of frames to their destinations.

[0068] Before this communication sequence begins, it is confirmed that the AP MLD, Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD support MLO and the sounding method shown in Figure 4. Also, before this communication sequence begins, the AP MLD and Single RF Non-AP MLD share information about the Enabled Link, which is the link that the Single RF Non-AP MLD has enabled for sending and receiving signals. In this communication sequence, it is assumed that the Single RF Non-AP MLD has set Link1 as the Enabled Link.

[0069] When the AP MLD acquires the transmission right on Link1, it transmits a Sounding Announcement signal on Link1 that includes information about the start of sounding.

[0070] When Non-AP MLD1 and Non-AP MLD2 receive a Sounding Announcement signal from the AP MLD on Link 1, they suppress all transmissions other than sounding. Furthermore, when Single RF Non-AP MLD receives a Sounding Announcement signal from the AP MLD on Link 1, which is set as the Enabled Link, it suppresses all communications other than sounding and changes the Enabled Link based on the information about the transmission link of the subsequent Sounding Trigger signal or Sounding Announcement signal sent by the AP MLD, which was notified in the Sounding Announcement signal. In this example communication sequence, the Single RF Non-AP MLD changes the Enabled Link from Link 1 to Link 2.

[0071] Next, the AP MLD acquires the transmission right in Link2 and transmits a Sounding Trigger signal on Link2 to induce the transmission of a Test signal for sounding.

[0072] When Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD receive a Sounding Trigger signal from the AP MLD on Link 2, they each transmit a Test signal on Link 2 at the same time based on the information in the Sounding Announcement signal and Sounding Trigger signal.

[0073] Furthermore, the Single RF Non-AP MLD changes the Enabled Link after transmitting a Test signal on Link 2. In this example communication sequence, the Single RF Non-AP MLD changes the Enabled Link from Link 2 to Link 1.

[0074] Thereafter, Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD each transmit a Test signal at the same timing on Link1 based on the information in the Sounding Announcement signal and Sounding Trigger signal.

[0075] Note that the AP MLD may again transmit a Sounding Trigger signal to induce the transmission of a Test signal before transmitting a Test signal on Link 1. Alternatively, the AP MLD may also transmit a Sounding Announcement signal on Link 2, after which Non-AP MLD 1, Non-AP MLD 2, and Single RF Non-AP MLD may transmit Test signals on Link 1.

[0076] When the AP MLD receives the test signals simultaneously transmitted on Link 1 and Link 2 from Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD, it calculates information about the uplink propagation loss with each of Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD based on information about the received signal strength and transmission power. Note that before starting this communication sequence, the AP MLD, Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD may perform calibration to correct for errors in their transmission and reception circuits. The AP MLD may calculate weight information to use when implementing DL MU-MIMO based on this calibration information and information about the test signals.

[0077] The AP MLD then determines resource allocation for UL MU communication based on information about the calculated uplink propagation losses with each of the Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD. If the AP MLD determines that the Enabled Link of the Single RF Non-AP MLD needs to be changed during this determination, it may transmit a signal (Enabled Link Request) to the Single RF Non-AP MLD requesting a change of the Enabled Link. This signal includes information about the new Enabled Link and may also include information about the reason for the change request. For example, if the observed channel condition shows that the channel condition between the AP and the Single RF Non-AP MLD is better for Link 2 than for Link 1, the AP MLD transmits a signal to the Single RF Non-AP MLD requesting that the Single RF Non-AP MLD switch the Enabled Link to Link 2.

[0078] The communication sequence shown in Figure 4 enables AP MLD to collect path loss data for multiple link bands while maintaining time correlation, even in case (2) where Non-AP MLD and Single RF Non-AP MLD are connected to AP MLD. In addition, AP MLD can allocate resources for UL MU communication taking into account the path loss data for all links.

[0079] Figure 5 shows an example of a communication sequence for performing uplink sounding in case (3) where a Configured Link is set. This assumes the communication system shown in Figure 1, where Non-AP MLD1 and Non-AP MLD2, which support MLO, are both connected to the AP MLD via Link 1 and Link 2.

[0080] The horizontal axis in Figure 5 is the time axis, and shows the communication operations over time on each link of AP MLD, Non-AP MLD1, and Non-AP MLD2. The square blocks drawn with solid lines indicate the corresponding communication device, link, and transmitted frame at that time, and the vertical solid arrows indicate the transmission of frames to their destinations.

[0081] Before this communication sequence starts, it is confirmed that the AP MLD, Non-AP MLD1, and Non-AP MLD2 support MLO and the sounding method shown in Fig. 5. Also, before this communication sequence starts, the AP MLD, Non-AP MLD1, and Non-AP MLD2 confirm information about the Configured Link, which is the link that receives and processes signals addressed to broadcasts. In the communication sequence example shown in Fig. 5, it is assumed that Non-AP MLD1 sets Link1 as the Configured Link, and Non-AP MLD2 sets Link2 as the Configured Link.

[0082] When the AP MLD acquires the transmission right on Link1, it transmits a Sounding Announcement signal on Link1 that includes information about the start of sounding.

[0083] Non-AP MLD1, which has Link1 set as the Configured Link, receives and processes this Sounding Announcement signal, and based on information about the transmission link of the subsequent Sounding Trigger signal or Sounding Announcement signal sent by the AP MLD notified by this signal, sets Link2, which is not a Configured Link, to receive and process signals addressed to broadcast.

[0084] In addition, Non-AP MLD2, which has Link2 set as the Configured Link, may perform reception processing of this Sounding Announcement signal, and may stop receiving the signal when it confirms that the destination address of this signal is a broadcast address.

[0085] Next, the AP MLD acquires the transmission right in Link2 and transmits a Sounding Trigger signal on Link2 to induce the transmission of a Test signal for sounding.

[0086] If there are three or more links available for MLO in the assumed communication system, the AP MLD may transmit the Sounding Announcement signal over multiple links and transmit the Sounding Trigger signal over the last link.

[0087] When Non-AP MLD1 and Non-AP MLD2 receive a Sounding Trigger signal from the AP MLD on Link2, they transmit Test signals on Link1 and Link2 at the same time based on the information in the Sounding Announcement signal and Sounding Trigger signal.

[0088] When the AP MLD receives the test signals transmitted simultaneously from Non-AP MLD1 and Non-AP MLD2, it calculates information about the uplink propagation loss with each of Non-AP MLD1 and Non-AP MLD2 from information about the received signal strength and transmission power.

[0089] The AP MLD then determines resource allocation for UL MU communication based on the calculated information on uplink propagation loss with each of Non-AP MLD1 and Non-AP MLD2. If this determination requires a change to the Configured Link set by Non-AP MLD1 or Non-AP MLD2, the AP MLD may send a signal to Non-AP MLD1 or Non-AP MLD2 requesting a change to the Configured Link. This signal includes information on the new Configured Link and may further include information on the reason for the change request. For example, if the observed channel condition shows that the channel condition between the AP and Non-AP MLD2 is better on Link1 than on Link2, the AP MLD sends a signal to Non-AP MLD2 requesting that Non-AP MLD2 switch the Configured Link to Link1.

[0090] Before starting this communication sequence, the AP MLD and the Non-AP MLD1 and Non-AP MLD2 may perform calibration to correct for errors in their transmission and reception circuits. The AP MLD may calculate weight information to be used when implementing DL MU-MIMO from information about this calibration and information about the test signal.

[0091] The communication sequence shown in Figure 5 enables AP MLD to collect path loss data for multiple link bands while maintaining time correlation. AP MLD also enables resource allocation for UL MU communication that takes into account the path loss data for all links.

[0092] D-2. Frame format of the signal used for sounding In this section, the frame format of each signal used in the communication sequence for sounding will be explained.

[0093] An example of the frame format of a Sounding Announcement signal is shown in Fig. 6. Each field of the illustrated frame will be explained below.

[0094] The Frame Control field contains information about the settings of the Sounding Announcement signal.

[0095] The Duration field contains information about the length of this frame.

[0096] The RA (Received Address) field contains information about the address of the destination terminal of this frame, which may be a broadcast address.

[0097] The TA (Transmitting Address) field contains information about the address of the source terminal of this frame. This address may be the address of an AP entity or the address of an MLD management entity.

[0098] The Sounding Control field includes information regarding notification of sounding according to the present disclosure. This information may be included in the Frame Control field. This information may include information indicating that the time interval between the transmission of the Sounding Announcement signal and the transmission of the Test signal is not a fixed time interval, is not a SIFS interval, or is delayed sounding.

[0099] The Sounding ID field contains information about the sounding identifier.

[0100] The Succeeding Link field contains information about the transmission link of the subsequent Sounding Trigger signal or Sounding Announcement signal transmitted by the AP MLD that is the sender of this signal, in other words, information about the link on which the channel state is observed. This information may also be indicated as information about the link (Enabled Link) enabled by the Single RF Non-AP MLD when the Single RF Non-AP MLD is connected to the AP MLD that is the sender of this signal. This information may also be indicated as information about the link on which the Non-AP MLD performs reception processing for the signal addressed to the broadcast when a Configured Link is set.

[0101] The Sounding Timeout field contains information about the timeout period during which the AP MLD that is the source of this signal waits for the right to transmit on another link and, if exceeded, stops sounding. This information may contain numerical information based on a predetermined time unit. This information may also contain information about the time unit. This information may also contain information about the link that set the timeout or the link that manages the timeout.

[0102] The STA Info field includes information about the identifier of the Non-AP MLD to be sounded. The STA Info field may be repeated the same number of times as the number of Non-AP MLDs to be sounded. This information may be an identifier of a Non-AP entity within the Non-AP MLD. This information may be an Association Identifier (AID) specified in IEEE 802.11. The STA Info field may include information about resource allocation for a Test signal to be transmitted by the Non-AP MLD to be sounded on the link on which the Sounding Announcement signal is transmitted. This resource allocation information may include information about an index of a known orthogonal matrix, information about a frequency interleaving index, and information about an OFDMA Resource Unit (RU). This resource allocation information may include information about transmission parameters of the Test signal to be transmitted by the Non-AP MLD to be sounded. This transmission parameter information may be information about a Modulation and Coding Scheme (MCS).

[0103] The Padding field contains information about adjusting the length of the frame.

[0104] The FCS (Frame Check Sequence) field contains information about error correction.

[0105] An example of the frame format of the Sounding Trigger signal is shown in Figure 7. Each field of the illustrated frame will be explained below.

[0106] The Frame Control field contains information about the settings of the Sounding Trigger signal.

[0107] The explanation of the Duration, RA, and TA fields is the same as that of the Sounding Announcement signal described above.

[0108] The Common Info field contains information for all Non-AP MLDs that are sounding targets. The Common Info field includes the Sounding ID field and the Report Request Info field.

[0109] The Sounding ID field contains information about the sounding identifier.

[0110] The Report Request Info field contains information about a request for transmission of a test signal by Non-AP MLD on a link other than the link on which the Sounding Trigger signal was transmitted, which is the target of sounding. This information includes information about the link on which the test signal transmission is requested.

[0111] The User Info field contains information for each Non-AP MLD to be sounded. The User Info field may be repeated for each Non-AP MLD to be sounded. Each User Info field contains a User Identifier field and a Resource Allocation field.

[0112] The User Identifier field contains information about the identifier of the Non-AP MLD to be sounded. This information may be the identifier of a Non-AP entity within the Non-AP MLD. This information may be the AID specified in IEEE 802.11.

[0113] The Resource Allocation field may include information regarding the allocation of resources used by the corresponding Non-AP MLD to transmit a Test signal. This resource allocation information may include information regarding an index of a known orthogonal matrix, information regarding an index of frequency interleaving, and information regarding an OFDMA RU. This resource allocation information may include information regarding transmission parameters of the Test signal transmitted by the corresponding Non-AP MLD. This transmission parameter information may be information regarding a modulation and coding scheme (MCS).

[0114] The explanation of the Padding and FCS fields is the same as for the Sounding Announcement signal.

[0115] An example of a frame format of a test signal is shown in Figure 8. Each field of the frame shown in the figure will be explained below. This frame format is modulated by OFDM (Orthogonal Frequency Division Multiplexing).

[0116] The Legacy Short Training Field (L-STF) and the Legacy Long Training Field (L-LTF) are known fixed symbols that are backward compatible.

[0117] The L-SIG (Legacy Signal field) is a notification field for this frame information that is backward compatible. The U-SIG (Universal Signal field) is a notification field for this frame information that is forward compatible. The EHT-SIG (Extremely High Throughput Signal field) is a notification field for this frame information. The information stored in these notification fields may include information indicating that it is a Signal signal of a Test signal.

[0118] EHT-STF is a known fixed symbol. EHT-LTF-1 to EHT-LTF-N are symbols obtained by multiplying the known fixed symbol by elements of a certain row in a known N×M (where N and M are integers and M≧N) orthogonal matrix Q. The rows of this orthogonal matrix Q are determined by information about the index of the known orthogonal matrix specified in the Sounding Announcement signal or Sounding Trigger signal. When row i is specified by this information, EHT-LTF-1 multiplies Q by the known fixed symbol. i,1 and EHT-LTF-N is multiplied by Q for a known fixed symbol. i,N is multiplied. i,j is the element in row i and column j of the orthogonal matrix Q. This makes it possible to multiplex N symbols. EHT-LTF-1 to EHT-LTF-N are transmitted across the entire frequency band used by this frame. Therefore, the communication device (AP MLD) that receives the Test signal separates EHT-LTF-1 to EHT-LTF-N through signal processing, and can obtain the received signal strength across the entire frequency band for each of the multiple communication devices that transmitted the Test signals.

[0119] Furthermore, among the OFDM subcarriers constituting the frame shown in Fig. 8, power may be superimposed only on subcarriers determined based on information about the frequency interleaving index specified in the Sounding Announcement signal or the Sounding Trigger signal. For example, by assigning odd-numbered subcarriers and even-numbered subcarriers to different communication devices, the communication device (AP MLD) that receives the test signal can estimate the received signal strength across the entire frequency band between the two communication devices that transmitted the test signals.

[0120] The Payload field includes information about the transmission power of each communication device that transmitted the Test signal. The Payload field may also include information about the buffer status of Non-AP MLD (in other words, the amount of data to be transmitted that each communication device that transmitted the Test signal has). The Payload field is transmitted by N communication devices using RUs designated based on the OFDMA RUs designated in the Sounding Announcement signal or the Sounding Trigger signal. In the example shown in FIG. 8, the Payload field is divided into N parts in the frequency direction and assigned to user areas (User signal area-1 to User signal area-N) of the N communication devices. Information about the transmission power of the Test signal transmitted from the corresponding communication device is stored in each user area.

[0121] By using the frame format shown in Figure 8 for the test signal, a communication device (AP MLD) that receives this test signal can calculate the inverse matrix of Q for the multiplexed signal by using the orthogonal matrix Q, and can separate the signals transmitted by the multiple communication devices using the index of the orthogonal matrix Q that it has assigned, the frequency interleaving index, and information about the OFDMA RUs. As a result, the communication device (AP MLD) that receives the test signal can obtain the received signal strength characteristics across the entire frequency band between the multiple communication devices that transmitted the test signals and the transmission power of each communication device. Therefore, it can calculate the path loss across the entire frequency band between the multiple communication devices that transmitted the test signals.

[0122] D-3. Operation of communication equipment during uplink sounding In this section, the operation of each communication device when performing uplink sounding will be described.

[0123] FIG. 9 shows in the form of a flowchart the processing steps executed by the AP MLD when performing uplink sounding.

[0124] First, the AP MLD decides to perform sounding of the uplink based on a sounding request from the AP entity or based on the AP MLD's own decision (step S901).

[0125] Next, the AP MLD determines sounding parameters and links on which sounding is to be started, and notifies the AP entities corresponding to each link on which sounding is to be started (step S902).

[0126] Then, when the corresponding AP entity acquires the transmission right for the link for which it has been decided to start sounding (Yes in step S903), the AP entity transmits a Sounding Announcement signal indicating that uplink sounding will start (step S904).

[0127] Furthermore, when the corresponding AP entity acquires the transmission right on another link (Yes in step S905), the AP MLD checks whether the Sounding Timeout has been exceeded (step S906). If the Sounding Timeout has been exceeded (Yes in step S906), the AP MLD ends this process.

[0128] If the Sounding Timeout has not expired (No in step S906), the AP entity that acquired the transmission right in step S905 transmits a Sounding Trigger signal on the link for which it acquired the transmission right (step S907). After that, each AP entity receives the Test signal induced by the Sounding Trigger signal by the Non-AP MLD on its corresponding link (step S908).

[0129] Then, based on the information of the test signal received from each AP entity, the AP MLD calculates information about the propagation loss with each non-AP MLD, determines resource allocation for UL MU communication (step S909), and ends this process. Note that, based on the observation results of the channel state of each link, the AP MLD may request the Single RF non-AP MLD to change the Enabled Link, or request the non-AP MLD that sets the Configured Link to change the Configured Link.

[0130] Furthermore, other links attempt to acquire the transmission right on the corresponding link (step S905) until the Sounding Timeout is exceeded (No in step S910). If the Sounding Timeout is exceeded (Yes in step S910) without the AP entity acquiring the transmission right on the other link (No in step S905), the AP MLD ends this process.

[0131] FIG. 10 shows in the form of a flowchart the processing steps executed by Non-AP MLD when uplink sounding is performed.

[0132] When a non-AP entity receives a Sounding Announcement signal from the AP MLD to which it is connected via any link (step S1001), the Non-AP MLD checks whether it has set a link for receiving signals addressed to broadcast, i.e., a Configured Link (step S1002). If a Configured Link has been set (Yes in step S1002), the Non-AP MLD sets the Configured Link so that subsequent signals addressed to broadcast will be received via another link (step S1003).

[0133] Then, when the Non-AP MLD receives a Sounding Trigger signal from the AP MLD on another link (step S1004), it transmits a Test signal from each non-AP entity to each link based on the information in the Sounding Trigger signal (step S1005), and then terminates this process.

[0134] FIG. 11 shows, in the form of a flowchart, the processing procedure executed by Single RF Non-AP MLD when uplink sounding is performed.

[0135] When the corresponding non-AP entity in the Enabled Link receives a Sounding Announcement signal from the AP MLD to which it is connected (step S1101), the Single RF non-AP MLD changes the Enabled Link to another link so that subsequent signals can be received on the other link (step S1102).

[0136] Then, when the corresponding non-AP entity receives a Sounding Trigger signal in the changed Enabled Link (step S1103), the Single RF non-AP MLD transmits a Test signal from the Enable Link based on the information in the Sounding Trigger signal (step S1104).

[0137] Thereafter, the Single RF non-AP MLD changes the Enabled Link to the original link (step S1105), and transmits a Test signal from the Enable Link based on the information of the Sounding Trigger signal (step S1104), thereby terminating this process.

[0138] D-4. Down Ring Sounding Next, an embodiment relating to downlink sounding will be explained for the above cases (1) to (3).

[0139] Figure 12 shows an example of a communication sequence for performing downlink sounding in case (1) where a Non-AP MLD is connected to an AP MLD. Here, the communication system shown in Figure 1 is assumed, and Non-AP MLD1 and Non-AP MLD2, which support MLO, are both connected to the AP MLD via Link 1 and Link 2.

[0140] 12 is the time axis, and shows the communication operations over time on each link of AP MLD, Non-AP MLD1, and Non-AP MLD2. Square blocks drawn with solid lines indicate the corresponding communication device, link, and transmitted frame at that time, and vertical solid arrows indicate the transmission of frames to their destinations.

[0141] Before starting this communication sequence, it is confirmed that the AP MLD, Non-AP MLD1, and Non-AP MLD2 support MLO and the sounding method shown in Fig. 12. Furthermore, before starting this communication sequence, the AP MLD, Non-AP MLD1, and Non-AP MLD2 may perform calibration to correct errors in their transmission and reception circuits. This calibration may be performed based on the calibration procedure specified in IEEE802.11.

[0142] When the AP MLD acquires the transmission right on Link 1, it transmits a Sounding Announcement signal on Link 1 that includes information about the start of downlink sounding. Note that the AP MLD may transmit a signal indicating that it has acquired the transmission right before the Announcement signal. This signal may be an RTS frame or a CTS frame specified in IEEE 802.11. The CTS frame may be a CTS-to-self frame sent to itself. The signal indicating that it has acquired the transmission right causes surrounding communication terminals to suppress communication.

[0143] The AP MLD transmits a Sounding Announcement signal to a broadcast destination. The Sounding Announcement signal used in downlink sounding may include information about a sounding identifier, information about the transmission link of a subsequent Sounding Trigger signal or Sounding Announcement signal transmitted by the AP MLD, information about the time until transmission of an NDP signal on another link begins, information about the timeout period during which the AP MLD waits for acquisition of a transmission right on another link and starts transmitting an NDP signal if the timeout period is exceeded, information about the timeout period during which the AP MLD waits for acquisition of a transmission right on another link and stops sounding if the timeout period is exceeded, information about the identifier of the Non-AP MLD to be sounded, and information about resource allocation for a Report signal to be transmitted by the Non-AP MLD to be sounded on the link on which the Sounding Announcement signal is transmitted. Details of the Sounding Announcement signal used in downlink sounding will be described later.

[0144] When Non-AP MLD1 and Non-AP MLD2 receive a Sounding Announcement signal from the AP MLD on Link 1, they suppress transmissions other than this sounding.

[0145] Next, the AP MLD acquires the transmission right on Link 2 and transmits an NDP Announcement signal on Link 2 indicating that it will transmit an NDP signal. Although not shown in FIG. 12, the AP MLD may transmit a signal indicating that it has acquired the transmission right before the NDP Announcement signal. The NDP Announcement signal may be a Sounding Announcement signal or an NDP Announcement signal specified in IEEE802.11. The NDP signal is a signal that includes only known fixed symbols and does not include data in the payload.

[0146] When Non-AP MLD1 and Non-AP MLD2 receive an NDP Announcement signal from the AP MLD on Link 2, they suppress transmissions other than this sounding.

[0147] In addition, if there are three or more links available for MLO in the assumed communication system, the AP MLD may transmit a Sounding Announcement signal over multiple links and transmit an NDP Announcement signal indicating that a Sounding Announcement signal or an NDP signal will be transmitted over the last link.

[0148] Furthermore, if the AP MLD can acquire transmission rights simultaneously on multiple links, the AP MLD may transmit one or more Sounding Announcement signals and one or more NDP Announcement signals simultaneously on each link.

[0149] AP MLD transmits a Sounding Announcement signal and an NDP Announcement signal via Link 1 and Link 2, respectively, and then simultaneously transmits an NDP signal via Link 1 and Link 2. AP MLD may transmit an NDP signal after a fixed time or after a SIFS interval from the completion of transmission of the last Sounding Announcement signal or NDP Announcement signal.

[0150] When Non-AP MLD1 and Non-AP MLD2 receive an NDP signal from the AP MLD on Link1 and Link2, they observe the signal reception strength or channel state based on the reception result.

[0151] After transmitting an NDP signal on Link 1 and Link 2, the AP MLD transmits a Sounding Trigger signal that triggers the transmission of a Report signal to report the sounding results. Although not shown in FIG. 12, the AP MLD may transmit a signal (described above) to acquire the transmission right before the Sounding Trigger signal. The AP MLD may transmit the Sounding Trigger signal simultaneously on both Link 1 and Link 2 as shown in FIG. 12, or may transmit it on only one of the links. The Sounding Trigger signal is transmitted as a broadcast signal. The Sounding Trigger signal may include information about the sounding identifier, information about a request for the transmission of a Report signal by the non-AP MLD that is the target of sounding on a link other than the link on which the Sounding Trigger signal was transmitted, information about the identifier of the non-AP MLD that is the target of sounding, and information about the resource allocation for the Report signal to be transmitted by the non-AP MLD that is the target of sounding. The Sounding Trigger signal may have the frame format shown in FIG. 7.

[0152] When Non-AP MLD1 and Non-AP MLD2 receive a Sounding Trigger signal from the AP MLD via Link 1 or Link 2, they transmit a Report signal on the link that received the Sounding Trigger signal, based on the information in the Sounding Announcement signal and the Sounding Trigger signal. In the example communication sequence shown in FIG. 12, the Sounding Trigger signal is transmitted via both Link 1 and Link 2, so Non-AP MLD1 and Non-AP MLD2 transmit Report signals on both links. Non-AP MLD1 and Non-AP MLD2 may transmit Report signals after a fixed time or after an SIFS interval from the completion of reception of the Sounding Trigger signal. Non-AP MLD1 and Non-AP MLD2 include information on the signal reception strength or channel state observed based on the reception result of the NDP signal from the AP MLD in the Report signal. Furthermore, Non-AP MLD1 and Non-AP MLD2 may include information on transmission power in the Report signal.

[0153] When the AP MLD receives Report signals from Non-AP MLD1 and Non-AP MLD2, it calculates the downlink path loss or channel matrix with each of Non-AP MLD1 and Non-AP MLD2 based on the signal reception strength or channel state stored in each Report signal. Furthermore, if each received Report signal contains information about the transmission power of Non-AP MLD1 and Non-AP MLD2, the AP MLD also calculates information about the uplink path loss with each of Non-AP MLD1 and Non-AP MLD2 from the information about the received signal strength and transmission power. Furthermore, the AP MLD may calculate weight information used by Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD when implementing UL MU-MIMO, based on information about calibration performed in advance and information stored in each received Report signal.

[0154] The AP MLD then determines resource allocation for UL and DL MU communications based on information about the channel matrix and path loss with each of the calculated Non-AP MLD1 and Non-AP MLD2.

[0155] The communication sequence shown in Figure 12 enables AP MLD to collect path loss data for multiple link bands while maintaining time correlation. AP MLD also enables resource allocation for MU communication that takes into account the path loss data for all links.

[0156] Figure 13 shows an example of a communication sequence for performing downlink sounding in case (2) where a Non-AP MLD and a Single RF Non-AP MLD are connected to an AP MLD. Here, the communication system shown in Figure 1 is assumed, and MLO-compatible Non-AP MLD1 and Non-AP MLD2 are both connected to the AP MLD via Link 1 and Link 2. Furthermore, the Single RF Non-AP MLD is connected to the AP MLD by switching the Enabled Link, which is the link that enables signal transmission and reception, between Link 1 and Link 2 as needed.

[0157] 13, the horizontal axis is the time axis, and shows the communication operation over time on each link of AP MLD, Non-AP MLD1 and Non-AP MLD2, and Single RF Non-AP MLD. The square blocks drawn with solid lines indicate the corresponding communication device, link, and transmitted frame at that time, and the vertical solid arrows indicate the transmission of frames to their destinations.

[0158] Before this communication sequence begins, it is confirmed that the AP MLD, Non-AP MLD1 and Non-AP MLD2, and Single RF Non-AP MLD support MLO and the sounding method shown in FIG. 13. Also, before this communication sequence begins, the AP MLD and Single RF Non-AP MLD share information about the Single RF Non-AP MLD's Enabled Link. In this communication sequence, it is assumed that the Single RF Non-AP MLD has set Link1 to Enabled Link. Also, before this communication sequence begins, the AP MLD, Non-AP MLD1 and Non-AP MLD2, and Single RF Non-AP MLD may perform calibration to correct errors in their respective transmission and reception circuits.

[0159] When the AP MLD acquires the transmission right on Link1, it transmits a Sounding Announcement signal on Link1 that includes information about the start of sounding.

[0160] When Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD receive a Sounding Announcement signal from the AP MLD on Link 1, they suppress transmissions other than this sounding.

[0161] Next, the AP MLD acquires the transmission right on Link2 and transmits a Sounding Announcement signal containing information about the start of sounding on Link2.

[0162] When Non-AP MLD1 and Non-AP MLD2 receive a Sounding Announcement signal from the AP MLD on Link 2, they suppress transmissions other than this sounding.

[0163] If there are three or more links available for MLO in the assumed communication system, the AP MLD may transmit the Sounding Announcement signal via multiple links and transmit the Sounding Announcement signal via the last link.

[0164] The AP MLD transmits a Sounding Announcement signal on Link 2, and then transmits an NDP signal on Link 1. If the assumed communication system has three or more links available for MLO, the AP MLD transmits a Sounding Announcement signal on the last link, and then transmits an NDP signal on Link 1.

[0165] When Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD receive an NDP signal from the AP MLD on Link 1, they observe the signal reception strength or channel state based on the reception result.

[0166] In addition, after receiving an NDP signal from AP MLD on Link 1, Single RF Non-AP MLD changes the Enabled Link from Link 1 to Link 2 based on information regarding the time until it starts transmitting an NDP signal on another link (Link 2) indicated in the Sounding Announcement signal.

[0167] After transmitting an NDP signal on Link 1, AP MLD waits until the time indicated in the Sounding Announcement signal regarding the start of transmission of an NDP signal on another link (Link 2) and then transmits the NDP signal on Link 2.

[0168] When Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD receive an NDP signal from the AP MLD on Link 2, they observe the signal reception strength or channel conditions based on the reception result.

[0169] After transmitting an NDP signal on Link 1 and Link 2, the AP MLD transmits a Sounding Trigger signal on Link 2 to induce the transmission of a Report signal for reporting the sounding result. Although not shown in Fig. 13, the AP MLD may transmit a signal (described above) to acquire the transmission right before the Sounding Trigger signal. The Sounding Trigger signal may have the frame format shown in Fig. 7.

[0170] When Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD receive a Sounding Trigger signal from the AP MLD, they transmit a Report signal on the link that received the Sounding Trigger signal, based on the information in the Sounding Announcement signal and the Sounding Trigger signal. Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD include in the Report signal information about the signal reception strength or channel state observed based on the reception result of the NDP signal from the AP MLD. Furthermore, Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD may include information about transmission power in the Report signal.

[0171] 13, a Sounding Trigger signal is transmitted on Link 2, so Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD transmit Report signals on Link 2. Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD may transmit Report signals after a fixed time or after an SIFS interval from the completion of reception of the Sounding Trigger signal.

[0172] When the AP MLD receives Report signals from Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD, it calculates the downlink path loss or channel matrix with each of Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD based on the signal reception strength or channel condition stored in each Report signal. Furthermore, if each received Report signal contains information about the transmission power of Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD, the AP MLD also calculates information about the uplink path loss with each of Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD from the information about the received signal strength and transmission power. In addition, AP MLD may calculate weight information to be used when Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD perform UL MU-MIMO based on information from calibration performed in advance and information stored in each received Report signal.

[0173] The AP MLD then determines resource allocation for UL and DL MU communication based on information about the channel matrix and path loss with each of the calculated Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD.

[0174] If, at the time of this decision, it is necessary to change the enabled link of the Single RF Non-AP MLD, the AP MLD may transmit a signal to the Single RF Non-AP MLD requesting a change of the enabled link. For example, if, as a result of observing the channel state, it is found that the channel state between the AP and the Single RF Non-AP MLD is better for Link 1 than for Link 2, the AP MLD transmits a signal to the Single RF Non-AP MLD requesting that it switch the enabled link to Link 1.

[0175] The signal requesting change of the enabled link includes information about the enabled link after the change, and may further include information about the reason for the change request. Furthermore, if the AP MLD calculates weight information for UL MU-MIMO, the signal requesting change may include the weight information. The weight information may be information equivalent to the Compressed Beamforming Report specified in IEEE 802.11.

[0176] The communication sequence shown in Figure 13 enables the AP MLD to collect path loss data for multiple link bands while maintaining time correlation, even in case (2) where the AP MLD is connected to the Non-AP MLD and the Single RF Non-AP MLD. Furthermore, the AP MLD can allocate resources for MU communication taking into account the path loss data for all links.

[0177] Figure 14 shows an example of a communication sequence for performing downlink sounding in case (3) where a Configured Link is set. Here, the communication system shown in Figure 1 is assumed, and Non-AP MLD1 and Non-AP MLD2 that support MLO are both connected to the AP MLD via Link 1 and Link 2.

[0178] 14 is the time axis, and shows the communication operation over time on each link of AP MLD, Non-AP MLD1, and Non-AP MLD2. Square blocks drawn with solid lines indicate the corresponding communication device, link, and transmitted frame at that time, and vertical solid arrows indicate the transmission of frames to their destinations.

[0179] Before starting this communication sequence, the AP MLD, Non-AP MLD1, and Non-AP MLD2 confirm that they support MLO and the sounding method shown in Fig. 14. Also, before starting this communication sequence, the AP MLD, Non-AP MLD1, and Non-AP MLD2 confirm information about the Configured Link, which is the link that receives and processes signals addressed to broadcasts. In the example communication sequence shown in Fig. 5, it is assumed that Non-AP MLD1 sets Link1 as the Configured Link, and Non-AP MLD2 sets Link2 as the Configured Link. Also, before starting this communication sequence, the AP MLD, Non-AP MLD1, and Non-AP MLD2 may perform calibration to correct errors in their transmission and reception circuits.

[0180] When the AP MLD acquires the transmission right on Link1, it transmits a Sounding Announcement signal on Link1 that includes information about the start of sounding.

[0181] Non-AP MLD1, which has Link1 set as the Configured Link, receives a Sounding Announcement signal from the AP MLD, and sets Link2, which is not a Configured Link, to receive and process signals addressed to broadcasts based on information about the transmission link of the subsequent Sounding Trigger signal or Sounding Announcement signal sent by the AP MLD notified by this signal.Non-AP MLD1 also suppresses communications other than this sounding.

[0182] Furthermore, Non-AP MLD2, which has Link2 set as the Configured Link, may receive a Sounding Announcement signal from the AP MLD and stop receiving the signal when it confirms that the destination address of this signal is a broadcast address.Non-AP MLD2 also suppresses communications other than this sounding.

[0183] Next, the AP MLD acquires the transmission right on Link 2 and transmits a signal indicating that it will transmit an NDP signal on Link 2. The signal indicating that it will transmit an NDP signal may be a Sounding Announcement signal or an NDP Announcement signal specified in IEEE 802.11. In the example shown in Fig. 14, a Sounding Announcement signal is used.

[0184] Non-AP MLD1 and Non-AP MLD2 receive a signal indicating that an NDP signal is to be transmitted on Link2, and suppress communications other than this sounding.

[0185] In addition, if there are three or more links available for MLO in the assumed communication system, the AP MLD may transmit a Sounding Announcement signal over multiple links and a signal indicating that an NDP signal will be transmitted over the last link.

[0186] After transmitting a signal indicating that an NDP signal is to be transmitted on Link 1 and Link 2, AP MLD transmits the NDP signal at the same timing on Link 1 and Link 2. AP MLD may transmit the NDP signal after a fixed time or after a SIFS interval from the completion of transmission of the last transmitted Sounding Announcement signal or a signal indicating that an NDP signal is to be transmitted.

[0187] When Non-AP MLD1 and Non-AP MLD2 receive an NDP signal from the AP MLD on Link1 and Link2, they observe the signal reception strength or channel state based on the reception result.

[0188] After transmitting an NDP signal on Link 1 and Link 2, the AP MLD transmits a Sounding Trigger signal that induces the transmission of a Report signal for reporting the sounding results. Although not shown in FIG. 14, the AP MLD may transmit a signal (described above) to acquire the transmission right before the Sounding Trigger signal. The AP MLD may transmit the Sounding Trigger signal simultaneously on both Link 1 and Link 2 as shown in FIG. 14, or may transmit it on only one of the links. The Sounding Trigger signal is transmitted with a broadcast address. The Sounding Trigger signal may have the frame format shown in FIG. 7.

[0189] When Non-AP MLD1 and Non-AP MLD2 receive a Sounding Trigger signal from the AP MLD via Link 1 or Link 2, they transmit a Report signal on the link that received the Sounding Trigger signal, based on the information in the Sounding Announcement signal and the Sounding Trigger signal. In the example communication sequence shown in FIG. 14, the Sounding Trigger signal is transmitted via both Link 1 and Link 2, so Non-AP MLD1 and Non-AP MLD2 transmit Report signals on both links. Non-AP MLD1 and Non-AP MLD2 may transmit Report signals after a fixed time or after an SIFS interval from the completion of reception of the Sounding Trigger signal. Non-AP MLD1 and Non-AP MLD2 include information on the signal reception strength or channel state observed based on the reception result of the NDP signal from the AP MLD in the Report signal. Furthermore, Non-AP MLD1 and Non-AP MLD2 may include information on transmission power in the Report signal.

[0190] When the AP MLD receives Report signals from Non-AP MLD1 and Non-AP MLD2, it calculates the downlink path loss or channel matrix with each of Non-AP MLD1 and Non-AP MLD2 based on the signal reception strength or channel state stored in each Report signal. Furthermore, if each received Report signal contains information about the transmission power of Non-AP MLD1 and Non-AP MLD2, the AP MLD also calculates information about the uplink path loss with each of Non-AP MLD1 and Non-AP MLD2 from the information about the received signal strength and transmission power. Furthermore, the AP MLD may calculate weight information used by Non-AP MLD1, Non-AP MLD2, and Single RF Non-AP MLD when implementing UL MU-MIMO, based on information about calibration performed in advance and information stored in each received Report signal.

[0191] The AP MLD then determines resource allocation for UL and DL MU communication based on the calculated channel matrices and path loss information for each of the Non-AP MLD1 and Non-AP MLD2. If this determination requires a change to the Configured Link set by Non-AP MLD1 or Non-AP MLD2, the AP MLD may send a signal to Non-AP MLD1 or Non-AP MLD2 requesting a change to the Configured Link. For example, if the observed channel conditions show that Link 1 is better than Link 2 for the channel conditions between the AP and Non-AP MLD2, the AP MLD sends a signal to Non-AP MLD2 requesting that Non-AP MLD2 switch the Configured Link to Link 1.

[0192] The Configured Link change request signal includes information about the changed Configured Link, but may also include information about the reason for the change request. Furthermore, if the AP MLD calculates UL MU-MIMO weight information, this signal may also include the weight information. The weight information may be information equivalent to the Compressed Beamforming Report specified in IEEE 802.11.

[0193] The communication sequence shown in Figure 14 enables AP MLD to collect path loss data for multiple link bands while maintaining time correlation, and also enables AP MLD to allocate resources for UL and DL MU communication taking into account the path loss data for all links.

[0194] D-5. Frame format of the signal used for downlink sounding This section explains the frame format of the signals used in the communication sequence for downlink sounding. The frame format of the signals used in uplink sounding has already been explained in Section D-2. Signals that use the same frame format for downlink sounding as for signals used in uplink sounding will not be explained here.

[0195] An example of the frame format of a Sounding Announcement signal used in downlink sounding is shown in Fig. 15. Each field of the illustrated frame will now be described.

[0196] The explanation of the Frame Control, Duration, RA, and TA fields is the same as that of the Sounding Announcement signal shown in FIG.

[0197] The Sounding Control field includes information regarding notification of sounding according to the present disclosure. This information may be included in the Frame Control field. This information may include information indicating that the time interval between the transmission of the Sounding Announcement signal and the transmission of the NDP signal and the Report signal is not a fixed time interval, is not a SIFS interval, or is delayed sounding.

[0198] The explanation of the Sounding ID and Succeeding Link fields is the same as that of the Sounding Announcement signal shown in FIG.

[0199] The NDP Offset Time field contains information about the offset time from when the AP MLD that is the source of the Sounding Announcement signal transmits an NDP signal on the link that transmitted the Sounding Announcement signal until when it starts transmitting an NDP signal on another link. This information may contain numerical information based on a predetermined time unit. This information may also contain information about the time unit. This information may also contain information about the link that set the timeout or the link that manages the timeout.

[0200] The NDP Tx Timeout field contains information about the timeout period during which the AP MLD, which is the sender of the Sounding Announcement signal, waits for the acquisition of the transmission right on another link, and if the timeout period expires, starts transmitting NDP on the link that sent the Sounding Announcement signal. This information may be determined based on information about the transition (change of enabled link) notified by the Single RF non-AP MLD. This information may contain numerical information based on a predetermined time unit. This information may also include information about the time unit. The information may also include information about the link that set the timeout or the link that manages the timeout.

[0201] The explanation of the STA Info, Padding, and FCS fields is the same as that of the Sounding Announcement signal shown in FIG.

[0202] The frame format of the Sounding Trigger signal used in downlink sounding is the same as the frame format of the Sounding Trigger signal used in uplink sounding, as shown in Fig. 7. However, the information included in the Resource Allocation field is information regarding resource allocation for the Report signal transmitted by the non-AP MLD.

[0203] The frame format of the Report signal used in downlink sounding is the same as the frame format of the Test signal used in uplink sounding shown in Fig. 8. However, in the Payload field, the fields (User signal area-1 to User signal area-N) multiplexed by frequency division store NDP observation information in each Non-AP MLD and Single RF non-AP MLD, or NDP observation information and information on transmit power. The NDP observation information may be information on received signal strength, or may be information equivalent to the Compressed Beamforming Report specified in IEEE802.11. Furthermore, if Non-AP MLD transmit power information is not included, EHT-LTF-1 to EHT-LTF-N may be omitted.

[0204] D-6. Downlink Sounding Communication Sequence The communication sequence in downlink sounding can also be expressed as follows:

[0205] The EHT beamformer initiates the sounding feedback sequence by transmitting an EHT NDP Announcement frame followed by an EHT NDP after a SIFS interval.

[0206] The EHT beamformer includes a STA Info field in the EHT NDP Announcement frame corresponding to each EHT beamformee from which Compressed Beamforming feedback is expected to be transmitted, and identifies the EHT beamformee by including the EHT beamformee's AID in the STA Info field.

[0207] The EHT NDP Announcement frame includes at least one STA Info field. The EHT NDP frame is transmitted either SIFS after the completion of transmission of the EHT NDP Announcement frame or at a timing specified in the EHT NDP Announcement frame.

[0208] D-7. Operation of communication equipment during downlink sounding In this section, the operation of each communication device when performing downlink sounding will be described.

[0209] 16 and 17 are flowcharts showing the processing steps executed by the AP MLD when performing downlink sounding.

[0210] First, the AP MLD decides to perform sounding of the uplink based on a sounding request from the AP entity or based on the AP MLD's own decision (step S1601).

[0211] Next, the AP MLD determines sounding parameters and links on which sounding is to be started, and notifies the AP entities corresponding to each link on which sounding is to be started (step S1602).

[0212] Then, when the corresponding AP entity acquires the transmission right for the link for which it has been decided to start sounding (Yes in step S1603), the AP entity transmits a Sounding Announcement signal indicating that it will start downlink sounding (step S1604).

[0213] Furthermore, when the corresponding AP entity acquires the transmission right on another link (Yes in step S1605), the AP MLD checks whether the NDP Tx Timeout has been exceeded (step S1606). If the NDP Tx Timeout has been exceeded (Yes in step S1606), the AP MLD ends this process.

[0214] If the NDP Tx Timeout has not been exceeded (No in step S1606), the AP entity that obtained the transmission right in step S1605 transmits a signal indicating NDP transmission on the link for which the transmission right has been obtained (step S1607).

[0215] Here, it is checked whether a Single RF non-AP MLD is connected to the AP MLD (step S1608).

[0216] If a Single RF non-AP MLD is not connected to the AP MLD (No in step S1608), each AP entity of the AP MLD transmits an NDP signal on its corresponding link (step S1616), and then each AP entity of the AP MLD transmits a Sounding Trigger signal on its corresponding link (step S1617).

[0217] On the other hand, if a Single RF non-AP MLD is connected to the AP MLD (Yes in step S1608), the AP entity that first transmitted the Sounding Announcement signal transmits an NDP signal on the ring corresponding to itself (step S1609). Then, when the NDP offset time has elapsed (Yes in step S1610), another AP entity in the AP MLD transmits an NDP signal on another link (step S1611), and that AP entity then transmits a Sounding Trigger signal on the same link (step S1612). Furthermore, the AP entity that first transmitted the Sounding Announcement signal transmits a Sounding Trigger signal on the ring corresponding to itself (step S1613).

[0218] When each AP entity transmits a Sounding Trigger signal on each link in steps S1612 and S1613, or step S1617, each AP entity receives a Report signal on its corresponding link (step S1614). Then, the AP MLD determines resource allocation for UL and DL MU communication based on the information in the Report signal received by each AP entity (step S1615), and terminates this processing. Note that the AP MLD may request a Single RF non-AP MLD to change the Enabled Link, or a non-AP MLD that sets a Configured Link to change the Configured Link, based on the channel state of each link determined based on the received Report signal.

[0219] Furthermore, other links attempt to acquire the transmission right on the corresponding links (step S1605) until the NDP Tx Timeout is exceeded (No in step S1618). If the NDP Tx Timeout is exceeded (Yes in step S1618) without the AP entity acquiring the transmission right on the other links (No in step S1605), the AP MLD ends this process.

[0220] FIG. 18 shows, in the form of a flowchart, the processing procedure executed by Non-AP MLD when performing downlink sounding.

[0221] When a non-AP entity receives a Sounding Announcement signal from the AP MLD to which it is connected via any link (step S1801), the Non-AP MLD checks whether it has set a link for receiving signals addressed to broadcast, i.e., a Configured Link (step S1802). If a Configured Link has been set (Yes in step S1802), the Non-AP MLD sets the Configured Link so that subsequent signals addressed to broadcast will be received via another link (step S1803).

[0222] Then, after receiving a Sounding Announcement signal from the AP MLD on another link (step S1804), each non-AP entity receives an NDP signal on its corresponding link and observes the signal reception strength or channel state based on the reception result (step S1805).

[0223] Thereafter, when the non-AP entity receives a Sounding Trigger signal that triggers the transmission of a Report signal for reporting the sounding results on each link (step S1806), it transmits a Report signal on the link on which the Sounding Trigger signal was received based on the information in the Sounding Announcement signal and the Sounding Trigger signal (step S1807), and then terminates this processing.

[0224] FIG. 19 shows, in the form of a flowchart, the processing procedure executed by Single RF Non-AP MLD when performing downlink sounding.

[0225] In the Single RF non-AP MLD, after the corresponding non-AP entity in the Enabled Link receives a Sounding Announcement signal from the AP MLD to which it is connected (step S1901), the corresponding non-AP entity in the Enabled Link receives an NDP signal from the AP MLD to which it is connected, and observes the signal reception strength or channel state based on the reception result (step S1902).

[0226] Next, based on the information indicated in the Sounding Announcement signal regarding the time until the transmission of the NDP signal begins on another link, the Single RF non-AP MLD changes the Enabled Link to another link so as to meet that time (step S1903).

[0227] Then, the Single RF non-AP MLD receives an NDP signal from the AP MLD to which the corresponding non-AP entity in the changed Enabled Link is connected, and observes the signal reception strength or channel condition based on the reception result (step S1904).

[0228] Thereafter, when the Single RF non-AP MLD receives a Sounding Trigger signal that induces the transmission of a Report signal for reporting the sounding results on the changed Enabled Link (step S1905), it transmits a Report signal on the link on which the Sounding Trigger signal was received based on the information in the Sounding Announcement signal and the Sounding Trigger signal (step S1906), and then terminates this processing. [Industrial Applicability]

[0229] Although the present disclosure has been described in detail above with reference to specific embodiments, it is obvious that those skilled in the art can make modifications or substitutions to the embodiments without departing from the spirit and scope of the present disclosure.

[0230] For example, by applying the present disclosure to a wireless LAN system conforming to the IEEE802.11 standard, it becomes possible to observe the channel state to acquire channel characteristics with high time correlation, thereby realizing high throughput. Of course, the same effect can be achieved even when the present disclosure is applied to a wireless system conforming to another communication standard.

[0231] In short, the present disclosure has been described in the form of examples, and the contents of the specification should not be interpreted as limiting. To determine the gist of the present disclosure, the claims should be taken into consideration.

[0232] The present disclosure may also be configured as follows.

[0233] (1) A communication device that performs wireless communication using multiple links, a first transmitter configured to transmit a first signal including information regarding a start of observation of channel conditions on some of the plurality of links; a second transmitter configured to transmit a second signal inducing a signal including information regarding observation of channel conditions on one or more of the plurality of links; A communication device comprising:

[0234] (2) the first signal includes information about the link on which the observation is performed; The communication device according to (1) above.

[0235] (3) the first signal includes information about a third signal for other communication devices to observe channel conditions; The communication device according to (1) above.

[0236] (4) transmitting the third signal simultaneously over two or more links; The communication device according to (3) above.

[0237] (5) transmitting the third signal at different timings over two or more links; The communication device according to (3) above.

[0238] (6) The second signal is a signal that induces a fourth signal for the communication device itself to observe a channel state. A communication device according to either (1) or (2) above.

[0239] (7) determining resource allocation for multi-user communication based on information about a channel state observed by the communication device itself from the fourth signal transmitted from another communication device in response to the second signal; The communication device according to (6) above.

[0240] (8) The second signal is a signal that induces a fifth signal including information about a channel state observed by another communication device. A communication device according to any one of (1), (3) to (5) above.

[0241] (9) determining resource allocation for multi-user communication based on information about channel conditions collected from the fifth signal transmitted by the other communication device in response to the second signal; The communication device according to (8) above.

[0242] (10) requesting another communication device to change the link for transmission and reception based on the information about the channel state; A communication device according to either (7) or (9) above.

[0243] (11) requesting other communication devices to change the link for receiving signals addressed to the broadcast based on the information about the channel state; A communication device according to either (7) or (9) above.

[0244] (12) A communication method for wireless communication using a plurality of links, a first transmitting step of transmitting a first signal including information regarding a start of observation of a channel state on a part of the plurality of links; a second transmitting step of transmitting a second signal that induces a signal containing information regarding observation of channel conditions on one or more of the plurality of links; A communication method comprising:

[0245] (13) A communication device that performs wireless communication using a plurality of links, transmitting a signal containing information regarding the observation of channel conditions on one or more of the plurality of links; Communication equipment.

[0246] (14) a first receiving unit that receives a first signal including information regarding a start of observation of a channel state on a part of the plurality of links; a second receiver configured to receive a signal inducing a second signal including information regarding observation of channel conditions on one or more of the plurality of links; Equipped with transmitting a signal including information regarding the observation of the channel condition in response to the first signal and the second signal; The communication device according to (13) above.

[0247] (15) The signal including information regarding the observation of the channel state is a fourth signal for another communication device to observe the channel state. The communication device according to any one of (13) and (14) above.

[0248] (16) The signal including information about the channel state is a fifth signal including information about the channel state observed by the communication device itself. The communication device according to any one of (13) and (14) above.

[0249] (17) The signal containing information about the channel state contains information about the transmission power of the signal. A communication device according to any one of (13) to (16) above.

[0250] (18) Changing the link for transmission and reception based on a request from the sender of the first signal or information included in the first signal. A communication device according to any one of (13) to (17) above.

[0251] (19) Changing a link for receiving a signal addressed to broadcast based on a request from a sender of the first signal or information included in the first signal. A communication device according to any one of (13) to (17) above.

[0252] (20) A communication method for wireless communication using a plurality of links, A method of communications comprising transmitting a signal containing information relating to observation of channel conditions on one or more of the plurality of links. [Explanation of symbols]

[0253] 200... communication device, 210... communication unit, 211... communication control unit 212...communication storage unit, 213...common data processing unit 214... individual data processing unit, 215... signal processing unit 216...wireless interface unit, 217...amplifier unit, 220...control unit 230...storage unit, 240...antenna

Claims

1. A communication device that performs wireless communication using a plurality of links, controlling transmission of a first signal to initiate monitoring of a channel condition on a first link among the plurality of links; Controlling transmission of a second signal, which induces a signal including information about observation of a channel state on the first link to two or more first other communication devices specified in the first signal, within a period acquired by the first signal; transmitting, within a period acquired by the first signal, a third signal that induces two or more second other communication devices designated by the first signal to transmit a signal including information about observation of a channel state on the first link; A communication device having a control unit that performs the above.

2. the first signal includes first information indicating the first other communication device and second information indicating the second other communication device; The communication device according to claim 1 .

3. the second signal includes the first information and the third signal includes the second information; The communication device according to claim 2 .

4. the first signal includes information about the link on which the observation is performed; The communication device according to claim 1 .

5. the first signal includes information regarding a sixth signal for other communication devices to observe channel conditions; The communication device according to claim 1 .

6. transmitting the sixth signal simultaneously over two or more links; The communication device according to claim 5 .

7. transmitting the sixth signal at different timings over two or more links; The communication device according to claim 5 .

8. the second signal is a signal that induces a fourth signal for the communication device itself to observe a channel state; The communication device according to claim 1 .

9. determining resource allocation for multi-user communication based on information on channel conditions observed by the communication device itself from the fourth signals transmitted from the first other communication device and the second other communication device in response to the second signal and the third signal; The communication device according to claim 8.

10. the second signal and the third signal are signals that induce a fifth signal that includes information about channel conditions observed by the first other communication device and the second other communication device. The communication device according to claim 1 .

11. determining resource allocation for multi-user communication based on information about channel conditions collected from the fifth signals transmitted by the first other communication device and the second other communication device in response to the second signal and the third signal; The communication device according to claim 10.

12. requesting the first other communication device and the second other communication device to change a link for transmission and reception based on the information about the channel state; 12. A communication device according to claim 9 or 11.

13. requesting the first other communication device and the second other communication device to change a link for receiving a signal addressed to broadcast based on the information about the channel state; The communication device according to claim 9.

14. A communication method for wireless communication using a plurality of links, comprising: a first transmitting step of transmitting a first signal to initiate monitoring of a channel condition on a first link among the plurality of links; a second transmitting step of transmitting, within a period acquired by the first signal, a second signal that induces a signal including information about observation of a channel state on the first link to two or more first other communication devices specified by the first signal; a third transmitting step of transmitting, within the period acquired by the first signal, a third signal that induces a signal including information about observation of a channel state on the first link to two or more second other communication devices specified by the first signal; A communication method comprising:

15. 2. A communication device that performs wireless communication using a plurality of links as either the first other communication device or the second other communication device according to claim 1, receiving a first signal to initiate monitoring of channel conditions on a first link of the plurality of links; receiving, within a time period acquired by the first signal, one of a second signal and a third signal that induces a signal containing information regarding observation of a channel condition on the first link; transmitting a signal including information regarding observation of a channel condition on the first link in response to receiving one of the second signal and the third signal; A communication device having a control unit that performs the above.

16. the signal including information regarding observation of the channel state is either a fourth signal for another communication device that transmitted the first signal to observe a channel state, or a fifth signal including information regarding a channel state observed by the communication device itself; 16. The communication device of claim 15.

17. the signal containing information about the observation of the channel condition includes information about the transmission power of the signal; 16. The communication device of claim 15.

18. changing a link for transmission and reception based on a request from a sender of the first signal or information included in the first signal; 16. The communication device of claim 15.

19. changing a link for receiving a signal addressed to broadcast based on a request from a sender of the first signal or information included in the first signal; 16. The communication device of claim 15.

20. 2. A communication method for performing wireless communication using a plurality of links as either the first other communication device or the second other communication device according to claim 1, receiving a first signal to initiate monitoring of channel conditions on a first link of the plurality of links; receiving, within a time period acquired by the first signal, one of a second signal and a third signal that induces a signal containing information regarding observation of a channel condition on the first link; transmitting a signal including information regarding observation of channel conditions on one or more of the plurality of links in response to receiving one of the second signal and the third signal; A communication method comprising:

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