Communication device, communication method, and integrated circuit

Abstract

The present invention improves channel estimation accuracy in wireless communication. This communication device comprises: a control circuit that sets, to a control signal, information relating to an additional reference signal for each destination device; and a transmission circuit that transmits the control signal.

Description

Technical Field

[0001] The present disclosure relates to a communication device and a communication method.

Background Art

[0002] As a successor standard to 802.11ax (hereinafter referred to as “11ax”), which is a standard of the Institute of Electrical and Electronics Engineers (IEEE) 802.11, the technical specification of 802.11be (hereinafter referred to as “11be”) is being advanced in a task group (TG, Task Group).

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

[0004] However, there is room for study on a method for improving channel estimation accuracy in wireless communication.

[0005] Non-limiting examples of the present disclosure contribute to providing a communication device and a communication method for improving channel estimation accuracy in wireless communication.

[0006] A communication device according to an embodiment of the present disclosure includes a control circuit that sets information regarding an additional reference signal for each destination device in a control signal, and a transmission circuit that transmits the control signal.

[0007] Note that these general or specific aspects may be implemented in a system, apparatus, method, integrated circuit, computer program, or recording medium, or may be implemented in any combination of a system, apparatus, method, integrated circuit, computer program, and recording medium.

[0008] According to an embodiment of the present disclosure, the channel estimation accuracy in wireless communication can be improved.

[0009] Further advantages and effects in an embodiment of the present disclosure will be clarified from the specification and drawings. Such advantages and / or effects are respectively provided by several embodiments and the features described in the specification and drawings, but not all necessarily need to be provided to obtain one or more identical features.

Brief Description of the Drawings

[0010]

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Mode for Carrying out the Invention

[0011] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings.

[0012] In 11be, for the purpose of improving channel estimation accuracy, a method of transmitting an Extream High Throuhput - LTF (EHT-LTF), which is more than the High Efficient non-Legacy Long Training Field (hereinafter referred to as HE-LTF) of 11ax determined from the number of Spatial Streams (SS), is being discussed (for example, Non-Patent Documents 1 and 2).

[0013] FIG. 1 shows an example of the EHT Physical Layer Convergence Procedure Protocol Data Unit (EHT PPDU) format for notifying EHT-LTF. In FIG. 1, the signal (SIG) field including the U-SIG field and the EHT-SIG field is a non-limiting example of a control signal. Also, as shown in FIG. 1, one or more EHT-LTFs can be set in the EHT PPDU. The EHT-LTF is a non-limiting example of an additional reference signal.

[0014] Also, Fig. 2 shows an example of the U-SIG and EHT-SIG formats when the number of destination users of the EHT MU PPDU is 1 (referred to as non-Multi-User Multiple-Input Multiple-Output (MU-MIMO) or SU (single user)). Fig. 3 shows an example of the U-SIG and EHT-SIG formats when the number of destination users of the EHT MU PPDU is more than 1 (referred to as MU-MIMO).

[0015] As shown in Figs. 2 and 3, the EHT-SIG field includes, for example, a common field common to a plurality of destination users and a user field for each destination user. As shown in Fig. 2, in the case of non-MIMO, one user field is provided in the EHT-SIG field. As shown in Fig. 3, in the case of MU-MIMO, the number of user fields provided in the EHT-SIG field corresponds to the number of destination users.

[0016] In the HE PPDU transmission in 11ax, for example, as shown in Fig. 4, the number of HE-LTFs included in the HE PPDU is determined based on the value of the number of spatial streams (hereinafter referred to as N STS and denoted) subfield included in the user information (also referred to as the User field) of the HE PPDUG, or the number of spatial streams notified by the Spatial Configuration subfield.

[0017] On the other hand, in the EHT PPDU transmission in 11be, for example, the number of EHT-LTF symbols included in the EHT PPDU is notified by the Number of EHT-LTF Symbols subfield (hereinafter referred to as N EHT-LTF ) included in the U-SIG. In the EHT PPDU, the number of EHT-LTFs included in the EHT PPDU can be determined based on the number of spatial streams in the same way as in 11ax. Also, in the EHT PPDU, N EHT-LTFBy notifying the number of EHT-LTF symbols that is more than the number of EHT-LTFs determined from the number of spatial streams, an EHT PPDU including more EHT-LTFs than a normal EHT PPDU can be realized.

[0018] When transmitting more EHT-LTFs than normal EHT-LTFs, an access point (Access Point (AP); also referred to as a "base station") may allocate twice the number of EHT-LTFs determined based on the number of spatial streams to each terminal (also referred to as a Station (STA)). For example, when allocating the number of spatial streams to two STAs 1 and 2 as [2, 1] respectively, the number of EHT-LTFs may be allocated as [4, 2].

[0019] A STA that has received a signal including more EHT-LTFs than HE-LTFs, for example, N EHT-LTF the number of EHT-LTFs notified by the N STS subfield and the number of spatial streams notified by the N

[0020] Note that N EHT-LTF may be included in the Common field of the EHT-SIG as a surplus subfield of the U-SIG.

[0021] Also, in IEEE 802.11n (hereinafter referred to as "11n"), there is a sounding PPDU transmitted to estimate the channel between a transmitter and a receiver. FIG. 5 shows an example of the HT-SIG2 format in 11n. In 11n, when the Not sounding subfield included in the HT-SIG2 = 0, it is transmitted as a Sounding PPDU.

[0022] A sounding PPDU may include, for example, an LTF (referred to as Data LTF (DLTF)) determined based on, for example, the number of spatial streams, and an LTF (referred to as Extention LTF (ELTF)) for transmitting additional spatial streams (extended spatial streams, or Extention spatial stream (ESS)). FIGS. 6 and 7 show an example of the relationship between the number of spatial streams (N STS / N ESS ) and the number of LTFs (N HT-DLTF / N HT-ELTF ). Note that the total value of the number of spatial streams and the number of extended spatial streams may be required to be, for example, 4 or less and less than or equal to the number of transmitting antennas.

[0023] Here, in MU-MIMO, the required channel estimation accuracy may vary for each user. For example, in MU-MIMO, when the same number of spatial streams is allocated to a plurality of users (in other words, when the transmission power per user is the same), the modulation schemes (in other words, Modulation and Coding Scheme (MCS)) may vary significantly between the destination users. When the MCS varies significantly between the destination users, high-order modulation signals are more susceptible to noise than low-order modulation signals, and thus signal errors are likely to occur.

[0024] In one embodiment of the present disclosure, for example, by including (or setting) a field (or information) related to an additional LTF (referred to as Extra-LTF) for each user in a control signal having a common field (or common information) and a user field (or user information), the channel estimation accuracy can be improved.

[0025] For example, by determining the allocation of Extra-LTF for each user according to the channel estimation accuracy required for each user and performing maximum ratio combining of a plurality of channel estimation values, the channel estimation accuracy can be improved. By improving the channel estimation accuracy, for example, signal errors can be reduced, and thus the wireless communication quality can be improved.

[0026] [Configuration of Wireless Communication System] A wireless communication system according to an embodiment of the present disclosure includes at least one access point (Access Point (AP), also referred to as a "base station") and one terminal (referred to as a Station (STA)).

[0027] For example, in Down Link (DL) communication, the AP corresponds to a "downlink wireless transmission device", and the STA corresponds to a "downlink wireless reception device". Also, in Up Link (UL) communication, the AP corresponds to an "uplink wireless reception device", and the STA corresponds to an "uplink wireless transmission device". Note that the STA may be referred to as a "user device" or simply a "user". The "downlink wireless reception device" can be positioned as the destination device in DL communication.

[0028] In an embodiment of the present disclosure, the AP may, for example, transmit a PPDU including control information of Extra-LTF to the STA in DL communication.

[0029] [Embodiment 1] In Embodiment 1, for example, the AP transmits a signal including Extra-LTF to the STA. Hereinafter, as a non-limiting example, a method for the AP to transmit a signal including Extra-LTF to the STA in 11be will be described.

[0030] An operation example of the AP and STA in this Embodiment 1 will be described. FIG. 8 is a sequence diagram showing an operation example of a wireless communication system in which the AP transmits an EHT PPDU including Extra-LTF to the STA in 11be.

[0031] The AP transmits a signal (capability request) requesting transmission of capability information (referred to as Capability) regarding Extra-LTF to the STA (for example, STA1, STA2) (S101). When the STA receives the Capability request, the Capability of the STA regarding Extra-LTF is transmitted to the AP that is the transmission source of the Capability request as, for example, a Capability response (S102).

[0032] The Capability regarding Extra-LTF may include, for example, at least one of the information on whether Extra-LTF is supported, the maximum number of LTFs that can be received in non-Orthogonal Frequency-Division Multiple Access (OFDMA) single-user transmission, and the maximum number of LTFs that can be received in multi-user transmission.

[0033] The AP selects, for example, an STA capable of transmitting Extra-LTF based on the capability obtained from the Capability request received from the STA, and schedules the frequency resource (referred to as a Recourse Unit (RU)), the spatial multiplexing method, and the modulation method (S103). Also, the AP generates, for example, an EHT PPDU including Extra-LTF based on the scheduling information (S104). At this time, the AP may include, for example, information for notifying the allocation of Extra-LTF (hereinafter sometimes referred to as "Extra-LTF information") in the EHT PPDU and transmit it to the STA (S105).

[0034] The STA that has received the Extra-LTF information from the AP performs, for example, the reception process of the EHT PPDU including the Extra-LTF information (S106). For example, the STA obtains N STS and N EHT-LTF Based on the values and the Extra-LTF information, the STA determines whether Extra-LTF is allocated to the EHT PPDU and performs channel estimation using the LTF.

[0035] Also, the STA performs, for example, equalization processing on the data part of the EHT PPDU based on the obtained channel estimation value, and demodulates and decodes the data part. Also, the STA transmits, for example, a response signal (referred to as an Acknowledge (ACK)) to the AP according to the error determination result of the decoded data signal (S107).

[0036] In the above-described example, the EHT PPDU including the Extra-LTF has been described. However, the above-described operation example may be applied to the EHT NDP PPDU including the Extra-LTF.

[0037] FIG. 9 is a block diagram showing a partial configuration example of a downlink wireless transmission device (for example, an AP) 100 according to an embodiment of the present disclosure. In the AP 100 shown in FIG. 9 (which corresponds to a communication device, for example), a control unit (which corresponds to a control circuit, for example) may set information regarding an additional reference signal (for example, Extra-LTF) for each destination device (for example, STA) in a control signal. A transmission unit (which corresponds to a transmission circuit, for example) transmits the control signal.

[0038] FIG. 10 is a block diagram showing a partial configuration example of a downlink wireless reception device (for example, an STA) 200 according to an embodiment of the present disclosure. In the STA 200 shown in FIG. 10 (which corresponds to a communication device, for example), a reception unit (which corresponds to a reception circuit, for example) receives a control signal including information regarding an additional reference signal (for example, Extra-LTF) for each destination device (for example, STA). A control unit (which corresponds to a control circuit, for example) may determine an additional reference signal to be used for channel estimation based on the information regarding the additional reference signal.

[0039] [Downlink Wireless Transmission Device of Embodiment 1] FIG. 11 is a block diagram showing a configuration example of the downlink wireless transmission device according to Embodiment 1 of the present disclosure. The downlink wireless transmission device (for example, an AP) 100 shown in FIG. 11 may include, for example, a wireless reception unit 101, a received signal decoding unit 102, a scheduling unit 103, a data generation unit 104, a data encoding unit 105, a data modulation unit 106, a preamble generation unit 107, and a wireless transmission unit 108.

[0040] At least one of the received signal decoding unit 102, the scheduling unit 103, the data generation unit 104, the data encoding unit 105, the data modulation unit 106, and the preamble generation unit 107 may be included in, for example, the control unit shown in FIG. 9. The wireless transmission unit 108 may be included in, for example, the transmission unit shown in FIG. 9.

[0041] The wireless reception unit 101 receives, via an antenna for example, the signal transmitted from the downlink wireless reception device (e.g., STA) 200 (see FIG. 10), and performs wireless reception processing such as down-conversion and Analog-to-Digital (A / D) conversion. The wireless reception unit 101 divides, for example, the received signal after the wireless reception processing into a preamble part (also called a preamble signal) and a data part (also called a data signal), and outputs the divided signal to the received signal decoding unit 102.

[0042] The received signal decoding unit 102 performs demodulation processing such as Fourier transform (e.g., Fast Fourier Transform (FFT)) on each of the preamble signal and the data signal input from the wireless reception unit 101, and may extract the control signals included in the preamble signal and the data signal respectively. The control signal may include information or parameters such as, for example, the frequency bandwidth (BW), MCS, or the coding method.

[0043] Also, the received signal decoding unit 102 may perform channel equalization, demodulation, and decoding on the data signal after Fourier transform using, for example, the control signal obtained from the preamble signal and the channel estimation signal, and perform error determination such as Cyclic Redundancy Check (CRC).

[0044] The received signal decoding unit 102 outputs, for example, the decoded data signal and the control signal to the scheduling unit 103 when there is no error in the data signal (in other words, decoding error). On the other hand, the received signal decoding unit 102 does not have to output the decoded data signal when there is an error in the data signal, for example.

[0045] The scheduling unit 103 may determine the scheduling information of the data signal to be transmitted to the downlink wireless reception device 200 based on, for example, the reception quality information of the data signal output from the received signal decoding unit 102, or the capability of the downlink wireless reception device (e.g., STA) 200.

[0046] The received quality information may include, for example, information such as Packet Error Rate (PER) and RSSI. The scheduling information may include, for example, information or parameters such as RU, MCS, error correction coding method, and Extra-LTF information. The scheduling information may be output to, for example, the data generation unit 104, the data encoding unit 105, the data modulation unit 106, and the preamble generation unit 107.

[0047] The data generation unit 104 generates, for example, a data sequence to be transmitted to the downlink wireless receiver 200 based on the scheduling information output from the scheduling unit 103, and outputs the data sequence to the data encoding unit 105.

[0048] The data encoding unit 105 performs encoding based on, for example, the data sequence output from the data generation unit 104 and the scheduling information (e.g., error correction coding method and MCS) output from the scheduling unit 103. The encoded data may be output to, for example, the data modulation unit 106.

[0049] The data modulation unit 106 performs modulation and inverse Fourier transform (e.g., Inverse Fast Fourier Transform (IFFT)) based on, for example, the encoded data output from the data encoding unit 105 and the scheduling information (e.g., modulation method) output from the scheduling unit 103. The modulated data signal may be output to, for example, the wireless transmission unit 108.

[0050] The preamble generation unit 107 generates a preamble signal including, for example, Extra-LTF or control information related to Extra-LTF (e.g., allocation information of Extra-LTF) based on the scheduling information output from the scheduling unit 103. The preamble signal may be modulated and subjected to IFFT processing in the preamble generation unit 107 and output to the wireless transmission unit 108.

[0051] The wireless transmission unit 108 generates a wireless frame (also referred to as a packet signal), for example, by adding the preamble signal output from the preamble generation unit 107 to the data signal output from the data modulation unit 106. Further, the wireless transmission unit 108 performs wireless transmission processing such as Digital-to-Analog (D / A) conversion and up-conversion to the carrier frequency on the wireless frame, and transmits the signal after the wireless transmission processing to the downstream wireless reception device 200 via the antenna.

[0052] [Downstream Wireless Reception Device of Embodiment 1] FIG. 12 is a block diagram showing a configuration example of the downstream wireless reception device according to the first embodiment. The downstream wireless reception device (for example, STA) 200 shown in FIG. 12 may include, for example, a wireless reception unit 201, a preamble demodulation unit 202, an Extra-LTF discrimination unit 203, a channel estimation unit 204, a data demodulation unit 205, a data decoding unit 206, a transmission signal generation unit 207, and a wireless transmission unit 208.

[0053] At least one of the preamble demodulation unit 202, the Extra-LTF discrimination unit 203, the channel estimation unit 204, the data demodulation unit 205, the data decoding unit 206, and the transmission signal generation unit 207 may be included in the control unit shown in FIG. 10, for example. The wireless reception unit 201 may be included in the reception unit shown in FIG. 10, for example.

[0054] The wireless reception unit 201 may receive the signal transmitted from the downstream wireless transmission device (for example, AP) 100 via the antenna and perform wireless reception processing such as down-conversion and A / D conversion. Further, the wireless reception unit 201 outputs the data signal extracted from the received signal after the wireless reception processing to the data demodulation unit 205 and outputs the preamble signal to the preamble demodulation unit 202, for example.

[0055] The preamble demodulation unit 202 extracts a control signal used for demodulation and decoding of the data part by performing demodulation processing such as Fourier transform (e.g., FFT) on the preamble signal output from the wireless reception unit 201, for example. This control signal may include information or parameters such as, for example, BW, MCS, error correction coding method, and Extra-LTF information. The preamble demodulation unit 202 may output the extracted control information to the data demodulation unit 205, the data decoding unit 206, the Extra-LTF determination unit 203, and the channel estimation unit 204, for example.

[0056] The Extra-LTF determination unit 203 determines whether the preamble of the received signal includes Extra-LTF based on the Extra-LTF information output from the preamble demodulation unit 202, for example. The determined information (hereinafter sometimes referred to as Extra-LTF determination information) may be output to the channel estimation unit 204, for example.

[0057] The channel estimation unit 204 performs channel estimation using a reference signal (e.g., LTF) included in the preamble, for example. For example, when Extra-LTF is allocated, the channel estimation unit 204 performs channel estimation using Extra-LTF in addition to the EHT-LTF (referred to as the Original LTF) determined based on the number of spatial streams allocated to the downlink wireless reception device based on the Extra-LTF determination information output from the Extra-LTF determination unit 203.

[0058] Also, the channel estimation unit 204, for example, performs maximum ratio combining on the channel estimation values respectively estimated using the Original LTF and the Extra-LTF, and outputs the combined channel estimation value to the data demodulation unit 205. In addition, a power correction value may be given to the combined channel estimation value in order to correct the power difference between the combined channel estimation value and the data part. Also, when Extra-LTF is not allocated, the channel estimation unit 204 does not have to perform channel estimation using Extra-LTF.

[0059] The data demodulation unit 205 performs processing such as Fourier transform (e.g., FFT) on the data signal output from the wireless reception unit 201, and demodulates the data signal using the control information output from the preamble demodulation unit 202 and the channel estimation value output from the channel estimation unit 204. The demodulated data signal may be output to, for example, the data decoding unit 206.

[0060] The data decoding unit 206 decodes the demodulated data signal output from the data demodulation unit 205 using, for example, the control information output from the preamble demodulation unit 202, performs error determination such as CRC, and outputs the error determination information, which is the determination result, to the transmission signal generation unit 207.

[0061] The transmission signal generation unit 207 generates a response signal (ACK or Block ACK (referred to as BA)), for example, based on the error determination information output from the data decoding unit. Further, the transmission signal generation unit 207 adds a preamble signal to the data signal, for example, to generate a wireless frame, and outputs it to the wireless transmission unit 208.

[0062] The wireless transmission unit 208 performs wireless transmission processing such as D / A conversion and up-conversion to the carrier frequency on the wireless frame output from the transmission signal generation unit 207, and transmits the signal after the wireless transmission processing to the downlink wireless transmission device 100 via the antenna.

[0063] [Operation Example] Next, an operation example of the downlink wireless transmission device (e.g., AP) 100 and the downlink wireless reception device (e.g., STA) 200 in the first embodiment will be described.

[0064] In one embodiment of the present disclosure, the control signal (also referred to as control information) transmitted from the downlink wireless transmission device 100 to the downlink wireless reception device 200 may include common information common to a plurality of users and user information specific to a plurality of users.

[0065] The control signal may include, for example, individual Extra-LTF information for a user (e.g., the downlink wireless receiving device 200). The control information may be, for example, the SIG field (U-SIG or EHT-SIG) of the EHT PPDU or a Trigger frame. Also, the Extra-LTF information may include, for example, information or parameters indicating at least one of the presence or absence of the Extra-LTF allocation and the number of Extra-LTF allocations.

[0066] [Method 1] In Method 1, for example, a subfield for notifying each of the user information with the Extra-LTF information may be included. For example, as shown in FIG. 13, an Extra-LTF subfield for notifying the allocation of the Extra-LTF may be included in the individual user fields of the EHT-SIG. The notification method by the Extra-LTF subfield will be described later in Specific Examples 1 to 3 of Method 1.

[0067] In the EHT-LTF, for example, regardless of the presence or absence of the Extra-LTF, a mapping matrix (referred to as a P-matrix) is added to multiplex a plurality of EHT-LTF symbols. In 11ac / ax, for example, as shown in Equation (1), the P-matrix to be used is determined according to the number of LTFs (N HE-LTF ). In 11n, for example, the P 4×4 P-matrix is used. P 4×4 is represented by, for example, Equation (2). The column components of the P-matrix correspond to each LTF symbol. On the other hand, the row components of the P-matrix correspond to the spatial streams, and the row components are multiplexed to each LTF symbol.

[0068]

Number

[0069]

Number

[0070] The P-matrix added to the EHT-LTF including the Extra-LTF may be determined based on, for example, the number of EHT-LTFs. This number of EHT-LTFs may be obtained, for example, by adding the number of Extra-LTFs to the number of EHT-LTFs determined based on the total number of spatial streams transmitted in MU-MIMO.

[0071] Fig. 14 shows an example of the P-matrix added to the EHT-LTF when two spatial streams are assigned to each of STA1 and STA2 and two Extra-LTFs are assigned to STA1. In this case, the AP adds, for example, the elements in the 1st to 4th rows and 1st to 4th columns of a 6-row 6-column P-matrix (referred to as P 6×6 to the Original LTF, and adds the elements in the 1st to 4th rows and 5th to 6th columns of P 6×6 to the Extra-LTF.

[0072] STA1 performs, for example, maximum ratio combining of the channel estimation values obtained from the Original LTF and the channel estimation values obtained from the Extra-LTF, and uses the result for equalization processing of the data part.

[0073] For the P-matrix added to the EHT-LTF including the Extra-LTF, a plurality of Original LTFs determined based on, for example, the total number of spatial streams transmitted by MU-MIMO may be used. Fig. 15 shows an example of the P-matrix added to the EHT-LTF when two spatial streams are assigned to each of STA1 and STA2 and four Extra-LTFs are assigned to STA1.

[0074] In this case, in addition to adding, for example, a 4-row 4-column P-matrix (referred to as P 4×4 to the Original LTF, the AP adds another P-matrix P 4×4 to the Extra-LTF.

[0075] STA1 performs maximum ratio combining on, for example, the channel estimation values obtained from the Original LTF and the two channel estimation values obtained from the Extra-LTF, and uses the result for the equalization process of the data part.

[0076] By allocating the Extra-LTF to a specific user as in Method 1, channel estimation using more LTFs than before becomes possible, and thus the channel estimation accuracy can be improved by maximum ratio combining.

[0077] [Specific Example 1 of Method 1] In Specific Example 1 of Method 1, the Extra-LTF information notifies, for example, the presence or absence of the Extra-LTF. Fig. 16 shows an example of the EHT-SIG format when notifying the presence or absence of the Extra-LTF in each user information.

[0078] The Extra-LTF subfield may be, for example, a 1-bit subfield. For example, when Extra-LTF = 1, it indicates that the Extra-LTF is allocated, and when Extra-LTF = 0, it indicates that the Extra-LTF is not allocated.

[0079] In Specific Example 1 of Method 1, the first STA may determine the number of Extra-LTFs for the first STA by referring to, for example, the user information addressed to another second STA. For example, Fig. 16 shows an example in which one spatial stream is allocated to each of STA1 and STA2, and two Extra-LTFs are allocated to STA1. The example of LTF allocation at this time is shown in Fig. 17.

[0080] STA1 and STA2 determine from the Spatial Configuration subfield that one spatial stream is allocated to each of STA1 and STA2 (in other words, determine that the total number of spatial streams = 2 is allocated).

[0081] In this case, one Original LTF is assigned to each of STA1 and STA2. STA1, for example, refers to the Extra-LTF in the User field of STA2 and identifies that no Extra-LTF is assigned to STA2. Also, STA1, for example, subtracts the total number of spatial streams (=2) notified in the Spatial Configuration subfield from the number of EHT-LTFs (=4) notified in the subfield EHT-LTF to determine the number of Extra-LTFs assigned to STA1 and derive the EHT-LTF index (1 - 3) to be referenced. EHT-LTF The number of EHT-LTFs notified in the subfield EHT-LTF (in this example, N = 4), subtracts the total number of spatial streams (=2) notified in the Spatial Configuration subfield to determine the number of Extra-LTFs assigned to STA1 and derive the EHT-LTF index (1 - 3) to be referenced.

[0082] On the other hand, STA2, for example, identifies that an Extra-LTF is assigned to STA1 based on the Extra-LTF in the User field of STA1. Also, STA2, similar to STA1, calculates the EHT-LTF index assigned to STA1 from the difference between the number of EHT-LTFs and the total number of spatial streams, and derives the EHT-LTF index (4) to be referenced by STA2.

[0083] [Specific Example 2 of Method 1] In Specific Example 2 of Method 1, the Extra-LTF information notifies, for example, the number of Extra-LTFs. FIG. 18 shows an example of the EHT-SIG format when notifying the number of Extra-LTFs in each user information. FIG. 18 shows an example where one spatial stream is assigned to each of STA1 and STA2 and two Extra-LTFs are assigned to STA1.

[0084] In this case, the method of notifying the number of Extra-LTFs may be, for example, to notify the number of Extra-LTFs by each Extra-LTF subfield. Also, the method of notifying the number of Extra-LTFs may be to limit the available number of Extra-LTFs (e.g., the number of Extra-LTFs is selected from [0, 2, 4, 8]) and notify.

[0085] [Specific Example 3 of Method 1] In Specific Example 3 of Method 1, a multiple of the initial (or Original) LTF number is notified as Extra-LTF information. Fig. 19 shows an example of the EHT-SIG format when the Extra-LTF number is notified as a multiple of the initial EHT-LTF number in each user information. Fig. 19 shows an example where one spatial stream is assigned to each of STA1 and STA2, and one Extra-LTF is assigned to STA1.

[0086] In this case, the Extra-LTF subfield included in each user information may be a 1-bit subfield, and when Extra-LTF = 1, LTFs twice the initial LTF number may be assigned (in other words, when Extra-LTF = 0, no Extra-LTF is assigned).

[0087] Note that the Extra-LTF subfield is not limited to a 1-bit subfield, and the multiple of the initial LTF number to be notified may be set to three times or four times or more by increasing the number of bits of the Extra-LTF subfield.

[0088] [Method 2] In Method 2, for example, the configuration (or format) of the control information is switched according to the presence or absence of Extra-LTF. For example, an Extra-LTF present subfield is added to U-SIG to notify the presence or absence of Extra-LTF.

[0089] For example, when one or more users to whom Extra-LTF is assigned are included in the transmitted signal, Extra-LTF present = 1 is notified, and when no user to whom Extra-LTF is assigned is included, Extra-LTF present = 0 is notified. The presence or absence of Extra-LTF may be notified according to any of Specific Examples 1 to 3 of Method 1.

[0090] By switching the configuration of the EHT-SIG according to whether or not there is a user to whom Extra-LTF is assigned in the transmission signal as in Method 2, the signaling overhead when not using Extra-LTF can be reduced.

[0091] [Specific Example 1 of Method 2] In Specific Example 1 of Method 2, when there is a user to whom Extra-LTF is assigned in the transmission signal, for example, an Extra-LTF bitmap may be added to the common information, and the presence or absence of Extra-LTF for each user may be notified by the Extra-LTF bitmap. In other words, when there is no user to whom Extra-LTF is assigned in the transmission signal, the common information may not include the Extra-LTF bitmap.

[0092] FIG. 20 shows an example of the EHT-SIG format when notifying the assignment of Extra-LTF by a bitmap in the common information.

[0093] The Extra-LTF bitmap may be, for example, a variable-length bitmap determined based on the number of user information included in the EHT-SIG. Also, the Extra-LTF bitmap may be, for example, a fixed-length bitmap based on the maximum number of multiplexed users in MU-MIMO.

[0094] The Extra-LTF bitmap may, for example, notify the presence or absence of Extra-LTF for each user with 1 bit as in Specific Example 1 of Method 1, or may notify the number of Extra-LTFs for each user with up to 3 bits as in Specific Example 2 of Method 1. Alternatively, as in Specific Example 3 of Method 1, it may be notified with 1 bit that LTFs that are multiples of the number of spatial streams notified by N STS are assigned.

[0095] According to Specific Example 1 of Method 2, by referring to the Extra-LTF bitmap, it is possible to determine the allocation of Extra-LTF to other users (in other words, it is not necessary to refer to the user information of other users), so the processing time can be reduced.

[0096] [Specific Example 2 of Method 2] In Specific Example 2 of Method 2, for example, when the transmitted signal includes a user to whom Extra-LTF is allocated, Extra-LTF information is added to the user information, and the presence or absence of Extra-LTF for each user is notified. Fig. 21 shows an example of the EHT-SIG format when notifying whether the user information includes Extra-LTF information in the common information.

[0097] For example, when the transmitted signal includes a user to whom Extra-LTF is allocated, an Extra-LTF subfield for notifying the Extra-LTF information to each user information is added. In other words, when the transmitted signal does not include a user to whom Extra-LTF is allocated, the Extra-LTF subfield does not have to be included in each user information.

[0098] According to Specific Example 2 of Method 2, when the number of destination users is small, the signaling overhead can be reduced compared to notifying the allocation of Extra-LTF by bitmap as in Specific Example 1 of Method 2.

[0099] [Specific Example 3 of Method 2] In Specific Example 3 of Method 2, for example, the notification method of Extra-LTF is changed according to the number of destination users. For example, assume a case where the common information includes a fixed-length Extra-LTF Bitmap based on the maximum number of multiplexed users in MU-MIMO. At this time, when the number of destination users of the transmission signal including Extra-LTF is equal to the maximum number of multiplexed users in MU-MIMO, similar to Specific Example 1 of Method 2, the presence or absence of Extra-LTF for each user may be notified by the Extra-LTF bitmap. On the other hand, when the number of destination users of the transmission signal including Extra-LTF is less than the maximum number of multiplexed users in MU-MIMO, for example, similar to Specific Example 2 of Method 2, the presence or absence of Extra-LTF may be notified in each user information.

[0100] According to Specific Example 3 of Method 2, by changing the notification method of Extra-LTF according to the number of destination users of the transmission signal including Extra-LTF, an efficient signaling method can be flexibly selected and the signaling method can be optimized.

[0101] [Method 3] In Method 3, for example, Extra-LTF information and MCS are combined to notify Extra-LTF information by user information. When notifying by combining Extra-LTF and MCS, for example, the modulation method and the number of Extra-LTFs may be combined and notified for each MCS index (Example 1), or the modulation method and the multiple of the number of Original LTFs may be combined and notified for each MCS index (Example 2).

[0102] For example, in the case of transmission for a single user (SU), as shown in FIG. 22, combinations of low-order modulation and Extra-LTF may be added to the MCS table separately for Example 1 and Example 2. In the case of transmission for multiple users (MU), for example, as shown in FIG. 23, combinations of high-order modulation and Extra-LTF may be added to the MCS table separately for Example 1 and Example 2.

[0103] Note that the combinations of Extra-LTF information and MCS shown in each of FIGS. 22 (Example 1) and 23 (Example 2) are non-limiting examples, and other combinations may also be used. Further, the combination of Extra-LTF information and MCS may be changed according to, for example, the number of destination users.

[0104] As in Method 3, by combining Extra-LTF information and MCS, it is possible to realize the notification of Extra-LTF information without increasing the signaling for notifying the Extra-LTF information.

[0105] [Embodiment 2] In Embodiment 1, an example of a method for allocating users separately from the time symbols of the LTF including Extra-LTF was described. In Embodiment 2, an example of a method for allocating a plurality of row components of the P-matrix to one spatial stream using code multiplexing will be described.

[0106] [Downlink Wireless Transmitting Apparatus of Embodiment 2] FIG. 24 is a block diagram showing a configuration example of a downlink wireless transmitting apparatus according to Embodiment 2. The downlink wireless transmitting apparatus (for example, (for example, AP) 100 illustrated in FIG. 24 may include, for example, a wireless receiving unit 101a, a received signal decoding unit 102a, a scheduling unit 103a, a data generation unit 104a, a data encoding unit 105a, a data modulation unit 106a, a preamble generation unit 107a, and a wireless transmitting unit 108a.

[0107] At least one of the received signal decoding unit 102a, the scheduling unit 103a, the data generation unit 104a, the data encoding unit 105a, the data modulation unit 106a, and the preamble generation unit 107a may be included in, for example, the control unit shown in FIG. 9. The wireless transmitting unit 108a may be included in, for example, the transmitting unit shown in FIG. 9.

[0108] The wireless reception unit 101a receives, via an antenna for example, a signal transmitted from a downlink wireless reception device (e.g., STA) 200, and performs wireless reception processing such as down-conversion and A / D conversion. The wireless reception unit 101a divides, for example, the received signal after the wireless reception processing into a preamble part and a data part, and outputs the divided signal to the received signal decoding unit 102a.

[0109] The received signal decoding unit 102a performs demodulation processing such as Fourier transform (e.g., FFT) on the preamble signal and the data signal input from the wireless reception unit 101a, respectively, and may extract control signals included in the preamble signal and the data signal, respectively. The control signal may include information or parameters such as, for example, BW, MCS, or coding method. Further, the received signal decoding unit 102a may perform channel equalization, demodulation, and decoding on the Fourier-transformed data signal using, for example, the control signal obtained from the preamble signal and the channel estimation signal, and perform error determination such as CRC.

[0110] When there is no error (in other words, decoding error) in the data signal, the received signal decoding unit 102a outputs the decoded data signal and the control signal to the scheduling unit 103a, for example.

[0111] The scheduling unit 103a determines, for example, scheduling information of the data signal to be transmitted to the downlink wireless reception device (e.g., STA) 200 based on the reception quality information of the data signal output from the received signal decoding unit 102a or the capability of the downlink wireless reception device.

[0112] The reception quality information may include information such as, for example, PER and RSSI. The scheduling information may include information or parameters such as, for example, RU, MCS, error correction coding method, and Extra-LTF information. The scheduling information may be output to, for example, the data generation unit 104a, the data coding unit 105a, the data modulation unit 106a, and the preamble generation unit 107a.

[0113] The data generation unit 104a generates, for example, a data sequence to be transmitted to the downlink wireless receiver 200 based on the scheduling information output from the scheduling unit 103a, and outputs the data sequence to the data encoding unit 105a.

[0114] The data encoding unit 105a performs encoding, for example, based on the data sequence output from the data generation unit 104a and the scheduling information (e.g., error correction coding method and MCS) output from the scheduling unit 103a. The encoded data may be output to, for example, the data modulation unit 106a.

[0115] The data modulation unit 106a performs spatial multiplexing by adding, for example, the spatial weight matrix output from the scheduling unit 103a to the encoded data output from the data encoding unit 105a. Further, the data modulation unit 106a performs modulation and inverse Fourier transform (e.g., IFFT) on the spatially multiplexed data based on the scheduling information (e.g., modulation method) output from the scheduling unit 103a, and outputs the data signal to the wireless transmission unit 108a.

[0116] The preamble generation unit 107a adds, for example, the P-matrix generated based on the scheduling information output from the scheduling unit 103a and the spatial weight matrix to the LTF. Further, the preamble generation unit 107a generates a preamble signal including information regarding the P-matrix (referred to as P-matrix information) added to the LTF, and outputs the preamble signal subjected to modulation and IFFT processing to the wireless transmission unit 108a.

[0117] The wireless transmission unit 108a generates a wireless frame (also called a packet signal), for example, by adding the preamble signal output from the preamble generation unit 107a to the data signal output from the data modulation unit 106a. Further, the wireless transmission unit 108a performs wireless transmission processing such as D / A conversion and up-conversion to the carrier frequency on the wireless frame, for example, and transmits the signal after the wireless transmission processing to the downstream wireless reception device 200 via the antenna.

[0118] [Downstream Wireless Reception Device of Embodiment 2] FIG. 25 is a block diagram showing a configuration example of the downstream wireless reception device according to Embodiment 2. The downstream wireless reception device (for example, STA) 200 illustrated in FIG. 25 may include, for example, a wireless reception unit 201a, a preamble demodulation unit 202a, a P-matrix determination unit 203a, a channel estimation unit 204a, a data demodulation unit 205a, a data decoding unit 206a, a transmission signal generation unit 207a, and a wireless transmission unit 208a.

[0119] At least one of the preamble demodulation unit 202a, the P-matrix determination unit 203a, the channel estimation unit 204a, the data demodulation unit 205a, the data decoding unit 206a, and the transmission signal generation unit 207a may be included in the control unit shown in FIG. 10, for example. The wireless reception unit 201a may be included in the reception unit shown in FIG. 10, for example.

[0120] The wireless reception unit 201a receives the signal transmitted from the downstream wireless transmission device (for example, AP) 100 via the antenna, for example, and may perform wireless reception processing such as down-conversion and A / D conversion. Further, the wireless reception unit 201a outputs the data signal extracted from the received signal after the wireless reception processing to the data demodulation unit 205a, and outputs the preamble signal to the preamble demodulation unit 202a.

[0121] The preamble demodulation unit 202a extracts a control signal used for demodulation and decoding of the data part by performing demodulation processing such as Fourier transform (e.g., FFT) on the preamble signal output from the wireless reception unit 201a. This control signal may include information or parameters such as, for example, BW, MCS, error correction coding method, and P-matrix information. The preamble demodulation unit 202a may output the extracted control information to, for example, the data demodulation unit 205a, the data decoding unit 206a, the P-matrix determination unit 203a, and the channel estimation unit 204a.

[0122] The P-matrix determination unit 203a determines, for example, the type (or size) of the P-matrix added to the LTF included in the preamble of the received signal and the allocation information of the P-matrix based on the P-matrix information output from the preamble demodulation unit 202a. The determined information (hereinafter sometimes referred to as P-matrix determination information) may be output to, for example, the channel estimation unit 204a.

[0123] The channel estimation unit 204a performs channel estimation using, for example, a reference signal (e.g., LTF) included in the preamble. For example, the channel estimation unit 204a performs channel estimation using the row vectors of the P-matrix corresponding to each spatial stream based on the P-matrix determination information output from the P-matrix determination unit 203a.

[0124] For example, when a plurality of row vectors of the P-matrix are added to one spatial stream assigned to the received signal, the channel estimation unit 204a performs channel estimation using each row vector and outputs the maximum ratio combined channel estimation value to the data demodulation unit 205a. On the other hand, when a plurality of P-matrices are not added to one spatial stream assigned to the received signal (in other words, when the row vectors of the P-matrix correspond to each spatial stream respectively), the channel estimation unit 204a performs channel estimation using, for example, the row vector and outputs the channel estimation value to the data demodulation unit 205a.

[0125] The data demodulation unit 205a performs processing such as FFT on the data signal output from the wireless reception unit 201a, and uses the control information output from the preamble demodulation unit 202a and the channel estimation value output from the channel estimation unit 204a to demodulate the data signal, and outputs the demodulated data signal to the data decoding unit 206a.

[0126] The data decoding unit 206a decodes the demodulated data signal output from the data demodulation unit 205a using the control information output from the preamble demodulation unit 202a, for example, performs error determination such as CRC, and outputs the error determination information to the transmission signal generation unit 207a.

[0127] The transmission signal generation unit 207a generates a response signal (ACK or Block ACK (referred to as BA)), for example, based on the error determination information output from the data decoding unit 206a. Further, the transmission signal generation unit 207a generates a wireless frame by adding a preamble signal to the data signal, for example, and outputs it to the wireless transmission unit 208a.

[0128] The wireless transmission unit 208a performs wireless transmission processing such as D / A conversion and up-conversion to the carrier frequency on the wireless frame output from the transmission signal generation unit 207a, and transmits the signal after the wireless transmission processing to the downlink wireless transmission device 100 via the antenna.

[0129] [Specific Example of Embodiment 2] In the specific example of Embodiment 2, for example, as shown in FIG. 26, a sub-field (referred to as Extra P-matrix) that notifies P-matrix information (for example, allocation information of the row components of the additional P-matrix) to each user field of the EHT-SIG is included. For example, as shown in FIG. 27, when the Extra P-matrix sub-field ≠ 0, the Extra P-matrix sub-field notifies the row index of the P-matrix to be additionally allocated. Extra P-matrix sub-field = 0 notifies that no additional P-matrix is allocated.

[0130] In this case, the type of the P-matrix added to the LTF may be determined based on the sum of the number of LTFs and the number of row components of the P-matrix to be added. In other words, the type of the P-matrix added to the LTF is not determined by referring to only the number of LTFs.

[0131] For example, in 11ax / 11ac, when the number of LTFs = 4, the P-matrix added to the LTF refers to the formula (1) shown in Embodiment 1, and it is determined to use P 4×4 On the other hand, in the specific example of Embodiment 2, the number of LTFs (N EHT-LTF ) = 4, and when the number of row indices of the Extra P-matrix (denoted as N ex-P index ) = 1, for the P-matrix added to the LTF, it is determined to use P 6×6 by referring to the following formula (3).

[0132]

Equation

[0133] Also, to allocate the row components of a plurality of P-matrices to one spatial stream, for example, a spatial weight matrix (referred to as a Q-matrix) is used. In 11ax / 11ac, the Q-matrix is a weight matrix composed of the number of transmit antennas × the number of spatial streams, and spatial division multiplexing is realized by adding it to the LTF and the data part.

[0134] However, in the specific example of Embodiment 2, the Q-matrix is a matrix composed of the number of transmit antennas × (the number of spatial streams + N ex-P index ). Therefore, when using the Extra P-matrix, the N STSThe value of the number of spatial streams notified in the subfield or Spatial Configuration subfield may be different from the value of the number of columns included in the Q-matrix. For example, in 11ax / ac, the number of columns of the Q-matrix = the number of spatial streams, whereas when using an Extra P-matrix, the number of columns of the Q-matrix = (the number of spatial streams + N_(ex-P index)).

[0135] To assign the row components of multiple P-matrices to one spatial stream, for example, a Q-matrix including multiple "1" components in the column vector corresponding to the spatial stream is used. Fig. 28 shows an example where one spatial stream is assigned to STA1 and STA2 respectively, and one row component of an additional P-matrix is assigned to STA1.

[0136] In this case, the first row of P 4×4 is assigned to STA1, and the second row of P 4×4 is originally assigned as the Original P-matrix components to STA2. STA1 identifies that the third row of P 4×4 is assigned as an additional row component based on the Extra P-matrix index information included in the User field addressed to STA1, and performs channel estimation using the first and third rows of P 4×4 respectively, and synthesizes the obtained channel estimation values. STA2 determines that no additional P-matrix is assigned based on the Extra P-matrix index information included in the User field addressed to STA2, and performs channel estimation using the second row of P 4×4 .

[0137] According to the specific example of Embodiment 2, since additional channel estimation can be performed using the row components of the additional P-matrix in the Extra P-matrix subfield, the channel estimation accuracy can be improved by maximum ratio combining of multiple channel estimation values.

[0138] [Overall Supplement] In Embodiment 1, an example of notifying Extra-LTF information using an EHT PPDU was shown, but the transmission of a Trigger base (TB) PPDU including Extra-LTF may be instructed using a Trigger frame.

[0139] For example, as in Method 1, Extra-LTF information (Extra-LTF subfield) may be added to each user information (User Info subfield) of the Trigger frame to indicate whether the TB PPDU to be transmitted to each user includes Extra-LTF. Fig. 29 shows an example of the Trigger frame User Info format when notifying Extra-LTF information in each user information.

[0140] Alternatively, for example, as shown in Fig. 30, a Trigger frame type for instructing Extra-LTF may be defined. When using a Trigger frame for instructing Extra-LTF, as in Specific Example 1 of Method 2, Trigger Dependent Common info may be rewritten as an Extra-LTF bitmap to notify the presence or absence of Extra-LTF for each user. Fig. 31 shows an example of the Common Info format of the Trigger frame in this case.

[0141] Alternatively, for example, as in Specific Example 2 of Method 2, an Extra-LTF present subfield may be added to the Common Info of the Trigger frame to notify the presence or absence of Extra-LTF in each User Info. Fig. 32 shows an example of the Trigger frame format in this case.

[0142] In the formula (1) of Embodiment 1 and the formula (3) of Embodiment 2, a method for determining the type of P-matrix based on the number of LTFs has been shown when the number of LTFs is 8 or less, but the number of LTFs may not be limited to 8 or less. For example, in 11be, when the number of LTFs is 16 or less, the type of P-matrix may be determined based on the number of LTFs.

[0143] Also, when using Extra-LTF and Midamble in combination (for example, when the channel estimation accuracy is likely to deteriorate due to channel fading), for example, as shown in FIG. 33, the LTF including Extra-LTF may be inserted into the data part as Midamble. In this case, the AP may notify the STA whether the Midamble is included in the data part according to the Doppler field included in the preamble, similar to 11ax.

[0144] Also, the AP may determine the allocation of Extra-LTF based on the number of receiving antennas of the STA. For example, when the AP identifies based on the capability of the STA that the STA has a predetermined number or more of receiving antennas, the AP may transmit to the STA a signal with a spatial stream number less than the number of receiving antennas of the STA.

[0145] The larger the number of receiving antennas of the STA, the easier it is to accurately separate the channels between the Original LTF and the Extra-LTF in the STA. Therefore, the channel estimation accuracy can be improved by maximum ratio combining the channel estimation values obtained by the Original LTF and the Extra-LTF respectively.

[0146] Also, the STA may request the transmission of a signal including Extra-LTF using the link adaptation control information for notifying the AP of the recommended transmission parameters. FIG. 34 shows an example of the format of the link adaptation control information. For example, the STA may combine the Extra-LTF information and the MCS as in Method 3 and request the AP for a signal including Extra-LTF by the HE-MCS field illustrated in FIG. 34.

[0147] The above describes each embodiment of the present disclosure.

[0148] (Other embodiments) In each of the above-described embodiments, operations in DL communication have been described. However, an embodiment of the present disclosure is not limited to DL communication and may be applied to, for example, UL communication or sidelink.

[0149] The present disclosure can be realized by software, hardware, or software in cooperation with hardware. Each functional block used in the description of the above embodiments can be realized as an LSI which is an integrated circuit, partially or entirely, and each process described in the above embodiments can be controlled, partially or entirely, by one LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of one chip so as to include a part or all of the functional blocks. The LSI may be provided with data input and output. Depending on the degree of integration, the LSI may also be referred to as an IC, a system LSI, a super LSI, or an ultra LSI.

[0150] The method of integrating into an integrated circuit is not limited to LSI, and may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. Also, after manufacturing the LSI, an FPGA (Field Programmable Gate Array) that can be programmed, or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used. The present disclosure may be realized as digital processing or analog processing.

[0151] Furthermore, if an integrated circuit technology that replaces the LSI appears due to the progress of semiconductor technology or another derived technology, of course, the technology may be used to integrate the functional blocks. The application of biotechnology and the like are possible as examples.

[0152] The present disclosure can be implemented in any type of device, apparatus, system having a communication function (collectively referred to as a communication device). The communication device may include a wireless transceiver (transceiver) and a processing / control circuit. The wireless transceiver may include a receiving unit and a transmitting unit, or may include them as functions. The wireless transceiver (transmitting unit, receiving unit) may include an RF (Radio Frequency) module and one or more antennas. The RF module may include an amplifier, an RF modulator / demodulator, or the like. Non-limiting examples of the communication device include a telephone (mobile phone, smartphone, etc.), a tablet, a personal computer (PC) (laptop, desktop, notebook, etc.), a camera (digital still / video camera, etc.), a digital player (digital audio / video player, etc.), a wearable device (wearable camera, smartwatch, tracking device, etc.), a game console, a digital book reader, a telehealth / telemedicine (remote healthcare / medical prescription) device, a vehicle or mobile transportation means with a communication function (automobile, airplane, ship, etc.), and combinations of the above various devices.

[0153] The communication device is not limited to being portable or movable, and includes any type of device, apparatus, system that is not portable or is fixed, for example, a smart home device (home appliance, lighting device, smart meter or measuring device, control panel, etc.), a vending machine, and any "thing" that can exist on the IoT (Internet of Things) network.

[0154] Communication includes data communication by a cellular system, a wireless LAN system, a communication satellite system, etc., and also includes data communication by combinations of these.

[0155] In addition, the communication device also includes devices such as a controller and a sensor that are connected or coupled to a communication device that executes the communication function described in the present disclosure. For example, a controller and a sensor that generate control signals and data signals used by the communication device that executes the communication function of the communication device are included.

[0156] In addition, the communication device includes infrastructure facilities that communicate with or control the above-described various non-limiting devices, such as base stations, access points, and any other devices, apparatuses, and systems.

[0157] The communication device according to an embodiment of the present disclosure includes a control circuit that sets information regarding an additional reference signal for each destination device in a control signal, and a transmission circuit that transmits the control signal.

[0158] In the communication device according to an embodiment of the present disclosure, the control signal includes common information common to a plurality of destination devices and individual information specific to the destination device, and the control circuit may set a field for notifying the individual information of information regarding the additional reference signal.

[0159] In the communication device according to an embodiment of the present disclosure, the information regarding the additional reference signal may be information indicating the presence or absence of the additional reference signal.

[0160] In the communication device according to an embodiment of the present disclosure, the information regarding the additional reference signal may be information indicating the number of the additional reference signals.

[0161] In the communication device according to an embodiment of the present disclosure, the information regarding the additional reference signal may be information indicating a multiple of the original number of the reference signals.

[0162] In the communication device according to an embodiment of the present disclosure, the control circuit may switch the configuration of the control signal according to the presence or absence of the additional reference signal.

[0163] In a communication device according to an embodiment of the present disclosure, when there is the additional reference signal, the control circuit may set, in common information common to a plurality of destination devices in the control signal, a bitmap indicating the presence or absence of the additional reference signal separately for each destination device.

[0164] In a communication device according to an embodiment of the present disclosure, when there is the additional reference signal, the control circuit may set information regarding the additional reference signal in individual information for each of a plurality of destination devices in the control signal.

[0165] In a communication device according to an embodiment of the present disclosure, the control circuit may change a method of notifying information regarding the additional reference signal using the control signal according to the number of destination devices having the additional reference signal.

[0166] In a communication device according to an embodiment of the present disclosure, the control circuit may set, in individual information for each of a plurality of destination devices in the control signal, information indicating a combination of information regarding the additional reference signal and Modulation and Coding Scheme (MCS).

[0167] In a communication device according to an embodiment of the present disclosure, the control circuit may set, in individual information for each of a plurality of destination devices in the control signal, allocation information of row components of a mapping matrix to be added to the additional reference signal.

[0168] A communication device according to an embodiment of the present disclosure includes a receiving circuit that receives a control signal including information regarding an additional reference signal for each destination device, and a control circuit that determines the additional reference signal to be used for channel estimation based on the information regarding the additional reference signal.

[0169] In a communication method according to an embodiment of the present disclosure, a communication device sets information regarding an additional reference signal for each destination device in a control signal and transmits the control signal.

[0170] In a communication method according to an embodiment of the present disclosure, a communication device receives a control signal including information regarding an additional reference signal for each destination device, and determines the additional reference signal to be used for channel estimation based on the information regarding the additional reference signal.

[0171] The disclosures of the specification, drawings, and abstract included in Japanese Patent Application No. 2021-005046 filed on January 15, 2021 are all incorporated herein by reference.

Industrial Applicability

[0172] An embodiment of the present disclosure is useful for a wireless communication system.

Description of Symbols

[0173] 100 Downlink wireless transmission device 101, 101a, 201, 201a Wireless reception unit 102, 102a Received signal decoding unit 103, 103a Scheduling unit 104, 104a Data generation unit 105, 105a Data encoding unit 106, 106a Data modulation unit 107, 107a Preamble generation unit 108, 108a, 208, 208a Wireless transmission unit 200 Downlink wireless reception device 202, 202a Preamble demodulation unit 203 Extra-LTF discrimination unit 203a P-matrix discrimination unit 204, 204a Channel estimation unit 205, 205a Data demodulation unit 206, 206a Data decoding unit 207, 207a Transmission signal generation unit

Claims

[

1. ] A control circuit that sets information regarding additional reference signals for each destination device in an Extremely High Throughput Physical Layer Convergence Procedure Protocol Data Unit (EHT PPDU), a transmission circuit that transmits the EHT PPDU, comprising: the information is included in the Common field of the EHT SIG as a surplus subfield of the U-SIG, the control circuit sets the number of EHT Long Training Fields (EHT-LTFs) in the EHT PPDU to be greater than the number of EHT-LTFs determined based on the number of spatial streams, a communication device. [

2. ] The information regarding the additional reference signal is information indicating the presence or absence of the additional reference signal, The communication device according to claim 1. [

3. ] The information regarding the additional reference signal is information indicating the number of the additional reference signals, The communication device according to claim 1. [

4. ] The information regarding the additional reference signal is information indicating a multiple of the original number of the reference signals, The communication device according to claim 1. [

5. ] A communication device sets information regarding additional reference signals for each destination device in an Extremely High Throughput Physical Layer Convergence Procedure Protocol Data Unit (EHT PPDU), transmits the EHT PPDU, the information is included in the Common field of the EHT SIG as a surplus subfield of the U-SIG, the number of EHT Long Training Fields (EHT-LTFs) in the EHT PPDU is set to be greater than the number of EHT-LTFs determined based on the number of spatial streams, a communication method. [

6. ] A control process that sets information regarding additional reference signals for each destination device in an Extremely High Throughput Physical Layer Convergence Procedure Protocol Data Unit (EHT PPDU), a transmission process that transmits the EHT PPDU, controls, the information is included in the Common field of the EHT SIG as a surplus subfield of the U-SIG, The control circuit sets the number of EHT Long Training Fields (EHT-LTFs) in the EHT PPDU to be greater than the number of EHT-LTFs determined based on the number of spatial streams. Integrated circuit.

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