Communication apparatus and communication method for tone-interleaved long training field allocation

Abstract

The present disclosure provides a communication apparatus and a communication method for tone-interleaved long training field allocation, the communication apparatus comprising: circuitry, which in operation, allocates (i) a plurality of pilot tones to a first group of spatial streams and a second group of spatial streams, each of the plurality of pilot tone separating a first data tones set and a second data tones set for transmitting a plurality of symbols, and (ii) even-number indexed data tones of the first data tones set to the first group of spatial streams and odd-number indexed data tones of the first data tones set to the second group of spatial streams; a transmitter, which in operation, transmits one or more symbols of the plurality of symbols to another communication apparatus through one of the first group of spatial streams and the second group of spatial streams on the first data tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

Description

[0001] Description

[0002] Title of Invention: COMMUNICATION APPARATUS AND COMMUNICATION METHOD FOR TONE-INTERLEAVED LONG TRAINING FIELD ALLOCATION

[0003] TECHNICAL FIELD

[0004] [1] The present disclosure relates to communication apparatuses and methods for tone-interleaved long training field (LTF) allocation, and more particularly, for allocating interleaved tones in an LTF.

[0005] BACKGROUND

[0006] [2] In 802.11 be-Extremely High Throughput (EHT), the number of required LTF symbols ( JVEHT.LTF) for multiple-input-multiple-output (MIMO) channel estimation increases with the number of spatial streams (Nss). The next-generation WLAN may support more spatial streams than 802.11 be. For example, more spatial streams may be supported in Multi-AP joint sounding and joint transmission. However, having more spatial streams requires more LTF symbols which increases the overhead.

[0007] [3] Additionally, although subcarrier-interleaved LTF for reducing the number of required LTF symbols in multi-access-point (multi-AP) joint sounding was proposed, there is no discussion on allocating interleaved tones in an LTF for reducing the number of LTF symbols for MIMO channel estimation.

[0008] [4] Therefore, there is thus a need for communication apparatus and method for tone- interleaved LTF allocation to address the issues, more particularly, to reduce the number of LTF symbols for MIMO channel estimation while maintain good channel estimation performance in the context of next generation wireless local access network (WLAN), where allocation of pilot tones should also be considered for phase and / or frequency offset correction.

[0009] [5] Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background of the disclosure. SUMMARY

[0010] [6] Non-limiting and exemplary embodiments facilitate providing communication apparatuses and communication methods for subcarriers modulation across multiple spatial streams in context of WLAN.

[0011] [7] In an embodiment, the present disclosure provides a communication apparatus comprising: circuitry, which in operation, allocates (i) a plurality of pilot tones to a first group of spatial streams and a second group of spatial streams, each of the plurality of pilot tone separating a first data tones set and a second data tones set for transmitting a plurality of symbols, and (ii) even-number indexed data tones of the first data tones set to the first group of spatial streams and odd-number indexed data tones of the first data tones set to the second group of spatial streams; a transmitter, which in operation, transmits one or more symbols of the plurality of symbols to another communication apparatus through one of the first group of spatial streams and the second group of spatial streams on the first data tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0012] [8] In another embodiment, the present disclosure provides a communication method comprising: allocating (i) a plurality of pilot tones to a first group of spatial streams and a second group of spatial streams, each of the plurality of pilot tones separating a first data tones set and a second data tones set for transmitting a plurality of symbols, and (ii) even-number indexed data tones of the first data tones set to the first group of spatial streams and oddnumber indexed data tones of the first data tones set to the second group of spatial streams; and transmitting one or more symbols of the plurality of symbols to another communication apparatus through one of the first group of spatial streams and the second group of spatial streams on the first data tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0013] [9] It should be noted that general or specific embodiments may be implemented as a system, a method, an integrated circuit, a computer program, a storage medium, or any selective combination thereof.

[0014]

[0010] Additional benefits and advantages of the disclosed embodiments will become apparent from the specification and drawings. The benefits and / or advantages may be individually obtained by the various embodiments and features of the specification and drawings, which need not all be provided in order to obtain one or more of such benefits and / or advantages.

[0015] BRIEF DESCRIPTION OF THE DRAWINGS

[0016]

[0011] Embodiments of the disclosure will be better understood and readily apparent to one of ordinary skilled in the art from the following written description, by way of example only, and in conjunction with the drawings, in which:

[0017]

[0012] Figure 1 shows a schematic diagram illustrating a single AP MU -Ml MO transmission between an AP and four STAs.

[0018]

[0013] Figure 2 shows a schematic diagram illustrating a multi-AP joint MU-MIMO transmission between two APs and six STAs.

[0019]

[0014] Figure 3 shows a MU PPDU format for a MIMO transmission to one or more users.

[0020]

[0015] Figure 4 shows a sounding NDP format. The sounding NDP is a variant of a MU PPDU.

[0021]

[0016] Figure 5 shows a schematic diagram illustrating a communication apparatus according to the present disclosure.

[0022]

[0017] Figure 6A shows a flowchart illustrating a communication method for tone- interleaved LTF allocation.

[0023]

[0018] Figure 6B shows a flowchart illustrating another communication method for tone- interleaved LTF allocation.

[0024]

[0019] Figure 7 shows a block diagram illustrating an example tone allocation of LTF symbols to two groups of spatial streams according to a first embodiment of the present disclosure.

[0025]

[0020] Figure 8 shows a block diagram illustrating an example transmitter processing for generating time domain LTF symbols according to the first embodiment of the present disclosure.

[0021] Figure 9 shows a block diagram illustrating an example tone allocation of LTF symbols to two groups of spatial streams according to a second embodiment of the present disclosure.

[0026]

[0022] Figure 10 shows a block diagram 1000 illustrating a first example tone allocation of LTF symbols to two groups of spatial streams according to the second embodiment of the present disclosure.

[0027]

[0023] Figure 11 shows a block diagram illustrating a second example tone allocation of LTF symbols to two groups of spatial streams according to the second embodiment of the present disclosure.

[0028]

[0024] Figure 12 shows a block diagram illustrating an example allocation of 242-tone resource unit (RD) of LTF symbols to two groups of spatial streams in a 20 MHz PPDU according to the second embodiment of the present disclosure.

[0029]

[0025] Figure 13 shows a block diagram illustrating an example allocation of 484-tone RL) of LTF symbols to two groups of spatial streams in a 40 MHz PPDU according to the second embodiment of the present disclosure.

[0030]

[0026] Figure 14 shows a block diagram illustrating a first example tone allocation of LTF symbols to two groups of spatial streams according to the third embodiment of the present disclosure.

[0031]

[0027] Figure 15 shows a block diagram illustrating a second example tone allocation of LTF symbols to two groups of spatial streams according to the second embodiment of the present disclosure.

[0032]

[0028] Figure 16 shows a block diagram illustrating an example allocation of 242-tone RU of LTF symbols to two groups of spatial streams in a 20 MHz PPDU according to the third embodiment of the present disclosure.

[0033]

[0029] Figure 17 shows a block diagram illustrating an example allocation of 484-tone RU of LTF symbols to two groups of spatial streams in a 40 MHz PPDU according to the third embodiment of the present disclosure.

[0030] Figure 18 shows a block diagram illustrating another example transmitter processing for generating time domain LTF symbols according to the third embodiment of the present disclosure.

[0034]

[0031] Figure 19 shows a diagram illustrating communication in a multi-AP system according to an embodiment of the present disclosure.

[0035]

[0032] Figure 20 shows a schematic diagram 2000 illustrating an example multi-AP system.

[0036]

[0033] Figure 21 shows a block diagram illustrating an example transmitter processing for generating time domain LTF symbols for first group of spatial streams according to an embodiment of the present disclosure.

[0037]

[0034] Figure 22 shows a block diagram illustrating an example transmitter processing for generating time domain LTF symbols for second group of spatial streams (Group 2 SS) according to an embodiment of the present disclosure.

[0038]

[0035] Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been depicted to scale. For example, the dimensions of some of the elements in the illustrations, block diagrams or flow charts may be exaggerated in respect to other elements to help an accurate understanding of the present embodiments.

[0039] DETAILED DESCRIPTION

[0040]

[0036] Some embodiments of the present disclosure will be described, byway of example only, with reference to the drawings. Like reference numerals and characters in the drawings refer to like elements or equivalents.

[0041]

[0037] In the following paragraphs, certain exemplifying embodiments are explained with reference to an access point (AP) and a station (STA) for subcarriers modulation across multiple spatial streams, especially in a multiple-input multiple-output (MIMO) wireless network.

[0042]

[0038] In the context of IEEE 802.11 (Wi-Fi) technologies, a station, which is interchangeably referred to as a STA, is a communication apparatus that has the capability to use the IEEE 802.11 protocol. Based on the IEEE 802.11-2016 definition, a STA can be any device that contains an IEEE 802.11-conformant media access control (MAC) and physical layer (PHY) interface to the wireless medium (WM).

[0043]

[0039] 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. The STA may be fixed or mobile. In the WLAN environment, the terms “STA”, “wireless client”, “user”, “user device”, and “node” are often used interchangeably.

[0044]

[0040] Likewise, an AP, which may be interchangeably referred to as a wireless access point (WAP) in the context of IEEE 802.11 (Wi-Fi) technologies, is a communication apparatus that allows STAs in a WLAN to connect to a wired network. The AP usually connects to a router (via a wired network) as a standalone device, but it can also be integrated with or employed in the router.

[0045]

[0041] As mentioned above, a STA in a WLAN may work as an AP at a different occasion, and vice versa. This is because communication apparatuses in the context of IEEE 802.1 1 (Wi-Fi) technologies may include both STA hardware components and AP hardware components. In this manner, the communication apparatuses may switch between a STA mode and an AP mode, based on actual WLAN conditions and / or requirements.

[0046]

[0042] In a MIMO wireless network, “multiple” may refer to multiple antennas used simultaneously for transmission and multiple antennas used simultaneously for reception, over a radio channel. In this regard, “multiple-input” may refer to multiple transmitter antennas, which input a radio signal into the channel, and “multiple-output” may refer to multiple receiver antennas, which receive the radio signal from the channel and into the receiver. For example, in an N x M MIMO network system, N is the number of transmitter antennas, M is the number of receiver antennas, and N may or may not be equal to M. For the sake of simplicity, the respective numbers of transmitter antennas and receiver antennas are not discussed further in the present disclosure.

[0047]

[0043] In a MIMO wireless network, single-user (SU) communications and multi-user (MU) communications can be deployed for communications between communication apparatuses such as APs and STAs. MIMO wireless network has benefits like spatial multiplexing and spatial diversity, which enable higher data rates and robustness through the use of multiple spatial streams.

[0048]

[0044] In various embodiments below, each of the terms “channel” and “subchannel” may be used interchangeably with any one of “band”, “subband” and “frequency segments”. The term “circuitry” may be used interchangeably with “module”.

[0049]

[0045] Figure 1 shows a schematic diagram 100 illustrating a single AP MU -Ml MO transmission between an AP 102 and four STAs 104, 106, 108, 110. The AP 102 transmits a signal (e.g., physical layer protocol data unit (PPDU)) through multiple spatial streams simultaneously to multiple STAs 104, 106, 108, 110. For example, the AP 102 may transmit a signal (e.g., PPDU) to four STAs 104, 106, 108, 1 10 through a total of 8 spatial streams (e.g., 8 antennas) where two spatial streams, illustrated as a group data transmission arrow 114, 116, 118, 120 in Figure 1 , are directed to each STA 104, 106, 108, 110, respectively.

[0050]

[0046] Figure 2 shows a schematic diagram 200 illustrating a multi-AP joint MU-MIMO transmission between two APs 202, 204 and six STAs 211-216. The APs 202, 204 behave and transmit like a single AP, and transmit signals through multiple spatial streams simultaneously to multiple STAs 21 1-216. For example, the primary AP 202 first sends a trigger 206 to a secondary AP 204, and then, the primary and secondary APs 202, 204 transmit signals through a total of 12 spatial streams where two spatial streams, illustrated as a group data transmission arrow 221 -226 in Figure 2, are directed to each STA 211 - 216, respectively.

[0051]

[0047] In MU-MIMO wireless network, both single-user (SU) and multi-user (MU) communications can be used for interactions between APs and STAs. MIMO technology enables higher data rate by utilizing multiple spatial streams.

[0052]

[0048] Figure 3 shows a MU PPDU format for a MIMO transmission to one or more users. The MU PPDU may include a Legacy Short Training Field (L-STF), a Legacy Long Training Field (L-LTF), a Legacy SIGNAL (L-SIG) field, a Repeated L-SIG (RL-SIG) field, a Universal SIGNAL (U-SIG) field, a SIGNAL (SIG) field, a Short Training Field (STF), a Long Training Field (LTF), a Data field and a Packet Extension (PE) field. The L-STF may refer to a non- high-throughput (non-HT) STF; the L-LTF may refer to a non-HT LTF; the L-SIG field may refer to a non-HT SIG field; the RL-SIG field may refer to a non-HT Repeated L-SIG field; while the data field carries the physical service data units (PSDUs).

[0049] The SIG field, STF and LTF fields may have a prefix derived from the name of the next generation WLAN. For example, in a next generation WLAN with an ultra high reliability (UHR) these fields may be named as UHR-SIG field, UHR-STF and UHR-LTF, respectively.

[0053]

[0050] The LTF field comprises WLTFLTF symbols for MIMO channel estimation. Each LTF symbol comprises data tones and pilot tones and each tone of the LTF symbol has a corresponding LTF sequence value selected from the set {-1 ,0,1}.

[0054]

[0051] Figure 4 shows a sounding NDP format. The sounding NDP is a variant of a MU PPDU. In particular, in a sounding NDP, the data field is not present. A sounding NDP may include a L-STF, a L-LTF, a L-SIG field, a RL-SIG field, a U-SIG field, a SIG field, a STF, an LTF and a PE field. The LTF field comprises NLTFLTF symbols for MIMO channel estimation. Each LTF symbol comprises data tones and pilot tones and each tone of the LTF symbol has a corresponding LTF sequence value selected from the set {-1 ,0,1}.

[0055]

[0052] When the defined PPDU format is used in a non-OFDMA transmission (single or multiple APs) including the SU transmission, PPDUs to multiple users using MU-MIMO and a sounding NDP, the LTF field enables the receiver to estimate the channel for the number of spatial streams Nssused for the transmission of the PSDU(s). In a MU-MIMO transmission, Nssis the total number of spatial streams for all the users. The estimated MIMO channel is an NRXx Nssmatrix where NRXdenotes the number of receive chains.

[0056]

[0053] On the other hand, when the defined PPDU format is used in an OFDMA transmission (single or multiple APs), the LTF field enables the receiver to estimate the channel for NSSrspatial streams (SS) used for the transmission of the PSDU(s) in the r- th resource unit (RU) or multiple resource unit (MRU). The estimated MIMO channel is an NRXx Nss,r matrix for each subcarrier in the r-th RU or MRU.

[0057]

[0054] As mentioned earlier, in 802.11 be-Extremely High Throughput (EHT), the number of required LTF symbols (WEHT.LTF) for multiple-input-multiple-output (MIMO) channel estimation increases with the number of spatial streams (Nss).

[0058]

[0055] Table 1 shows the initial number of EHT-LTFs required for different number of spatial streams.

[0059] [Table 1]

[0060]

[0056] However, having more spatial streams requires more LTF symbols which increases the overhead. Therefore, there is thus a need for communication apparatus and method for tone-interleaved LTF allocation to address the issues, more particularly, to reduce the number of LTF symbols for MIMO channel estimation while maintain good channel estimation performance in the context of next generation wireless local access network (WLAN).

[0061]

[0057] Figure 5 shows a schematic diagram illustrating a communication apparatus 500 according to the present disclosure. The communication apparatus 500 may be implemented as an AP or a STA.

[0062]

[0058] As shown in Figure 5, the communication apparatus 500 may include circuitry 514, at least one radio transmitter 502, at least one radio receiver 504, and at least one antenna 512 (for the sake of simplicity, only one antenna is depicted in Figure 5 for illustration purposes). The circuitry 514 may include at least one controller 506 for use in software and / or hardware aided execution of tasks that the at least one controller 506 is designed to perform, including but not limited to control of communications with one or more other communication apparatuses in a MIMO wireless network. The circuitry 514 may further include at least one transmission signal generator 508 and at least one receive signal processor 510. The at least one controller 506 may control the at least one transmission signal generator 508 for generating PPDUs to be sent through the at least one radio transmitter 502 to one or more other communication apparatuses. Here, the PPDU, for example, may be PPDUs used for downlink transmissions if the communication apparatus 500 is an AP. Alternatively, the PPDU may be PPDUs used for trigger-based uplink transmissions if the communication apparatus 500 is a STA. The at least one controller 506 may control the at least one receive signal processor 510 for processing MAC frames and PPDUs received through the at least one radio receiver 504 from the one or more other communication apparatuses under the control of the at least one controller 506. Here the PPDU, for example, may be PPDUs used for trigger-based uplink transmissions if the communication apparatus 500 is an AP. Alternatively, the PPDU may be PPDUs used for downlink transmissions if the communication apparatus 500 is a STA. The at least one transmission signal generator 508 and the at least one receive signal processor 510 may be stand-alone modules of the communication apparatus 500 that communicate with the at least one controller 506 for the above-mentioned functions, as shown in Figure 5. Alternatively, the at least one transmission signal generator 508 and the at least one receive signal processor 510 may be included in the at least one controller 506. It is appreciable to those skilled in the art that the arrangement of these functional modules is flexible and may vary depending on the practical needs and / or requirements. The data processing, storage and other relevant control apparatus can be provided on an appropriate circuit board and / or in chipsets. In various embodiments, when in operation, the at least one radio transmitter 502, at least one radio receiver 504, and at least one antenna 512 may be controlled by the at least one controller 506.

[0063]

[0059] The communication apparatus 500, when in operation, may provide functions required for tone-interleaved LTF allocation. For example, the communication apparatus 500 may be an AP, and the circuitry 514 (for example the at least one controller 506 of the circuitry 514) may be configured to allocates (i) a plurality of pilot tones to a first group of spatial streams (SS) (e.g., Group 1 SS) and a second group of spatial streams (Group 2 SS), each of the plurality of pilot tone separating a first data tones set and a second data tones set for transmitting a plurality of symbols, and (II) even-number indexed data tones of the first data tones set to the first group of spatial streams and odd-number indexed data tones of the first data tones set to the second group of spatial streams. The at least one radio transmitter 502 may transmit one or more symbols of the plurality of symbols to another communication apparatuses (e.g., another AP or STA) through one of the first group of spatial streams and the second group of spatial streams on the first data tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0064]

[0060] In one embodiment, the circuitry 514 (for example the at least one controller 506 of the circuitry 514) may further allocate (iii) even-number indexed data tones of the second data tones set to the first group of spatial streams and odd-numbered indexed data tones of the second data tones set to the second group of spatial streams. The at least one radio transmitter 502 may transmit another one or more symbols of the plurality of symbols to the another communication apparatuses through the one of the first group of spatial streams and the second group of spatial streams on the second data tones set allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0065]

[0061] In various embodiments, the circuitry 514 (for example the at least one controller 506 of the circuitry 514) may further allocate (iii) odd-number indexed data tones of the second data tones set to the first group of spatial streams and even -numbered indexed data tones of the second data tones set to the second group of spatial streams. The at least one radio transmitter 502 may transmit another one or more symbols of the plurality of symbols to the another communication apparatuses through the one of the first group of spatial streams and the second group of spatial streams on the second data tones set allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0066]

[0062] In an embodiment, the circuitry 514 (for example the at least one controller 506 of the circuitry 514) may further allocate (iv) even-number indexed data tones of a third data tones set to the first group of spatial streams and odd-number indexed data tones of the third data tones set to the second group of spatial streams, where the third data tones set and the first data tones set are separated by a direct current tones set. The at least one radio transmitter 502 may transmit yet another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the third tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0067]

[0063] In an alternative embodiment, the circuitry 514 (for example the at least one controller 506 of the circuitry 514) may further allocate (iv) odd-number indexed data tones of a third data tones set to the first group of spatial streams and even-number indexed data tones of the third data tones set to the second group of spatial streams, wherein the third data tones set and the first data tones set are separated by a direct current tones set. The at least one radio transmitter 502 may transmit yet another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the third tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0068]

[0064] In various embodiments, the circuitry 514 (for example the at least one transmission signal generator 508 of the circuitry 514) may generate a signal comprising (i) a signal field comprising the plurality of symbols and (ii) another signal field indicating a size of the signal field and the allocation of the plurality of pilot tones, the first data tones set and the second data tones set. Additionally, the another signal field may further comprise a first signal field indicating the size of the signal field and a second signal field indicating the allocation of the plurality of pilot tones, the first data tones set and the second data tones set.

[0069]

[0065] In one embodiment, the circuitry 514 (for example the controller 506 of the circuitry 514) may group number of spatial streams into the first group of spatial streams and another number of spatial streams into the second group of spatial streams, where At is a total number of available spatial streams for transmitting the plurality of symbols.

[0070]

[0066] In another embodiment, each of the first group of spatial streams is mapped to a transmit chain of first group of communication apparatuses and each of the second group of spatial streams is mapped to a transmit chain of a second group of communication apparatuses, and the another signal field comprises a third signal field indicating a difference in a number of spatial streams between the first group of spatial streams and the second group of spatial streams, and the circuitry 514 (for example the controller 506 of the circuitry 514) may determine a first number of spatial streams and a second number of spatial streams based on the difference in the number of spatial streams, and group the first number of spatial streams into the first group of spatial streams and the second number of spatial streams into the second group of spatial streams.

[0071]

[0067] Figure 6A shows a flowchart 600 illustrating a communication method for tone- interleaved LTF allocation according to an embodiment of the present disclosure. The communication method may be implemented by a communication apparatus, for example, may be an AP. In step 602, a step of generating a signal, the signal containing one or more spatial streams containing a plurality of pilot tones and at least one of a first data tones set and a second data tones set.

[0072]

[0068] Figure 6B shows a flowchart 610 illustrating another communication method for tone-interleaved LTF allocation. The communication method may be implemented by a communication apparatus, for example, may be an AP according to various embodiments of the present disclosure. In step 612, a step of allocating (i) a plurality of pilot tones to a first group of spatial streams and a second group of spatial streams, each of the plurality of pilot tones separating a first data tones set and a second data tones set for transmitting a plurality of symbols, and (ii) even-number indexed data tones of the first data tones set to the first group of spatial streams and odd-number indexed data tones of the first data tones set to the second group of spatial streams is carried out. In step 614, a step of transmitting one or more symbols of the plurality of symbols to another communication apparatus through one of the first group of spatial streams and the second group of spatial streams on the first data tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams is carried out.

[0073]

[0069] Figure 7 shows a block diagram 700 illustrating an example tone allocation of LTF symbols to two groups of spatial streams (Group 1 SS, Group 2 SS) according to a first embodiment of the present disclosure. The Nssspatial streams (SS) are grouped into Group 1 SS with NSS G1SS, and Group 2 SS with NSS G2SS. In this embodiment, the same set of pilot tones (tone index number [-116, -90, -48, -22, 22, 48, 90, 116]) are allocated to the LTF symbols of Group 1 SS and the LTF symbols of Group 2 SS, the pilot tones allocation is symmetric around direct current (DC) tone index number [0] for phase and / or frequency offset correction. The remaining tones from tone index numbers [-122] and

[0122] are data tones of LTF symbols. The even-number-indexed data tones are allocated to Group 1 SS while the odd-number-indexed data tones are allocated to Group 2 SS. More particularly, the LTF sequence for Group 1 SS has nonzero values at the evennumber-indexed data tones, while the LTF sequence for Group 2 SS has nonzero values at the odd-number-indexed data tones, such that Group 1 and Group 2 SSs are active on even-number-indexed data tones and odd-number-indexed data tones of the LTF symbols, respectively.

[0074]

[0070] In this embodiment, the total number of spatial streams are evenly allocated to Group 1 and Group 2, that is Group 1 SS consist of the 1stto the [ / Vss / 21-th SS; Group 2 SS consist of the ([Nss / 2] + l)-th to the N5S-th SS, or Group 1 SS consist of the 1stto the [A / ss / 2 J -th SS; Group 2 SS consist of the ([iVss / 2 J + 1 )-th to the Ns$-th SS. In other words, a first number of spatial streams of Ceil (^2) or Floor^ / 2) are grouped and allocated to Group 1 SS while a second number of spatial streams of are grouped and allocated to Group 2 SS. Alternatively, even-indexed SSs (e.g., SS index = 0, 2, 4, ...) may be allocated to Groupl and odd-indexed SSs (e.g., SS index = 1 , 3, 5, ...) may be allocated to Group2. Table 2 shows example numbers of spatial streams allocated to Group 1 SS (NSS G1) and Group 2 SS (NSS>G2) from the total number of spatial streams Nssand the initial / VLTF. The Initial AfLTFis determined based on the maximum of NSS>C1and ^ss,G2 such that the orthogonality is maintained within each SS group. Orthogonality between the SS groups is realized thanks to the allocation of interleaved tones in an LTF. Advantageously, the number of LTF symbols is reduced. In addition, the pilot tones specified in 802.11 be can be used without the need for introducing new pilot tones.

[0075] [Table 2]

[0076]

[0071] Figure 8 shows a block diagram 800 illustrating an example transmitter processing for generating time domain LTF symbols according to the first embodiment of the present disclosure. The LTF sequence value at the fc-th subcarrier of the LTF symbols for Group 1 and Group 2 SS is denoted as LTFGI .R and LTFG2, / T, respectively. LTFGU is selected from {—1,1} at the even-index data tones and pilot tones, and takes zero value for the remaining tones. LTFG2,R is selected from {—1,1} at the odd-index data tones and pilot tones, and takes zero value for the remaining tones. The subcarriers of each LTF symbol are multiplied by entries belonging to a matrix asshown in equation (1 ): where / fPilotis the set of pilot subcarrier indices. PLTFand f?LTFare the same as those defined in 802.1 1 be. QLTF ■ An Inverse Discrete Fourier Transform (IDFT) unit 806a-806n converts the subcarrier on a transmit chain, which are frequency-domain data, into time-domain data for transmission.

[0077]

[0073] Figure 9 shows a block diagram 900 illustrating an example tone allocation of LTF symbols to two groups of spatial streams (Group 1 SS, Group 2 SS) according to a second embodiment of the present disclosure. In this embodiment, the same set of pilot tones are allocated to Group 1 SS and Group 2 SS, the pilot tones allocation is symmetric around direct current tone index number (not shown). In this embodiment, when first data tones set 902 and second data tones set 904) are separated by a pilot tone 903, the evennumber-indexed data tones of the first tones set 902 are allocated to Group 1 SS and the odd-number-indexed data tones of the first tones set 902 are allocated to Group 2 SS; and the odd-numbered indexed data tones of the second tones set 904 are allocated to Group 1 SS and the even-numbered indexed data tones of the second tones set 904 are allocated to Group 2 SS. The Group 1 and Group 2 SS are active on different data tones of the LTF symbols. In particular, the data tones where Group 1 or Group 2 SS are active alternate between even and odd indices, with the parity changing when crossing pilot tones. Advantageously, channel interpolation errors at the two data tones near the pilot tone are reduced and placing the data tones next to the pilot tones may improve the performance for phase and / or frequency offset correction by improving channel estimation for the pilot tones.

[0078]

[0074] Additionally, in this second embodiment, the data tones where Group 1 or Group 2 SS are active are symmetric (i.e., form a symmetric pair) around the DC tones set. In other words, the data tone set having negative subcarrier index number range and the data tone set having the same but positive subcarrier index number range will form a symmetric pair around the DC tones set and share the same tone allocations. Figure 10 shows a block diagram 1000 illustrating a first example tone allocation of LTF symbols to two groups of spatial streams (Group 1 SS, Group 2 SS) according to the second embodiment of the present disclosure, where the number of DC tones in the DC tones set is 3, 7, 11 , or any number that increases by 4 thereafter. Figure 11 shows a block diagram 1100 illustrating a second example tone allocation of LTF symbols to two groups of spatial streams (Group 1 SS, Group 2 SS) according to the second embodiment of the present disclosure, where the number of DC tones in the DC tones set is 5, 9, 13 or any number that increases by 4 thereafter. Similar to the first embodiment of the present disclosure, when first data tones set and second data tones set are separated by a pilot tone (e.g., pilot tone 1003 separating data tones sets 1002 and 1004 in Figure 10, pilot tone 1103 separating data tones sets 1102 and 1104 in Figure 11), the even-number-indexed data tones of the first tones set (e.g., data tones set 1002, 1102) is allocated to Group 1 SS and the odd-number-indexed data tones of the first tones set is allocated to Group 2 SS; and the odd-number indexed data tones of the second tones set (e.g., data tones set 1004, 1104) is allocated to Group 1 SS and the even-numbered indexed data tones of the second tones set are allocated to Group 2 SS. Additionally, two tones sets that are symmetric around the DC tones set 1010, 1110 form a symmetric pair and share a same data tone allocation. For example, data tones set 1006, 1106 and data tones set 1012, 1112 are symmetric around the DC tones set, forming a symmetric pair (in this case, they are also separated by the DC tones set), thus they contain the same data tone allocation, i.e., the even-number-indexed data tones are allocated to Group 1 SS and the oddnumber-indexed data tones are allocated to Group 2 SS. Advantageously, such symmetric tone distribution around DC simplifies LTF sequence design.

[0079]

[0075] Figure 12 shows a block diagram 1200 illustrating an example allocation of 242- tone resource unit (RU) of LTF symbols to two groups of spatial streams (Group 1 SS, Group 2 SS) in a 20 MHz PPDU according to the second embodiment of the present disclosure, where the number of DC tones in the DC tones set is 3. Figure 13 shows a block diagram 1300 illustrating an example allocation of 484-tone RU of LTF symbols to two groups of spatial streams (Group 1 SS, Group 2 SS) in a 40 MHz PPDU according to the second embodiment of the present disclosure, where the number of DC tones in the DC tones set is 5, or DC tone index numbers are [-2:2],

[0080]

[0076] The transmitter processing for generating time domain LTF symbols according to the second embodiment of the present disclosure is similar to that according to the first embodiment illustrated in Figure 8. The LTF sequence value at the fc-th subcarrier of the LTF symbols for Group 1 and Group 2 SS is denoted as LTFGI .R and LTFG2, / C, respectively. LTFGI , / T is selected from {—1,1} at the data tones where Group 1 SS are active according to the second embodiment above and pilot tones, and takes zero value for the remaining tones. LTFG2,R is selected from {—1,1} at the at the data tones where Group 2 SS are active according to the second embodiment above and pilot tones, and takes zero value for the remaining tones. The subcarriers of each LTF symbol are multiplied by entries belonging to a matrix ,ALTF, as shown in equation (1).

[0081] Fourier Transform (IDFT) unit 806a-806n converts the subcarrier on a transmit chain, which are frequency-domain data, into time-domain data for transmission.

[0082]

[0078] Alternatively, in a third embodiment, the data tones where Group 1 or Group 2 SS are active form a mirror-symmetric pair around the DC tones set. In other words, the data tone set having negative subcarrier index number range and the data tone set having the same but positive subcarrier index number range will form a mirror-symmetric pair around the DC tones set and have opposite tone allocations. Figure 14 shows a block diagram 1400 illustrating a first example tone allocation of LTF symbols to two groups of spatial streams (Group 1 SS, Group 2 SS) according to the third embodiment of the present disclosure, where the number of DC tones in the DC tones set is 3, 7, 11 , or any number that increases by 4 thereafter. Figure 15 shows a block diagram 1500 illustrating a second example tone allocation of LTF symbols to two groups of spatial streams (Group 1 SS, Group 2 SS) according to the second embodiment of the present disclosure, where the number of DC tones in the DC tones set is 5, 9, 13, or any number that increases by 4 thereafter. Similar to the first and second embodiments of the present disclosure, when first data tones set and second data tones set are separated by a pilot tone (e.g., pilot tone 1503 separating data tones sets 1402 and 1404 in Figure 14, pilot tone 1503 separating data tones sets 1502 and 1504 in Figure 15), the even-number-indexed data tones of the first tones set (e.g., data tones set 1402, 1502) is allocated to Group 1 SS and the odd-number-indexed data tones of the first tones set is allocated to Group 2 SS; and the odd-number indexed data tones of the second tones set (e.g., data tones set 1404, 1504) is allocated to Group 1 SS and the even-numbered indexed data tones of the second tones set are allocated to Group 2 SS. Additionally, two tones sets that are symmetric around the DC tones set 1410, 1510 form a mirror-symmetric pair and have opposite data tone allocations. For example, data tones set 1406, 1506 having negative index number range and data tones set 1412, 1512 having same but positive index number range form a mirror-symmetric pair (in this case, they are also separated by the DC tones set), thus they contain opposite data tone allocation, i.e., the even-number- indexed data tones of data tones set 1406, 1506 are allocated to Group 1 SS and the odd-number-indexed data tones of data tones set 1406, 1506 are allocated to Group 2 SS in data tones set 1406, 1506 while it is opposite in data tones set 1412, 1512, that is the odd-number-indexed data tones of data tones set 1412, 1512 are allocated to Group 1 SS and even-number-indexed data tones of data tones set 1412, 1512 are allocated to Group 2 SS. Advantageously, Group 1 and Group 2 SS can share the same LTF sequence to reduce the memory needed to store the LTF sequences.

[0083]

[0079] Figure 16 shows a block diagram 1600 illustrating an example allocation of 242- tone RU of LTF symbols to two groups of spatial streams (Group 1 SS, Group 2 SS) in a 20 MHz PPDU according to the third embodiment of the present disclosure, where the number of DC tones in the DC tones set is 3. Figure 17 shows a block diagram 1700 illustrating an example allocation of 484-tone RU of LTF symbols to two groups of spatial streams (Group 1 SS, Group 2 SS) in a 40 MHz PPDU according to the third embodiment of the present disclosure, where the number of DC tones in the DC tones set is 5, or DC tone index numbers are [-2:2].

[0084]

[0080] In one example, the transmitter processing for generating time domain LTF symbols according to the third embodiment of the present disclosure is similar to that according to the first embodiment illustrated in Figure 8. Figure 18 shows a block diagram 1800 illustrating another example transmitter processing for generating time domain LTF symbols according to the third embodiment of the present disclosure. Due to the mirror symmetric tone distribution for Group 1 and Group 2 SS, LTFGI,* and LTFG2, / < can be derived from a common LTF sequence 1802 whose value at the k-th subcarrier is denoted as LTF*. In this example, LTFGI.R = LTF^ and LTFG2A = LTF.^, where LTF / < is selected from {—1,1} at the pilot tones and data tones where the Group 1 SS are active, according to this embodiment, and takes zero value for the remaining tones. The subcarriers of each LTF symbol are multiplied by entries belonging to a matrix ALTF,asshown in equation (1). spatial stream before applying a beamforming steering matrix Q£TF 1804 for subcarrier k, [ J icates a matrix consisting of columns 1 to Nssof QLTF. An IDFT unit 1806a-1806n converts the subcarrier on a transmit chain, which are frequency-domain data, into time-domain data for transmission.

[0085]

[0082] According to the present disclosure, a SIG field of an PPDU may comprise an indication of tone-interleaved LTF. 802.11be supports three EHT-LTF types: 1x EHT-LTF, 2x EHT-LTF, and 4x EHT-LTF. The LTF type for tone-interleaved LTF, as introduced in various embodiments above, may be limited to 4x LTF, as Group 1 or Group 2 SS are active on both even-index and odd-index tones. In 802.11 be, bits 4-5 of the common field of the EHT-SIG field of the PPDU indicates the guard interval (Gl) duration and LTF size.

[0086]

[0083] Table 3 shows EHT-LTF type and Gl duration combinations for various EHT PPDU formats

[0087]

[0088] [Table 3]

[0089]

[0084] Additionally or alternatively, a common field of a SIG field of a sounding NDP may be modified to support tone-interleaved LTF indication. Table 4 shows exemplary subfields of a common field of a SIG field of a sounding NDP supporting tone-interleaved LTF indication according to an embodiment of the present disclosure. The common field may comprise a Spatial Reuse subfield, a GI-LTF Size subfield, a Number of LTF Symbols subfield, a Number Of Spatial Stream (Nss) subfield, a Beamformed subfield, a Disregard subfield, a CRC subfield and tail bits. In particular, the GI+LTF size at bit numbers 4 and 5 (B4-B5) which indicates the Gl duration and LTF size subfield is set to 0 to indicate 2* LTF + 0.8 ps Gl; 1 to indicate 2* LTF + 1.6 ps Gl; 3 to indicate 4* LTF + 3.2 ps Gl, and is modified so that it can be set to 2 to indicate 4* LTF + 3.2 ps Gl with tone interleaving.

[0090] [Table 4]

[0091]

[0085] Additionally or alternatively, a common field of a SIG field of a PPDU for a SU transmission and non-OFDMA transmission to multiple users may be modified to support tone-interleaved LTF indication. Table 5 shows exemplary subfields of a common field of a SIG field of a PPDU for a SU transmission and non-OFDMA transmission to multiple users for supporting tone-interleaved LTF indication according to an embodiment of the present disclosure. The common field may comprise a Spatial Reuse subfield, a GI-LTF Size subfield, a Number of LTF Symbols subfield, a LDPC Extra Symbol Segment subfield, a Pre-FEC Padding Factor subfield, a PE Disambiguity subfield, a Tone-Interleaved LTF subfield, a Disregard subfield, and a Number of Non-OFDMA Users subfield. In particular, the GI+LTF size at bit numbers 4 and 5 (B4-B5) which indicates the Gl duration and LTF size subfield is set to 0 to indicate 2* LTF + 0.8 ps Gl; 1 to indicate 2* LTF + 1 .6 ps Gl; 2 to indicate 4x LTF + 0.8 ps Gl; and 3 to indicate 4* LTF + 3.2 ps GL For tone-interleaved LTF, the GI+LTF Size subfield should be set to 2 or 3. It is noted that in 802.11 be, bit numbers 13-16 (B13-B16) are bits in Disregard subfield which are set to all 1s. One bit in the Disregard subfield (B13-B16) can be used for indicating tone-interleaved LTF. For example, B13 is set to 1 to indicate tone-interleaved LTF and 0 if it is otherwise, while B14-B16 remain bits in Disregard subfield.

[0092] [Table 5]

[0093]

[0086] Additionally or alternatively, a common field of a SIG field of a PPDU for OFDMA transmission may be modified to support tone-interleaved LTF indication. Table 6 shows example subfields of a common field of a SIG field of a PPDU for OFDMA transmission for supporting tone-interleaved LTF indication according to an embodiment of the present disclosure. The common field may comprise a Spatial Reuse subfield, a GI-LTF Size subfield, a Number of LTF Symbols subfield, a LDPC Extra Symbol Segment subfield, a Pre-FEC Padding Factor subfield, a PE Disambiguity subfield, a Tone-Interleaved LTF subfield, a Disregard subfield and other necessary subfields (not shown in Table 6). In particular, the GI+LTF size at bit numbers 4 and 5 (B4-B5) which indicates the Gl duration and LTF size subfield is set to 0 to indicate 2* LTF + 0.8 ps Gl; 1 to indicate 2* LTF + 1.6 ps Gl; 2 to indicate 4* LTF + 0.8 ps Gl; and 3 to indicate 4* LTF + 3.2 ps Gl. For tone- interleaved LTF, the GI+LTF Size subfield should be set to 2 or 3. It is noted that in 802.1 1 be, bit numbers 13-16 (B13-B16) are bits in Disregard subfield which are set to all 1s. One bit in the Disregard field (B13-B16) can be used for indicating tone-interleaved LTF. For example, B13 is set to 1 to indicate tone-interleaved LTF and 0 if it is otherwise, while B14-B16 remain bits in Disregard subfield.

[0094] [Table 6]

[0087] Figure 19 shows a diagram 1900 illustrating communication in a multi-AP system according to an embodiment of the present disclosure. In joint sounding for a multi-AP system, where multiple APs transmit sounding NDPs simultaneously, the primary AP 1902 sends a Joint Sounding Trigger 1912 to the secondary APs 1904 to initiate joint sounding. After an inter-frame space (IFS) duration 1914, the primary and secondary APs 1902, 1904 simultaneously transmit the sounding NDPs 1916a-1916n. After another IFS duration 1918, the STAs 1906 then send the sounding feedbacks 1920a-1920n to all the sounding APs 1902, 1904 through uplink MU transmission.

[0095]

[0088] According to an embodiment resent disclosure, in multi-AP joint sounding when a beamforming steering matrixn°t applied, the spatial streams are directly mapped to the transmit chains. Instead of an even allocation of spatial streams, the number of spatial streams in Group 1 and Group 2 can be determined based on the number of transmit chains NTXof different APs.

[0096]

[0089] For example, Group 1 SS transmits on the antennas of one set of APs, AP[1], AP[2], ..., AP[J], participating in joint sounding, and the number of spatial streams in Group 1 SS may be calculated using equation (2).

[0097]

[0090] Group 2 SS transmits on the antennas of the other set of APs, AP[J+1], AP[J+2], ..., AP[L], participating in joint sounding, and the number of spatial streams in Group 2 SS may be calculated using equation (3).

[0098]

[0091] Figure 20 shows a schematic diagram 2000 illustrating an example multi-AP system consisting of three APs where each AP has 4 transmits chains. When the example Multi-AP system is performing multi-AP joint sounding following the example procedure shown in Figure 19, AP[1] and AP[2] may be grouped as one set of APs while AP[3] may be grouped as another set of AP. Group 1 SS transmits on the antennas of one set of APs, on the transmit chains of AP[1] and AP[2] (JVG1 / 5S= 8), while Group 2 SS transmits on the antennas of another set of APs, on transmit chains of AP[3] (NC2,ss — 4)- Each AP transmits spatial streams that belong either to Gorup 1or Group 2, but not both. Advantageously, the number of LTF symbols is reduced for joint sounding.

[0099]

[0092] Figure 21 shows a block diagram 2100 illustrating an example transmitter processing for generating time domain LTF symbols for first group of spatial streams (Group 1 SS) according to an embodiment of the present disclosure. In this example, the LTF sequence value at the k-th subcarrier of the LTF symbols for Group 1 , LTFGi.fr is illustrated. LTFGI.R is selected from {-1,1} at the data tones where Group 1 SS are active according to the first, second or third embodiment above and pilot tones, and takes zero value for the remaining tones. In this case, the number of spatial streams in Group 1 SS is calculated based on the number of transmit chains of respectively. The subcarriers of each LTF symbol are multiplied by entries belonging to a matrixF, of each transmit chain.

[0100]

[0093] Figure 22 shows a block diagram 2200 illustrating an example transmitter processing for generating time domain LTF symbols for second group of spatial streams (Group 2 SS) according to an embodiment of the present disclosure. In this example, the LTF sequence value at the k-th subcarrier of the LTF symbols for Group 2, LTFG2,k is illustrated. LTFG2,R is selected from {—1,1} at the data tones where Group 2 SS are active according to the first, second or third embodiment aboveand pilot tones, and takes zero value for the remaining tones. In this case, the number of spatial streams in Group 2 SS is calculated based on the number of transmit chains of AP[J+1], AP[J+2], ... AP[J], i.e., NTX, APQ+I]> NTX, AP[J+2]> - - - ,NTX, AP[L]> respectively. The subcarriers of each LTF symbol are multiplied by entries belonging to a matrix ALTF, of each transmit chain. defined in 802.11 be corresponding to different NLTF. I / ?LTF I m,n = [I’LTFII.H- 1 < m,n < NLTF, i.e., single stream pilots are used. For example, at the k-th subcarrier of the n-th LTF symbol for the 1 st SS of the Group 1 SS, LTFGI.R is multiplied by or spatial streams corresponding to transmit chains of an AP, a CSD 1802 of the AP is inserted for each spatial stream. An IDFT unit converts the subcarrier on each transmit chain, which are frequency-domain data, into time-domain data for transmission.

[0101]

[0095] When spatial streams are allocated based on the number of transmit chains of different APs in Multi-AP joint sounding without applying a beamforming steering matrix (B13 of the common field for sounding NDP is set to 0), the number of spatial streams for Group 1 and Group 2 shall be indicated in the common field of the SIG field for a sounding NDP.

[0102]

[0096] A common field of a SIG field of a sounding NDP may be modified to support tone- interleaved LTF indication. Table 7 shows exemplary subfields of a common field of a SIG field of a sounding NDP for supporting tone-interleaved LTF indication according to an embodiment of the present disclosure. The common field may comprise a Spatial Reuse subfield, a GI-LTF Size subfield, a Number of LTF Symbols subfield, an Nss subfield, a Beamformed subfield, a Disregard subfield, a CRC subfield and tail bits. In particular, the GI+LTF size at bit numbers 4 and 5 (B4-B5) which indicates the Gl duration and LTF size subfield is set to 0 to indicate 2* LTF + 0.8 ps Gl; 1 to indicate 2* LTF + 1.6 ps Gl; 3 to indicate 4* LTF + 3.2 ps Gl, and is modified so that it can be set to 2 to indicate 4* LTF + 3.2 ps Gl with tone interleaving. Additionally, the difference between NSS G1and NSS C2(NGI,SS ~ NG2,SSOR^G2,ss ~ ^ci,ss) 'sindicated using B14-B15 which are bits in Disregards subfield in 11 be. NSS G1and NSS G2can be computed based on Nss (B9-B12) and the indicated difference

[0103] [Table 7]

[0104]

[0097] The present disclosure can be realized by software, hardware, or software in cooperation with hardware. Each functional block used in the description of each embodiment described above can be partly or entirely realized by an LSI such as an integrated circuit, and each process described in each embodiment may be controlled partly or entirely by the same LSI or a combination of LSIs. The LSI may be individually formed as chips, or one chip may be formed so as to include a part or all of the functional blocks. The LSI may include a data input and output coupled thereto. The LSI here may be referred to as an IC, a system on a chip (SoC), a system LSI, a super LSI, or an ultra LSI depending on a difference in the degree of integration. However, the technique of implementing an integrated circuit is not limited to the LSI and may be realized by using a dedicated circuit, a general-purpose processor, or a special-purpose processor. In addition, an FPGA (Field Programmable Gate Array) that can be programmed after the manufacture of the LSI or a reconfigurable processor in which the connections and the settings of circuit cells disposed inside the LSI can be reconfigured may be used. The present disclosure can be realized as digital processing or analogue processing. If future integrated circuit technology replaces LSIs as a result of the advancement of semiconductor technology or other derivative technology, the functional blocks could be integrated using the future integrated circuit technology. Biotechnology can also be applied.

[0105]

[0098] The present disclosure can be realized by any kind of apparatus, device or system having a function of communication, which is referred to as a communication apparatus.

[0099] Some non-limiting examples of such a communication apparatus include a phone (e.g., cellular (cell) phone, smart phone), a tablet, a personal computer (PC) (e.g., laptop, desktop, netbook), a camera (e.g., digital still / video camera), a digital player (digital audio / video player), a wearable device (e.g., wearable camera, smart watch, tracking device), a game console, a digital book reader, a telehealth / telemedicine (remote health and medicine) device, and a vehicle providing communication functionality (e.g., automotive, airplane, ship), and various combinations thereof.

[0106]

[0100] The communication apparatus is not limited to be portable or movable, and may also include any kind of apparatus, device or system being non-portable or stationary, such as a smart home device (e.g., an appliance, lighting, smart meter, control panel), a vending machine, and any other “things” in a network of an “Internet of Things (loT)”.

[0107]

[0101] The communication may include exchanging data through, for example, a cellular system, a wireless LAN system, a satellite system, etc., and various combinations thereof.

[0108]

[0102] The communication apparatus may comprise a device such as a controller or a sensor which is coupled to a communication device performing a function of communication described in the present disclosure. For example, the communication apparatus may comprise a controller or a sensor that generates control signals or data signals which are used by a communication device performing a communication function of the communication apparatus.

[0109]

[0103] The communication apparatus also may include an infrastructure facility, such as a base station, an access point, and any other apparatus, device or system that communicates with or controls apparatuses such as those in the above non-limiting examples.

[0110]

[0104] It will be understood that while some properties of the various embodiments have been described with reference to a device, corresponding properties also apply to the methods of various embodiments, and vice versa.

[0111]

[0105] In the following paragraphs, certain exemplifying embodiments are explained with reference to terms related to wireless network technology and the present disclosure regarding communication apparatuses and methods for tone-interleaved long training field allocation, namely:

[0112] Example 1. A communication apparatus comprising: circuitry, which in operation, allocates (i) a plurality of pilot tones to a first group of spatial streams and a second group of spatial streams, each of the plurality of pilot tone separating a first data tones set and a second data tones set for transmitting a plurality of symbols, and (ii) even-number indexed data tones of the first data tones set to the first group of spatial streams and odd-number indexed data tones of the first data tones set to the second group of spatial streams; and a transmitter, which in operation, transmits one or more symbols of the plurality of symbols to another communication apparatus through one of the first group of spatial streams and the second group of spatial streams on the first data tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0113] Example 2. The communication apparatus of example 1 , wherein the circuitry further allocates (iii) even-number indexed data tones of the second data tones set to the first group of spatial streams and odd-number indexed data tones of the second data tones set to the second group of spatial streams; and the transmitter transmits another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the second data tones set allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0114] Example 3 The communication apparatus of example 1 , wherein the circuitry further allocates (iii) odd-number indexed data tones of the second data tones set to the first group of spatial streams and even-number indexed data tones of the second data tones set to the second group of spatial streams; and the transmitter transmits another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the second data tones set allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0115] Example 4. The communication apparatus of example 3, wherein the circuitry further allocates (iv) even-number indexed data tones of a third data tones set to the first group of spatial streams and odd-number indexed data tones of the third data tones set to the second group of spatial streams, wherein the third data tones set and the first data tones set are separated by a direct current tones set, and the transmitter transmits yet another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the third tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0116] Example 5. The communication apparatus of example 3, wherein the circuitry further allocates (iv) odd-number indexed data tones of a third data tones set to the first group of spatial streams and even-number indexed data tones of the third data tones set to the second group of spatial streams, wherein the third data tones set and the first data tones set are separated by a direct current tones set, and the transmitter transmits yet another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the third tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0117] Example 6. The communication apparatus of example 1 , wherein the circuitry further generates a signal comprising (i) a signal field comprising the plurality of symbols and (ii) another signal field indicating a size of the signal field and the allocation of the plurality of pilot tones, the first data tones set and the second data tones set.

[0118] Example 7. The communication apparatus of example 6, wherein the another signal field further comprises a first signal field indicating the size of the signal field and a second signal field indicating the allocation of the plurality of pilot tones, the first data tones set and the second data tones set.

[0119] Example 8. The communication apparatus of example 1 , wherein the circuitry groups of spatial streams into the first group of spatial streams and number of spatial streams into the second group of spatial streams, where At is a total number of available spatial streams for transmitting the plurality of symbols.

[0120] Example 9. The communication apparatus of example 6, wherein each of the first group of spatial streams is mapped to a transmit chain of first group of communication apparatuses and each of the second group of spatial streams is mapped to a transmit chain of a second group of communication apparatuses, and the another signal field comprises a third signal field indicating a difference in a number of spatial streams between the first group of spatial streams and the second group of spatial streams, wherein the circuitry determines a first number of spatial streams and a second number of spatial streams based on the difference in the number of spatial streams, and group the first number of spatial streams into the first group of spatial streams and the second number of spatial streams into the second group of spatial streams.

[0121] Example 10. A communication method comprising: allocating (i) a plurality of pilot tones to a first group of spatial streams and a second group of spatial streams, each of the plurality of pilot tones separating a first data tones set and a second data tones set for transmitting a plurality of symbols, and (II) even-number indexed data tones of the first data tones set to the first group of spatial streams and oddnumber indexed data tones of the first data tones set to the second group of spatial streams; and transmitting one or more symbols of the plurality of symbols to another communication apparatus through one of the first group of spatial streams and the second group of spatial streams on the first data tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0122] Example 11. The communication method of example 10, further comprising: allocating (iii) even-number indexed data tones of the second data tones set to the first group of spatial streams and odd-number indexed data tones of the second data tones set to the second group of spatial streams; and transmitting another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the second data tones set allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0123] Example 12. The communication method of example 10, further comprising: allocating (iii) odd-number indexed data tones of the second data tones set to the first group of spatial streams and even-number indexed data tones of the second data tones set to the second group of spatial streams; and transmitting another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the second data tones set allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0124] Example 13. The communication method of example 12, further comprising: allocating (iv) even-number indexed data tones of a third data tones set to the first group of spatial streams and odd-number indexed data tones of the third data tones set to the second group of spatial streams, wherein the third data tones set and the first data tones set are separated by a direct current tones set; and transmitting yet another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the third tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0125] Example 14. The communication method of example 12, further comprising: allocating (iv) odd-number indexed data tones of a third data tones set to the first group of spatial streams and even-number indexed data tones of the third data tones set to the second group of spatial streams, wherein the third data tones set and the first data tones set are separated by a direct current tones set; and transmitting yet another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the third tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

[0126] Example 15. The communication method of example 10, further comprising: generating a signal comprising (i) a signal field comprising the plurality of symbols and (ii) another signal field indicating a size of the signal field and the allocation of the plurality of pilot tones, the first data tones set and the second data tones set.

[0127] Example 16. The communication method of example 15, wherein the another signal field further comprises a first signal field indicating the size of the signal field and a second signal field indicating the allocation of the plurality of pilot tones, the first data tones set and the second data tones set.

[0128] Example 17. The communication method of example 10, the communication method further comprising: grouping number of spatial streams into the first group of spatial streams and another number of spatial streams into the second group of spatial streams, where N is a total number of available spatial streams for transmitting the plurality of symbols. Example 18. The communication method of example 15, wherein each of the first group of spatial streams is mapped to a transmit chain of first group of communication apparatuses and each of the second group of spatial streams is mapped to a transmit chain of a second group of communication apparatuses, and the another signal field comprises a third signal field indicating a difference in a number of spatial streams between the first group of spatial streams and the second group of spatial streams, the communication method further comprising: determining a first number of spatial streams and a second number of spatial streams based on the difference in the number of spatial streams; and grouping the first number of spatial streams into the first group of spatial streams and the second number of spatial streams into the second group of spatial streams.

[0129]

[0106] It will be appreciated by a person skilled in the art that numerous variations and / or modifications may be made to the present disclosure as shown in the specific embodiments without departing from the spirit or scope of the disclosure as broadly described. The present embodiments are, therefore, to be considered in all respects illustrative and not restrictive.

Claims

CLAIMS1 . A communication apparatus comprising: circuitry, which in operation, allocates (i) a plurality of pilot tones to a first group of spatial streams and a second group of spatial streams, each of the plurality of pilot tone separating a first data tones set and a second data tones set for transmitting a plurality of symbols, and (II) even-number indexed data tones of the first data tones set to the first group of spatial streams and odd-number indexed data tones of the first data tones set to the second group of spatial streams; and a transmitter, which in operation, transmits one or more symbols of the plurality of symbols to another communication apparatus through one of the first group of spatial streams and the second group of spatial streams on the first data tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

2. The communication apparatus of claim 1 , wherein the circuitry further allocates (iii) even-number indexed data tones of the second data tones set to the first group of spatial streams and odd-number indexed data tones of the second data tones set to the second group of spatial streams; and the transmitter transmits another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the second data tones set allocated to the one of the first group of spatial streams and the second group of spatial streams.

3. The communication apparatus of claim 1 , wherein the circuitry further allocates (iii) odd-number indexed data tones of the second data tones set to the first group of spatial streams and even-number indexed data tones of the second data tones set to the second group of spatial streams; and the transmitter transmits another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the second data tones set allocated to the one of the first group of spatial streams and the second group of spatial streams.

4. The communication apparatus of claim 3, wherein the circuitry further allocates (iv) even-number indexed data tones of a third data tones set to the first group of spatial streams and odd-number indexed data tones of the third data tones set to the second group of spatial streams, wherein the third data tones set and the first data tones set are separated by a direct current tones set, and the transmitter transmits yet another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the third tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

5. The communication apparatus of claim 3, wherein the circuitry further allocates (iv) odd-number indexed data tones of a third data tones set to the first group of spatial streams and even-number indexed data tones of the third data tones set to the second group of spatial streams, wherein the third data tones set and the first data tones set are separated by a direct current tones set, and the transmitter transmits yet another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the third tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

6. The communication apparatus of claim 1 , wherein the circuitry further generates a signal comprising (i) a signal field comprising the plurality of symbols and (ii) another signal field indicating a size of the signal field and the allocation of the plurality of pilot tones, the first data tones set and the second data tones set.

7. The communication apparatus of claim 6, wherein the another signal field further comprises a first signal field indicating the size of the signal field and a second signal field indicating the allocation of the plurality of pilot tones, the first data tones set and the second data tones set.

8. The communication apparatus of claim 1 , wherein the circuitry groups Floor(^ / 2) or Cei l(^ / 2) number of spatial streams into the first group of spatial streams and anothernumber of spatial streams into the second group of spatial streams, where AZ is a total number of available spatial streams for transmitting the plurality of symbols.

9. The communication apparatus of claim 6, wherein each of the first group of spatial streams is mapped to a transmit chain of first group of communication apparatuses and each of the second group of spatial streams is mapped to a transmit chain of a second group of communication apparatuses, and the another signal field comprises a third signal field indicating a difference in a number of spatial streams between the first group of spatial streams and the second group of spatial streams, wherein the circuitry determines a first number of spatial streams and a second number of spatial streams based on the difference in the number of spatial streams, and group the first number of spatial streams into the first group of spatial streams and the second number of spatial streams into the second group of spatial streams.

10. A communication method comprising: allocating (i) a plurality of pilot tones to a first group of spatial streams and a second group of spatial streams, each of the plurality of pilot tones separating a first data tones set and a second data tones set for transmitting a plurality of symbols, and (II) even-number indexed data tones of the first data tones set to the first group of spatial streams and oddnumber indexed data tones of the first data tones set to the second group of spatial streams; and transmitting one or more symbols of the plurality of symbols to another communication apparatus through one of the first group of spatial streams and the second group of spatial streams on the first data tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.11 . The communication method of claim 10, further comprising:allocating (ill) even-number indexed data tones of the second data tones set to the first group of spatial streams and odd-number indexed data tones of the second data tones set to the second group of spatial streams; and transmitting another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the second data tones set allocated to the one of the first group of spatial streams and the second group of spatial streams.

12. The communication method of claim 10., further comprising: allocating (iii) odd-number indexed data tones of the second data tones set to the first group of spatial streams and even-number indexed data tones of the second data tones set to the second group of spatial streams; and transmitting another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the second data tones set allocated to the one of the first group of spatial streams and the second group of spatial streams.

13. The communication method of claim 12, further comprising: allocating (iv) even-number indexed data tones of a third data tones set to the first group of spatial streams and odd-number indexed data tones of the third data tones set to the second group of spatial streams, wherein the third data tones set and the first data tones set are separated by a direct current tones set; and transmitting yet another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the third tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

14. The communication method of claim 12, wherein further comprising: allocating (iv) odd-number indexed data tones of a third data tones set to the first group of spatial streams and even-number indexed data tones of the third data tones set to the second group of spatial streams, wherein the third data tones set and the first data tones set are separated by a direct current tones set; andtransmitting yet another one or more symbols of the plurality of symbols to the another communication apparatus through the one of the first group of spatial streams and the second group of spatial streams on the third tones sets allocated to the one of the first group of spatial streams and the second group of spatial streams.

15. The communication method of claim 10, further comprising: generating a signal comprising (i) a signal field comprising the plurality of symbols and (ii) another signal field indicating a size of the signal field and the allocation of the plurality of pilot tones, the first data tones set and the second data tones set.

Images