Communication device and method

Abstract

A first communication device configured to communicate with one or more second communication devices by receiving a physical layer protocol data unit (PPDU) having a defined bandwidth and at least a preamble, the first communication device comprising circuitry configured to determine a plurality of data tones allocated to one or more distributed resource units, each distributed resource unit having data tones distributed over the defined bandwidth of the PPDU, and based on the determined plurality of data tones of the one or more distributed resource units, select and allocate a plurality of training tones consisting of a defined sequence to training symbols contained in one or more training fields. Further, the circuitry is configured to send an indication to the one or more second communication devices to instruct the one or more second communication devices to include the one or more training fields within the preamble of the PPDU and to send the PPDU in response to the indication.

Description

Technical Field

[0001] This disclosure relates to communication devices and methods, and in particular to communication devices and methods for distributed resource units. Background Technology

[0002] Orthogonal Frequency Division Multiple Access (OFDMA) is a multi-user access technology that has been adopted by Wireless Local Area Networks (WLANs) since the 802.11ax amendment. OFDMA enables WLAN access points (APs) to serve multiple client sites (STAs) in parallel. This is achieved by flexibly dividing the WLAN bandwidth into smaller resource units (RUs), which the AP can then dynamically allocate to different devices. An RU is contained in the data field of a Physical Layer (PHY) Protocol Data Unit (PPDU) and consists of a set of tones, each tone being a defined subcarrier with a defined bandwidth within the PPDU bandwidth, excluding frequencies used for protection, direct conversion (DC), or empty tones.

[0003] Recently, distributed resource units (dRUs) have been proposed for next-generation WLANs aimed at ultra-high reliability (UHR). Compared to conventional resource units (rRUs), where the tones of RUs are selected as consecutive blocks of adjacent tones, the tones corresponding to dRUs are distributed across the bandwidth of the PPDU. This results in lower spectral density and the ability to transmit dRUs at higher power. Therefore, using dRUs can increase communication range and improve reliability.

[0004] However, the known training mechanisms and PHY operations may be insufficient for proper synchronization, channel estimation, and frequency tracking when using dRU. Therefore, it is desirable to define new or modified training fields and corresponding PHY operations to facilitate the use of dRU.

[0005] The “Background Art” description provided herein is intended to generally present the context of this disclosure. The work of the inventors currently named, to the extent described in this background section, and in any aspect of the description that may not constitute prior art at the time of filing, is not expressly or impliedly acknowledged as prior art to this disclosure. Summary of the Invention

[0006] The objective is to facilitate the use of Distributed Resource Units (dRUs), particularly by enabling proper synchronization, channel estimation, and / or frequency tracking when using dRUs. Another objective is to provide corresponding methods and corresponding computer programs and non-transitory computer-readable recording media storing a computer program product for implementing the methods, with less overhead.

[0007] According to the present invention, a first communication device is provided, configured to communicate with a second communication device by receiving a Physical Layer Protocol Data Unit (PPDU) having a defined bandwidth and at least a preamble. The first communication device includes circuitry configured to: - Determine the set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed across the defined bandwidth of the PPDU. - Based on a determined set of data tones from one or more distributed resource units, select a set of training tones consisting of defined sequences that will be assigned to training symbols contained in one or more training fields, and - Send an instruction to one or more second communication devices, the instruction indicating to the one or more second communication devices to include one or more training fields in the preamble of the PPDU in response to the instruction, and send the PPDU.

[0008] According to another aspect, a first communication device is provided, configured to communicate with one or more second communication devices by transmitting Physical Layer Protocol Data Units (PPDUs) having a defined bandwidth and at least a preamble. The first communication device includes circuitry configured to: - Determine the set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed across a defined bandwidth of PPDU. - Based on a determined set of data tones from one or more distributed resource units, select a set of training tones consisting of defined sequences that will be assigned to training symbols contained in one or more training fields, and - Include one or more training fields in the preamble of the PPDU and send the PPDU to one or more second communication devices.

[0009] According to another aspect, a second communication device is provided, configured to communicate with a first communication device by transmitting a Physical Layer Protocol Data Unit (PPDU) having a defined bandwidth and at least a preamble. The second communication device includes circuitry configured to: - Determine the set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed across a defined bandwidth of PPDU. - Based on the determined set of data tones from one or more distributed resource units, determine the set of training tones consisting of defined sequences that will be assigned to training symbols contained in one or more training fields, and - Receive an instruction from a first communication device to include one or more training fields in the preamble of the PPDU in response to the instruction, and send the PPDU.

[0010] According to another aspect, a second communication device is provided, configured to communicate with a first communication device by receiving a Physical Layer Protocol Data Unit (PPDU) having a defined bandwidth and at least a preamble. The second communication device includes circuitry configured to: - Determine the set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed across a defined bandwidth of PPDU. - Based on the determined set of data tones from one or more distributed resource units, determine the set of training tones consisting of defined sequences that will be assigned to training symbols contained in one or more training fields, and - Receive the PPDU from the first communication device, wherein one or more training fields are contained in the preamble of the PPDU.

[0011] According to another aspect, corresponding methods are provided, including a computer program (which, when run on a computer, causes the computer to perform the steps of the methods disclosed herein), and a non-transitory computer-readable recording medium (which stores a computer program product that, when executed by a processor, causes the methods disclosed herein to be performed).

[0012] The implementation methods are defined in the appended dependent claims. It should be understood that the disclosed methods, computer programs, and computer-readable recording media have similar and / or identical additional implementations to the claimed access points and sites, as defined in the dependent claims and / or disclosed herein.

[0013] One aspect of this disclosure is providing a modified training field for dRU operation. The modified training field includes a training tone specifically selected by a first communication device relative to a data tone allocated to one or more dRUs. The first communication device may send an instruction to one or more second communication devices to use the modified training field in a PPDU sent to the first communication device. Additionally or alternatively, the first communication device may be configured to include the modified training field in the preamble of the PPDU sent by the first communication device to the one or more second communication devices.

[0014] The modified training fields and corresponding physical layer operations enable improved time and frequency synchronization, accurate channel estimation, and / or frequency tracking when using dRU.

[0015] The foregoing paragraphs have been provided as a general description and are not intended to limit the scope of the following claims. The described embodiments, along with further advantages, will be best understood with reference to the following detailed description taken in conjunction with the accompanying drawings. Attached Figure Description

[0016] A more complete understanding of this disclosure and its many accompanying advantages will be readily obtained when the following detailed description is considered in conjunction with the accompanying drawings, in which: Figure 1 A schematic diagram illustrating the tone allocation of a conventional RU (rRU) within a 20 MHz PPDU is shown.

[0017] Figure 2 This diagram illustrates the composition of a PPDU used for a physical layer implementation of extremely high throughput.

[0018] Figure 3 This diagram illustrates a variation of the long training field.

[0019] Figure 4A This diagram illustrates OFDMA operation using a dRU for downlink communication.

[0020] Figure 4B This diagram illustrates OFDMA operation using dRU for uplink communication.

[0021] Figure 5 A schematic diagram illustrating an example of power distribution for an ultra-high reliability PPDU is shown.

[0022] Figure 6A A schematic diagram illustrating the first example of training tone selection for dRU operation is shown.

[0023] Figure 6B A schematic diagram illustrating a second example of training tone selection for dRU operation is shown.

[0024] Figure 7A This diagram illustrates the data tone selection for the 106-tone dRU.

[0025] Figure 7B The description is based on Figure 7A A diagram illustrating the training pitch selection for the dRU.

[0026] Figure 8A A schematic diagram illustrating the data tone selection for the three dRUs is shown.

[0027] Figure 8B The description is based on Figure 8A A schematic diagram of the first example of training pitch selection for the dRU.

[0028] Figure 8C The description is based on Figure 8A A schematic diagram of the second example of training pitch selection for the dRU.

[0029] Figure 9This diagram illustrates a first example of training pitch selection using a loop pattern.

[0030] Figure 10 This diagram illustrates a second example of training pitch selection using a loop pattern.

[0031] Figure 11 This diagram illustrates the selection of training tones for a specific dRU pair.

[0032] Figure 12 A schematic diagram illustrating the first example of training pitch selection for 1×LTF symbols is shown.

[0033] Figure 13 A diagram illustrating a second example of training pitch selection for a 1×LTF symbol is shown.

[0034] Figure 14 A flowchart illustrating an implementation of a first communication method for a first communication device.

[0035] Figure 15 A flowchart illustrating another embodiment of the first communication method of the first communication device.

[0036] Figure 16 A flowchart illustrating an implementation of a second communication method for a second communication device.

[0037] Figure 17 A flowchart illustrating another embodiment of the second communication method of the second communication device. Detailed Implementation

[0038] Referring now to the accompanying drawings, in which the same reference numerals denote the same or corresponding parts in various views, Figure 1 This diagram illustrates the location of a conventional RU (rRU) within a 20 MHz PPDU in a High Efficiency (HE) PHY layer implementation (i.e., an implementation based on the 802.11ax™ WLAN standard amendment). Various RUs are defined by their size (i.e., the number of tones they occupy) (e.g., 26-tone RU, 52-tone RU, 106-tone RU, etc.). The tones within the RU are used to carry data or contain pilot sequences for frequency tracking and phase noise compensation. Figure 1 As shown, the tones of the rRU are selected as consecutive blocks of adjacent tones. Therefore, for example, a 52-tone RU consists of 52 adjacent tones within the PPDU bandwidth. On the other hand, the tones of the dRU are essentially distributed across the PPDU bandwidth, as will be discussed in more detail below. It should be understood that the dRU can have tones distributed across a portion or the entire PPDU bandwidth, and unallocated spectral portions are allowed within the PPDU bandwidth.

[0039] In addition, such as Figure 1 As shown, some tones are reserved for special purposes and therefore cannot be assigned to RUs. This applies to both rRUs and dRUs. Reserved tones include, for example, guard tones at the top and bottom of the PPDU bandwidth, as well as tones for empty subcarriers (zero tones) and direct current (DC).

[0040] Figure 2 This diagram illustrates the composition of a PPDU used for an Extremely High Throughput (EHT) PHY layer implementation (i.e., an implementation based on the draft 802.11be™ WLAN standard amendment).

[0041] The PPDU 200 consists of a preamble 201 and a data field 202. In the preamble, the EHT modulation field 203 is transmitted using a PHY configuration compatible with legacy equipment, while the EHT modulation field 204 supports more advanced PHY configurations, including OFDMA transmission. In uplink transmissions, STA transmissions assigned to a specific RU occupy only the EHT modulation field 204 of the tone determined by that RU. This avoids conflicts with transmissions from other STAs and supports channel estimation within the assigned RU.

[0042] Figure 3 The diagram illustrates three variations 301, 302, and 303 of the Long Training Field (LTF) design for EHT.

[0043] These variants differ in the number of available pitch locations to which the training pitch can be mapped in the training field.

[0044] The first variant, indicated here by reference numeral 301, is the 4×EHT-LTF. In this variant, all tones except for some reserved tones (i.e., DC 304 and guard tone 305) are available to be assigned as training tones in the training field. All tones except the reserved tones are referred to below as valid tones.

[0045] The second variant, indicated here by reference numeral 302, is 2×EHT-LTF. In this variant, approximately only half of the effective tones (e.g., even tones considering only the tone index) are available for training tone allocation in the training field. Furthermore, in this variant, the available tones can be distributed at specific locations to generate a periodic signal in the time domain. Thus, the first 2×EHT-LTF symbol 307 and the second 2×EHT-LTF symbol 308 can be transmitted within the time of a conventional OFDM symbol (excluding the guard interval (GI)). In other words, the length of a single 2×EHT-LTF symbol is half the OFDM symbol time.

[0046] The third variant, indicated here by reference numeral 303, is a 1×EHT-LTF. In this variant, approximately one-quarter of the effective tones are available for training tone allocation in the training field. Similar to the second variant, the available tones can be distributed at specific locations to generate a periodic signal in the time domain. Thus, the first, second, third, and fourth 1×EHT-LTF symbols 309, 310, 311, and 312 can be transmitted within the time of a conventional OFDM symbol. Therefore, the length of a single 1×EHT-LTF symbol is one-quarter of the OFDM symbol time.

[0047] The symbols for half an OFDM symbol time will be referred to as "2×LTF symbols" and symbols for one-quarter OFDM symbol time as "1×LTF symbols". Furthermore, 4×EHT-LTF will be referred to as "Type I training field", 2×EHT-LTF as "Type II training field", and 1×EHT-LTF as "Type III training field". For the LTFs proposed using the UHR operation with dRU, the corresponding LTF types 4×EHT-LTF, 2×EHT-LTF, and 1×EHT-LTF will be denoted as 4×LTF, 2×LTF, and 1×LTF, respectively.

[0048] Figure 4A and Figure 4B These are schematic diagrams illustrating OFDMA operation using dRU.

[0049] Figure 4A This illustrates downlink (DL) communication. Figure 4B This shows uplink (UL) communication.

[0050] For example, in Figure 4A In this process, access point 401 uses a multi-user PPDU (MU-PPDU) to send DL data to the first STA 402 and the second STA 403. Within the MU-PPDU, different dRUs are assigned to different STAs. Figure 4A In this configuration, the first dRU 404 is assigned to the first STA 402, and the second dRU 405 is assigned to the second STA 403. STAs 402 and 403 receive and decode the MU-PPDU to extract the data assigned to their respective dRUs.

[0051] Figure 4BThis illustrates UL communication using dRUs. First, access point 401 sends a trigger frame (TF) 406 to first STA 402 and second STA 403. The TF may contain configuration information for trigger-based PPDUs (TB-PPDUs), i.e., information allowing STAs to create TB-PPDUs in a specific format and information on how to send the TB-PPDUs to access point 401. In response to the TF, first STA 402 and second STA 403 send UL data to access point 401 using dRUs specifically allocated to them. For example, in... Figure 4B In the example, the first STA uses the third dRU 407 to transmit the TB-PPDU, and the second STA 403 uses the fourth dRU 408 to transmit the TB-PPDU to the access point 401. All tones not assigned to any STA are not modulated.

[0052] exist Figure 4A and Figure 4B In this implementation, access point 401 is the "first communication device," and STAs 402 and 403 are the "second communication devices." It should be understood that the number of second communication devices is not limited to... Figure 4A and Figure 4B The number of stations shown is not specified. It should be noted that although the first and second communication devices shown herein are specifically designed to exchange PPDUs configured specifically for dRUs, the implementation does not preclude the possibility that the first and second communication devices may communicate by sending and receiving conventional PPDUs without dRUs.

[0053] To enable STA 402 and 403 to decode MU-PPDU or transmit TB-PPDU, dRU configuration information, hereinafter referred to as configuration information, should be provided to the STA. For example, configuration information may be included in the preamble of the MU-PPDU (for DL ​​communication) or in the TF (for UL communication). For DL ​​communication, configuration information may be, for example, part of a signaling field, U-SIG, or UHR-SIG field in the PPDU.

[0054] The dRU configuration information may include one or more of the following: power allocation information (dRU power allocation level), type information for one or more training fields (LTF type), number of training symbols, and tone allocation information for one or more training fields (LTF tone allocation). The type information for one or more training fields may include one or more of the following: density or interval between training tones, duration of training symbols in the training field, and guard interval duration of training symbols in the training field.

[0055] dRU configuration information complements dRU allocation information. dRU allocation information indicates the composition of the dRU and its association with the STA, while dRU configuration information can indicate how training fields are configured for the dRU and how power is allocated to one or more fields of the PPDU.

[0056] Figure 5 This is a schematic diagram illustrating an example of power allocation for a PPDU in a UHR.

[0057] The PPDU 500 includes a preamble 501, which has a conventional modulation field 502 and one or more training fields 503 associated with the distributed resource unit included in the data field 504 of the PPDU 500. The conventional modulation field 502 (hereinafter referred to as the pre-UHR modulation field) and one or more training fields 503 and data field 504 (hereinafter collectively referred to as the UHR modulation field) can be considered to have their own power settings.

[0058] For example, the power boost in the data field of the dRU can depend on the tone density. Typically, the pre-UHR modulation field has a subcarrier spacing that is four times wider than the UHR modulation field, which means a lower spectral density. Therefore, as long as the spectral density of the dRU is greater than or equal to the spectral density of the pre-UHR modulation field, the pre-UHR modulation field can transmit at the same power as the dRU.

[0059] When a long-range or maximum power boost is expected for the dRU, the transmit power limit of the pre-UHR modulation field may be lower than that of the UHR modulation field. This means that the STF and LTF fields of one or more training fields 503 are critical for fine synchronization and should all be transmitted with the same power boost as the dRU data field 504, such as... Figure 5 As shown.

[0060] Therefore, in various implementations, the power level of one or more training fields 503 can be selected to be equal to the power level set for the data field 504 including the distributed resource unit, and equal to or higher than the power level of the conventional modulation field 502. Thus, the various fields of the PPDU preamble can be transmitted at different power levels as appropriate.

[0061] Various examples of LTF designs are described below with reference to the accompanying drawings. Individual designs or specific combinations thereof can be used as various embodiments according to this disclosure.

[0062] Figure 6A and Figure 6B A schematic diagram of the LTF design for the first type of training field used in dRU operations is shown.

[0063] As mentioned earlier, the first type of training field corresponds to a 4×LTF, where all valid tones are available for training tone selection. Therefore, training tones can be selected one-to-one based on the tones assigned to the dRU. In other words, for each data tone assigned to the dRU, a corresponding training tone can be selected and assigned in the training field.

[0064] Figure 6A An example of selecting and assigning training tones for four dRUs is shown. Here, the first dRU is a 26-tone dRU with a minimum tone interval of 9, the second dRU is a 52-tone dRU with a minimum tone interval of 4, the third dRU is another 52-tone dRU with a minimum tone interval of 4, and the fourth dRU is a 106-tone dRU with a minimum tone interval of 2. In this configuration, almost the entire bandwidth of the PPDU is occupied by the data tones of the dRUs. The positions of the training tones within training field 601A (represented here by tone index numbers) are selected in a one-to-one manner. That is, the position of the first set of training tones 602 in training field 601 for the first dRU corresponds to the position of the data tones of the first dRU in the data field. Similarly, the position of the second set of training tones 603 in training field 601 for the second dRU corresponds to the position of the data tones of the second dRU in the data field. Likewise, the third and fourth sets of training tones 604 and 605 correspond to the remaining data tones of the third and fourth dRUs, respectively. Tones not used by any dRU are set to zero (zero tone 606).

[0065] Figure 6B Another example of the first type of training field is shown. Figure 6B The diagram illustrates the selection of training tones for training field 601B for five associated dRUs. Here, the dRUs comprise four 52-tone dRUs and one 26-tone dRU. As previously described, the training tones are selected one-to-one with respect to the data tones assigned to the dRUs. For each data tone in a dRU, the corresponding training tone is selected in the training field. For unassigned data tones, the corresponding training tone is set to zero.

[0066] Figure 7A and Figure 7B The LTF design for the second type of training field used in dRU operation is shown.

[0067] As mentioned earlier, the second type of training field corresponds to a 2×LTF, where only about half of all valid tones can be used to train tone selection. An example of the set of about half of all valid tones is shown in... Figure 7ALeft side. Here, all even-numbered tones relative to the pitch index are labeled as training tones. In another example, approximately half of the set of all valid tones can also be achieved by labeling odd-numbered tones relative to the pitch index as tones that can be selected as training tones.

[0068] also, Figure 7A The data tone selection for the first 106-tone dRU 701 and the second 106-tone dRU 702 is shown. From Figure 7A It is readily apparent that not all assigned data tones in the first dRU 701 and the second dRU 702 can be directly mapped to even tones that are optional training tones. In this example, only about half of the data tones in each dRU actually have associated training tones from the optional training tones in the second type of training field. Therefore, the receiving STA must interpolate the channel estimate obtained from the selected training tones to the locations of data tones that do not have direct mappings.

[0069] Figure 7B An example is shown showing how to select training tones for the first and second dRUs 701, 702.

[0070] Here, the training tones are chosen as the intersection of the available 2×LTF tone positions (even tones) with each dRU (direct tone mapping). This method simplifies implementation, and for a tone plan with equal even and odd tone assignments in each dRU, half the tones will directly match the 2×LTF tones. However, this method may lead to training tone clustering and produce a large tone gap between the data tones and training tones in the dRU. To avoid clustering, refer to the following... Figure 8A , Figure 8B and Figure 8C The training pitch is distributed across the entire bandwidth.

[0071] Figure 8A , Figure 8B and Figure 8C Another LTF design for a second type of training field is shown for dRU operation.

[0072] Figure 8A The diagram illustrates the data tone selection for the first 106-tone dRU 801, the second 106-tone dRU 802, and the third 26-tone dRU 803. Here, the first and second dRUs 801 and 802 are assigned to the first STA and the second STA, respectively. The third dRU 803 is not assigned. As previously mentioned, not all data tones can be directly mapped to the optional training tones of the 2×LTF symbols.

[0073] Figure 8B Show how to target Figure 8AThe example shown is a first instance of dRU configuration selecting training tones. In this example, training tones are selected to spread across the entire bandwidth, thus avoiding large gaps (spread tone mapping) between the selected training tones and the data tones of the dRU tones. Considering Figure 7B The mapping in the data can avoid aggregation, but may result in fewer training tones that directly match the data tones of the dRU.

[0074] Figure 8B The mapping shown can be easily implemented by first aggregating the allocated dRUs (e.g., Figure 8A The tone indices of dRU1 and dRU2 are used, and each tone is mapped to each dRU in an alternating manner. "Alternating" should be interpreted broadly, so irregular alternation is possible. For example, if we have two 106-tone dRUs, their LTF tones will be selected in a simple alternating manner, but if we add a 26-tone dRU on top of them, its LTF tones will be inserted with a wider tone interval. In this case, the alternation is based on the dRU size, with the larger dRU being placed more frequently than the smaller dRU.

[0075] exist Figure 8B In the mapping shown, the pitch positions of the data pitches directly mapped to the third dRU 803 are ignored in the training pitch selection. This can be achieved by referring to... Figure 8C An overview of training tone selection is provided to alleviate this problem.

[0076] Figure 8C Show how to target Figure 8A The second example of selecting the training tone in the dRU configuration shown is shown. Figure 8C The mapping shown is Figure 8B The mapping shown is similar, but it takes advantage of the fact that the third dRU is not assigned in this scenario. Therefore, Figure 8C The distribution operation also uses the pitch positions of the unassigned data pitches directly mapped to the third dRU 803 to assign training pitches to the first dRU 801 and the second dRU 802. As a result, the selected training pitches are better distributed across the entire bandwidth, and depending on the DC and guard pitch positions, a near-uniform distribution (uniformly distributed pitch mapping) can be achieved. Figure 8C As shown, some training tones selected for the first dRU 801 and the second dRU 802 correspond to the tone positions mapped to the unassigned third 26 tone dRU 803.

[0077] exist Figure 7B , Figure 8B and Figure 8C In the diagram, the mapped training tones of the first and second dRUs are shown respectively. It should be understood that... Figure 7B , Figure 8Band Figure 8C The individual mappings shown are combined to form a single 2×LTF symbol.

[0078] Figure 9 Another LTF design for a second type of training field is shown for dRU operation.

[0079] Figure 9 The mapping shown creates a training field that generates a cyclic pattern in the time domain. This cyclic pattern can be used on the receiver side to improve synchronization and frequency offset compensation.

[0080] For this cyclic mode, two symbols, 901 and 902, are generated, each lasting half an OFDM symbol time. Figure 9 In the example, the data tones of 26-tone dRU 900 are mapped to the first symbol 901 and the second symbol 902 to create a loop pattern.

[0081] The first symbol 901 is created by assigning a tone sequence (similar to the sequence in a 2×EHT-LTF) to dRU tones whose positions match the 2×EHT-LTF tone positions. This is essentially any even tone, taking into account both positive and negative indices (e.g., -128 to 127 in a 20MHz PPDU with 256 subcarriers). The second symbol 902 is obtained by mapping the same sequence to dRU tones that do not match the 2×EHT-LTF tone positions (i.e., all odd tones in the dRU). For most tones, this mapping results in a tone offset 903 based on a fixed number of tones based on the dRU tone interval (tones near the DC subcarrier may be offset by different values). Depending on the tone's position in the first symbol relative to the second symbol, the resulting tone offset can be positive or negative.

[0082] At the receiver, the two peaks can be observed by offsetting each second symbol 902 with the corresponding tone offset and correlating them all with the first symbol 901. The results of this correlation can be used to improve carrier frequency offset and phase offset compensation.

[0083] For OFDM demodulation, the first symbol 901 is repeated in the time domain to form a full-size OFDM symbol, and after OFDM demodulation, it provides channel estimates for even-numbered tones in the dRU. Additionally, the second symbol 902 is also repeated, but the repeated block is multiplied by a phase offset based on the block size. After OFDM demodulation, it provides channel estimates for odd-numbered tones in the dRU.

[0084] Figure 10 Another LTF design for a second type of training field used in dRU operations is shown.

[0085] Figure 10Mapping in Figure 9 The mapping is similar, except that the 52-tone dRU 1000 is mapped to the first symbol 1001 and the second symbol 1002. In this example, the tone offset 1003 from the first symbol 1001 to the second symbol 1002 is negative. Figure 10 The mapping shown also generates a cyclic pattern in the time domain, which can be utilized by the receiver, as referenced above. Figure 9 As stated above.

[0086] Figure 9 and Figure 10 Examples of 26-tone dRUs and 52-tone dRUs are shown respectively. In both examples, the positions of even and odd tones depend on the dRU size and the corresponding tone pattern. Therefore, the interleaving pattern of 2×LTF symbols is not always as shown. Figure 10 As shown. Furthermore, the pitch offset is determined by the underlying dRU pitch planning. If a layered pitch plan is constructed to maximize the minimum pitch interval between dRUs, the resulting pitch offset is 9.

[0087] It should be noted that Figure 9 and Figure 10 The cyclical pattern is achieved through a frequency shift between the majority of tones in the first training tone set and the second training tone set. In this case, "majority of tones" means that the shift will occur in all tones except those close to the DC tone position.

[0088] Figure 11 Another LTF design for a second type of training field used in dRU operations is shown.

[0089] In this example, a second type of training field is created for the dRU pair. The pair includes a first dRU 1101 and a second dRU 1102, wherein the second dRU 1102 is the same size as the first dRU 1101 and has a pitch adjacent to the pitch of the first dRU 1101.

[0090] In this scenario, training tones are selected such that half of the tones in the training field correspond to the first dRU 1101, and the other half to the second dRU 1102. Since each dRU has an equal number of even and odd tones, the segmentation between tones matching each dRU in the training field is equal. Different segmentations may occur based on dRU tone planning, but as long as the tones of the dRU pairs are close to each other, the receiver can estimate the segmentation from the adjacent tone interpolation channel.

[0091] Figure 12 and Figure 13Another LTF design using 1×LTF symbols instead of 2×LTF symbols is shown. As mentioned earlier, the symbol duration of 1×LTF symbols is half that of 2×LTF symbols, so only about a quarter of the effective pitches are available for training pitch selection.

[0092] Therefore, the distance between the dRU data pitch and the training pitch increases compared to using 2×LTF symbols. On the other hand, using 1×LTF symbols can significantly reduce time overhead.

[0093] Generally, the use of 1×LTF notations follows the same method as described above for 2×LTF notations. The difference is that the pitch interval of 1×LTF pitches is twice that of 2×LTF pitches, so pitch groups will be divided into 4 groups instead of 2 groups (e.g., even and odd).

[0094] Figure 12 As shown in the reference Figure 7A and Figure 7B The aforementioned direct pitch mapping method, however, uses essentially 1×LTF symbols that can be used to train pitch selection every four pitches. Similarly, Figure 13 As shown in the reference Figure 8A , Figure 8B and Figure 8C The dispersed tone mapping method and the uniform dispersed tone mapping method are described, but both use the 1×LTF symbol.

[0095] Furthermore, it should be noted that cyclic patterns can also be generated using 1×LTF symbols. Therefore, refer to... Figure 9 and Figure 10 The outlined approach can be similarly applied to 1×LTF symbols. A specific implementation will require four 1×LTF symbols instead of two 2×LTF symbols. Otherwise, the overall concept remains the same.

[0096] Figure 14A flowchart illustrating an implementation (uplink communication) of a first communication method 1400 for a first communication device (e.g., an access point) communicating with a second communication device (e.g., a station) via a PPDU is shown. The PPDU has a defined bandwidth and at least a preamble. In a first step 1401, the first communication device determines a set of data tones to be assigned to one or more distributed resource units, each distributed resource unit having data tones distributed across the defined bandwidth of the PPDU. In a second step 1402, based on the determined set of data tones for the one or more distributed resource units, the first communication device selects a set of training tones consisting of a defined sequence and to be assigned to training symbols included in one or more training fields. Any method described in detail above can be used to select the training tones. Subsequently, in step 1403, the first communication device sends an instruction to one or more second communication devices, instructing them to include one or more training fields within the preamble of the PPDU in response to the instruction, and transmits the PPDU.

[0097] Figure 15 A flowchart illustrating another embodiment (downlink communication) of a first communication method 1500 for a first communication device (e.g., an access point) communicating with a second communication device (e.g., a station) by transmitting a PPDU is shown. The PPDU has a defined bandwidth and at least a preamble. In a first step 1501, the first communication device determines a set of data tones to be assigned to one or more distributed resource units, each distributed resource unit having data tones distributed across the defined bandwidth of the PPDU. In a second step 1502, based on the determined set of data tones for the one or more distributed resource units, the first communication device selects a set of training tones consisting of a defined sequence and to be assigned to training symbols contained in one or more training fields. Any method described in detail above can be used to select the training tones. Subsequently, in step 1503, the first communication device includes one or more training fields within the preamble of the PPDU and transmits the PPDU to the one or more second communication devices.

[0098] Figure 14 and Figure 15 Separate methods for uplink and downlink communication are shown. It should be understood that the first communication device can be configured to perform both methods.

[0099] Figure 16A flowchart illustrating an implementation (uplink communication) of a second communication method 1600 for a second communication device (e.g., a station) communicating with a first communication device (e.g., an access point) by transmitting a PPDU is shown. The PPDU has a defined bandwidth and at least a preamble. In a first step 1601, the second communication device determines a set of data tones to be assigned to one or more distributed resource units, each distributed resource unit having data tones distributed across the defined bandwidth of the PPDU. In a second step 1602, based on the determined set of data tones of the one or more distributed resource units, the second communication device determines a set of training tones consisting of a defined sequence and to be assigned to training symbols included in one or more training fields. Subsequently, in step 1603, the second communication device receives an instruction from the first communication device to include one or more training fields within the preamble of the PPDU and transmit the PPDU in response to the received instruction. Thus, the second communication device transmits the PPDU in response to the received instruction.

[0100] Figure 17 A flowchart illustrating an implementation (downlink communication) of a second communication method 1700 for a second communication device (e.g., a station) communicating with a first communication device (e.g., an access point) via a PPDU is shown. The PPDU has a defined bandwidth and at least a preamble. In a first step 1701, the second communication device determines a set of data tones to be assigned to one or more distributed resource units, each distributed resource unit having data tones distributed across the defined bandwidth of the PPDU. In a second step 1702, based on the determined set of data tones of the one or more distributed resource units, the second communication device determines a set of training tones consisting of a defined sequence and to be assigned to training symbols contained in one or more training fields. Subsequently, in step 1703, the second communication device receives a PPDU from the first communication device, wherein the one or more training fields are contained within the preamble of the PPDU.

[0101] Figure 16 and Figure 17 Separate methods for uplink and downlink communication are shown. It should be understood that a second communication device can be configured to perform both methods.

[0102] Finally, there are some considerations regarding pilot tone allocation. Pilot tones are used to track and compensate for frequency and phase offsets in PPDU reception. It is desirable to keep the pilot tones of the LTF and data fields identical to allow for consistent phase tracking. In the proposed 4×LTF design, selecting a tone in the dRU with sufficient frequency space between them to achieve good phase tracking is sufficient. However, for 2×LTF and 1×LTF designs, the LTF tone and the corresponding dRU tone do not always match. In this case, the pilot tone is selected to match both the LTF and dRU tones simultaneously, while maintaining sufficient tone spacing between them.

[0103] In summary, this disclosure presents first and second communication devices (e.g., AP and STA) and corresponding methods for facilitating the use of dRU. Specifically, methods for training field design and power allocation are disclosed. These methods allow for proper synchronization, channel estimation, and / or frequency tracking when using dRU.

[0104] The device can be implemented by corresponding units or circuits, such as processors, processing circuits, computers, dedicated hardware, etc., that perform the functions of the device. Alternatively, common units or circuits, such as common processors or computers, can implement the various functions of the device, or separate units or components can be used to represent the circuit together.

[0105] Therefore, the foregoing discussion and description of this disclosure are merely exemplary embodiments. As those skilled in the art will understand, this disclosure may be embodied in other specific forms without departing from its spirit or essential characteristics. Therefore, the disclosure of this disclosure is intended to be illustrative and not to limit the scope of this disclosure and the other claims. This disclosure (including any readily identifiable variations taught herein) partially defines the scope of the foregoing claims, such that no inventive subject matter is presented to the public.

[0106] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude multiple. A single element or other unit can fulfill the functions of several items recited in the claims. The fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used advantageously.

[0107] As long as the embodiments of this disclosure have been described as being implemented at least in part by a data processing device controlled by software, it will be appreciated that non-transitory machine-readable media carrying such software, such as optical discs, magnetic disks, semiconductor memories, etc., are also considered to represent an embodiment of this disclosure. Furthermore, such software may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems.

[0108] The components of the disclosed devices, apparatuses, and systems can be implemented by corresponding hardware and / or software components, such as appropriate circuits or circuit structures. A circuit is a structural combination of electronic components, including conventional circuit elements, integrated circuits (including application-specific integrated circuits), standard integrated circuits, application-specific standard products, and field-programmable gate arrays (FPGAs). Furthermore, circuits include central processing units, graphics processing units, and microprocessors programmed or configured according to software code. Circuits do not include pure software, although they include the aforementioned hardware that executes the software. Circuits or circuit structures can be implemented by a single device or unit, multiple devices or units, chipsets, or processors.

[0109] The following is a list of further implementations of the disclosed subject matter: 1. A first communication device configured to communicate with one or more second communication devices by receiving Physical Layer Protocol Data Units (PPDUs), the PPDUs having a defined bandwidth and at least a preamble, the first communication device including circuitry configured to: - Determine the set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed across a defined bandwidth of PPDU. - Based on a determined set of data tones from one or more distributed resource units, select a set of training tones consisting of defined sequences that will be assigned to training symbols contained in one or more training fields, and - Send an instruction to one or more second communication devices, which instructs the devices to include one or more training fields in the preamble of the PPDU in response to the instruction, and send the PPDU.

[0110] 2. According to the first communication device of embodiment 1, the circuit is further configured to: indicate to one or more second communication devices that: the PPDU includes a data field comprising one or more distributed resource units, and select the power level of one or more training fields based on the power level set for the data field comprising one or more distributed resource units.

[0111] 3. The first communication device according to embodiment 1 or 2, wherein the circuit is further configured to indicate to one or more second communication devices that configuration information is included in the signaling field of the preamble, the configuration information including at least one of power allocation information, type information of one or more training fields, number information of training symbols, and tone allocation information of one or more training fields.

[0112] 4. The first communication device according to any of the foregoing embodiments, wherein the circuitry is further configured to: indicate to one or more second communication devices that: a first type of training field is included in one or more training fields, wherein a training tone set is selected in the first type of training field by mapping tones in a data tone set of one or more distributed resource units to available tones in a one-to-one manner.

[0113] 5. The first communication device according to embodiment 4, wherein the circuit is configured to indicate to one or more second communication devices that any remaining tones within the defined bandwidth that were not selected for the training tone set are set to zero.

[0114] 6. A first communication device according to any one of embodiments 1 to 3, wherein the circuit is configured to: indicate to one or more second communication devices that: at least one second type of training field is included in one or more training fields, in which only even-numbered tones among all available tones within a defined bandwidth can be selected for training a set of tones, and the set of tones for training is selected by mapping the tones in the data tone set of one or more distributed resource units to even-numbered available tones.

[0115] 7. According to the first communication device of embodiment 6, wherein the training tone set is selected as the intersection of an even number of available tones and a data tone set of one or more distributed resource units.

[0116] 8. The first communication device according to embodiment 6, wherein the training tone set is selected by distributing the tones in the data tone set of one or more distributed resource units across a defined bandwidth in an alternating manner to an even number of available tones.

[0117] 9. A first communication device according to embodiment 6, wherein the circuit is configured to indicate to one or more second communication devices that the data tone of one or more distributed resource units in the PPDU is mapped to an even number of available tones using one or more unallocated distributed resource units in the PPDU.

[0118] 10. The first communication device according to embodiment 6, wherein at least one training field of a second type includes a first symbol and a second symbol, and the training tone set includes a first training tone set assigned to the first symbol and a second training tone set assigned to the second symbol.

[0119] 11. A first communication device according to embodiment 10, wherein the first symbol and the second symbol each have a symbol time that is half the symbol time of an OFDM symbol.

[0120] 12. A first communication device according to embodiment 10 or 11, wherein the circuit is configured to indicate to one or more second communication devices that a first training tone set and a second training tone set are selected based on a data tone set of a single distributed resource unit in one or more distributed resource units.

[0121] 13. A first communication device according to embodiment 10, wherein the circuit is configured to indicate to one or more second communication devices that a first training tone set and a second training tone set are selected to form a loop pattern.

[0122] 14. The first communication device according to embodiment 12, wherein the circuit is configured to: indicate to one or more second communication devices that: a first training tone set is selected by mapping the tones in the data tone set of a single distributed resource unit to an even number of available tones in a one-to-one manner, and a second training tone set is selected based on the tones in the data tone set of a single distributed resource unit that do not match the first training tone set.

[0123] 15. A first communication device according to embodiment 6, wherein the data tone set allocated to one or more distributed resource units includes a first data tone set allocated to a first distributed resource unit and a second data tone set allocated to a second distributed resource unit, each set being of equal size, and circuitry is configured to indicate to one or more second communication devices that a training tone set is selected by mapping the tones in the first data tone set of the first distributed resource unit to the first half of the even-number available tones, and mapping the tones in the second data tone set of the second distributed resource unit to the second half of the even-number available tones.

[0124] 16. The first communication device according to embodiment 15, wherein the tones in the first data tone set and the tones in the second data tone set are adjacent to each other in pairs at a defined distance, preferably one.

[0125] 17. A first communication device according to any of the preceding embodiments, wherein the preamble includes a conventional modulation field, and one or more training fields include at least one training field associated with at least one of one or more distributed resource units, and the circuitry is configured to indicate to one or more second communication devices that: a power level is selected for at least one training field such that it is equal to the power level set for a data field including at least one distributed resource unit, and equal to or higher than the power level set for the conventional modulation field.

[0126] 18. A first communication device configured to communicate with one or more second communication devices by transmitting a Physical Layer Protocol Data Unit (PPDU) having a defined bandwidth and at least a preamble, the first communication device including circuitry configured to: - Determine the set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed across a defined bandwidth of PPDU. - Based on a determined set of data tones from one or more distributed resource units, select a set of training tones consisting of defined sequences that will be assigned to training symbols contained in one or more training fields, and - Include one or more training fields in the preamble of the PPDU and send the PPDU to one or more second communication devices.

[0127] 19. The first communication device according to embodiment 18, wherein the circuitry is further configured to: include a first data field comprising one or more distributed resource units in the PPDU, and select the power level of one or more training fields based on the power level set for the data field comprising one or more distributed resource units.

[0128] 20. A first communication device according to embodiment 18 or 19, wherein the circuitry is further configured to include configuration information in the signaling field of the preamble, the configuration information including at least one of power allocation information, type information of one or more training fields, number information of training symbols, and tone allocation information of one or more training fields.

[0129] 21. A first communication device according to any one of embodiments 18 to 20, wherein the circuitry is further configured to include a first type of training field within one or more training fields, wherein a training tone set is selected in the first type of training field by mapping tones in a data tone set of one or more distributed resource units to available tones in a one-to-one manner.

[0130] 22. A first communication device according to embodiment 21, wherein the circuit is configured to set any remaining tones within a defined bandwidth that have not been selected for training the tone set to zero.

[0131] 23. A first communication device according to any one of embodiments 18 to 20, wherein the circuit is configured to: include at least one second type of training field in one or more training fields, wherein only even-numbered tones among all available tones within a defined bandwidth can be selected for training a set of tones, and to select a set of tones for training by mapping tones in a set of data tones of one or more distributed resource units to even-numbered available tones.

[0132] 24. The first communication device according to embodiment 23, wherein the training tone set is selected as the intersection of an even number of available tones and a data tone set of one or more distributed resource units.

[0133] 25. A first communication device according to embodiment 23, wherein the training tone set is selected by distributing the tones in the data tone set of one or more distributed resource units across a defined bandwidth in an alternating manner to an even number of available tones.

[0134] 26. A first communication device according to embodiment 23, wherein the circuitry is configured to: map the data tone of one or more distributed resource units in a PPDU to an even number of available tones using one or more unallocated distributed resource units in a PPDU.

[0135] 27. A first communication device according to embodiment 23, wherein at least one training field of the second type includes a first symbol and a second symbol, and the training tone set includes a first training tone set assigned to the first symbol and a second training tone set assigned to the second symbol.

[0136] 28. The first communication device according to embodiment 27, wherein the first symbol and the second symbol each have a symbol time that is half the symbol time of an OFDM symbol.

[0137] 29. A first communication device according to embodiment 27 or 28, wherein the circuitry is configured to select a first training tone set and a second training tone set based on a data tone set of a single distributed resource unit in one or more distributed resource units.

[0138] 30. A first communication device according to embodiment 27, wherein the circuit is configured to: select a first training tone set and a second training tone set to form a loop pattern.

[0139] 31. A first communication device according to embodiment 29, wherein the circuit is configured to: select a first training tone set by mapping tones in the data tone set of a single distributed resource unit to an even number of available tones in a one-to-one manner, and select a second training tone set based on tones in the data tone set of a single distributed resource unit that do not match the first training tone set.

[0140] 32. A first communication device according to embodiment 23, wherein the data tone set allocated to one or more distributed resource units includes a first data tone set allocated to a first distributed resource unit and a second data tone set allocated to a second distributed resource unit, each set having the same size, and the circuit is configured to select a training tone set by mapping the tones in the first data tone set of the first distributed resource unit to the first half of the even-number available tones, and mapping the tones in the second data tone set of the second distributed resource unit to the second half of the even-number available tones.

[0141] 33. The first communication device according to embodiment 32, wherein the tones in the first data tone set and the tones in the second data tone set are adjacent to each other in pairs at a defined distance, preferably one.

[0142] 34. A second communication device configured to communicate with a first communication device by transmitting a Physical Layer Protocol Data Unit (PPDU) having a defined bandwidth and at least a preamble, the second communication device including circuitry configured to: - Determine the set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed across a defined bandwidth of PPDU. - Based on the determined set of data tones from one or more distributed resource units, determine the set of training tones consisting of defined sequences that will be assigned to training symbols contained in one or more training fields, and - Receive an instruction from the first communication device to include one or more training fields in the preamble of the PPDU in response to the received instruction, and send the PPDU.

[0143] 35. A second communication device according to embodiment 34, wherein the circuit is configured to: determine a set of data tones to be allocated to one or more distributed resource units based on an instruction received from a first communication device.

[0144] 36. A second communication device according to embodiment 34 or 35, wherein the circuit is configured to: determine a set of training tones to be assigned to training symbols contained in one or more training fields based on an instruction received from a first communication device.

[0145] 37. A second communication device according to any one of embodiments 34 to 36, wherein the circuit is configured to receive configuration information, the configuration information including at least one of power allocation information, type information of one or more training fields, number of training symbols, and tone allocation information of one or more training fields, and to send a PPDU based on the received configuration information.

[0146] 38. A second communication device configured to communicate with a first communication device by receiving a Physical Layer Protocol Data Unit (PPDU) having a defined bandwidth and at least a preamble, the second communication device including circuitry configured to: - Determine the set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed across a defined bandwidth of PPDU. - Determine the set of training tones consisting of defined sequences and to be assigned to training symbols contained in one or more training fields; determine the set of data tones based on one or more distributed resource units; and - Receive a PPDU from a first communication device, wherein one or more training fields are contained in the preamble of the PPDU.

[0147] 39. A second communication device according to embodiment 38, wherein the circuit is configured to receive an instruction contained in a PPDU received from the first communication device.

[0148] 40. A second communication device according to embodiment 39, wherein the circuit is configured to determine a set of data tones to be allocated to one or more distributed resource units based on an instruction received from a first communication device.

[0149] 41. A second communication device according to embodiment 39 or 40, wherein the circuitry is configured to determine a set of training tones to be assigned to training symbols contained in one or more training fields based on an instruction received from a first communication device.

[0150] 42. A second communication device according to any one of embodiments 38 to 41, wherein the circuit is configured to receive configuration information including at least one of power allocation information, type information of one or more training fields, number of training symbols, and tone allocation information of one or more training fields, and to transmit a PPDU based on the received configuration information.

[0151] 43. A first communication method of a first communication device, the first communication device communicating with one or more second communication devices by receiving Physical Layer Protocol Data Units (PPDUs), the PPDUs having a defined bandwidth and at least a preamble, the first communication method comprising: - Determine the set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed across a defined bandwidth of PPDU. - Based on a determined set of data tones from one or more distributed resource units, select a set of training tones consisting of defined sequences that will be assigned to training symbols contained in one or more training fields, and - Send an instruction to one or more second communication devices, which instructs the devices to include one or more training fields in the preamble of the PPDU in response to the instruction, and send the PPDU.

[0152] 44. A first communication method of a first communication device, the first communication device communicating with a second communication device by sending a Physical Layer Protocol Data Unit (PPDU), the PPDU having a defined bandwidth and at least a preamble, the first communication method comprising: Determine a set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed across a defined bandwidth of the PPDU. Based on a determined set of data tones from one or more distributed resource units, a set of training tones consisting of defined sequences is selected and will be assigned to training symbols contained in one or more training fields. One or more training fields are included in the preamble of the PPDU and the PPDU is sent to one or more second communication devices.

[0153] 45. A second communication method of a second communication device, the second communication device communicating with a first communication device by sending a Physical Layer Protocol Data Unit (PPDU), the PPDU having a defined bandwidth and at least a preamble, the second communication method comprising: Determine the set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed across a defined bandwidth of PPDU. Based on a determined set of data tones from one or more distributed resource units, a set of training tones consisting of defined sequences is determined and will be assigned to training symbols contained in one or more training fields. Receive an instruction from a first communication device to include one or more training fields in the preamble of the PPDU in response to the received instruction, and send the PPDU.

[0154] 46. ​​A second communication method of a second communication device, the second communication device communicating with a first communication device by receiving a Physical Layer Protocol Data Unit (PPDU), the PPDU having a defined bandwidth and at least a preamble, the second communication method comprising: Determine the set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed across a defined bandwidth of PPDU. Based on a determined set of data tones from one or more distributed resource units, a set of training tones consisting of defined sequences is determined and will be assigned to training symbols contained in one or more training fields. Receive a PPDU from a first communication device, wherein one or more training fields are contained in the preamble of the PPDU.

[0155] 47. A non-transitory computer-readable recording medium storing a computer program product which, when executed by a processor, causes the method according to embodiment 43 to be executed.

[0156] 48. A non-transitory computer-readable recording medium storing a computer program product that, when executed by a processor, causes the method according to embodiment 44 to be executed.

[0157] 49. A non-transitory computer-readable recording medium storing a computer program product which, when executed by a processor, causes the method according to embodiment 45 to be executed.

[0158] 50. A non-transitory computer-readable recording medium storing a computer program product that, when executed by a processor, causes the method according to embodiment 46 to be executed.

Claims

1. A first communication device configured to communicate with one or more second communication devices by receiving a Physical Layer Protocol Data Unit (PPDU) having a defined bandwidth and at least a preamble, the first communication device including circuitry configured to: Determine the set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed across a defined bandwidth of PPDU; Based on the determined set of data tones of the one or more distributed resource units, select a set of training tones consisting of defined sequences and to be assigned to training symbols contained in one or more training fields; and Send an instruction to the one or more second communication devices, the instruction instructing the one or more second communication devices to include the one or more training fields in the preamble of the PPDU in response to the instruction, and send the PPDU.

2. The first communication device according to claim 1, wherein, The circuit is further configured to: indicate to the one or more second communication devices that the PPDU includes a data field comprising the one or more distributed resource units, and to select the power level of the one or more training fields based on the power level set for the data field comprising the one or more distributed resource units.

3. The first communication device according to claim 1, wherein, The circuit is further configured to indicate to the one or more second communication devices that configuration information is included in the signaling field of the preamble, the configuration information including at least one of power allocation information, type information of the one or more training fields, number of training symbols, and tone allocation information of the one or more training fields.

4. The first communication device according to claim 1, wherein, The circuit is further configured to indicate to the one or more second communication devices that a first type of training field is included within the one or more training fields, wherein the training tone set is selected by mapping the tones in the data tone set of the one or more distributed resource units to available tones in a one-to-one manner.

5. The first communication device according to claim 4, wherein, The circuit is configured to instruct the one or more second communication devices to set any remaining tones within the defined bandwidth that were not selected for the training tone set to zero.

6. The first communication device according to claim 1, wherein, The circuit is configured to: indicate to the one or more second communication devices that: at least one second type of training field is included in the one or more training fields, in which only even-numbered tones among all available tones within the defined bandwidth can be selected for the training tone set, and to select the training tone set by mapping the tones in the data tone set of the one or more distributed resource units to even-numbered available tones.

7. The first communication device according to claim 6, wherein: (i) The training pitch set is selected as the intersection of the even-numbered available pitches and the data pitch sets of the one or more distributed resource units, or (ii) The training tone set is selected to be distributed across the defined bandwidth by alternatingly mapping tones from the data tone set of the one or more distributed resource units to an even number of available tones.

8. The first communication device according to claim 6, wherein, The circuit is configured to instruct the one or more second communication devices to map the data tone of the one or more distributed resource units in the PPDU to the even-numbered available tone.

9. The first communication device according to claim 6, wherein, The at least one training field of the second type includes a first symbol and a second symbol, and the training tone set includes a first training tone set assigned to the first symbol and a second training tone set assigned to the second symbol.

10. The first communication device according to claim 6, wherein, The circuit is configured to instruct the one or more second communication devices to select a pilot tone within the training tone set that matches the pilot tone position in the data tone set assigned to the one or more distributed resource units.

11. The first communication device according to claim 1, wherein, The preamble includes a conventional modulation field, and the one or more training fields include at least one training field associated with at least one of the one or more distributed resource units, and the circuit is configured to indicate to the one or more second communication devices to select a power level for the at least one training field, the power level being equal to and higher than the power level set for the conventional modulation field, and for a data field including at least one distributed resource unit.

12. A first communication device configured to communicate with one or more second communication devices by transmitting a Physical Layer Protocol Data Unit (PPDU) having a defined bandwidth and at least a preamble, the first communication device including circuitry configured to: Determine the set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed across a defined bandwidth of PPDU; Based on the determined set of data tones of the one or more distributed resource units, a set of training tones consisting of defined sequences and to be assigned to training symbols contained in one or more training fields is selected; and The one or more training fields are included in the preamble of the PPDU, and the PPDU is sent to the one or more second communication devices.

13. A second communication device configured to communicate with a first communication device by transmitting a Physical Layer Protocol Data Unit (PPDU) having a defined bandwidth and at least a preamble, the second communication device including circuitry configured to: Determine the set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed across a defined bandwidth of PPDU; Based on the determined set of data tones of the one or more distributed resource units, a set of training tones consisting of defined sequences and to be assigned to training symbols contained in one or more training fields is determined. and Receive an instruction from the first communication device to include the one or more training fields in the preamble of the PPDU in response to the received instruction, and send the PPDU.

14. The second communication device according to claim 13, wherein, The circuit is configured to: receive configuration information, the configuration information including at least one of power allocation information, type information of the one or more training fields, number of training symbols, and pitch allocation information of the one or more training fields, and send the PPDU based on the received configuration information.

15. A second communication device configured to communicate with a first communication device by receiving a Physical Layer Protocol Data Unit (PPDU) having a defined bandwidth and at least a preamble, the second communication device including circuitry configured to: Determine the set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed across a defined bandwidth of PPDU; Based on the determined set of data tones of the one or more distributed resource units, a set of training tones consisting of defined sequences and to be assigned to training symbols contained in one or more training fields is determined. and Receive the PPDU from the first communication device, wherein the one or more training fields are included in the preamble of the PPDU.

16. A first communication method of a first communication device, wherein the first communication device communicates with one or more second communication devices by receiving Physical Layer Protocol Data Units (PPDUs), wherein the PPDUs have a defined bandwidth and at least a preamble, the first communication method comprising: Determine a set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed over a defined bandwidth of the PPDU; Based on the determined set of data tones of the one or more distributed resource units, select a set of training tones consisting of defined sequences and to be assigned to training symbols contained in one or more training fields; and Send an instruction to the one or more second communication devices, the instruction instructing the one or more second communication devices to include the one or more training fields in the preamble of the PPDU in response to the instruction, and send the PPDU.

17. A first communication method of a first communication device, wherein the first communication device communicates with a second communication device by sending a Physical Layer Protocol Data Unit (PPDU), the PPDU having a defined bandwidth and at least a preamble, the first communication method comprising: Determine a set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed over a defined bandwidth of the PPDU; Based on the determined set of data tones of the one or more distributed resource units, a set of training tones consisting of defined sequences and to be assigned to training symbols contained in one or more training fields is selected; and The one or more training fields are included in the preamble of the PPDU, and the PPDU is sent to one or more second communication devices.

18. A second communication method of a second communication device, wherein the second communication device communicates with a first communication device by sending a Physical Layer Protocol Data Unit (PPDU), the PPDU having a defined bandwidth and at least a preamble, the second communication method comprising: Determine a set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed over a defined bandwidth of the PPDU; Based on the determined set of data tones of the one or more distributed resource units, a set of training tones consisting of defined sequences and to be assigned to training symbols contained in one or more training fields is determined. and Receive an instruction from the first communication device to include the one or more training fields in the preamble of the PPDU in response to the received instruction, and send the PPDU.

19. A second communication method for a second communication device, wherein the second communication device communicates with a first communication device by receiving a Physical Layer Protocol Data Unit (PPDU), the PPDU having a defined bandwidth and at least a preamble, the second communication method comprising: Determine a set of data tones to be allocated to one or more distributed resource units, each distributed resource unit having data tones distributed over a defined bandwidth of the PPDU; Based on the determined set of data tones of the one or more distributed resource units, a set of training tones consisting of defined sequences and to be assigned to training symbols contained in one or more training fields is determined. and Receive the PPDU from the first communication device, wherein the one or more training fields are contained in the preamble of the PPDU.

20. A non-transitory computer-readable recording medium storing a computer program product, which, when executed by a processor, causes the method according to any one of claims 16, 17, 18, and 19 to be performed.

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