Communication device, information processing device, control method, and program

Abstract

To allow a PHY frame to communicate information that communication is performed using nine or more streams.SOLUTION: A PHY preamble is used that has L-STF, L-LTF, L-SIG, EHT-SIG-A including a 4-bit or more field indicating the number of space-time streams, EHT-STF, and EHT-LTF, in that order.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an apparatus compliant with the IEEE802.11 series standards.

Background Art

[0002] As a communication standard for wireless local area networks (Wireless LAN), the IEEE802.11 series standards are known. In the IEEE802.11ax standard, high peak throughput is achieved by using MIMO technology that communicates using multiple antennas (Patent Document 1). Note that MIMO is an abbreviation for Multi-Input Multi-Output.

[0003] Currently, as a successor standard to the IEEE802.11ax standard for further throughput improvement, a Study Group called IEEE802.11 EHT (Extremely High Throughput) has been established.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As one of the measures for throughput improvement aimed at by EHT, increasing the number of space-time streams (hereinafter referred to as SS) of the MIMO method to a maximum of 16 has been considered.

[0006] However, conventionally, there has been no PHY preamble configuration capable of notifying that the number of streams is 9 or more, and it has not been possible to notify in the PHY preamble that the number of streams is, for example, 16.

[0007] In view of the above problems, an object of the present invention is to enable communication in a PHY frame when the number of streams is 9 or more.

Means for Solving the Problems

[0008] The communication device of the present invention has transmission means for transmitting a first frame compliant with the IEEE802.11 standard and having a PHY preamble and a data field. The PHY preamble has a Legacy Short Training Field (L-STF), a Legacy Long Training Field (L-LTF), a Legacy Signal Field (L-SIG), a first Short Training Field (STF), and a first Long Training Field (LTF). In the PHY preamble, the first STF is arranged behind the L-SIG, and further, between the L-SIG and the first STF, there is a sub-field of 4 or more consecutive bits indicating at least the number of streams used for communication. A 1-bit subfield indicating information regarding Coding, and It has a signal field having a sub-field of 4 consecutive bits used for CRC, and the data field includes data transmitted using a stream corresponding to the number of streams stored in a sub-field of 4 or more consecutive bits indicating the number of streams.

[0009] Also, a communication device according to another aspect of the present invention is a communication device. Receiving means for receiving a frame having a PHY preamble and a data field compliant with the IEEE802.11 standard, and processing means for processing the frame received by the receiving means, wherein the PHY preamble includes a Legacy Short Training Field (L-STF), a Legacy Long Training Field (L-LTF), a Legacy Signal Field (L-SIG), a first Short Training Field (STF), and a first Long Training Field (LTF). In the PHY preamble, the first STF is arranged behind the L-SIG, and further, between the L-SIG and the first STF, there is a sub-field of at least 4 consecutive bits indicating the number of streams used for communication. A 1-bit subfield indicating information regarding Coding, and A signal field having a sub-field of 4 consecutive bits used for CRC, and the processing means processes the data transmitted using the stream corresponding to the number of streams stored in the sub-field of 4 consecutive bits included in the data field and indicating the number of streams.

[0010] Also, an information processing apparatus according to another aspect of the present invention includes generating means for generating a frame having a PHY preamble and a data field compliant with the IEEE802.11 standard. The PHY preamble includes a Legacy Short Training Field (L-STF), a Legacy Long Training Field (L-LTF), a Legacy Signal Field (L-SIG), a first Short Training Field (STF), and a first Long Training Field (LTF). In the PHY preamble, the first STF is arranged behind the L-SIG, and further, between the L-SIG and the first STF, there is a sub-field of at least 4 consecutive bits indicating the number of streams used for communication. A 1-bit subfield indicating information regarding Coding, andIt has a signal field having a continuous 4-bit subfield used for CRC, and the data field contains data transmitted using a stream corresponding to the number of streams stored in a continuous subfield of 4 bits or more indicating the number of streams.

Advantages of the Invention

[0011] According to the present invention, it is possible to communicate in a PHY frame that the number of streams is 9 or more.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0013] FIG. 1 shows an example of a network configuration according to the present embodiment. The wireless communication system in FIG. 1 is a wireless network composed of a base station 102 and a plurality of stations (hereinafter, STAs) 103, 104, and 105. Here, the base station 102 is, for example, an Access Point (hereinafter, AP) compliant with the IEEE802.11 series standards. However, it is not limited to this, and the base station 102 may be a Group Owner (hereinafter, GO) compliant with the Wi-Fi Direct standard. When the base station 102 is a GO, the plurality of STAs 103 to 105 are also called Clients. Note that IEEE is an abbreviation for The Institute of Electrical and Electronics Engineers.

[0014] The base station 102 constructs a wireless network 101 and transmits a beacon including the identification information of the wireless network. Here, the dotted line shown as the wireless network 101 in FIG. 1 indicates the range that the signal transmitted by the base station 102 can reach, and the base station 102 can communicate with the STAs within the range of the dotted line. Further, the base station 102 may have a relay function.

[0015] When the base station 102 receives a Probe Request signal (probe request) from an STA, it transmits a Probe Response signal (probe response) including the identification information as a response. Note that the identification information of the wireless network is, for example, a Service Set Identifier (hereinafter, SSID).

[0016] Also, the base station 102 communicates with each of the STAs 103 to 105 according to the wireless communication method of the IEEE802.11 EHT standard. The base station 102 establishes a wireless link with each of the STAs 103 to 105 via a predetermined association process or the like. Further, the base station 102 and each of the STAs 103 to 105 have a plurality of antennas, and high-throughput data transmission by MIMO communication is possible. For example, when each of the base station 102 and the STA has 16 antennas, MIMO communication of 16 streams (Space-Time Stream) is possible in the communication between the base station 102 and the STA.

[0017] Here, MIMO is an abbreviation for Multi-Input Multi-Output, and it is a technology in which a plurality of antennas of a single or a plurality of communication devices use the same channel at the same time to improve the utilization efficiency of channel resources. In this embodiment, the communication using the MIMO technology is called MIMO communication.

[0018] In particular, MIMO communication performed between the base station 102 and one STA is called single-user MIMO (hereinafter referred to as SU MIMO). On the other hand, MIMO communication performed between the base station 102 and multiple STAs is called multi-user MIMO (hereinafter referred to as MU MIMO).

[0019] FIG. 2 shows the hardware configuration of each of the base station 102 and STAs 103 to 105 (hereinafter collectively referred to as communication devices). The communication device includes a storage unit 201, a control unit 202, a functional unit 203, an input unit 204, an output unit 205, a communication unit 206, and a plurality of antennas 207.

[0020] The storage unit 201 is composed of one or more memories such as ROM and RAM, and stores programs for performing various operations described later and various information such as communication parameters for wireless communication. Note that, as the storage unit 201, in addition to memories such as ROM and RAM, storage media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, and DVDs may be used. Further, the storage unit 201 may include a plurality of memories and the like.

[0021] The control unit 202 is composed of one or more processors such as a CPU or MPU, an ASIC (application-specific integrated circuit), a DSP (digital signal processor), an FPGA (field programmable gate array), etc. Here, CPU is the initials of Central Processing Unit, and MPU is the initials of Micro Processing Unit. By executing the program stored in the storage unit 201, the communication device is controlled. Note that the control unit 202 may control the communication device in cooperation with the program stored in the storage unit 201 and the OS (Operating System). Further, the control unit 202 may be composed of a plurality of processors such as a multi-core, and control the communication device.

[0022] In addition, the control unit 202 controls the functional unit 203 to execute a predetermined function. The predetermined function is, for example, an imaging function if the communication device is a camera. Also, for example, if the communication device is a printer, it is a printing function. Also, for example, if the communication device is a projector, it is a projection function. The predetermined function is not limited to these, and various functions are conceivable. Note that the functional unit 203 is hardware for executing the predetermined function.

[0023] The input unit 204 receives various operations from the user. The output unit 205 performs various outputs to the user. Here, the output by the output unit 205 includes at least one of display on the screen, audio output by the speaker, vibration output, etc. Note that both the input unit 204 and the output unit 205 may be realized by one module such as a touch panel.

[0024] The communication unit 206 controls wireless communication compliant with the IEEE802.11 EHT standard, wireless communication compliant with Wi-Fi, IP (Internet Protocol) communication control, etc. Also, the communication unit 206 controls the antenna 207 to transmit and receive wireless signals for wireless communication. Since the antenna 207 corresponds to 16-stream MIMO communication of the IEEE802.11 EHT standard, it has 16 antennas here. Note that the number of antennas 207 is not limited to 16.

[0025] Next, in this embodiment, the frame configuration transmitted and received by the communication device for wireless communication compliant with the IEEE802.11 EHT standard will be described with reference to FIGS. 3 and 4. FIG. 3 is an EHT SU (Single User) PPDU (Physical layer Protocol Data Unit) as a first example of the frame. The EHT SU PPDU is a frame used when performing SU MIMO communication. Note that the Physical layer is abbreviated as PHY.

[0026] Figure 4 shows an EHT ER (Extended Range) SU (Single User) PPDU (Physical layer Protocol Data Unit) as a second frame example. The EHT ER SU PPDU is a frame used when performing SU MIMO communication with an extended communication range. These are collectively referred to as EHT PPDU.

[0027] The EHT PPDU has a physical layer (Physical Layer, hereinafter PHY) preamble and a data field. The PHY preamble includes an STF (Short Training Field), an LTF (Long Training Field), and a SIG (Signal Field).

[0028] First, the frame structure of the EHT SU PPDU will be described using FIG. 3. The EHT SU PPDU in FIG. 3 is a PPDU used in SU MIMO communication.

[0029] A PHY preamble is arranged at the beginning of the EHT SU PPDU. In the PHY preamble, in order to maintain backward compatibility with legacy devices, L-STF 301, L-LTF 302, and L-SIG 303 are arranged in this order from the beginning. Here, a legacy device refers to a Non-EHT device (a device not compliant with the EHT standard), that is, a device compliant with any one of the IEEE802.11a / b / g / n / ac / ax standards.

[0030] Also, L-STF is an abbreviation for Legacy Short Training Field and is used for detection of PHY frame signals, automatic gain control (AGC), timing detection, etc.

[0031] L-LTF302 is arranged immediately after L-STF301. L-LTF is the abbreviation of Legacy Long Training Field and is used for high-precision frequency and time synchronization, acquisition of propagation channel information (CSI), etc. Note that CSI is the abbreviation of Channel State Information.

[0032] Also, L-SIG303 is arranged immediately after L-LTF302. L-SIG is the abbreviation of Legacy Signal Field and is used to transmit control information including data transmission rate and PHY frame length information.

[0033] The above various legacy fields (L-STF301, L-LTF302, and L-SIG303) have the same configuration as the frames of IEEE802.11a / b / g / n / ac / ax. Thus, legacy devices can decode the data of the above various legacy fields.

[0034] EHT-SIG-A305 is arranged immediately after L-SIG303. EHT-SIG-A is the abbreviation of Extremely High Throughput (EHT) Signal A Field and is composed of EHT-SIG-A1 and EHT-SIG-A2 in this order. EHT-SIG-A1 contains the information shown in Table 1, and EHT-SIG-A2 contains the information shown in Table 2. These information are used for the reception processing of EHT PPDU.

[0035] Note that RL-SIG304 may be arranged between L-SIG303 and EHT-SIG-A305. RL-SIG304 is the abbreviation of Repeated L-SIG and is a field containing the same content as L-SIG303.

[0036]

Table 1

[0037]

Table 2

[0038] Here, the number of Space-Time Streams (SS) included in EHT-SIG-A1, that is, the field indicating the number of streams, will be described. Here, this field is called the NSTS And Midamble Periodicity field. The NSTS And Midamble Periodicity field consists of 4 bits and is located at B23 to B26, which indicates 23 bits after the leading bit of EHT-SIG-A1.

[0039] The number of streams indicated by this field varies depending on the value of the Doppler field in EHT-SIG-A2. When the value of the Doppler field is 0, it indicates that the channel variation is small, and the number of streams can be set from 1 to 16. Here, the value obtained by subtracting 1 from the actual number of streams is stored in this field. That is, for example, when representing 1 stream, all 4 bits are set to "0", and when representing 16 streams, for example, all 4 bits are set to "1" and stored.

[0040] On the other hand, when the value of the Doppler field is 1, it indicates that the channel variation is large, and the number of streams to be set is limited to 1 to 8. In this case, only the first 3 bits indicate the number of streams. Even in this case, since the last 1 bit in the NSTS And Midamble Periodicity field indicates the midamble period, 4 bits are ensured as the field length.

[0041] Note that regardless of the value of the Doppler field, the number of SSs may be set from 1 to 16.

[0042] Also, in this embodiment, since 4 bits are allocated to the NSTS And Midamble Periodicity field, the maximum number of streams that can be indicated is 16. However, assuming an extension in a subsequent standard of the IEEE 802.11 EHT standard, 5 bits or more may be allocated so that a larger number of streams than 16 can be indicated. By allocating 4 bits or more to the NSTS And Midamble Periodicity field in this way, a number of streams of 9 or more can be indicated.

[0043] Immediately after the EHT-SIG-A305 including such stream number information, the EHT-STF306 is arranged. EHT-STF is an abbreviation for Extremely High Throughput (EHT) Short Training Field and is used to improve automatic gain control in MIMO communication.

[0044] And immediately after the EHT-STF306, the EHT-LTF307 is arranged. EHT-LTF is an abbreviation for Extremely High Throughput (EHT) Long Training Field and is used for channel estimation in MIMO communication.

[0045] Immediately after the EHT-LTF307, the data field 308 is arranged. Note that a Packet extention 309, which is an extension field, may be arranged immediately after the data field 308. The data field 308 contains data of MIMO communication transmitted with the number of streams indicated by the NSTS And Midamble Periodicity field of the EHT-SIG-A1.

[0046] A communication device that has received an EHT SU PPDU recognizes the number of streams based on the NSTS And Midamble Periodicity field of the EHT-SIG-A1. Then, by performing processing according to the recognized number of streams, for example, reception processing of data of MIMO communication transmitted with 16 streams is performed.

[0047] Next, the frame structure of the EHT ER SU PPDU will be described with reference to FIG. 4. The EHT ER SU PPDU also has the same configuration as the EHT SU PPDU. That is, the fields are arranged in the order of L-STF401, L-LTF402, L-SIG403, EHT-SIG-A405, EHT-STF406, HE-LTF407, and data field 408. Similarly, an RL-SIG404 may be arranged between the L-SIG403 and the EHT-SIG-A405. Similarly, a Packet extention409 may be arranged immediately after the data field 408. Also, since the information included in each field is the same as the content included in each field of the EHT SU PPDU, the description thereof will be omitted.

[0048] Next, the operation of the communication device when transmitting or receiving these frames will be described. When the base station 102 transmits an EHT PPDU, the control unit 202 of the base station 102 generates data to be included in the data field 308 or 408. This generation is realized by the control unit 202 reading and executing a program stored in the storage unit 201 of the base station 102. Then, a frame including the data and including the above PHY preamble is generated by the control unit 202, or the communication unit 206, or by their cooperation. Then, the communication unit 206 transmits the generated frame via the antenna 207.

[0049] On the one hand, the communication unit 206 of STA103 receives an EHT PPDU having the above frame configuration from the base station 102. Then, the control unit 202 or the communication unit 206 of STA103 refers to the NSTS And Midamble Periodicity field included in the EHT-SIG-A1 of the PHY preamble to recognize the number of streams in the data field. And the communication unit 206 of STA103 performs processing according to the recognized number of streams, for example, performs reception processing of data of MIMO communication transmitted with 16 streams. Then, the control unit 202 acquires the data obtained by the reception processing from the communication unit 206. Based on the data thus obtained, the control unit 202 of STA103 performs various controls such as output control (display, printing, etc. of data).

[0050] In addition to the base station 102 and STA103 to 105 which are communication devices, it is also possible to implement the above on an information processing device (for example, a chip) that generates the PHY preamble. In this case, it is preferable that the information processing device can be connected to a plurality of antennas.

[0051] By using the above frame configuration of the EHT PPDU, it is possible to communicate in the PHY frame that the number of streams is 9 or more. In the above description, EHT was described as an abbreviation for Extremely High Throughput, but it may also be interpreted as an abbreviation for Extreme High Throughput.

[0052] Also, in the EHT-SIG-A of the PHY preamble in the EHT MU PPDU, which is a PPDU used in MU MIMO communication, the NSTS And Midamble Periodicity field may not be present. That is, when the base station 102 transmits an EHT MU PPDU, there is no field of 4 bits or more indicating the number of streams in the EHT-SIG-A included in the EHT MU PPDU. Also, in the PHY preamble of the beacon or Probe Response signal transmitted by the base station 102, although the legacy field is included, the EHT-SIG-A may not be included. In this way, the base station 102 can also switch whether to arrange the EHT-SIG-A and whether to arrange a field of 4 bits or more indicating the number of streams in the EHT-SIG-A according to the signal to be transmitted.

[0053] Also, the order of the sub-fields of EHT-SIG-A1 and A2 is not limited to the above example and can be appropriately interchanged. Also, some or all of the sub-fields other than the NSTS And Midamble Periodicity field may not be present. Note that when the Doppler field does not exist, the NSTS And Midamble Periodicity field may be defined in the same way as when the value of the Doppler field is 0.

[0054] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium and causing one or more processors in a computer of the system or device to read and execute the program. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

Claims

1. A communication device, comprising transmission means for transmitting a frame having a PHY preamble and a data field compliant with the IEEE 802.11 standard, wherein the PHY preamble includes a Legacy Short Training Field (L-STF), a Legacy Long Training Field (L-LTF), a Legacy Signal Field (L-SIG), a first Short Training Field (STF), and a first Long Training Field (LTF), and has, in the PHY preamble, the first STF is arranged behind the L-SIG, and further between the L-SIG and the first STF, there is included a signal field having at least a continuous 4-bit or more sub-field indicating the number of streams used for communication, a 1-bit sub-field indicating information regarding Coding, and a continuous 4-bit sub-field used for CRC, and the data field includes data transmitted using a stream corresponding to the number of streams stored in the sub-field. The communication device is characterized by this.

2. The communication device according to claim 1, characterized in that a Repeated Legacy Signal Field (RL-SIG) is further included between the L-SIG and the field of the PHY preamble.

3. The communication device further includes a plurality of antennas, and the transmission means transmits the frame via the plurality of antennas. The communication device according to claim 1 or 2 is characterized by this.

4. The communication device according to any one of claims 1 to 3, characterized in that a sub-field for storing Spatial Reuse information is included at a position before the sub-field of the PHY preamble and behind the L-SIG.

5. The communication device according to any one of claims 1 to 4, wherein the frame is a SU (Single User) PPDU (Physical layer Protocol Data Unit).

6. The communication device according to any one of claims 1 to 4, wherein the frame is an ER (Extended Range) SU (Single User) PPDU (Physical layer Protocol Data Unit).

7. The communication device according to any one of claims 1 to 6, wherein the subfield is 4 bits.

8. The communication device according to any one of claims 1 to 7, wherein information indicating that the number of streams used for communication with respect to the subfield is 16 is stored in the frame transmitted by the transmitting means when a predetermined condition is satisfied.

9. A communication device, a receiving means for receiving a frame having a PHY preamble and a data field compliant with the IEEE802.11 standard, a processing means for processing the frame received by the receiving means, having, the PHY preamble includes a Legacy Short Training Field (L-STF), a Legacy Signal Field (L-SIG), a first Short Training Field (STF), and a first Long Training Field (LTF), having, In the PHY preamble, the first STF is arranged behind the L-SIG, and further, between the L-SIG and the EHT-STF, there is included a signal field having a sub-field of at least 4 consecutive bits indicating the number of streams used for communication, a sub-field of 1 bit indicating information regarding Coding, and a sub-field of 4 consecutive bits used for CRC. The processing means processes data transmitted using a stream corresponding to the number of streams included in the data field and stored in the sub-field. A communication device characterized by this.

10. The communication device further has a plurality of antennas. The receiving means receives the frame via the plurality of antennas. The communication device according to claim 9, characterized by this.

11. An information processing device, A generating means for generating a frame having a PHY preamble and a data field compliant with the IEEE 802.11 standard, having, The PHY preamble has a Legacy Short Training Field (L-STF), a Legacy Long Training Field (L-LTF), a Legacy Signal Field (L-SIG), a first Short Training Field (STF), and a first Long Training Field (LTF). having, In the PHY preamble, the first STF is arranged behind the L-SIG, and further, between the L-SIG and the first STF, there is included a signal field having a sub-field of at least 4 consecutive bits indicating the number of streams used for communication, a sub-field of 1 bit indicating information regarding Coding, and a sub-field of 4 consecutive bits used for CRC. The data field includes data transmitted using a stream corresponding to the number of streams stored in the sub-field. An information processing apparatus characterized by the above.

12. A control method for a communication device, A PHY preamble including at least a Legacy Short Training Field (L-STF), a Legacy Long Training Field (L-LTF), a Legacy Signal Field (L-SIG), a first Short Training Field (STF), and a first Long Training Field (LTF), wherein the arrangement relationship of the fields in the PHY preamble is such that the first STF is arranged behind the L-SIG, and further, between the L-SIG and the first STF, there is arranged a first field including at least a continuous 4-bit or more sub-field indicating the number of streams used for communication, a 1-bit sub-field indicating information regarding Coding, and a continuous 4-bit sub-field used for CRC, and a transmission step of transmitting a frame including a data field including data transmitted using a stream corresponding to the number of streams stored in the sub-field.

13. A control method for a communication device, A receiving step of receiving a frame having a PHY preamble and a data field, A processing step of processing the frame received in the receiving step, having, The PHY preamble has a Legacy Short Training Field (L-STF), a Legacy Long Training Field (L-LTF), a Legacy Signal Field (L-SIG), a first Short Training Field (STF), and a first Long Training Field (LTF). In the PHY preamble, the first STF is arranged behind the L-SIG, and further between the L-SIG and the first STF, there is a field including at least a continuous sub-field of 4 bits or more indicating the number of streams used for communication, a 1-bit sub-field indicating information regarding Coding, and a continuous 4-bit sub-field used for CRC. The processing step is a communication device characterized by processing data transmitted using a stream corresponding to the number of streams included in the data field and stored in the sub-field.

14. A control method for an information processing device, A PHY preamble including at least a Legacy Short Training Field (L-STF), a Legacy Long Training Field (L-LTF), a Legacy Signal Field (L-SIG), a first Short Training Field (STF), and a first Long Training Field (LTF), wherein the arrangement relationship of the fields in the PHY preamble is such that the first STF is arranged behind the L-SIG, and further between the L-SIG and the first STF, there is arranged a first field including at least a continuous sub-field of 4 bits or more indicating the number of streams used for communication, a 1-bit sub-field indicating information regarding Coding, and a continuous 4-bit sub-field used for CRC, and a control method characterized by having a generation step of generating a frame having a data field including data transmitted using a stream corresponding to the number of streams stored in the sub-field.

15. A program for operating a computer as the communication device according to any one of Claims 1 to 10.

16. A program for operating a computer as the information processing device according to Claim 11.

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