Communication device, communication method, and integrated circuit

Abstract

To provide a technique for MIMO channel estimation.SOLUTION: A communication device includes: a circuit that generates a physical layer protocol data unit (PPDU) to be transmitted with single frequency resources, the PPDU including a first field indicating a first number of a symbol of a long training field (LTF) for estimating a multiple-input multiple-output (MIMO) channel, the first number being greater than a second number of the symbol of the LTF determined based on the number of spatial streams (Nss); and a transmitter that transmits the PPDU.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to a communication device and a communication method for channel estimation, and more particularly, to a communication device and a communication method for channel estimation in a multiple-input multiple-output (MIMO) wireless network.

Background Art

[0002] In the standardization of next-generation wireless local area networks (WLANs), new wireless access technologies having backward compatibility with IEEE802.11a / b / g / n / ac / ax technologies are being studied in the IEEE802.11 working group and are named Extremely High Throughput (EHT) WLANs.

[0003] In EHT WLANs, in order to greatly increase the peak throughput and capacity compared to 802.11ax High Efficiency (HE) WLANs, it is desirable to increase the maximum number of spatial streams from 8 to 16, particularly in the case of multi-user MIMO (MU-MIMO) transmission.

[0004] However, there has been no study on a communication device and a communication method for MIMO channel estimation in the context of EHT WLANs.

[0005] Therefore, there is a need for a communication device and a communication method that provide a feasible technical solution for MIMO channel estimation in the context of EHT WLANs. Furthermore, other desirable functions and features will become apparent by reading the following detailed description and the claims in conjunction with the accompanying drawings and this background art of the present disclosure.

Summary of the Invention

[0006] One non - limiting and exemplary embodiment contributes to providing an apparatus for MIMO channel estimation in the context of EHT WLAN.

[0007] According to an embodiment of the present disclosure, there is provided a communication device comprising: a circuit configured to generate a Physical Layer Protocol Data Unit (PPDU) transmitted on a single frequency resource, the PPDU including a first field indicating a first number of symbols of a Long Training Field (LTF) for estimating a Multiple - input multiple - output (MIMO) channel, the first number being greater than a second number of the symbols of the LTF determined based on the number of spatial streams (Nss); and a transmitter configured to transmit the PPDU.

[0008] According to an embodiment of the present disclosure, there is provided a communication method including: generating a Physical Layer Protocol Data Unit (PPDU) transmitted on a single frequency resource, the PPDU including a first field indicating a first number of symbols of a Long Training Field (LTF) for estimating a Multiple - input multiple - output (MIMO) channel, the first number being greater than a second number of the symbols of the LTF determined based on the number of spatial streams (Nss); and transmitting the PPDU.

[0009] Note that a general or specific embodiment may be implemented as a system, a method, an integrated circuit, a computer program, a storage medium, or any optional combination thereof.

[0010] Further benefits and advantages of the disclosed embodiments will become apparent from the specification and the drawings. These benefits and / or advantages may be obtained individually by the various embodiments and features of the specification and the drawings, provided that not all of these features are required to obtain one or more of such benefits and / or advantages.

Brief Description of the Drawings

[0011] Embodiments of the present disclosure will be more deeply understood and readily apparent to those skilled in the art by reading further with reference to the drawings in conjunction with the following description, which is described only as an example below. It will be understood by those skilled in the art that the elements in the figures are shown in a concise and clear manner and are not necessarily drawn to scale. For example, the dimensions of some elements in the illustrations, block diagrams, or flowcharts may be exaggerated relative to other elements for a better understanding of the present disclosure.

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Mode for Carrying Out the Invention

[0012] Some embodiments of the present disclosure will be described by way of example only with reference to the drawings. Similar reference numerals and reference characters in the drawings refer to similar or identical elements.

[0013] In the following paragraphs, certain exemplary embodiments are described in relation to an access point (AP) and a station (STA) that estimate channels, particularly in a MIMO wireless network.

[0014] In the context of IEEE802.11 (Wi-Fi (registered trademark; hereinafter omitted) technology), a station (also sometimes referred to synonymously as STA) is a communication device having the ability to use the 802.11 protocol. Based on the definition of IEEE802.11-2007, a STA can be any device including an IEEE802.11-2007 compliant medium access control (MAC) and physical layer (PHY) interface to a wireless medium (WM).

[0015] For example, a STA may be a laptop, a desktop personal computer (PC), a personal digital assistant (PDA), an access point, or a Wi-Fi phone in a wireless local area network (WLAN) environment. A STA may be stationary or mobile. In a WLAN environment, the terms "STA", "wireless client", "user", "user device", and "node" are often used synonymously.

[0016] Similarly, an AP (also sometimes referred to synonymously as a wireless access point (WAP) in the context of IEEE802.11 (Wi-Fi) technology) is a communication device that enables a STA within a WLAN to connect to a wired network. An AP is typically connected (via a wired network) to a router as a stand-alone device, although the AP may be an integral part of the router itself.

[0017] As described above, a STA in a WLAN can function as an AP in various cases, and vice versa. This is because a communication device in the context of IEEE802.11 (Wi-Fi) technology can include both the hardware elements of a STA and the hardware elements of an AP. Thus, the communication device can switch between the STA mode and the AP mode based on the actual WLAN state and / or requirements.

[0018] In a MIMO wireless network, "multiple" means a plurality of antennas used simultaneously for transmission and a plurality of antennas used simultaneously for reception through all wireless channels. In this regard, "multiple-input" means a plurality of transmitter antennas that input a wireless signal into a channel, and "multiple-output" means a plurality of receiver antennas that receive a wireless signal from the channel into a receiver. For example, in an N×M MIMO network system, N is the number of transmitter antennas and M is the number of receiver antennas, and N may or may not be equal to M. In the present disclosure, for the sake of brevity, the number of transmitter antennas and the number of receiver antennas will not be further discussed.

[0019] In a MIMO wireless network, single-user communication and multi-user communication can be carried out for communication between communication devices such as an AP and a STA.

[0020] Figure 1A shows a schematic diagram of single-user MIMO communication 100 between AP 102 and STA 104 in a MIMO wireless network. As shown, the MIMO wireless network can include one or more STAs (e.g., STA 104, STA 106, etc.). In single-user MIMO communication 100, AP 102 uses multiple antennas (e.g., four antennas as shown in Figure 1A) to transmit multiple spatial streams, and all spatial streams are directed to one communication device (i.e., STA 104). For the sake of brevity, the multiple spatial streams directed to STA 104 are shown as grouped data transmission arrows 108 directed to STA 104.

[0021] Single-user MIMO communication 100 may be configured for two-way transmission. As shown in Figure 1A, in single-user MIMO communication 100, STA 104 can use multiple antennas (e.g., two antennas as shown in Figure 1A) to transmit multiple spatial streams, and all spatial streams are directed to AP 102. For the sake of brevity, the multiple spatial streams directed to AP 102 are shown as grouped data transmission arrows 110 directed to AP 102.

[0022] Therefore, the single-user MIMO communication 100 shown in Figure 1A enables both uplink single-user transmission and downlink single-user transmission in a MIMO wireless network.

[0023] Figure 1B shows the format of a physical layer protocol data unit (PPDU) 150 used for the single-user MIMO communication shown in Figure 1A. Such a PPDU 150, also referred to as a single-user PPDU by synonym, may be used for both downlink single-user transmission and uplink single-user transmission.

[0024] For example, when the MIMO wireless network is a next-generation WLAN with ultra-high throughput (such as an EHT WLAN where the maximum number of spatial streams increases from 8 to 16), the single-user PPDU 150 shown in FIG. 1B can include a non-high-throughput short training field (L-STF), a non-high-throughput long training field (L-LTF), a non-high-throughput signal field (L-SIG), a repeated L-SIG (RL-SIG), an ultra-high-throughput signal A (EHT-SIG-A) field 154, an ultra-high-throughput short training field (EHT-STF), an ultra-high-throughput long training field (EHT-LTF) 152, a data field, and a packet extension (PE) field. It should be understood that if the IEEE802.11 working group uses a new name instead of "EHT WLAN" for the next-generation WLAN with ultra-high throughput, the prefix "EHT" in the above fields may change accordingly.

[0025] In a single-user PPDU and any other type of PPDU, the EHT-LTF is used to provide information for a receiver (the receiver of the STA in downlink transmission or the receiver of the AP in uplink transmission) to estimate the channel used by a transmitter (the transmitter of the AP in downlink transmission or the transmitter of the STA in uplink transmission) for communication. The data field is of variable length and carries the user data payload.

[0026] In the single-user PPDU 100, the transmitter provides training for N STS,total spatiotemporal streams used for the transmission of a physical layer service data unit (PSDU) in a predetermined resource unit (RU) of the data field, where N STS,totalrepresents the number of resource units (RUs) in the time-frequency domain in RU. For example, when the bandwidth of a single-user PPDU 100 is 20 MHz, a given RU is a 242-tone RU. Various types of RUs are defined in IEEE 802.11ax.

[0027] FIG. 2A shows a schematic diagram of downlink multi-user MIMO communication 200 between an AP 202 and multiple STAs 204, 206, 208 in a MIMO wireless network.

[0028] A MIMO wireless network can include one or more STAs (e.g., STA 204, STA 206, STA 208, etc.). In downlink multi-user MIMO communication 200, the AP 202 uses multiple antennas to simultaneously transmit multiple streams to the STAs 204, 206, 208 within the network. For example, two spatial streams can be directed to STA 206, another spatial stream can be directed to STA 204, and yet another spatial stream can be directed to STA 208. For the sake of brevity, the two spatial streams directed to STA 206 are shown as grouped data transmission arrows 212, the spatial stream directed to STA 204 is shown as a data transmission arrow 210, and the spatial stream directed to STA 208 is shown as a data transmission arrow 214.

[0029] FIG. 2B shows the format of a PPDU 250 used for downlink multi-user MIMO communication between an AP and multiple STAs. Such a PPDU 250 is referred to as a multi-user PPDU 250.

[0030] As shown in FIG. 2B, when the MIMO wireless network is an ultra-high throughput network (such as an EHT WLAN), the multi-user PPDU 250 may be referred to as an EHT MU PPDU 250 and includes an L-STF, an L-LTF, an L-SIG, an RL-SIG, an EHT-SIG-A field 254, an ultra-high throughput signal B (EHT-SIG-B) field 256, an EHT-STF, an EHT-LTF 252, a data field, and a PE field. Compared with the single-user PPDU 150, the multi-user PPDU 250 includes additional signal fields (e.g., EHT-SIG-B 256), which signal user-specific resource allocation information (e.g., the number of spatial-temporal streams, starting stream index, allocated RUs) for each of the multiple STAs / users communicating with the AP. It should be understood that if the IEEE802.11 working group uses a new name instead of "EHT WLAN" for the next generation of ultra-high throughput WLANs, the prefix "EHT" in the above fields may change accordingly.

[0031] As described above, the EHT-LTF in the multi-user PPDU 250 is used to provide information for the receiver (i.e., the receiver of the STA in downlink multi-user MIMO communication) to estimate the channel used by the transmitter (i.e., the transmitter of the AP in downlink multi-user MIMO communication) for communication. The data field is of variable length and carries the user data payload.

[0032] In the multi-user PPDU 250, the transmitter provides training for the N STS,r,total spatial-temporal streams used for transmitting the PSDU in the r-th RU of the data field, where N STS,r,total represents the number of spatial-temporal streams across all STAs / users in the r-th RU.

[0033] To enable uplink multi-user transmission in multi-user MIMO communication, trigger based communication is provided to a MIMO wireless network. In this regard, FIG. 3A shows a schematic diagram of uplink multi-user MIMO communication 300 (i.e., trigger based communication 300) between an AP 302 and a plurality of STAs 304, 306, 308 in a MIMO wireless network.

[0034] Since a plurality of STAs 304, 306, 308 participate in trigger based MIMO communication, in order to manage uplink transmission in trigger based MIMO communication, the AP 302 needs to coordinate the simultaneous transmission of the plurality of STAs 304, 306, 308.

[0035] To do so, as shown in FIG. 3A, the AP 302 simultaneously transmits trigger information 309, 311, 313 to the plurality of STAs 304, 306, 308 to indicate user-specific resource allocation information (e.g., the number of spatio-temporal streams, the leading stream index, the allocated RUs) that each STA can use. The trigger information is included in a trigger frame, or in the MAC header of a Control Wrapper frame, a Quality of Service (QoS) Data frame, or a management frame. The plurality of STAs 304, 306, 308 can prepare for uplink transmissions 310, 312, 314 to the AP 302 according to the user-specific resource allocation information indicated in the trigger information in response to the trigger information.

[0036] FIG. 3B shows the format of a PPDU 350 used for trigger based communication between an AP and a plurality of STAs. Such a PPDU is referred to as a trigger based PPDU 350.

[0037] In the trigger-based PPDU 350, the transmitter of user u in the r-th RU uses N STS,r,u space-time streams for training for the N STS,r,u space-time streams in the r-th RU for user u, where N

[0038] As shown in Figure 3B, when the MIMO wireless network is an ultra-high throughput network (such as an EHT WLAN), the trigger-based PPDU 350 includes the same fields as those included in the single-user PPDU 150, provided that the EHT-STF in the trigger-based PPDU 350 can have a longer duration than the EHT-STF in the single-user PPDU 150.

[0039] It should be understood that Figures 1A, 2A, and 3A are shown for the purpose of exemplifying the mechanisms of the single-user MIMO communication or multi-user MIMO communication described above. For the sake of brevity, specific components (such as transmitters, receivers, etc.) of the APs 102, 202, 302 and STAs 104, 106, 204, 206, 208, 304, 306, 308 are not shown.

[0040] Furthermore, for the sake of brevity, each of the APs 102, 202, 302 in Figures 1A, 2A, and 3A is shown as including four antennas for data transmission. It will be understood by those skilled in the art that the APs 102, 202, 302 may include more antennas in order to achieve high throughput. For example, when the MIMO wireless network is an ultra-high throughput network (such as an EHT WLAN where the maximum number of spatial streams is 16 as described above), each of the APs 102, 202, 302 can include 16 antennas for data transmission. The number of antennas each of the STAs 104, 106, 204, 206, 208, 304, 306, 308 has can vary accordingly.

[0041] Embodiments of the present disclosure provide various technical solutions for channel estimation in the single-user MIMO communication or multi-user MIMO communication described above. As a more important and advantageous point, the technical solutions of the present disclosure contribute to channel estimation in a very high throughput MIMO wireless network (such as an EHT WLAN where the maximum number of spatial streams increases from 8 to 16).

[0042] To support communication in a next-generation WLAN (e.g., EHT WLAN) where the maximum number of spatial streams increases from 8 to 16, the EHT-LTFs of the single-user PPDU 150, multi-user PPDU 250, and trigger-based PPDU 350 need to support up to 16 spatial streams.

[0043] However, the long training fields (LTFs) of various types of PPDUs in existing technologies cannot support up to 16 spatial streams. For example, in the HE WLAN introduced in IEEE802.11ax, the high-efficiency long training field (HE-LTF) of the HE PPDU can only support up to 8 spatial streams.

[0044] To support communication in a next-generation WLAN (e.g., EHT WLAN) where the maximum number of spatial streams increases from 8 to 16, the present disclosure advantageously provides a communication device and a communication method configured to construct / generate an EHT-LTF to support up to 16 spatial streams for channel estimation in the single-user MIMO communication or multi-user MIMO communication described above.

[0045] FIG. 4 shows a schematic diagram partially sectionalized of a communication device 400 in MIMO communication according to various embodiments of the present disclosure. The communication device 400 may be implemented as an AP 102, 202, 302 or a STA 104, 106, 204, 206, 208, 304, 306, 308 according to various embodiments.

[0046] As shown in FIG. 4, the communication device 400 generally includes at least one wireless transmitter 402, at least one wireless receiver 404, a plurality of antennas 412 (for the sake of simplicity, only one antenna is shown in FIG. 4 for illustration), and at least one controller 406. The controller 406 is used in the software and hardware-assisted execution of tasks (including the control of communication with one or more other transmission devices in a MIMO wireless network) designed to be executed. At least one controller 406 can control at least one transmission signal generator 408 that generates a PPDU transmitted to one or more other communication devices through at least one wireless transmitter 402, and at least one reception signal processor 410 that processes the PPDU received from one or more other communication devices through at least one wireless receiver 404. As shown in FIG. 4, at least one transmission signal generator 408 and at least one reception signal processor 410 can be stand-alone modules of the communication device 400 that communicate with at least one controller 406 for the functions described above. Alternatively, at least one transmission signal generator 408 and at least one reception signal processor 410 may be included in at least one controller 406. Those skilled in the art will understand that the configuration of these functional modules is flexible and can vary according to actual needs and / or requirements. A data processing device, a storage device, and other related control devices may be provided on a suitable circuit board and / or chipset. In various embodiments, during operation, at least one wireless transmitter 402, at least one wireless receiver 404, and at least one antenna 412 may be controlled by at least one controller 406.

[0047] In the embodiment shown in FIG. 4, at least one wireless receiver 404, together with at least one reception signal processor 410, forms the receiver of the communication device 400. This receiver of the communication device 400 provides the functions necessary for channel estimation during operation.

[0048] In some embodiments, at least one wireless transmitter 402 can transmit a PPDU to one or more other communication devices in a MIMO wireless network during operation. The PPDU includes an LTF (i.e., EHT-LTF) that facilitates one or more other communication devices to estimate respective channels for respective communications with the communication device.

[0049] For example, in downlink single-user MIMO communication, the communication device 400 is an AP, and one or more other communication devices in the MIMO wireless network are STAs. During operation, at least one wireless transmitter 402 of the AP 400 transmits a PPDU in the format of a single-user PPDU to the receiver of the STA.

[0050] Similarly, in uplink single-user MIMO communication, the communication device 400 is an STA, and one or more other communication devices in the MIMO wireless network are APs. During operation, at least one wireless transmitter 402 of the STA 400 transmits a PPDU in the format of a single-user PPDU to the receiver of the AP.

[0051] In downlink multi-user MIMO communication, the communication device 400 is an AP, and one or more other communication devices in the MIMO wireless network include a plurality of STAs. During operation, at least one wireless transmitter 402 of the AP 400 transmits a PPDU in the format of a multi-user PPDU to the receiver of each STA of the plurality of STAs.

[0052] In trigger-based MIMO communication, the communication device 400 is an STA, and one or more other communication devices in the MIMO wireless network are APs. During operation, at least one wireless transmitter 402 of the STA 400 transmits a PPDU in the format of a trigger-based PPDU to the receiver of the AP.

[0053] In a single-user PPDU, a multi-user PPDU, or a trigger-based PPDU, the LTF includes a plurality of LTF symbols for a receiver of one or more other communication devices to estimate respective channels for respective communications with a transmitter of the communication device in single-user communication or multi-user communication.

[0054] In the present disclosure, at least one controller 406 of the communication device 400 sets the number (N LTF ) of LTF symbols for generating the LTF in the PPDU.

[0055] In some examples, in downlink single-user MIMO communication and downlink multi-user MIMO communication, at least one controller 406 of the AP 400 determines N LTF when setting N LTF to generate a single-user PPDU or a multi-user PPDU. In uplink single-user MIMO communication, at least one controller 406 of the STA 400 determines N LTF when setting N LTF to generate a single-user PPDU.

[0056] In some other examples, in trigger-based MIMO communication, N LTF is determined by at least one controller of the AP and is included in the trigger information as described above. When the STA 400 receives the trigger information from the AP, at least one controller 406 of the STA 400 sets NLTF by extracting N LTF from the trigger information and generates a trigger-based PPDU.

[0057] In various embodiments of the present disclosure, N LTF depends on the maximum value (N STSMAX ) of the number of spatio-temporal streams for each RU in the PPDU. That is, N STSMAX is equal to the maximum value of N r for r = 0,..., N STS,r,total - 1 (N ris the number of RUs in the data field of the PPDU). As described above, to support communication in next-generation WLANs where the maximum number of spatial streams increases from 8 to 16, the LTF of the single-user PPDU, multi-user PPDU, or trigger-based PPDU in the present disclosure supports up to 16 spatial streams. In this regard, N in the PPDU STSMAX may be 9 or more.

[0058] FIG. 5 shows an example of the N LTF determination according to the first embodiment of the present disclosure. In this example, at least one controller 406 of the AP 400 (in downlink single-user MIMO communication, downlink multi-user MIMO communication, and trigger-based MIMO communication) or at least one controller 406 of the STA 400 (in uplink single-user MIMO communication) determines N STSMAX When is even, N LTF is determined to be equal to N in the PPDU STSMAX , and when N STSMAX is an odd number other than 1, N LTF is determined to be equal to N in the PPDU STSMAX +1.

[0059] As shown in the N LTF determination table 500 of FIG. 5, when N in the PPDU STSMAX is an even number such as 2, 4, 6, 8, 10, 12, 14, or 16, N LTF is determined to be equal to N STSMAX 2, 4, 6, 8, 10, 12, 14, or 16. When N in the PPDU STSMAX is an odd number other than 1, such as 3, 5, 7, 9, 11, 13, or 15, N LTF is determined to be equal to N STSMAX +1 (i.e., 2, 4, 6, 8, 10, 12, 14, or 16).

[0060] In this example, when the MIMO communication is downlink single-user MIMO communication, at least one controller 406 of the AP 400, when generating a PPDU in the format of a single-user PPDU, has N in the SIG-A (i.e., EHT-SIG-A) field STSMAX (i.e., N STS,total ) shown. In this way, after the receiver of the STA decodes the SIG-A field, in order to estimate the channels available for communication with the AP 400, it can derive N STSMAX from N LTF .

[0061] When the MIMO communication is uplink single-user MIMO communication, at least one controller 406 of the STA 400, when generating a PPDU in the format of a single-user PPDU, has N STSMAX (i.e., N STS,total ) shown. In this way, after the receiver of the AP decodes the SIG-A field, in order to estimate the channels available for communication with the STA 400, it can derive N STSMAX from N LTF .

[0062] When the MIMO communication is downlink multi-user MIMO communication, at least one controller 406 of the AP 400, when generating a PPDU in the format of a multi-user PPDU, shows N LTF in the SIG-A field, and shows user-specific resource allocation information for each user in the SIG-B (i.e., EHT-SIG-B) field. The user-specific resource allocation information includes the number of spatio-temporal streams, the starting stream index, and the allocated RUs. In this way, the receiver of the STA can directly extract N LTF from the SIG-A field in order to estimate the channels available for communication with the AP 400, and can derive its own user-specific resource allocation information from the SIG-B field.

[0063] When the MIMO communication is trigger-based MIMO communication, for each user, user-specific resource allocation information (e.g., the number of spatio-temporal streams, the starting stream index, and the allocated RUs) and N LTF are determined by the AP and notified to each of the STAs 400 participating in the trigger-based MIMO communication within the trigger information. The trigger information triggers the trigger-based MIMO communication when received by each of the STAs 400. In this scenario, the PPDU in the format of the trigger-based PPDU generated by at least one transmission signal generator 408 of the STAs 400 does not include N LTF and the user-specific resource allocation information. Because the AP is the one that first determines N LTF and the user-specific resource allocation information, the AP already recognizes N LTF and the user-specific resource allocation information.

[0064] (In the receivers of STAs (in downlink single-user MIMO communication and downlink multi-user MIMO communication) or the receivers of APs (in uplink single-user MIMO communication and trigger-based MIMO communication)) To enable MIMO channel estimation, all spatio-temporal streams are spread across the data tones of all LTF symbols by one row of the P LTF matrix. Different spatio-temporal streams use different rows of the P LTF matrix. How the LTF symbols in the single-user PPDU, multi-user PPDU, or trigger-based PPDU are generated according to the P LTF matrix is detailed in IEEE802.11ax.

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[0065] Figures 6A and 6B show two examples of N LTF determination according to the second embodiment of this disclosure. In this embodiment, at least one controller 406 of the AP 400 (in downlink single-user MIMO communication, downlink multi-user MIMO communication, and trigger-based MIMO communication) or at least one controller 406 of the STA 400 (in uplink single-user MIMO communication) STSMAX when N is an odd number smaller than the threshold, N LTF is determined to be equal to N + 1 in the PPDU, and when N STSMAX is an odd number greater than or equal to the threshold, N STSMAX is determined to be equal to N in the PPDU. Further, when N LTF in the PPDU is an even number, at least one controller 406 of the AP 400 (in downlink single-user MIMO communication, downlink multi-user MIMO communication, and trigger-based MIMO communication) or at least one controller 406 of the STA 400 (in uplink single-user MIMO communication) STSMAX determines N to be equal to N STSMAX . LTF is determined to be equal to N STSMAX .

[0066] For example, N in FIG. 6A LTF As shown in the decision table 600, the threshold may be set to 5. In this example, when N in the PPDU STSMAX is an odd number (such as 3) smaller than the threshold 5, N LTF is determined to be equal to N STSMAX +1, that is, 4. When N STSMAX is an odd number (such as 5, 7, 9, 11, 13, or 15) greater than or equal to the threshold 5, N LTF is determined to be equal to N STSMAX 5, 7, 9, 11, 13, or 15. Further, when N in the PPDU STSMAX is an even number (such as 2, 4, 6, 8, 10, 12, 14, or 16), N LTF is determined to be equal to N STSMAX 2, 4, 6, 8, 10, 12, 14, or 16.

[0067] In another example, N in FIG. 6B LTF As shown in the decision table 650, the threshold may be set to 7. In this example, when N in the PPDU STSMAX is an odd number (such as 3 or 5) smaller than the threshold 7, N LTF is determined to be equal to N STSMAX +1, that is, 4 or 6. When N STSMAX is an odd number (such as 7, 9, 11, 13, or 15) greater than or equal to the threshold 7, N LTF is determined to be equal to N STSMAX 7, 9, 11, 13, or 15. Further, when N in the PPDU STSMAX is an even number (such as 2, 4, 6, 8, 10, 12, 14, or 16), N LTF is determined to be equal to N STSMAX 2, 4, 6, 8, 10, 12, 14, or 16.

[0068] In the embodiments shown in FIGS. 6A and 6B, to enable MIMO channel estimation at the receiver of the STA (in downlink single-user MIMO communication and downlink multi-user MIMO communication) or at the receiver of the AP (in uplink single-user MIMO communication and trigger-based MIMO communication), all spatio-temporal streams are P as defined below LTF spread over the data tones of all LTF symbols by one row of the matrix. Different spatio-temporal streams use different rows of the P LTF matrix. How the LTF symbols in a single-user PPDU, multi-user PPDU, or trigger-based PPDU are generated according to the P LTF matrix is detailed in IEEE802.11ax When the threshold is 5

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[0069] In equations (2) and (3), P 4×4 , P 6×6 , P 8×8 , P 12×12 , and P 16×16 are the same as those described above, and P 5×5 , P 7×7 , P 9×9 , P 10×10 , P 11×11 , P 13×13 , P 14×14 , and P 15×15 are defined as follows in this disclosure

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[0070] In the above embodiments, in single-user MIMO communication for uplink and downlink, downlink multi-user MIMO communication, and trigger-based MIMO communication, N LTF can be determined or derived, and the threshold may be prestored and memorized in both the AP and the STA.

[0071] Alternatively, the threshold may be settable by the AP. When the threshold is settable, the threshold may be indicated by the AP among the information elements that carry the BSS (Basic Service Set) operation parameters and can be included in the beacon frame, probe response frame, association response frame, or reassociation response frame. In this case, N LTF can be determined or derived, and the threshold retrieved from the most recently received information element in uplink single-user MIMO communication and downlink single-user MIMO communication is memorized in the STA.

[0072] The channel quality should be good enough to support a larger N, and thus, when a larger N STSMAX is used in the data field, it should be noted that the channel estimation accuracy does not decrease even if the number of LTF symbols is small. Thus, according to the second embodiment of the present disclosure, the physical layer (PHY) throughput can be advantageously improved when a larger N STSMAX is used in data transmission. STS is used.

[0073] Considering the first and second embodiments shown in FIGS. 5, 6A, and 6B, in uplink and downlink single-user MIMO communications, downlink multi-user MIMO communications, and trigger-based MIMO communications, an N LTF predetermined and stored in both the AP and the STA in advance so that N LTF can be determined or derived. The N STSMAX and N LTF can be shown by a correspondence relationship between

[0074] Alternatively, in a third embodiment of the determination of N according to the present disclosure, the correspondence relationship between N LTF and N STSMAX and N LTF need not be predetermined. At least one controller 406 of the AP 400 (in downlink single-user MIMO communication, downlink multi-user MIMO communication, and trigger-based MIMO communication) or at least one controller 406 of the STA 400 (in uplink single-user MIMO communication) determines N LTF for each PPDU, the correspondence relationship between N STSMAX and N LTF may be set on a case-by-case basis.

[0075] In the third embodiment, the duration of the data field of the PPDU is (for example, a higher MCS and / or a larger NSTSMAX When it is relatively short (due to, for example, a lower MCS and / or a smaller N), from the perspective of PHY throughput, the importance of reducing the LTF overhead becomes higher than the importance of improving the channel estimation accuracy. Therefore, N LTF may be equal to N STSMAX . It should be noted that the channel quality should be good enough to support a higher MCS and / or a larger N STSMAX . In such a case, when a higher MCS and / or a larger N STSMAX are used in the data field, the channel estimation accuracy does not decrease even if the number of LTF symbols is small.

[0076] On the other hand, when the duration of the data field of the PPDU is relatively long (due to, for example, a lower MCS and / or a smaller N STSMAX ), from the perspective of PHY throughput, the importance of reducing the LTF overhead becomes lower than the importance of improving the channel estimation accuracy. Therefore, N LTF may be larger than N STSMAX .

[0077] In a third embodiment, at least one controller 406 of the AP 400 in downlink single-user MIMO communication or at least one controller 406 of the STA 400 in uplink single-user MIMO communication shows both N STSMAX (i.e., N STS,total ), and the correspondence between N STSMAX and N LTF when generating a PPDU in the format of a single-user PPDU. For example, in the SIG-A field, 1-bit signaling can be used to indicate whether N LTF is equal to N STSMAX or equal to N STSMAX +1. Similarly, N LTF is equal to N STSMAX , equal to N STSMAX +1, equal to N STSMAX +2, or NSTSMAX To indicate whether it is equal to +3, 2-bit signaling can be used.

[0078] In the third embodiment, when the MIMO communication is downlink multi-user MIMO communication or trigger-based MIMO communication, the signaling requirements are the same as those required in the embodiment shown in FIG. 5.

[0079] It will be understood by those skilled in the art that the third embodiment advantageously further improves the PHY throughput.

[0080] In the third embodiment, in order to enable MIMO channel estimation in the receiver of the STA (in downlink single-user MIMO communication and downlink multi-user MIMO communication) or the receiver of the AP (in uplink single-user MIMO communication and trigger-based MIMO communication), all space-time streams are spread over the data tones of all LTF symbols by one row of the P LTF matrix (2). Different space-time streams use different rows of the P LTF matrix. How the LTF symbols in a single-user PPDU, multi-user PPDU, or trigger-based PPDU are generated according to the P LTF matrix is detailed in IEEE802.11ax.

[0081] The third embodiment may be used in combination with the first embodiment or the second embodiment. As an example, at least one controller 406 of the AP 400 in downlink single-user MIMO communication or at least one controller 406 of the STA 400 in uplink single-user MIMO communication first follows the first embodiment shown in FIG. 5 or the second embodiment shown in FIGS. 6A and 6B, N STSMAX based on N LTF the initial value of (i.e., N LTF,iniDetermine . Next, at least one controller 406 of the AP 400 in downlink single-user MIMO communication or at least one controller 406 of the STA 400 in uplink single-user MIMO communication, when generating a PPDU in the format of a single-user PPDU, within the SIG-A field, N STSMAX (i.e., N STS,total ), and both the correspondence between N LTF,ini and N LTF are shown. For example, in the SIG-A field, to indicate whether N LTF is equal to N LTF,ini or equal to N LTF,ini + 1, 1-bit signaling can be used. Similarly, to indicate whether N LTF is equal to N LTF,ini , equal to N LTF,ini + 1, equal to N LTF,ini + 2, or equal to N LTF,ini + 3, 2-bit signaling can be used.

[0082] In another example, at least one controller 406 of the AP 400 in downlink single-user MIMO communication or at least one controller 406 of the STA 400 in uplink single-user MIMO communication, when generating a PPDU in the format of a single-user PPDU, within the SIG-A field, N STSMAX (i.e., N STS,total ) and both a threshold are shown. For example, in the SIG-A field, to indicate whether the threshold is 3 or 5, 1-bit signaling can be used. Thus, according to the N LTF determination table shown in FIG. 6A or FIG. 6B, N STSMAX in the SIG-A field and the threshold can be used to derive N LTF .

[0083] FIG. 7 shows an exemplary flowchart for generating an LTF in a PPDU in a communication device according to the second embodiment shown in FIGS. 6A and 6B. This flowchart is suitable for facilitating channel estimation in uplink single-user MIMO communication, downlink single-user MIMO communication, and downlink multi-user MIMO communication. In downlink single-user MIMO communication and downlink multi-user MIMO communication, the communication device is an AP. In uplink single-user MIMO communication, the communication device is a STA.

[0084] In step 702, the communication device determines N in the PPDU. STSMAX The PPDU may be a single-user PPDU in uplink and downlink single-user MIMO communications, or a multi-user PPDU in downlink multi-user MIMO communication.

[0085] In step 704, the communication device sets N by determining N based on a threshold and N. STSMAX For details of the determination of N, refer to the description related to FIGS. 6A and 6B. LTF LTF LTF

[0086] In step 706, the communication device determines a P matrix based on N. LTF LTF The P matrix may be selected from a predetermined P matrix based on N. In step 708, the communication device generates an LTF based on the P matrix, N, and N. Then, the generated LTF is transmitted by the wireless transmitter of the communication device together with other fields in the PPDU. LTF LTF LTF LTF LTF STSMAX

[0087] It will be understood that the above steps 702, 704, 706, and 708 may be performed by the same or different components of the communication device. For example, the above steps 702, 704, 706, and 708 may be performed by a controller of the communication device, a transmission signal processor of the communication device, or any other component of the communication device that is deemed appropriate.

[0088] FIG. 8 shows a flowchart of estimating a channel in a communication device during downlink or uplink single-user MIMO communication according to the second embodiment shown in FIGS. 6A and 6B. In downlink single-user MIMO communication, the communication device is a STA. In uplink single-user MIMO communication, the communication device is an AP.

[0089] In step 802, the communication device extracts N STSMAX (i.e., N STS,total ) from the signaling information field in the received PPDU. The received PPDU may be a single-user PPDU. The signaling information field may be the SIG-A field of the single-user PPDU as described above.

[0090] In step 804, the communication device determines N STSMAX based on a threshold and N LTF . Details of the determination of N LTF are described in connection with FIGS. 6A and 6B.

[0091] In step 806, the communication device determines a P LTF matrix based on N LTF . The P LTF matrix may be selected from a predetermined P LTF matrix based on N LTF . In step 808, the communication device uses the P LTF matrix, N LTF , and N STSMAX in single-user MIMO communication.Based on this, channel estimation is performed using the LTF of the received PPDU.

[0092] It will be understood that the above steps 802, 804, 806, and 808 may be performed by the same or different components of the communication device. For example, the above steps 802, 804, 806, and 808 may be performed by a controller of the communication device, a receiver of the communication device, or any other component of the communication device that is actually considered appropriate.

[0093] FIG. 9 shows a flowchart for estimating a channel at a STA during downlink multi-user MIMO communication according to the second embodiment shown in FIGS. 6A and 6B.

[0094] In step 902, the STA extracts N from the signaling information field in the PPDU received from the AP. LTF The PPDU may be a multi-user PPDU. The signaling information field may be the SIG-A field of the multi-user PPDU as described above.

[0095] In step 904, the STA determines a P matrix based on N for subsequent channel estimation. LTF based on LTF The P matrix LTF may be selected from a predetermined P matrix based on N. LTF based on LTF predetermined

[0096] In step 906, the STA determines its user-specific resource allocation information from another signaling information in the multi-user PPDU. This another signaling information field may be the SIG-B field of the multi-user PPDU. The user-specific resource allocation information includes the number of spatio-temporal streams, the start stream index, and the allocated RUs.

[0097] In step 908, the STA uses the LTF of the received PPDU to perform channel estimation based on the P LTF matrix, N LTF , and its own user-specific resource allocation information.

[0098] It will be understood that the above steps 902, 904, 906, and 908 may be performed by the same or different components of the STA. For example, the above steps 902, 904, 906, and 908 may be performed by a controller of the STA, a receiver of the STA, or any other component of the STA that is actually considered appropriate.

[0099] FIG. 10 shows a flowchart for generating the LTF in the PPDU at the STA according to the second embodiment shown in FIGS. 6A and 6B. This flowchart is suitable for facilitating channel estimation in trigger-based MIMO communication.

[0100] In step 1002, the STA receives trigger information from the AP. The trigger information triggers trigger-based MIMO communication.

[0101] In step 1004, the STA sets N LTF by extracting N LTF from the trigger information. The STA also extracts its own user-specific resource allocation information from the trigger information.

[0102] As shown in FIG. 10, N LTF in the trigger information is determined by the AP in step 1001. Step 1001 includes two sub-steps 1001a and 1001b. a. In step 1001a, the AP determines N STSMAX in the PPDU. b. In step 1001b, the AP determines N STSMAX based on a threshold and N LTFBy determining N LTF is set.

[0103] In step 1006, the STA determines the P LTF matrix based on N LTF for generating a subsequent trigger-based PPDU. The P LTF matrix may be selected from a predetermined P LTF matrix based on N LTF and may be selected from a predetermined P

[0104] In step 1008, the STA generates the LTF based on the P LTF matrix, N LTF , and its user-specific resource allocation information.

[0105] Subsequently, the generated LTF is transmitted by the STA's wireless transmitter to the AP for channel estimation in trigger-based MIMO communication together with other fields in the PPDU.

[0106] It will be understood that the above steps 1002, 1004, 1006, and 1008 may be performed by the same or different components of the STA. For example, the above steps 1002, 1004, 1006, and 1008 may be performed by the STA's controller, the STA's transmission signal generator, or any other component of the STA that is considered appropriate.

[0107] FIG. 11 shows a flowchart for estimating a channel at an AP during trigger-based MIMO communication according to the second embodiment shown in FIGS. 6A and 6B.

[0108] In step 1102, the AP determines the P LTF matrix based on the N LTF determined in step 1001b for generating a subsequent trigger-based PPDU. The P LTF matrix may be selected from a predetermined P LTF matrix based on N LTF and may be selected from a predetermined P

[0109] In step 1104, the AP performs channel estimation using the LTF of the received PPDU for each user / STA in trigger-based MIMO communication based on the P LTF matrix and user-specific resource allocation information for each user. The received PPDU may be a trigger-based PPDU. The user-specific resource allocation information includes the allocated RU, the number of spatio-temporal streams, and the starting stream index.

[0110] It will be understood that the above steps 1102 and 1104 may be performed by the same or different components of the AP. For example, the above steps 1102 and 1104 may be performed by a controller of the AP, a receiver of the AP, or any other component of the AP that is actually considered appropriate.

[0111] FIG. 12 shows a flowchart for generating the LTF in the PPDU in a communication device according to the above-described third embodiment (not shown). This flowchart is suitable for facilitating channel estimation in uplink single-user MIMO communication, downlink single-user MIMO communication, and downlink multi-user MIMO communication. In downlink single-user MIMO communication and downlink multi-user MIMO communication, the communication device is the AP. In uplink single-user MIMO communication, the communication device is the STA.

[0112] In step 1202, the communication device determines the N STSMAX in the PPDU. The PPDU may be a single-user PPDU in uplink single-user MIMO communication and downlink single-user MIMO communication, or a multi-user PPDU in downlink multi-user MIMO communication.

[0113] In step 1204, the communication device determines N STSMAX based on NLTF By determining, N LTF is set. N LTF Details of the determination of N are described in connection with the third embodiment of the present disclosure.

[0114] In step 1206, the communication device determines a P LTF matrix based on N LTF matrix. The P LTF matrix may be selected from a predetermined P LTF matrix based on N LTF matrix.

[0115] In step 1208, the communication device generates an LTF based on the P LTF matrix, N LTF , and N STSMAX . Then, the generated LTF is transmitted by the wireless transmitter of the communication device together with other fields in the PPDU.

[0116] It will be understood that steps 1202, 1204, 1206, and 1208 above may be performed by the same or different components of the communication device. For example, steps 1202, 1204, 1206, and 1208 above may be performed by a controller of the communication device, a transmission signal generator of the communication device, or any other component of the communication device that is considered appropriate.

[0117] FIG. 13 shows a flowchart of channel estimation in a communication device during uplink single-user MIMO communication and downlink single-user MIMO communication according to the third embodiment described above. In downlink single-user MIMO communication, the communication device is a STA. In uplink single-user MIMO communication, the communication device is an AP.

[0118] In step 1302, the communication device obtains N STSMAX and N LTFExtract it. The received PPDU may be a single-user PPDU. The signaling information field may be the SIG-A field of the single-user PPDU as described above.

[0119] In step 1304, the communication device determines the P LTF matrix based on N LTF . The P LTF matrix may be selected from a predetermined P LTF matrix based on N LTF .

[0120] In step 1306, the communication device uses the LTF of the received PPDU to perform channel estimation based on the P LTF matrix, N LTF , and N STSMAX in downlink single-user MIMO communication or uplink single-user MIMO communication.

[0121] It will be understood that steps 1302, 1304, and 1306 above may be performed by the same or different components of the communication device. For example, steps 1302, 1304, and 1306 above may be performed by a controller of the communication device, a receiver of the communication device, or any other component of the communication device that is actually considered appropriate.

[0122] FIG. 14 shows a flowchart for estimating a channel at a STA during downlink multi-user MIMO communication according to the third embodiment.

[0123] Steps 1402, 1404, 1406, and 1408 are the same as steps 902, 904, 906, and 908 described in connection with FIG. 9.

[0124] Figure 15 shows a flowchart for generating the LTF in the PPDU at the STA according to the third embodiment. This flowchart is suitable for facilitating channel estimation in trigger-based MIMO communication.

[0125] In step 1502, the STA receives trigger information from the AP. The trigger information triggers trigger-based MIMO communication.

[0126] In step 1504, the STA extracts N LTF and its own user-specific resource allocation information from the trigger information.

[0127] As shown in Figure 15, N in the trigger information LTF is determined by the AP in step 1501. Step 1501 includes two sub-steps 1501a and 1501b. a. In step 1501a, the AP determines N in the PPDU STSMAX . b. In step 1501b, the AP sets N STSMAX by determining N LTF based on N LTF and the duration of the data field in the PPDU.

[0128] In step 1506, the STA determines the P LTF matrix based on N LTF for subsequent LTF generation. The P LTF matrix may be selected from a predetermined P LTF matrix based on N LTF .

[0129] In step 1508, the STA generates the LTF based on the P LTF matrix, N LTF , and its own user-specific resource allocation information.

[0130] Thereafter, the generated LTF is transmitted by the STA's wireless transmitter to the AP for channel estimation in trigger-based MIMO communication, together with other fields in the PPDU.

[0131] It will be understood that the above steps 1502, 1504, 1506, and 1508 may be executed by the same or different components of the STA. For example, the above steps 1502, 1504, 1506, and 1508 may be executed by the STA's controller, the STA's transmission signal generator, or any other component of the STA that is actually considered appropriate.

[0132] FIG. 16 shows a flowchart of channel estimation at the AP during trigger-based MIMO communication according to the third embodiment.

[0133] Steps 1602 and 1604 are the same as steps 1102 and 1104 described in relation to FIG. 11.

[0134] FIG. 17 shows another schematic example of a communication device in single-user MIMO communication and multi-user MIMO communication according to the various embodiments described above. This communication device can serve the role of the AP.

[0135] Similar to the schematic example of the communication device shown in FIG. 4, the communication device 1700 in the schematic example of FIG. 17 includes at least one wireless transmitter 1702, at least one wireless receiver 1704, a plurality of antennas 1712 (for the sake of simplicity, only one antenna is shown in FIG. 17), and at least one controller 1706. The controller 1706 is used in the software and hardware-assisted execution of tasks (including the control of communication with one or more other transmitting devices in a MIMO wireless network) that it is designed to perform. At least one controller 1706 can control at least one transmission signal generator 1708 that generates a PPDU to be transmitted to one or more other communication devices through the wireless transmitter 1702 in downlink single-user MIMO communication and downlink multi-user MIMO communication, and at least one received signal processor 1710 that processes the PPDU received from one or more other communication devices through the wireless receiver 1704 in uplink single-user MIMO communication and trigger-based MIMO communication. At least one controller 1706 of the AP 1700 may also be used to control the generation of a PPDU carrying trigger information for trigger-based MIMO communication. As shown in FIG. 17, at least one transmission signal generator 1708 and at least one received signal processor 1710 may be stand-alone modules of the communication device 1700 that communicate with at least one controller 1706 for the functions described above. Alternatively, at least one transmission signal generator 1708 and at least one received signal processor 1710 may be included in at least one controller 1706. Those skilled in the art will understand that the configuration of these functional modules is flexible and can vary according to actual needs and / or requirements. A data processing device, a storage device, and other related control devices may be provided on a suitable circuit board and / or chipset. In various embodiments, during operation, at least one wireless transmitter 1702, at least one wireless receiver 1704, and at least one antenna 1712 may be controlled by at least one controller 1706.

[0136] At least one controller 1706 of the AP 1700 may include an N LTF decider 1742, a scheduler 1714, and a control information analyzer 1716. The scheduler 1714 may be configured to generate user-specific resource allocation information (e.g., the number of spatio-temporal streams, the starting stream index, and the allocated RUs) for each user / STA in downlink multi-user MIMO communication and trigger-based MIMO communication during operation, or to generate user-specific resource allocation information (e.g., the number of spatio-temporal streams) for a user in downlink single-user MIMO communication. N LTF The decider 1742 may be configured to determine an N for generating an LTF in a PPDU based on user-specific resource allocation information in downlink MIMO communication, trigger-based MIMO communication, and downlink single-user MIMO communication during operation. LTF The control information analyzer 1716 may be configured to cooperate with the received signal processor 1710 to control channel estimation and data demodulation.

[0137] At least one transmission signal generator 1708 may include a P LTF matrix generator 1718, a trigger information generator 1720, an LTF generator 1722, and a PPDU generator 1724. P LTF The matrix generator 1718 may be configured to determine a P matrix based on the N provided by the generator 1742 during operation. LTF The N provided by the generator 1742 LTF Based on the N, a P LTF matrix. The LTF generator 1722 may be configured to generate an LTF based on the P matrix generated by the matrix generator 1718 and the N provided by the generator 1742 during operation. LTF The P matrix generated by the matrix generator 1718 LTF matrix and the N LTF The N provided by the generator 1742 LTFand the user-specific resource allocation information provided by the scheduler 1714. In operation, the PPDU generator 1724 can generate a PPDU including the LTF generated by the LTF generator 1722 in accordance with the user-specific resource allocation information provided by the scheduler 1714.

[0138] At least one receiving signal processor 1710 is LTF The control information analyzer 1716 may include a matrix generator 1726, a data demodulator and decoder 1728, a channel estimator 1730, and a control information demodulator and decoder 1732. In operation, the control information demodulator and decoder 1732 may demodulate and / or decode a SIG-A field of a single-user PPDU or a trigger-based PPDU received via the wireless receiver 1704. The control information analyzer 1716 may extract N STSMAX , N LTF , and user specific resource allocation information, and in the case of trigger-based PPDUs, the scheduler 1714 to N STSMAX , N LTF , and obtain user-specific resource allocation information for each user. P LTF The matrix generator 1726 uses the N LTF Based on P LTF The channel estimator 1730 can generate a matrix based on the N STSMAX , N LTF , and user-specific resource allocation information, and P LTF P generated by the matrix generator 1726 LTF In operation, the data demodulator and decoder 1728 may demodulate and / or decode a data field of a received PPDU based on the user specific resource allocation information provided by the control information analyzer 1716 and the estimated MIMO channel provided by the channel estimator 1730.

[0139] FIG. 18 shows another schematic example of a communication device in single-user MIMO communication and multi-user MIMO communication according to the various embodiments described above. This communication device can serve as an STA.

[0140] Similar to the schematic example of the communication device shown in FIGS. 4 and 17, the communication device 1800 in FIG. 18 includes at least one wireless transmitter 1802, at least one wireless receiver 1804, a plurality of antennas 1812 (for the sake of brevity, only one antenna is shown in FIG. 18), and at least one controller 1806. The controller 1806 is used in the software and hardware-assisted execution of tasks (including the control of communication with one or more other transmission devices in a MIMO wireless network) designed to be executed. At least one controller 1806 can control at least one transmission signal generator 1808 that generates a PPDU transmitted to one or more other communication devices through the wireless transmitter 1802 in uplink single-user MIMO communication and trigger-based MIMO communication, and at least one reception signal processor 1810 that processes the PPDU received from one or more other communication devices through the wireless receiver 1804 in downlink single-user MIMO communication and downlink multi-user MIMO communication. As shown in FIG. 18, at least one transmission signal generator 1808 and at least one reception signal processor 1810 may be stand-alone modules of the communication device 1800 that communicate with at least one controller 1806 for the functions described above. Alternatively, at least one transmission signal generator 1808 and at least one reception signal processor 1810 may be included in at least one controller 1806. Those skilled in the art will understand that the configuration of these functional modules is flexible and can vary according to actual needs and / or requirements. A data processing device, a storage device, and other related control devices may be provided on a suitable circuit board and / or chipset. In various embodiments, during operation, at least one wireless transmitter 1802, at least one wireless receiver 1804, and at least one antenna 1812 may be controlled by at least one controller 1806.

[0141] At least one controller 1806 of STA 1800 is N LTFIt may include a determiner 1842, a scheduler 1814, a control information analyzer 1816, and a trigger information analyzer 1822. The scheduler 1814 may be configured to generate user-specific resource allocation information (e.g., the number of spatio-temporal streams) for a user in uplink single-user MIMO communication during operation. N LTF The determiner 1842 may be configured to determine, during operation, an N for generating an LTF in a PPDU based on user-specific resource allocation information in uplink single-user MIMO communication. LTF The control information analyzer 1816 may be configured to control channel estimation and data demodulation in cooperation with the reception signal processor 1810. The trigger information analyzer 1822 may be configured to extract, during operation, N LTF and its own user-specific resource allocation information from the trigger information received through the reception signal processor 1810 and the radio receiver 1804 with the assistance of the control information analyzer 1816.

[0142] At least one transmission signal generator 1808 may include a P LTF matrix generator 1818, an LTF generator 1820, and a PPDU generator 1824. P LTF The matrix generator 1818 may be configured to determine a P LTF matrix based on N provided by the generator 1842 or N provided by the trigger information analyzer 1822 in trigger-based MIMO communication in uplink single-user MIMO communication during operation. LTF The LTF generator 1820 may be configured to, during operation, use the P LTF matrix generated by the matrix generator 1818 and N LTF matrix and N provided by the generator 1842. LTF N LTF provided by the generator 1842. LTFBased on the user-specific resource allocation information provided by the scheduler 1814 in uplink single-user MIMO communication or the user-specific resource allocation information of its own provided by the trigger information analyzer 1822 in trigger-based MIMO communication, an LTF can be generated. During operation, the PPDU generator 1824 can generate a PPDU including the LTF generated by the LTF generator 1820 according to the user-specific resource allocation information provided by the scheduler 1814 in single-user MIMO communication or the user-specific resource allocation information of its own provided by the trigger information analyzer 1822 in trigger-based MIMO communication.

[0143] At least one receive signal processor 1810 is P LTF It may include a matrix generator 1826, a data demodulator / decoder 1828, a channel estimator 1830, and a control information demodulator / decoder 1832. During operation, the control information demodulator / decoder 1832 can demodulate and / or decode both the SIG-A field of the single-user PPDU received through the wireless receiver 1804 or both the SIG-A field and the SIG-B field of the multi-user PPDU. The control information analyzer 1816 determines N STSMAX , N LTF , and its own user-specific resource allocation information. P LTF The matrix generator 1826 can generate a P LTF matrix based on the N LTF provided by the control information analyzer 1816. The channel estimator 1830 uses the N STSMAX , N LTF , its own user-specific resource allocation information, and the P LTF matrix generated by the matrix generator 1826. The P LTFBased on the matrix and, channel estimation can be performed using the LTF of the received PPDU. During operation, the data demodulator / decoder 1828 can demodulate and / or decode the data field of the received PPDU based on its own user-specific resource allocation information provided by the control information analyzer 1816 and the estimated MIMO channel provided by the channel estimator 1830.

[0144] As described above, embodiments of the present disclosure provide an advanced communication system, communication method, and communication device that enable channel estimation in both single-user communication and multi-user communication in an ultra-high throughput MIMO WLAN network and improve the physical layer throughput in the MIMO WLAN network.

[0145] The present disclosure can be implemented by software, by hardware, or by software cooperating with hardware. Each functional block used in the description of each of the above-described embodiments can be implemented, in part or in whole, by an LSI such as an integrated circuit, and each process described in each embodiment can be controlled, in part or in whole, by the same LSI or a combination of LSIs. The LSI can be formed individually as a chip, or one chip can be formed so as to include part or all of the functional blocks. The LSI can include a data input / output section coupled to itself. The LSI is also referred to as an IC, a system LSI, a super LSI, or an ultra LSI according to the difference in the degree of integration. However, the technology for implementing the integrated circuit is not limited to the LSI, and can be implemented by using an application-specific circuit, a general-purpose processor, or a dedicated processor. Furthermore, an FPGA (field programmable gate array) that can be programmed after the manufacture of the LSI, or a reconfigurable processor that can reconfigure the connection and setting of circuit cells arranged inside the LSI can also be used. The present disclosure can be implemented as digital processing or analog processing. As a result of the progress of semiconductor technology or another derivative technology, when the LSI is replaced by future integrated circuit technology, the functional blocks can be integrated using the future integrated circuit technology. Biotechnology can also be applied.

[0146] The present disclosure can be implemented by any type of device, apparatus, or system having a communication function (referred to as a communication device).

[0147] The communication device can include a transceiver and a processing / control circuit. The transceiver can include a receiver and a transmitter, and / or can function as a receiver and a transmitter. The transceiver (as a transmitter and a receiver) can include an RF (radio frequency) module including an amplifier, an RF modulator / demodulator, etc., and one or more antennas.

[0148] Some non-limiting examples of such communication devices include telephones (e.g., mobile phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, netbooks), cameras (e.g., digital still / video cameras), digital players (digital audio / video players), wearable devices (e.g., wearable cameras, smartwatches, tracking devices), game consoles, e-book readers, telemedicine / telehealth (telemedicine·pharmacy) devices, vehicles that provide communication functions (e.g., automobiles, airplanes, ships), and various combinations thereof.

[0149] The communication device is not limited to being portable or mobile, and can include any type of device, apparatus, or system that is non-portable or stationary, such as smart home devices (e.g., home appliances, lighting, smart meters, control panels), vending machines, and any other "things" within the network of the "Internet of Things (IoT)".

[0150] Communication can include exchanging data through, for example, cellular systems, wireless LAN systems, satellite systems, among others, and various combinations thereof.

[0151] The communication device can include devices such as a controller or sensor coupled to a communication device that executes the communication functions described in the present disclosure. For example, the communication device can include a controller or sensor that generates control signals or data signals used by a communication device that executes the communication functions of the communication device.

[0152] The communication device can further include infrastructure facilities, such as base stations, access points, and any other devices, apparatuses, or systems that communicate with or control devices such as those in the non-limiting examples above.

[0153] It will be understood by those skilled in the art that numerous changes and / or modifications can be made to the present disclosure as shown in the specific embodiments without departing from the spirit or scope of the present disclosure as broadly described. Accordingly, the embodiments herein should be considered in all respects to be illustrative and not restrictive.

Claims

1. Generate a Physical Layer Protocol Data Unit (PPDU) transmitted on a single frequency resource, wherein the PPDU includes a first field indicating a first number of symbols of a Long Training Field (LTF) for estimating a Multiple - input multiple - output (MIMO) channel, wherein the first number is greater than a second number of the symbols of the LTF determined based on the number of spatial streams (Nss), a circuit for generating the PPDU, a transmitter for transmitting the PPDU, A communication device comprising the above.

2. The frequency resource is a resource unit, The communication device according to claim 1.

3. The PPDU is used for single - user transmission, The communication device according to claim 1.

4. The second number is defined in the standard specification, The communication device according to claim 1.

5. The first number is selected from a plurality of candidates, The communication device according to claim 1.

6. In a first case where the Nss is an even number, the second number is equal to the Nss, In a second case where the Nss is an odd number other than 1, the second number is equal to a value obtained by adding 1 to the Nss, The communication device according to claim 1.

7. The first number is a value based on the format of the PPDU, The communication device according to claim 1.

8. The Nss is greater than 8, The communication device according to claim 1.

9. Generate a Physical Layer Protocol Data Unit (PPDU) transmitted on a single frequency resource, wherein the PPDU includes a first field indicating a first number of symbols of a Long Training Field (LTF) for estimating a Multiple - input multiple - output (MIMO) channel, wherein the first number is greater than a second number of the symbols of the LTF determined based on the number of spatial streams (Nss), A step of generating the PPDU, A step of transmitting the PPDU, A communication method comprising the above.

10. Generate a Physical Layer Protocol Data Unit (PPDU) transmitted on a single frequency resource, wherein the PPDU includes a first field indicating a first number of symbols of a Long Training Field (LTF) for estimating a Multiple - input multiple - output (MIMO) channel, The first number is greater than the second number of the symbols of the LTF determined based on the spatial stream number (Nss), a process of generating the PPDU, a process of transmitting the PPDU, an integrated circuit for controlling the above.

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