Communication apparatus and communication method for uplink low latency transmission in relay operation

Abstract

The present disclosure provides a first communication apparatus comprising: circuitry, which in operation, is configured to detect a receipt of data of a first traffic type during a transmission of a signal comprising one or more frames of a second traffic type to a second communication apparatus on a first resource of a plurality of resources allocated for the transmission of the signal; and a transmitter, which in operation, transmits one of (i) the data of the first traffic type and (ii) an indication of the receipt of the data of the first traffic type to the second communication apparatus on a second resource of the plurality of resources.

Description

[0001] Title Of Invention: COMMUNICATION APPARATUS AND COMMUNICATION METHOD FOR

[0002] UPLINK LOW LATENCY TRANSMISSION IN RELAY OPERATION

[0003] TECHNICAL FIELD

[0004] [1] The following disclosure relates to a communication apparatus and a communication method, and more particularly, for uplink (UL) low latency (LL) transmission in relay operation.

[0005] BACKGROUND

[0006] [2] Ultra High Reliability Study Group (UHR SG) was approved in July 2022 meeting with objectives to: (i) increase throughput at different Signal to Interference and Noise Ratio (SINR) level; (ii) reduce latency; and (Hi) improve reliability. Relay operation is being considered in some contributions as being able to increase throughput and improve reliability. Low latency is already a key objective in UHR SG. There are a lot of discussions about finding a solution for low latency (LL) data. However, there are not much discussion in UHR SG about LL data in relay operation, in particular, uplink (UL) solution for relay of LL data.

[0007] [3] For UL, one challenge is that non-AP STA may have limited opportunity to transmit to Relay in Data Relay Phase 1. If LL Data arrives when the non-AP STA has already started transmitting non-LL Data to Relay, it may need to wait for a long time after Data Relay Phase 2 before it can transmit LL data. Furthermore, there may be more than 1 non-AP STA being relayed. If LL Data arrives at a non-AP STA when a second non-AP STA is transmitting non-LL Data to Relay, there is no mechanism to interrupt and prioritize LL Data for the first non-AP STA.

[0008] [4] There is thus a need for a communication apparatus and a communication method for UL LL transmission in relay operation that prioritises LL data over ongoing non-LL data to solve the above-mentioned issues. 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.

[0009] SUMMARY

[0010] [5] Non-limiting and exemplary embodiments facilitate providing communication apparatuses and communication methods for UL LL transmission in relay operation.

[0011] [6] In a first aspect, the present disclosure provides a first communication apparatus comprising: circuitry, which in operation, is configured to detect a receipt of data of a first traffic type during a transmission of a signal comprising one or more frames of a second traffic type to a second communication apparatus on a first resource of a plurality of resources allocated for the transmission of the signal; and a transmitter, which in operation, transmits one of (i) the data of the first traffic type and (ii) an indication of the receipt of the data of the first traffic type to the second communication apparatus on a second resource of the plurality of resources.

[0012] [7] In a second aspect, the present disclosure provides a second communication apparatus comprising: a receiver, which in operation, receives, one of (i) data of a first traffic type and (ii) an indication of a receipt of the data of the first traffic type from a first communication apparatus on a second resource of a plurality of resources allocated for a signal after receiving at least a part of the signal on a first resource of the plurality of resources; circuitry, which in operation, is configured to process the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type

[0013] [8] In a third aspect, the present disclosure provides a communication method implemented by a first communication apparatus comprising: detecting a receipt of data of a first traffic type during a transmission of a signal comprising one or more frames of a second traffic type to a second communication apparatus on a first resource of a plurality of resources allocated for the transmission of the signal; and transmitting one of (i) the data of the first traffic type and (ii) an indication of the receipt of the data of the first traffic type to the second communication apparatus on a second resource of the plurality of resources.

[0014] [9] In a fourth aspect, the present disclosure provides a communication method implemented by a second communication apparatus comprising: receiving one of (i) data of a first traffic type and (ii) an indication of a receipt of the data of the first traffic type from a first communication apparatus on a second resource of a plurality of resources allocated for a signal after receiving at least a part of the signal on a first resource of the plurality of resources; processing the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type.

[0015]

[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.

[0016] BRIEF DESCRIPTION OF THE DRAWINGS

[0017]

[0011] The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to illustrate various embodiments and to explain various principles and advantages in accordance with present embodiments, in which:

[0018] Figure 1 shows a schematic diagram illustrating a downlink (DL) relay transmission procedure involving an access point (AP), a Relay station (STA) and a non-AP STA(s).

[0019] Figure 2 shows a schematic diagram illustrating an uplink (UL) relay transmission procedure involving an AP, a Relay STA and a non-AP STA(s). Figure 3 shows an exemplary DL low latency data (LL) transmission in Relay operation involving STAs and a Relay.

[0020] Figure 4 shows a schematic diagram illustrating UL and DL Relay operations involving an AP, a Relay and a non-AP STA.

[0021] Figure 5 shows a schematic diagram illustrating a conventional UL Relay operation for LL Data transmission among involving an AP, a Relay and a non-AP STA.

[0022] Figure 6 shows a schematic view of a communication apparatus according to the present disclosure.

[0023] Figure 7 shows a flow chart illustrating a communication method according to the present disclosure.

[0024] Figure 8 shows a flow chart illustrating another communication method according to the present disclosure.

[0025] Figure 9 shows an exemplary structure of an aggregated media access control (MAC) protocol data unit (A-MPDU) of a physical layer protocol data unit (PPDU) according to the first embodiment of the present disclosure.

[0026] Figure 10 shows a first exemplary structure of an A-MPDU of a PPDU comprising a LL indication according to the first embodiment of the present disclosure.

[0027] Figure 1 1 A shows an existing A-MPDU delimiter format of the MPDU of Figure 10.

[0028] Figure 11 B shows an exemplary LL indication subframe in the MPDU of Figure 10 which converted from the existing A-MPDU delimiter format. Figure 12 shows a second exemplary structure of an A-MPDU of a PPDU comprising a LL indication according to the first embodiment of the present disclosure.

[0029] Figure 13 shows a flow chart illustrating a process implemented by a non-AP STA according to the first embodiment of the present disclosure.

[0030] Figure 14 shows a flow chart illustrating a process implemented by a Relay according to the first embodiment of the present disclosure.

[0031] Figure 15 shows an example LL A-MPDU subframe according to an embodiment of the present disclosure.

[0032] Figure 16 shows a MAC Header of a MPDU subframe according to an embodiment of the present disclosure.

[0033] Figure 17 shows an exemplary process when using the A-MPDU structure in Figure 10 in one scenario.

[0034] Figure 18 shows an exemplary process when using the A-MPDU structure in Figure 10 in another scenario.

[0035] Figure 19 shows an exemplary process when using the A-MPDU structure in Figure 12 in one scenario.

[0036] Figure 20 shows an exemplary process when using the A-MPDU structure in Figure 12 in another scenario.

[0037] Figure 21 show an exemplary A-MPDU structure in Figure 10 after LL data arrives. Figure 22 show an exemplary A-MPDU structure in Figure 12 after LL data arrives.

[0038] Figure 23 shows an exemplary schematic diagram illustrating an UL data transmission procedure involving an AP, a Relay and a non-AP STA according to the second embodiment of the present disclosure.

[0039] Figure 24 shows an exemplary format of a Trigger frame soliciting UL transmission from a non-AP STA according to the second embodiment of the present disclosure.

[0040] Figure 25 shows a flow chart illustrating a process implemented by a non-AP STA according to the second embodiment of the present disclosure.

[0041] Figure 26 shows a flow chart illustrating a process implemented by a Relay according to the second embodiment of the present disclosure.

[0042] Figure 27 shows an exemplary format of a Trigger frame in Figure 24 with multiple User Info fields.

[0043] Figure 28 shows another exemplary format of a Trigger frame in Figure 24.

[0044] Figure 29 shows another exemplary schematic diagram illustrating an UL data transmission procedure involving an AP, a Relay and a non-AP STA with LL RU allocation notification according to the second embodiment of the present disclosure.

[0045] Figure 30 shows an exemplary format of the LL RU notification element according to the second embodiment of the present disclosure.

[0046] Figure 31 shows still another exemplary format of a Trigger frame in Figure 24. Figure 32 shows an exemplary PPDU where LL data arrives during the ongoing transmission of the PPDU according to the second embodiment of the present disclosure.

[0047] Figure 33 shows another exemplary PPDU where LL data arrives during the ongoing transmission of the PPDU according to the second embodiment of the present disclosure.

[0048] Figure 34 shows still another exemplary schematic diagram illustrating an UL relay transmission procedure involving an AP, a Relay, a non-AP STA and a third-party STA according to the second embodiment of the present disclosure.

[0049] Figure 35 shows still another exemplary schematic diagram illustrating another UL relay transmission procedure involving an AP, a Relay, a non-AP STA and a third-party STA according to the second embodiment of the present disclosure.

[0050] Figure 36 shows still another exemplary schematic diagram illustrating yet another UL relay transmission procedure involving an AP, a Relay, a non-AP STA and a third-party STA according to the second embodiment of the present disclosure.

[0051] Figure 37 shows another exemplary format of the Trigger frame in Figure 24 with multiple User Info fields and a specific format of User Info 1 field.

[0052] Figure 38A shows an exemplary specific format of User Info 2 field in Figure 37.

[0053] Figure 38B shows an exemplary specific format of User Info field 3 in Figure 37.

[0054] Figure 39 shows an exemplary schematic diagram illustrating an UL data transmission procedure involving an AP, a Relay and a non-AP STA according to the third embodiment of the present disclosure. Figure 40 shows an exemplary format of a Trigger frame according to the third embodiment of the present disclosure.

[0055] Figure 41 shows an exemplary format of a Common Info field of the Trigger frame of Figure 40 according to the third embodiment of the present disclosure.

[0056] Figure 42 shows an exemplary small trigger-based (TB) PPDU according to an embodiment of the present disclosure.

[0057] Figure 43 shows another exemplary schematic diagram illustrating an UL data transmission procedure involving an AP, a Relay, a non-AP STA and a third-party STA according to the third embodiment of the present disclosure.

[0058] Figure 44 shows another exemplary format of a Trigger frame according to the third embodiment of the present disclosure.

[0059] Figure 45 shows an exemplary schematic diagram illustrating an UL data transmission procedure involving an AP, a Relay and a non-AP STA according to the fourth embodiment of the present disclosure.

[0060] Figure 46 shows an exemplary format of a T rigger frame for soliciting an LL ultra high reliability (UHR) TB PPDU according to the fourth embodiment of the present disclosure.

[0061] Figure 47 shows an exemplary format of a Common Info field of the Trigger frame in Figure 46.

[0062] Figure 48 shows an exemplary LL UHR TB PPDU according to the fourth embodiment of the present disclosure. Figure 49 shows another exemplary schematic diagram illustrating a UL data transmission procedure involving an AP, a Relay and a non-AP STA according to the fourth embodiment of the present disclosure.

[0063] Figure 50 shows yet another exemplary schematic diagram illustrating UL data transmission procedure involving an AP, a Relay and a non-AP STA according to the fourth embodiment of the present disclosure.

[0064] Figure 51 shows an exemplary format of a frame according to the fourth embodiment of the present disclosure.

[0065] Figure 52 shows an exemplary schematic diagram illustrating a UL data transmission procedure involving an AP, a Relay and a non-AP STA according to the fifth embodiment of the present disclosure.

[0066] Figure 53 shows an exemplary schematic diagram illustrating a Relay Setup Phase of an UL data transmission procedure involving an AP, a Relay and a non-AP STA according to the fifth embodiment of the present disclosure.

[0067] Figure 54 shows an exemplary format of a multi-user Request-To-Send (MU-RTS) Triggered Transmission Opportunity (TXOP) Sharing (TXS) frame according to the fifth embodiment of the present disclosure.

[0068] Figure 55 shows another exemplary schematic diagram illustrating a UL data transmission procedure involving an AP, a Relay and a non-AP STA according to the fifth embodiments of the present disclosure.

[0069] Figure 56 shows an exemplary format of a Relay notification element according to the fifth embodiment of the present disclosure. Figure 57 shows yet another exemplary schematic diagram illustrating a UL data transmission procedure involving an AP, a Relay and a non-AP STA according to the fifth embodiment of the present disclosure.

[0070] Figure 58 shows still yet another exemplary schematic diagram illustrating a UL data transmission procedure involving an AP, a Relay and a non-AP STA according to the fifth embodiment of the present disclosure.

[0071] Figure 59 shows an exemplary A-MPDU frame structure according to an embodiment of the present disclosure.

[0072] Figure 60 shows an exemplary End-of-frame (EOF) Padding subframe of EOF Padding subframes subfield in the A-MPDU frame in Figure 59.

[0073] Figure 61 shows an exemplary format of an Extremely High Throughput (EHT) Trigger frame according to an embodiment of the present disclosure.

[0074] Figure 62A shows an exemplary format of a EHT variant User Info field that is applicable to User Info List in Figure 61 .

[0075] Figure 62B shows another exemplary format of a Special User Info field that is applicable to User Info List in Figure 61 .

[0076] Figure 63 shows an exemplary format of a Common Info field that is applicable to Common Info in Figure 61.

[0077] DETAILED DESCRIPTION

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

[0078]

[0013] 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.

[0079]

[0014] 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 802.1 1 -2016 definition, a STA can be any device that contains an IEEE 802.1 1 -conformant media access control (MAC) and physical layer (PHY) interface to the wireless medium (WM).

[0080]

[0015] For example, a STA may be a laptop, a desktop personal computer (PC), a personal digital assistant (PDA), a vehicle (e.g. connected vehicle), an AR / VR / XR equipment, 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.

[0081]

[0016] Likewise, an AP, which may be interchangeably referred to as a wireless access point (WAP) in the context of IEEE 802.1 1 (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.

[0082]

[0017] In various embodiments below, the term “Relay” may refer to a STA that acts as a relay between at least two STAs, two APs or one STA and one AP. The term may be used interchangeably with the term “Relay STA”, “Relay Device”, “AP with a backhaul link”, or “Relay Multi-link device (Relay MLD)”, wherein a backhaul link may refer to a wireless or wired link between APs. For clarification of doubt, when both Relay STA and non-AP STA are concerned, for example, appear in a figure or its accompanying text, the term “Relay” may be used to refer to Relay STA whereas the term “STA” may be used to describe the non-AP STA, respectively.

[0083]

[0018] 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 802.11 (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.

[0084]

[0019] 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.

[0085]

[0020] 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.

[0086]

[0021] 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”.

[0022] Relay operation is being considered in some contributions as being able to increase throughput and improve reliability. Figure 1 shows a schematic diagram 100 illustrating a downlink (DL) relay transmission procedure 100 involving an AP, a RelaySTA (hereinafter may be referred to as “Relay” in the present disclosure) and a non-AP STA(s). The relay transmission procedure may use Triggered Transmission Opportunity (TXOP) Sharing (TXS) procedure 102 defined in IEEE 802.11. After the TXS procedure 102, data starts to transmit from the AP to the non-APSTA(s) through the Relay. For exam pie, upon the completion of the TXS procedure 102, the AP may initiate a transmission of a PPDU (PPDU1 ) 104 for the non-AP STA(s) to the Relay, with a short interframe spacing (SIFS) interposed between the TXS procedure and the data transmission. Following the transmission of PPDU (PPDU1) 104 to the Relay, a SIFS ensues before the Relay transmits an acknowledgement frame (Ack1 ) 106 back to the AP. Subsequently, following a SIFS, the Relay proceeds to transmit a PPDU (PPDU2) 108 to the non-AP STA(s). Following the transmission of PPDU (PPDU2) 108 from the Relay to the non-AP STA(s), a SIFS is introduced before the non-AP STAs transmits an acknowledgement fra me (Ack2) 110 back to the Relay. Subsequently, subsequent to a SIFS, the Relay transmits an acknowledgment frame (Ack3) 112 back to the AP.

[0087]

[0023] Figure 2 shows a schematic diagram illustrating an uplink (UL) relay transmission procedure 200 involving an AP, a Relay and a non-AP STA(s). The relay transmission procedure 200 may use Triggered Transmission Opportunity (TXOP) Sharing (TXS) procedure 202 defined in IEEE 802.1 1 . Further, a Trigger frame may be transmitted after the TXS procedure 202 and before data starts to transmit from the non-AP STA(s) to the AP through the Relay. For example, upon the completion of the TXS procedure 202, the AP may initiate a transmission of a Trigger frame 204 to the Relay and the non-AP STA(s), with a short interframe spacing (SIFS) interposed between the TXS procedure and the transmission of the trigger frame. Following the transmission of the trigger frame, a SIFS ensues before the non-AP STA(s) transmits a PPDU (PPDU1 ) 206 to the Relay. Subsequently, following a SIFS, the Relay transmits an acknowledgement frame (Ack1 ) 208 back to the non-AP STA(s), and a SIFS is introduced before the Relay transmits a PPDU (PPDU2) 210 to the AP. After PPDU2 210 is transmitted, a Short Interframe Space (SIFS) is introduced before the AP transmits an acknowledgement frame (Ack2) 212 back to the Relay. Subsequent to the acknowledgement frame (Ack2) 212, a SIFS ensues before the Relay transmits an acknowledgment frame (Ack3) 214 back to the non-AP STA(s).

[0088]

[0024] Figure 3 shows an exemplary DL low latency data (LL) transmission in Relay operation 300 involving STAs such as 302, 306, 308 and a Relay 304. The STA 302 may transmit a Request-To- Send (RTS) frame 310 to the Relay 304 to initiate TXS procedure, and the Relay 304 may transmit a Clear-To-Send (CTS) frame 312 to STA 302. The STA 302 then sends data 314 which contains an indication of LL packet transmission for STA 308, and LL transmission completion time information to the Relay 304 and the Relay 304 sends an acknowledgement frame 316 back to the STA 302. Based on the LL transmission completion time information and information from TXS procedure, the time by which the LL data (e.g., latency sensitive data to STA 308) is to be transmitted (shown as line 326) and remaining time for data transmission (e.g., transmission of non-LL data to STA 306) can be calculated and the Relay can transmit or discard the data accordingly. In this case, the Relay 304 determines that there is remaining time for transmission of data to the STA 306 and thus transmits a RTS frame 318 to STA 306. STA 306 transmits a CTS frame 320 to the Relay 304, and the Relay 304 then transmits the data 322 within the calculated transmission completion time, and STA 306 transmits an acknowledgement frame back to the Relay 304. The Relay 304 then transmits the LL data 328 to STA 308.

[0089]

[0025] As mentioned earlier, there are not much discussion in UHR SG about LL data in relay operation, in particular, uplink (UL) solution for relay of LL data.

[0090]

[0026] Figure 4 shows a schematic diagram 400 illustrating UL and DL Relay operations involving an AP, a Relay and a non-AP STA (herein referred to as “STA”). After a relay setup phase, there are two data relay phrases. In the first Data Relay Phase 1 , for UL Relay operation, the Data Relay Phase 1 is carried out between the STA and the Relay, during which the STA transmits data (e.g., non-LL data) to the Relay; and for DL Relay operation, the Data Relay Phase 1 is carried out between the AP and the Relay, during which the AP transmits data (e.g., non-LL data) to the Relay. For DL operation, during Data Relay Phase 1 , LL Data may arrive at the AP when the AP is transmitting its data. For UL operation, during Data Relay Phase 1 , LL Data may arrive at the STA when the STA is transmitting its data. In the second Data Relay Phase 2, for the UL Relay operation, the Data Relay Phase 2 is carried out between the Relay and the AP to enable the Relay to forward the data received from the STA to the AP; and for the DL Relay operation, the Data Relay Phase 2 is carried out between the Relay and the STA to enable the relay to forward the data received from the AP to the STA. It is noted that, during Data Relay Phase 1 , the arrival of LL Data at the STA for UL transmission or the arrival of LL Data at the AP for DL transmission is non-predictable.

[0091]

[0027] Figure 5 shows a schematic diagram 500 illustrating a conventional UL Relay operation for LL Data transmission involving an AP, a Relay and a non-AP STA. In this example, during the Relay Setup Phase, the AP may transmit a CTS-to-self frame and a multi-user RTS TXS frame to communicate the TXOP to the Relay and the Relay transmits a CTS frame back to the AP. Subsequently, the Data Relay Phase 1 is carried out between the STA and the Relay. The Relay first transmits a trigger frame to the non-AP STA to solicit data (e.g., non-LL Data) from the non-AP STA. During the transmission of the data by the non-AP STA, LL Data for AP may arrive. The Relay will transmit a block acknowledgement (BA) frame to the STA after the data transmission is completed, and the Relay will first transmit the data to the AP. The AP which receives the data will then transmit a BA frame to the Relay. Subsequently, once the data transmission is completed, the Relay then transmits a trigger frame to the non-AP STA to solicit the LL Data received during the transmission of the data by the non-AP STA during the Data Relay Phase 1 . The non-AP STA upon receipt of the trigger frame then transmits the LL Data to the Relay. The Relay then transmits the LL Data to the AP (not shown). It is noted that there is a delay for LL Data to be transmitted, as illustrated as Tdelayin Figure 5.

[0092]

[0028] total time delay Tdelayfor LL Data can be calculated using equation (1), where there are 2 BA frame transmitted and 5 SIFS during the delay. equation (1 ) where

[0093] X: remaining time of the original non-LL Data transmission after LL Data arrives

[0094] TDatatotal transmission time of the non-LL Data, preamble transmission time is 46.4 ps

[0095] TBAtransmission time of BlockAck frame, 22 octets

[0096] TSIFS- 1® Ps

[0097] ^Trigger : transmission time of Trigger frame, 33 octets

[0098]

[0029] It is noted that, for UL, one challenge is that non-AP STA may have limited opportunity to transmit to Relay in Data Relay Phase 1 . If LL Data arrives when the non-AP STA has already started transmitting non-LL Data (on-going uplink transmission) to Relay, if there is no priority transmission for LL Data, it needs to wait for non-LL data transmission finishes after Data Relay Phase 2, and AP acknowledges successful reception, then starts transmitting after being triggered, which will cause some delay for low latency Data. Furthermore, there may be more than 1 non-AP STA being relayed. If LL Data arrives at a non-AP STA when a second non-AP STA is transmitting non-LL Data to Relay, there is no mechanism to interrupt and prioritize LL Data for the first non-AP STA.

[0099]

[0030] Table 1 shows the maximum length of an A-MPDU (octets) of a PPDU.

[0100] Table 1

[0101]

[0031] Maximum EHT PPDU duration is 5.484ms. MGS 13 is used. Data rate is 2882.4 Mb / s. Total time delay is more than 5.564 ms. Suppose the Data size is 8000 bytes, and MGS 13 is used. Data rate is 2882.4 Mb / s. Total time delay is more than 129 ps.

[0032] There is thus a need for a communication apparatus and a communication method for UL

[0102] LL transmission in relay operation that prioritises LL data over ongoing non-LL data to solve the above-mentioned issues.

[0103]

[0033] Various embodiments below provide a communication apparatus and a communication method implemented by a communication apparatus during data relay phase between an non-AP STA and a Relay STA (herein after may be referred to as “Relay” in the present disclosure), the communication apparatus comprising circuitry, which in operation, is configured to detect reception of a low latency data(LLD) during an ongoing data transmission, and determine to prioritize a transmission of LLD over the ongoing data transmission based on resources for the ongoing transmission and a transmitter, which in operation, transmits the LLD. In one option (option 1), the circuitry, which in operation, determines to prioritize the transmission of LLD if resources for the ongoing transmission is available for transmitting the LLD; In another option (option 2), the circuitry, which in operation, determines to prioritize the transmission of LLD if resources for the ongoing transmission is not available for transmit ting the LLD but available for transmitting an indication for the LLD. The embodiments below also provide another communication method implemented by such communication apparatus where the circuitry, which in operation, determines to prioritize the transmission of LLD if a gap between segments of a Physical Layer Convergence Protocol Data Unit (PPDU) of the ongoing transmission is available for transmitting an indication for the LLD with the LLD. More details will be described in the accompanying description.

[0104]

[0034] Figure 6 shows a schematic view of a communication apparatus 600 according to the present disclosure. The communication apparatus 600 may be implemented as an AP, a Relay or a non-AP STA.

[0105]

[0035] As shown in Figure 6, the communication apparatus 600 may include circuitry 614, at least one radio transmitter 602, at least one radio receiver 604, and at least one antenna 612 (for the sake of simplicity, only one antenna is depicted in Figure 6 for illustration purposes). The circuitry 614 may include at least one controller 606 for use in software and / or hardware aided execution of tasks that the at least one controller 606 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 614 may further include at least one transmission signal generator 608 and at least one receive signal processor 610. The at least one controller 606 may control the at least one transmission signal generator 608 for generating PPDUs and MAC frames (e.g., Trigger frames, CTS frames, RTS frames, MU-RTS TXS frames, BA frames) to be sent through the at least one radio transmitter 602 to one or more other communication apparatuses. Here, the PPDUs and MAC frames, for example, may be PPDUs and frames used for downlink transmissions if the communication apparatus 602 is an AP; alternatively, the PPDUs and MAC frames may be PPDUs and frames used for trigger-based uplink transmissions if the communication apparatus 600 is a non-AP STA; and the PPDUs and MAC frames may be PPDUs and frames used for downlink and / or uplink transmissions if the communication apparatus 600 is a Relay. The at least one controller 606 may control the at least one receive signal processor 610 for processing PPDUs and MAC frames received through the at least one radio receiver 604 from the one or more other communication apparatuses under the control of the at least one controller 606. Here the PPDUs and MAC frames, for example, may be PPDUs and frames used for trigger-based uplink transmissions if the communication apparatus 600 is an AP; alternatively, the PPDUs and MAC frames may be PPDUs used for downlink transmissions if the communication apparatus 600 is a STA; and the PPDUs and MAC frames may be PPDUs and frames used for downlink and / or uplink transmissions if the communication apparatus 600 is a Relay. The at least one transmission signal generator 608 and the at least one receive signal processor 610 may be stand-alone modules of the communication apparatus 600 that communicate with the at least one controller 606 for the above-mentioned functions, as shown in Figure 6. Alternatively, the at least one transmission signal generator 608 and the at least one receive signal processor 610 may be included in the at least one controller 606. 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 602, at least one radio receiver 604, and at least one antenna 612 may be controlled by the at least one controller 606.

[0106]

[0036] Figure 7 shows a flow chart illustrating a communication method 700 according to the present disclosure. The communication apparatus 600, when in operation, may provide functions required for low latency transmission and perform the method in Figure 7. For example, the communication apparatus 600 may be a STA, and the circuitry 614 (for example the controller 606 of the circuitry 614) is configured to carry out step 702 to detect a receipt of data of a first traffic type (e.g., low latency type) during a transmission of a signal (e.g., PPDU) comprising one or more frames of a second traffic type (e.g., non-low latency type) to another communication apparatus (e.g., a Relay), on a first resource of a plurality of resources (e.g., time slots and frequency slots) allocated for the transmission of the signal. The at least one radio transmitter 602 may carry out step 704 and transmit one of (i) the data of the first traffic type and (ii) an indication of the receipt of the data of the first traffic type to another communication apparatus on a second resource of the plurality of resources.

[0107]

[0037] In addition to the aforementioned examples of traffic types, it will be appreciated that there are other examples of traffic types, which may include traffic identifier (TID), Access Categories, enhanced access categories, status whether pre-emption is enabled or not for the traffic, priority levels (may referred to as priority values alternatively) for traffics, types corresponding to classification of traffics on higher layer or other standards (e.g. Differentiated Services Code Point (DSCP)), and existence of expiry indication for data in the traffic (for example, traffics are classified into a first type that has expiry indication and a second type that does not have expiry indication.)

[0108]

[0038] Data of the first traffic type may be regarded as low latency (LL) data, deterministic latency data, streaming data, or low jitter data. Criteria used to classify the first traffic type and second traffic type may be specified in the standard. For example, specific traffic types (e.g., Access Categories for voice and video, TIDs that are in specific range of identifier values, etc.) are classified to the first traffic type. In another example, traffic with a high priority level (e.g. a priority level equals to or higher than a threshold, a priority level index equals to or smaller than a threshold) may be classified to LL data. Alternatively, the classification distinguishing between the first and second traffic types may be identified through negotiation process between an AP and a non-AP STA, or determined and advertised by an AP.

[0109]

[0039] In one embodiment, in step 702, where the receipt of the data of the first traffic type is detected during a transmission of a first frame of the signal (e.g., MAC Protocol Data Unit (MDPU) of PPDU), the circuitry 614 (for example the controller 606 of the circuitry 614) is configured to further determine whether a first remaining resource of the plurality of resources after the transmission of the first frame is sufficient for transmitting the data of the first traffic type, and in step 704, The at least one radio transmitter 602 may transmit the one of (i) the data of the first traffic type and (i) the indication of the receipt of the data of the first traffic type on the first remaining resource in response to a result of the determination.

[0110]

[0040] In this embodiment, additionally, in step 702, the circuitry 614 (for example the controller 606 of the circuitry 614) is configured to further refrain a second frame of the second traffic type of the signal subsequent to the first frame from transmitting to the another communication apparatus on the first remaining resource after the transmission of the first frame, and insert a third frame comprising the one of (i) the data of first traffic type and (ii) the indication of the receipt of the data of the first traffic type into the signal such that the at least one radio transmitter 602 may the third frame through the signal after the transmission of the first frame in step 704.

[0111]

[0041] In this embodiment, additionally, in step 702 or after step 704 is carried out, the circuitry (for example the controller 606 of the circuitry 614) is configured to further determine if a second remaining resource of the plurality of resources after the transmission of the third frame is sufficient for transmitting the second frame, and in step 704, the at least one radio transmitter 602 may transmit the second frame through the signal after the transmission of the third frame in response to determining that the second remaining resource is sufficient.

[0042] In another embodiment, the signal comprises two or more smaller signals, the two or more smaller signals being transmitter one after another after every first pre-configured time frame, and during the transmission of the two or more smaller signals, the receipt of the data of the first traffic type is detected in step 702, and the at least one radio transmitter 602 may in step 704 transmits a second signal comprising the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type on a third remaining resource of the plurality of resources after a second pre-configured time frame to the second communication apparatus based on the result of the detection.

[0112]

[0043] In this another embodiment, additionally, in step 702, the circuitry (for example the controller 606 of the circuitry 614) is configured to further detect whether there is a transmission of another signal to the another communication apparatus within the first pre-configured time frame after the one of the two or more smaller signals is transmitted, and refrain another one of the two or more smaller signals subsequent to the one of the two or more smaller signals from transmitting to the another communication apparatus after the first pre-configured time frame in response to the detection of the transmission of the another signal.

[0113]

[0044] In this another embodiment, additionally, the at least one radio receiver 610 may receive a block acknowledgement (BA) frame from another communication apparatus, and the at least one radio transmitter 602 may transmit the another one of the two or more smaller signals, which is refrained from being transmitting, after receiving the BA frame.

[0114]

[0045] In yet another embodiment, the at least one radio receiver 610 may receive from another communication apparatus a trigger frame comprising information of an allocation of the second resource prior to the transmission of the signal. Such trigger frame may comprise transmission parameters of the data of the first traffic type, and the one radio transmitter 602 may transmit the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type using the transmission parameters. Alternatively, the circuitry 614 (for example the controller 606 of the circuitry 614) may receive an information element comprising the information of the allocation of the second resource prior to the transmission of the signal; and the trigger frame comprises information signaling that the second resource allocated by the information element is enabled for transmitting the data of the first traffic type.

[0115]

[0046] In various embodiments, the at least one radio transmitter 602 may transmits the indication of the receipt of the data of the first traffic type on the second resource and the at least one radio receiver 610 may receive a trigger frame soliciting the data of the first traffic type, the trigger frame comprising transmission parameters of the data of the first traffic type; and the transmitter transmits a third signal comprising the data of the first traffic type to the second communication apparatus using the transmission parameters upon receiving the trigger frame. Additionally, where the at least one radio receiver 610 receives a fourth signal comprising the trigger frame and a BA frame indicating a successful reception of the first signal, the at least one radio transmitter 602 may transmit the third signal upon receiving the fourth signal.

[0116]

[0047] Figure 8 shows a flow chart illustrating another communication method 800 according to the present disclosure. The communication apparatus 600, when in operation, may provide functions required for low latency transmission and perform the method in Figure 8. For example, the communication apparatus 600 may be a Relay, and the at least one radio receiver 604 may carry out step 802 to receive one of (i) data of a first traffic type (e.g., LL type) and (ii) an indication of a receipt of the data of the first traffic type from another communication apparatus (e.g., a non-AP STA) on a second resource of a plurality of resources (e.g., time slots and frequency slots) allocated for a signal (e.g., a PPDU) after receiving at least a part of the signal on a first resource of the plurality of resources. The circuitry 614 (for example the at least one receive signal processor 610 of the circuity 614) is configured to carry out step 804 and process the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type.

[0117]

[0048] In one embodiment, in step 804, the circuitry 614 (for example the at least one receive signal processor 610 of the circuity 614) is configured to further determine that the indication of the receipt of the data of the first traffic type is received, and the at least one radio transmitter 602 may transmit a trigger frame soliciting the data of the first traffic type to the another communication apparatus. Additionally, the at least one radio transmitter 602 may transmit a second trigger frame comprising information of an allocation of the second resource or information signaling that the second resource allocated by an information element is enabled for transmitting the data of the first traffic type prior to the transmission of the signal. Additionally, the trigger frame further comprises transmission parameters of the data of the first traffic type.

[0118]

[0049] In this embodiment, additionally or alternatively, the trigger frame signals (i) a transmission of the first signal comprising two or more smaller signals, the two or more smaller signals being transmitted one after another after every first pre-configured time frame, and (ii) a transmission of the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type by the first communication apparatus after a second pre-configured time frame after one of the two or more smaller signals is transmitted if the first communication apparatus detects a receipt of the data of the first traffic type during a transmission of the one of the two or more smaller signals.

[0119]

[0050] In another embodiment, in step 804, the circuitry 614 (for example the at least one receive signal processor 610 of the circuity 614) is configured to identify the data of the first traffic type from the first signal, and the at least one radio transmitter 602 may transmit to the data of the first traffic type prior to or concurrent with data of the first signal to yet another communication apparatus (e.g., AP). In this embodiment, the at least one radio receiver 604 may receive from the yet another communication apparatus a trigger frame comprising a first signal field signaling one of (i) a transmission of the data of the first traffic type prior to the data of the first signal and (ii) a transmission of the data of the first traffic type concurrent with the data of the first signal, and the transmitter performs the one of (i) the transmission of the data of the first traffic type prior to the data of the first signal and (ii) the transmission of the data of the first traffic type concurrent with the data of the first signal. Additionally, such trigger frame further comprises a second signal field indicating an available time period shared by the yet another communication apparatus during which the communication apparatus 600 is allowed to transmit signals to the yet another communication apparatus and the another communication apparatus so as to receive the one of (i) the data of a first traffic type and (ii) the indication of a receipt of the data of the first traffic type from the another communication apparatus and to transmits the data of the first traffic type to the yet another communication apparatus.

[0120]

[0051] The present disclosure introduces a communication apparatus and a communication method for LL data transmission in a relay operation, which prioritizes UL LL data in two phases: Data Relay Phase 1 (STA-Relay) and Data Relay Phase 2 (Relay-AP). In Data Relay Phase 1 between a STA and a Relay, the transmission data can be prioritized through two methods: (i) LL insertion method and (ii) TXOP Preemption method.

[0121]

[0052] In the LL insertion method, which will be described in the following, for example by means of the first and the second embodiment, a non-AP STA may check frequency-time resource (e.g., slots) for an ongoing transmission (e.g., non-LL Data transmission) and insert LL data and / or LL indication into the PPDL) to be transmitted to the Relay. For this method, when a LL data arrives at a non-AP STA, the non-AP STA will check if the remaining frequency-time resource for the ongoing transmission is enough for the LL data transmission. If the remaining frequency-time resource is enough for the LL data, the non-AP STA then prioritizes the transmission of the LL Data over the ongoing transmission and transmits the LL Data to the Relay. However, if the remaining frequencytime resource (e.g., slots) is not enough for the transmission of the LL data, the non-AP STA will transmit a LL indication to the Relay. When the Relay receives the LL indication, it may later send a Trigger frame to the non-AP STA to solicit the LL Data.

[0122]

[0053] In the TXOP Preemption method, which will be described with more details in the following third embodiment, a non-AP STA may divide a larger PPDU into two or more smaller PPDUs with time gaps therebetween, i.e. , the two or more smaller PPDUs of the larger PPDU are transmitted in sequence with an pre-emption time gap (preconfigured time frame) introduced between each pair of adjacent smaller PPDUs, to allow LL Indication being transmitted from STAs with LL Data.

[0054] According to the following paragraphs, a first embodiment of the present disclosure is described, where a LL-MPDU subframe comprising LL data or LL indication may be inserted into aggregated MPDU (A-MPDU) of a PPDU during its on-going transmission.

[0123]

[0055] Figure 9 shows an exemplary structure of an A-MPDU 900 of a PPDU according to the first embodiment of the present disclosure. In this first embodiment, when LL data arrives at a non-AP STA during an ongoing transmission of the PPDU (herein may be referred to as “ongoing PPDU”) by the non-AP STA, for example, during the time when the non-AP STA is transmitting the A-MPDU subframe 1 902, the non-AP STA may check if the remaining frequency-time resource is enough for LL data and determine whether to transmit LL data or LL indication in the A-MPDU of the ongoing PPDU. If the remaining frequency-time resourceis enough for the transmission of the LL Data, the non-AP STA may insert LL A-MPDU subframe 904 containing the LL data directly after the current A-MPDU subframe 1 902. After transmitting LL A-MPDU subframe 1 902, the non-AP STA may continue transmission of LL A-MPDU subframes 904 if remaining transmission resource (e.g., time) is enough. End-of-frame (EOF) Padding bits 906 may be added to meet the required PPDU Length. However, if the remaining frequency-time resource for LL Data is not enough, non-AP STA may add LL Indication 906 at or near the end of A-MPDU 900 to notify the Relay, which sends a Trigger frame to non-AP STA to solicit the LL data. It is appreciated that only LL A-MPDU subframe is inserted into A-MPDU structure 900 without LL indication at the end of the A-MPDU, for example, in case that the remaining frequency-time resource for LL data is enough; or only LL indication is inserted at the end of A-MPDU structure 900 without LL A-MPDU subframe 904, for example, in case that the remaining frequency-time resource for LL data is not enough.

[0124]

[0056] Figure 10 shows a first exemplary structure of an A-MPDU 1000 of a PPDU comprising a LL indication according to the first embodiment of the present disclosure. In this example, provided that the non-AP STA determines that the remaining frequency-time resource is not enough for LL data transmission, a LL indication (4 octets) 1004 will be inserted into the A-MPDU 1000 next to the final A-MPDU subframe (A-MPDU subframe n) 1002 near the end of the A-MPDU 1000. EOF padding bits are added to meet the required PPDU length. The advantage of such LL insertion method to insert an LL indication into the A-MPDU 1000 next to the final A-MPDU subframe 1004 is that it does not only indicate LL traffic arrival, but the information about the LL traffic can also be included in the indication subframe.

[0125]

[0057] Figure 1 1 A shows an existing A-MPDU delimiter format 1100 of the MPDU 1000 of Figure 10, and Figure 1 1 B shows an exemplary LL indication subframe 1 110 in the MPDU 1000 of Figure 10 which converted from the existing A-MPDU delimiter format 1 100. The A-MPDU subframe under the existing delimiter format comprises an EOF padding field followed by a Reserved field, a MPDU Length field, a CRC field and a Delimiter Signature field. For the purpose to contain a LL indication, such MPDU subframe under the delimiter format may be changed, in particular, the Reserved field may be changed to a Low Latency Indication field to indicate the arrival of the low latency data and the MPDU Length field may be changed to LL Information field to indicate the LL packet information. For example, the LL Indication field may be set to 1 if LL data arrives; otherwise it is set to 0.

[0126]

[0058] Figure 12 shows a second exemplary structure of an A-MPDU 1200 of a PPDU comprising a LL indication according to the first embodiment of the present disclosure. The current A-MPDU structure is reused to form the A-MPDU 1200 and the Reserved field in the EOF Padding subframes 1204 of the EOF Padding bits 1202 is modified to contain an LL indication 1206. The advantage of such LL insertion method to insert an LL indication into the EOF padding bits 1202 of the A-MPDU 1 1 100 is that no additional subframe is added and therefore it is more efficient.

[0127]

[0059] In one implementation, if LL data arrives when the non-AP STA is transmitting a A-MPDU (e.g., at A-MPDU subframe 1 ) of an UHR PPDU, the non-AP STA will check whether the remaining frequency-time resource is enough for transmitting LL data. If the remaining frequency-time resource is enough, the non-AP STA may insert the LL A-MPDU immediately after finishing transmitting the A-MPDU subframe and transmits the LL A-MPDU. The non-AP STA checks the remaining frequency-time resource after finishing transmitting the LL A-MPDU, and decides whether to transmit the non-LL A-MPDU (e.g., block 904 of Figure 9) or add EOF Padding (e.g., block 906 of Figure 9). Until PPPDU length is met as required. In particular, if the remaining frequency-time resource is enough for transmitting the next non-LL A-MPDU, the non-AP STA may insert the non-LL A-MPDU immediately after LL A-MPDU; if the remaining frequency-time resource is not enough for transmitting the next non-LL A-MPDU, the non-AP STA may add EOF Padding until the PPDU length is met as required. The non-AP STA may repeat the above process for each remaining non-LL A- MPDU to check whether after transmitting the previous non-LL A-MPDU, the remaining frequencytime resource is enough for transmitting the subsequent non-LL A-MPDU. The LL A-MPDU may include an indication of LL to differentiate from non-LL A-MPDU.

[0128]

[0060] Figure 13 shows a flow chart 1300 illustrating a process implemented by a non-AP STA according to the first embodiment of the present disclosure. In step 1302, the non-AP STA may transmit a A-MPDU subframe. In step 1304, it is determined whether a LL data arrival is detected. If a receipt or arrival of LL data is detected, step 1306 is carried out; otherwise step 1312 is carried out. In step 1306, it is determined whether a remaining frequency-time resource is enough for LL data transmission. If there is a remaining frequency-time resource is enough for LL data transmission, step 1310 is caried out; otherwise step 1308 is carried out. In step 1310, the non-AP STA may indicate LL data arrival in LL indication subframe or EOF Padding subfield.

[0129]

[0061] In step 1310, the non-AP STA may insert LL A-MPDU subframe after finishing the current A-MPDU subframe transmission. In step 1312, it is determined whether non-LL data A-MPDU transmission has finished. If non-LL data A-MPDU transmission has finished, step 1314 is carried out; otherwise the process may end. In step 1314, a remaining frequency-time resource is enough for non-LL data transmission. If the remaining frequency-time resource is not enough for non-LL data transmission, step 1316 is carried out; otherwise the process may end. In step 1316, if a receipt or arrival of LL data is detected in step 1304, the non-AP STA may insert EOF Padding or LL Indication subframe until meeting the required PPDU length and the process may end.

[0130]

[0062] Figure 14 shows a flow chart 1400 illustrating a process implemented by a Relay according to the first embodiment of the present disclosure. In step 1402, the Relay may receive a UHR PPDU (signal), check all A-MPDU subframes and check a LL indication subfield. In step 1404, the Relay may determine whether the LL indication subfield is set to 1 . If the LL indication subfield is set to 1 , step 1408 is carried out; otherwise step 1406 is carried out. In step 1406, it is determined whether a LL A-MPDU subframe(s) is found. If LL A-MPDU subframe(s) is found, step 1412 is carried out; otherwise step 1410 is carried out. In step 1408, it is determined whether a LL A-MPDU subframe(s) is found, step 1414 is carried out; otherwise step 1416 is carried out. In step 1410, the Relay sends a block acknowledgment (BA) frame to the non-AP STA and forwards the non-LL Data to the AP. In step 1412, the Relay sends a BA frame to non-AP STA; and constructs a LL PPDU using a LL A- MPDU subframe and prepare for transmitting to the AP. In step 1414, the Relay decides whether to solicit UL LL data or sends LL data contained in the PPDU to the AP first. In step 1416, the Relay sends a BA frame to the non-AP STA, then after SIFS time, sends a trigger frame to the non-AP STA soliciting LL data.

[0131]

[0063] An LL indication may be included in the MPDU Delimiter of the LL A-MPDU subframe, so that when the Relay receives the A-MPDU, it can differentiate between LL A-MPDU and non-LL A- MPDU. Figure 15 shows an example LL A-MPDU subframe 1500 according to an embodiment of the present disclosure. The LL A-MPDU subframe 1500 may comprise a MPDU Delimiter field and a Padding field. The MPDU Delimiter field may comprise an EOF field, a LL Flag field, a MPDU length field, a CRC field and a Delimiter Signature field. The LL Flag field may be originally a Reserved field, but may be set to 1 to indicate the MPDU is a LL MPDU, and set to 0 to indicate otherwise.

[0132]

[0064] Alternatively, an LL indication may be included in the MAC Header of the LL A-MPDU subframe. Figure 16 shows a MAC Header of a A-MPDU subframe 1600 according to an embodiment of the present disclosure. The A-MPDU subframe 1600 comprises a MAC Header which comprises a Frame Control field, a Duration field, three Address fields (Address 1 , Address 2, Address 3), a Sequence Control field, another Address field (Address 4), a Quality of Service (QoS) field and a HT Control field. The Control field may comprise a A-Control field. The A-Control subfield comprises a Control List field and a Padding field. The Control List field comprises a Control ID field and a Control Information field. The Control ID value is set to 10 which was Reserved to indicate the LL MPDU. The +HT Control subfield (not shown) in Frame Control field is set to 1 to indicate the frame contains an HT Control field.

[0133]

[0065] Figure 17 shows an exemplary process when using the A-MPDU structure in Figure 10 in one scenario. The A-MPDU may comprise one or more A-MPDU subframe and an LL indication subfield 1702 prior to the EOF Padding subfield 1704 at the end of the A-MPDU 1700. In this scenario, one LL data may arrive when the non-AP STA is transmitting a A-MPDU (A-MPDU subframe 1 ), and the non-AP STA will insert the LL A-MPDU immediately after finishing the on-going A-MPDU transmission, for example, when it determines that the remaining frequency-time resource is enough for transmitting the LL data. The LL indication subfield 1702 indicates the arrival of LL data. Alternatively, as shown in Figure 19, the LL indication, which indicates the arrival of LL data, may be included in the EOF Padding subfield 1902 at the end of the A-MPDU 1900.

[0134]

[0066] If one LL data arrive when the non-AP STA is transmitting a A-MPDU subframe (A-MPDU subframe 1 ) and there is enough remaining frequency-time resource for transmitting the LL data. A LL A-MPDU subframe 1704 comprising the LL data may be inserted into the MPDU subsequent to the A-MPDU subframe 1 , for example, right next to A-MPDU subframe 1 so that the LL A-MPDU subframe 1704 will be transmitted immediately after finishing the transmission of the A-MPDU subframe 1 . The A-MPDU may further comprise a LL indication subfield 1702 near the end of the A- MPDU before EOF Padding subfield 1706, the LL indication subfield 1702 indicating the arrival of LL data. Alternatively, as shown in Figure 19, the LL indication, which indicates the arrival of LL data may be included in the EOF Padding subfield 2002 at the end of the A-MPDU 1902.

[0135]

[0067] Figure 18 shows an exemplary process when using the A-MPDU structure in Figure 10 in another scenario. In this scenario, multiple LL data may arrive when the non-AP STA is transmitting a A-MPDU. If multiple LL data arrive when the non-AP STA is transmitting a A-MPDU subframe (A- MPDU subframe 1 ) and there is enough remaining frequency-time resource for transmitting the LL data. Multiple LL A-MPDU subframes corresponding to the multiple LL data may be inserted into the MPDU subsequent to the A-MPDU subframe 1. In this example, two LL A-MPDU subframes 1812, 1814 are inserted into the A-MPDU. One of the LL A-MPDU subframes 1812 is inserted right next to the A-MPDU subframe 1 before A-MPDU subframe 2, and another one 1814 is inserted between the A-MPDU subframe 2 and A-MPDU subframe n, so that the LL A-MPDU subframes will be transmitted after finishing the transmission of the A-MPDU subframe 1 . The A-MPDU comprises a LL indication subfield 1802 near the end of the A-MPDU before EOF Padding subfield 1806, the LL indication subfield 1802 indicating the arrival of LL data. Alternatively, as shown in Figure 20, the LL indication, which indicates the arrival of LL data, may be included in the EOF Padding subfield 2002 at the end of the A-MPDU.

[0136]

[0068] However, if the non-AP STA determines that the remaining frequency-time resource is not enough for transmitting LL data, the non-AP STA may indicate the LL data arrival at the end (i.e., in EOF Padding subfield) or near to the end of the A-MPDU (in a LL indication subframe prior to EOF Padding subfield in the A-MPDU.

[0137]

[0069] Figure 21 show an exemplary A-MPDU structure 2100 in Figure 10 after LL data arrives. The A-MPDU 2100 may comprise a LL indication subframe 2102 near the end of the A-MPDU 2100 before EOF Padding subfield 2104, the LL indication subframe 2102 indicating the arrival of LL data. The LL indication subframe may comprise an EOF subfield, a LL indication subfield, a LL information subfield, a ORC subfield and a Delimiter Signature subfield. The LL indication subfield is set to 1 if LL data arrives during the transmission and 0 if otherwise. Alternatively, as shown in Figure 22, the LL indication, which indicates the arrival of LL data may be included in the EOF Padding subfield 2202 at the end of the A-MPDU 2200 without a separate LL indication subframe. The EOF Padding subfield 2202 comprises a EOF Padding subframes and EOF Padding Octets added to meet the PPDU length. The EOF Padding subframes comprises a EOF subfield, a LL indication subfield, a MPDU Length subfield a CRC subfield and a Delimiter Signature subfield.

[0138]

[0070] The A-MPDU 2100, 2200 in the MAC layer with the LL indication may then be converted to PSDU in the PSY layer before transmitting it to the Relay. The Relay receiving such A-MPDU 2100, 2200 with the LL indication (without the LL data) may then send a Trigger frame to the non-AP STA to solicit the LL data from the non-AP STA.

[0139]

[0071] According to the following paragraphs, a second embodiment of the present disclosure is described, where a LL-MPDU subframe comprising LL data or LL indication may be inserted into aggregated MPDU (A-MPDU) of a PPDU during its on-going transmission in resource units (Rus) specifically reserved for transmitting the LL data or the LL indication.

[0140]

[0072] In this embodiment, a RU may be reserved for LL data and a non-AP STA may transmit an UHR PPDU non-LL A-MPDU (non-LL data) using other, non-reserved Rus (e.g., RU1 as shown in Figures 32 and 33) to a Relay and LL A-MPDU comprising the LL data or an LL indication frame using the reserved RU (e.g., RU2) if LL data arrives. The RU allocation information be included in the Trigger frame that solicits the UHR PPDU. In this disclosure, such reserved RU for LL data is called LL RU to differentiate from other RU / MRUs.

[0141]

[0073] When LL data for AP arrives at an ongoing uplink transmission (non-LL A-MPDU transmission) from the non-AP STA to the Relay, the non-AP STA may check if the remaining frequency-time resource is enough for LL data and determine whether to transmit the LL data or LL indication in the LL RU.

[0142]

[0074] An A-MPDU delimiter format or the LL indication (sub)frame from the A-MPDU shown in Figures 17-18B and 21 may be reused as the format of the LL indication frame. The LL indication frame may contain information of low latency Data arrival and low latency packet size.

[0143]

[0075] Figure 23 shows an exemplary schematic diagram 2300 illustrating an UL data transmission procedure involving an AP, a Relay and a non-AP STA according to the second embodiment of the present disclosure. The RU allocation information needs to be indicated in the Trigger frame during the Data Relay Phase 1 (between STA and Relay) 2304 after the Relay Setup Phase 2302. After a Relay Setup Phase, the Relay may transmit a Trigger frame 2312 to the non-AP STA (STA1 ). The non-AP STA may transmit a PPDU comprising data for the AP on non-reserved HU to the Relay. During an ongoing transmission of the PPDU, LL data for AP may arrive at the non-AP STA, and the non-AP STA may transmit insert the LL data or an indication of the LL data (not shown in Figure 23) in the PPDU on the LL RU. After the transmission of the PPDU, the Relay may transmit a BA frame to acknowledge receipt of the data, and a Data Relay Phase 2 between the Relay and the AP is carried out.

[0144]

[0076] Figure 24 shows an exemplary format of a Trigger frame 2400 soliciting UL transmission from a non-AP STA according to the second embodiment of the present disclosure. The Trigger frame (TF) 2400 comprises a Frame Control field, a Duration field, a Recipient Address (RA) field, a Transmitter Address (TA) field, a Common Information field, a User Information field, a Padding field and a frame check sequence (FCS) field. The Common Information field further comprises a Trigger Type subfield, a UL Length subfield, a More TF subfield, a CS Required subfield, a UL Bandwidth (BW) subfield, a Guard Interval (Gl) And High Efficiency / Extremely High Throughput Long Training Field (HE / EHT-LTF) Type / Triggered TXOP Sharing Mode subfield, a Multiple Allocated Rus Enable subfield 2402, a Number Of HE / EHT-LTF Symbols subfield, a LDPC Extra Symbol Segment subfield, an AP Tx Power subfield, a Pre-FEC Padding Factor subfield, a PE Disambiguity subfield, an UL Spatial Reuse subfield, a HE / EHT Primary 160 MHz (P160) subfield, a Special User Information Field Flag subfield, a EHT Reserved subfield, and a Trigger Dependent Common Information subfield. The Multiple Allocated Rus Enable subfield 2402 is changed from a Reserved field and is set to 1 to indicate non-AP STA transmitting through multiple allocated Rus is enabled, and 0 otherwise.

[0145]

[0077] Figure 25 shows a flow chart 2500 illustrating a process implemented by a non-AP STA according to the second embodiment of the present disclosure. In step 2502, the non-AP STA may transmit non-LL data on non-LL RU (e.g., RU1). In step 2504, LL data arrives at the non-AP STA. The non-AP STA then checks if the remaining frequency-time resource is enough for LL data transmission, for example, the remaining time slots on LL RU are enough for LL data transmission. If there is enough remaining frequency-time resource, step 2506 is carried out; otherwise step 2508 is carried out. In step 2506, the non-AP STA transmits LL data on LL RU using transmission parameters specified in the Trigger frame and non-LL data on non-LL RU to the Relay. In step 2508, the non-AP STA may send a LL indication frame on LL RU to indicate the arrival of LL data.

[0146]

[0078] Figure 26 shows a flow chart 2600 illustrating a process implemented by a Relay according to the second embodiment of the present disclosure. In step 2602, the Relay may keep listening for signals on both non-LL RU and LL RU. In step 2604, when the Relay receive a signal from a non- AP STA, the Relay determines whether a LL indication or LL data is transmitted on the LL RU. If there is no LL indication or LL data, step 2606 is carried out; otherwise, step 2608 is carried out. In step 2606, the Relay processes non-LL data using normal procedure and the process may end.

[0147]

[0079] In step 2608, the Relay determines whether it receives a LL indication or LL data. If a LL indication is received, step 2612 is carried out; if LL data is received, step 2610 is carried out; if both LL indication and LL data are received, step 2614 is carried out. In step 2610, the Relay sends a BA frame to the non-AP STA and forwards the LL data to the AP prior to or concurrently with the non- LL data. In step 2612, the Relay sends a BA frame to the non-AP STA, then after SIFS time, sends a trigger frame to the non-AP STA to solicit the LL data. In step 2614, the Relay decides whether to solicit UL LL data from the non-AP STA or sends the LL Data contained in the PPDU to the AP first.

[0148]

[0080] Figure 27 shows an exemplary format of a Trigger frame 2700 in Figure 24 with multiple User Info fields. No new trigger type is defined. The existing basic trigger type is reused. The Trigger frame 2700 may be similar to that shown in Figure 24, which comprises a Frame Control field, a Duration field, a RA field, a TA field, a Common Information field, one or more User Information field (in this example, User Info 1 field 2702 and User Info 2 field 2704), a Padding field and a FCS field. Each User Info field comprises a AID12 subfield, a RU Allocation subfield, a UL FEC Coding Type subfield, a UL UHR MCS subfield, a LL RU Flag subfield, a SS Allocation / RA-RU Information subfield, a UL Target Receive Power subfield, a Primary Secondary 160 MHz (PS160) subfield and a Trigger Dependent User Info subfield.

[0081] The AID12 subfield is set to the AID of the non-AP STA, and the non-AP STA should check AID12 subfield of all User Info fields. The LL RU Flag subfield was a Reserved field. Multiple User Info fields are used to indicate RU allocation information and transmission parameters of non-LL data and LL data. In particular, the LL RU Flag subfield (e.g., LL RU Flag subfield 2718 of User Info 2 field 2704) is set to 1 to indicate the User Info field is used to specify LL data transmission parameters and RU Allocation information, and the RU Allocation subfield 2716 indicates the allocated LL RU; and the LL RU Flag subfield (e.g., LL RU Flag subfield 2714 of User Info 1 field 2702) is set to 0 otherwise, for example, for non-LL data transmission parameters and RU allocation information and the RU Allocation subfield 2712 indicates Rus (e.g., RU1 ) allocated for non-LL data.

[0149]

[0082] Alternatively, the LL data reuses the transmission parameters of non-LL data and in this case, the Trigger frame for soliciting UL transmission may not need to have an additional User Info field to specify some or all LL data transmission parameters and only one User Info field is needed. The trigger frame contains information of LL RU allocation (e.g., a fixed RU or a non-fixed RU as the reserved LL RU), and doesn’t necessarily contain all of the transmission parameters of LL Data.

[0150]

[0083] The Relay may indicate a fixed / pre-configured RU to be used as the reserved LL RU. Such LL RU allocation information of the LL RU can be notified using a new information element (e.g., LL RU notification element). The Relay only indicates whether to use this LL RU in the Trigger frame and the data transmitted on the LL RU reuses the non-LL RU transmission parameters. Advantageously, there is no need to modify the Trigger Dependent User Info field.

[0151]

[0084] Alternatively, the Relay may indicate a RU to be used as the reserved LL RU. Such RU is not fixed (herein referred to as “non-fixed RU”). In this case, the Trigger Dependent User Info field is modified to LL RU Allocation field, which contains RU allocation information of LL RU. The data transmitted on the LL RU reuses the non-LL transmission parameters. Advantageously, the RU allocation is flexible, i.e. , the LL RU is adaptively allocated.

[0085] Figure 28 shows another exemplary format of a Trigger frame 2800 in Figure 24. The Trigger frame 2800 may be similar to that shown in Figure 24, which comprises a Frame Control field, a Duration field, a RA field, a TA field, a Common Information field, one User Information field, a Padding field and a FCS field. The User Info field comprises a AID12 subfield, a RU Allocation subfield, a UL FEC Coding Type subfield, a UL UHR MCS subfield, a LL RU Enable subfield, a SS Allocation / RA-RU Information subfield, a UL Target Receive Power subfield, a Primary Secondary 160 MHz (PS160) subfield and a Trigger Dependent User Info subfield. The new LL RU Enable subfield is set to 1 to indicate the LL RU, for example, the fixed RU notified using a new information element (e.g., LL RU notification element shown in Figure 30) during or prior to the Relay Setup Phase, is enabled for transmitting LL data or LL indication and is set to 0 otherwise. Such LL RU Enable subfield was originally reserved. The LL data transmitted on the LL RU reuses the non-LL data transmission parameters. The LL RU should be a small sized RU.

[0152]

[0086] Figure 29 shows another exemplary schematic diagram 2900 illustrating an UL data transmission procedure involving an AP, a Relay and a non-AP STA with LL RU allocation notification according to the second embodiment of the present disclosure. To indicate RU allocation information of the fixed LL RU for transmitting LL indication or LL data, the AP may during or prior to the Relay Setup Phase 2902, transmit a LL RU notification element 2904 with RU allocation information of the LL RU to the Relay and the Relay sends an Ack frame back to the AP. The Relay may then transmit a LL RU notification element 2906 with RU allocation information of the LL RU to the non-AP STA, and the non-AP Sta sends an Ack frame back to the Relay.

[0153]

[0087] Figure 30 shows an exemplary format 3000 of the LL RU notification element 2902, 2904 (See, Figure 29) according to the second embodiment of the present disclosure. The LL RU notification element 2902, 2904 may comprise an Element ID field, a Length field, an Element ID Extension field and a LL RU allocation field. The Element ID field may be set to 255, Element ID Extension field may be set to 1 15, which was Reserved element. The LL RU Allocation field may indicate the RU Allocation information of the LL RU for transmitting LL indication or LL data.

[0088] Figure 31 shows still another exemplary format of a Trigger frame 3100 in Figure 24. The Trigger frame 3100 may be similar to that shown in Figure 24, which comprises a Frame Control field, a Duration field, a RA field, a TA field, a Common Information field, one User Information field, a Padding field and a FCS field. The User Info field comprises a AID12 subfield, a RU Allocation subfield, a UL FEC Coding Type subfield, a UL UHR MCS subfield, a LL Flag subfield, a SS Allocation / RA-RU Information subfield, a UL Target Receive Power subfield, a Primary Secondary 160 MHz (PS160) subfield and a LL RU Allocation / Trigger Dependent User Info field. The new LL Flag subfield is set to 1 to indicate that the LL RU Allocation / Trigger Dependent User Info field contains LL RU allocation information of LL RU. The data transmitted on the LL RU reuses the non- LL data transmission parameters. Such LL Flag subfield was originally Reserved. The new LL Flag subfield is set to 0 to indicate that the final subfield, i.e., the LL RU Allocation / Trigger Dependent User Info subfield, is a Trigger Dependent User Info subfield.

[0154]

[0089] Figure 32 shows an exemplary PPDU where LL data arrives during the ongoing transmission of the PPDU according to the second embodiment of the present disclosure. In this example, the non-AP STA transmits the PPDU to the Relay, for example, after the Relay transmits a Trigger frame soliciting the UL transmission. The RU1 is allocated for transmitting non-LL data, i.e., non-LL A-MPDU, whereas RU2 is reserved for transmitting LL data. When no LL data arrives, no data is transmitted in the PPDU on the reserved RU2. When LL data arrives, the non-AP STA will determine whether the remaining frequency-time resource is enough for transmitting the LL data to the Relay. In this example, it is determined that the remaining frequency-time resource is enough for transmitting the LL data, therefore the non-AP STA starts transmitting the LL data 3202 in the PPDU on the LL RU (RU2) immediately after receiving the LL data. After the LL data 3202 has been transmitted on the LL RU, no data is transmitted in the PPDU on the LL RU.

[0155]

[0090] Figure 33 shows another exemplary PPDU where LL data arrives during the ongoing transmission of the PPDU according to the second embodiment of the present disclosure. In this example, the non-AP STA transmits the PPDU to the Relay, for example, after the Relay transmits a Trigger frame soliciting the UL transmission. The RU1 is allocated for transmitting non-LL data, i.e. , non-LL A-MPDU, whereas RU2 is reserved for transmitting LL data. When no LL data arrives, no data is transmitted in the PPDU on the reserved RU2. When LL data arrives, the non-AP STA will determine whether the remaining frequency-time resource is enough for transmitting the LL data to the Relay. In this example, it is determined that the remaining frequency-time resource is not enough for transmitting the LL data, therefore the non-AP STA may only transmit an LL indication 3302 in the PPDU on the LL RU (RU2) to the Relay. After the LL indication 3302 has been transmitted on the LL RU, no data is transmitted in the PPDU on the LL RU.

[0156]

[0091] It is noted that an A-MPDU delimiter format or the LL indication (sub)frame from the A- MPDU shown in Figures 17-18B and 21 may be reused as the format of the LL indication frame. Advantageously, the transmission of the non-LL A-MPDUs on the allocated RU1 is not affected by the arrival of LL data.

[0157]

[0092] According to the second embodiment of the present disclosure, if a third-party STA receives LL data for the AP during an ongoing transmission of non-LL data on the allocated non-LL RU by the non-AP STA, the LL data can be transmitted by the third-party STA on the LL RU to the Relay.

[0158]

[0093] Figure 34 shows still another exemplary schematic diagram 3400 illustrating an UL relay transmission procedure involving an AP, a Relay, a non-AP STA and a third-party STA according to the second embodiment of the present disclosure. After the relay setup phase is completed, the Relay sends a Trigger frame 3402 to the non-AP STA (STA1) and the third-party STA (STA2) to solicit UL relay transmission and specifying the non-LL RU and LL RU and, optionally, the transmission parameters for LL data. The format of the Trigger frame 3402 may be similar to that illustrated in Figure 27, where the AID12 subfield of User Info 1 field 2702 indicates the AID of STA1 , the RU Allocation subfield 2712 indicates RU1 as the RU for non-LL data transmission, and the LL RU Flag subfield 2714 is set to 0 to specify non-LL data transmission for STA1 ; whereas the AID12 subfield of User Info field 2704 indicates the AID of STA2 , RU Allocation subfield 2716 indicates the RU (e.g., RU2) reserved for LL data transmission, and the LL RU Flag subfield 2718 is set to 1 to specify LL data transmission for STA2. The RA field of the TF is set to broadcast address. No new

[0159] Trigger Type is defined and only the existing Basic Trigger type is reused in the Trigger frame 3402.

[0160]

[0094] STA1 then transmits an UHR PPDU 3404 with non-LL data on non-LL RU to the Relay, and with LL RL) reserved for LL data, i.e., no data is transmitted on the LL RL) if no LL data for the AP arrives. When LL data arrives at the third-party STA (STA2) during the ongoing data transmission of the UHR PPDU 3404 by the STA1 , STA2 will determine whether the remaining frequency-time resource is enough for transmitting the LL data to the Relay. In this example, it is determined that the remaining frequency-time resource is enough for transmitting the LL data, therefore STA2 may start transmitting the LL data 3406 on the LL RU (RU2) immediately after receiving the LL data. After the Relay receives the non-LL data, the Relay will transmit a BA frame to STA1 and STA2 to acknowledge receipt of the non-LL data and LL data. Subsequently, the Relay will first transmit the LL data to the AP. The AP will transmit a BA frame back to the Relay to confirm receipt of the LL data. The Relay then transmits the non-LL data after the LL data transmission, and the AP will transmit a BA frame back to the Relay to confirm receipt of the non-LL data.

[0161]

[0095] Figure 35 shows still another exemplary schematic diagram 3500 illustrating another UL relay transmission procedure involving an AP, a Relay, a non-AP STA and a third-party STA according to the second embodiment of the present disclosure. After the relay setup phase is completed, the Relay sends a Trigger frame 3502 to the non-AP STA (STA1 ) and the third-party STA (STA2) to solicit UL relay transmission and specifying the non-LL RU and LL RU and, optionally, the transmission parameters for LL data. The format of the T rigger frame 3502 may be similar to that illustrated in Figure 27, where the AID12 subfield of User Info 1 field 2702 indicates the AID of STA1 , the RU Allocation subfield 2712 indicates RU1 as the RU for non-LL data transmission, and the LL RU Flag subfield 2714 is set to 0 to specify non-LL data transmission for STA1 ; whereas the AID12 subfield of User Info field 2704 indicates the AID of STA2 , RU Allocation subfield 2716 indicates the RU (e.g., RU2) reserved for LL data transmission, and the LL RU Flag subfield 2718 is set to 1 to specify LL data transmission for STA2. The RA field of the TF is set to broadcast address. No new Trigger Type is defined and only the existing Basic Trigger type is reused in the Trigger frame 3402.

[0096] STA1 then transmits an UHR PPDU 3504 with non-LL data on non-LL RU to the Relay, and with LL RU reserved for LL data, i.e., no data is transmitted on the LL RU if no LL data for the AP arrives. When LL data arrives at the third-party STA (STA2) during the ongoing data transmission of the UHR PPDU 3504 by the STA1 , STA2 will determine whether the remaining frequency-time resource is enough for transmitting the LL data to the Relay. In this example, it is determined that the remaining frequency-time resource is not enough for transmitting the LL data, therefore STA2 may only transmit an LL indication 3506 on the LL RU (RU2) to the Relay. After the Relay receives the non-LL data with the LL indication 3506, the Relay will transmit a BA frame to STA1 to acknowledge receipt of the non-LL data and then a Trigger frame (TF) to STA2 to solicit the LL data. STA2 upon receipt of the Trigger frame then transmits the LL data to the Relay, and the Relay will transmit a BA frame back to STA2 to acknowledge receipt of the LL data. The Relay will then transmit the LL data to the AP. The AP will transmit a BA frame back to the Relay to confirm receipt of the LL data. The Relay then transmits the non-LL data after the LL data transmission, and the AP will transmit a BA frame back to the Relay to confirm receipt of the non-LL data.

[0162]

[0097] Alternatively, if there are LL Data arriving at multiple STAs, each non-AP STA may send the LL Indication in the Reserved RU immediately or to some pre-defined time slots in order to avoid collisions. Figure 36 shows still another exemplary schematic diagram 3600 illustrating yet another UL relay transmission procedure involving an AP, a Relay, a non-AP STA and a third-party STA according to the second embodiment of the present disclosure. After the relay setup phase is completed, the Relay sends a Trigger frame 3602 to the non-AP STA (STA1 ) and the third-party STA (STA2) to solicit UL relay transmission and specifying the non-LL RU and LL RU and, optionally, the transmission parameters for LL data. The format of the T rigger frame 3602 may be similar to that illustrated in Figure 27, where the AID12 subfield of User Info 1 field 2702 indicates the AID of STA1 , the RU Allocation subfield 2712 indicates RU1 as the RU for non-LL data transmission, and the LL RU Flag subfield 2714 is set to 0 to specify non-LL data transmission for STA1 ; whereas the AID12 subfield of User Info field 2704 indicates the AID of STA2 , RU Allocation subfield 2716 indicates the RU (e.g., RU2) reserved for LL data transmission, and the LL RU Flag subfield 2718 is set to 1 to specify LL data transmission for STA2. The RA field of the TF is set to broadcast address. No new

[0163] Trigger Type is defined and only the existing Basic Trigger type is reused in the Trigger frame 3602.

[0164]

[0098] STA1 then transmits an UHR PPDU 3604 with non-LL data on non-LL RU to the Relay, and with LL RL) reserved for LL data, i.e., no data is transmitted on the LL RL) if no LL data for the AP arrives. In this example, during the ongoing data transmission of the UHR PPDU 3604 by the STA1 , first LL data arrives at STA1 . STA1 will determine whether the remaining frequency-time resource is enough for transmitting the first LL data to the Relay. In this example, it is determined that the remaining frequency-time resource is not enough for transmitting the first LL data, therefore STA1 may only transmit a first LL indication 3606 on the LL RU (RU2) to the Relay. Subsequently, still during the ongoing data transmission of the UHR PPDU 3604 by the STA1 , second L data arrives at the third party STA (STA2). STA2 will then determine the remaining frequency-time resource is enough for transmitting the second LL data to the Relay. In this example, it is determined that the remaining frequency-time resource is not enough for transmitting the second LL data, therefore STA2 may only transmit a second LL indication 3608 on the LL RU (RU2) to the Relay. After the Relay receives the non-LL data with the LL indications 3606, 3608, the Relay will transmit a BA frame to STA1 to acknowledge receipt of the non-LL data and then a Trigger frame (TF) to STA2 to solicit the LL data. STA1 and STA2, upon receipt of the Trigger frame, then transmits the respective LL data to the Relay, in this case, STA1 and STA2 simultaneously transmit the respective LL data on different RUs (e.g., RU1 , RU2, or other Rus) to the Relay. The Relay will transmit a BA frame back to STA2 to acknowledge receipt of the LL data. The Relay will then transmit the LL data to the AP. The AP will transmit a BA frame back to the Relay to confirm receipt of the LL data. The Relay then transmits the non-LL data after the LL data transmission, and the AP will transmit a BA frame back to the Relay to confirm receipt of the non-LL data.

[0165]

[0099] Figure 37 shows another exemplary format of the Trigger frame 3700 in Figure 24 with multiple User Info fields and a specific format of User Info 1 field.

[0100] The Trigger frame (TF) 3700 may have a format analogous to that illustrated in Figure 27 and employed in the UL transmission procedures illustrated in Figures 34 and 35, except that there are three User Info fields (User Info field 1 3702, User Info field 2 3704, User Info field 3 3706) in the frame 3700. The first User Info field 3702 (User Info field 1 ) allocates RU1 for STA1 for transmission of non-LL data, the second User Info field 3704 (User Info field 2) allocates RU2 (LL RU) for STA1 for transmission of LL data received by STA1 and the third User Info field 3706 (User Info field 3) allocates RU2 (LL RU) for STA2 for transmission of LL data received by STA2. The RA field of the TF is set to broadcast address. Similarly, no new Trigger Type is defined and only the existing Basic Trigger type is reused in the Trigger frame 3602.

[0166]

[0101] The AID12 subfield 3712 of the first User Info field 3702 indicates the AID of STA1 , the RU Allocation subfield 3714 indicates RU1 as the RU for non-LL data transmission, and the LL RU Flag subfield 3716 is set to 0 to specify non-LL data transmission to STA1 .

[0167]

[0102] Figure 38A shows an exemplary specific format of User Info 2 field in Figure 37 while Figure 38B shows an exemplary specific format of User Info field 3 in Figure 37. The exemplary formats of User Info fields may solicit specifying LL data transmission parameters to be used by different non- AP STAs (STA1 , STA2). The User Info fields may be used as the second User Info field 3704 and the third User Info field 3706 of the Trigger frame 3702, used in the UL transmission procedure illustrated in Figure 36.

[0168]

[0103] The AID12 subfield 3802 in Figure 38A is set to the AID of STA1 , while the AID12 subfield 3812 of the User Info field 3706 in Figure 38B is set to the AID of STA2. Read together with Figure 37, the AID12 subfield 3802 may be the AID12 subfield of the User Info field 3704, and the AID12 subfield 3812 may be the AID12 subfield of the User Info field 3706. The RU Allocation subfields 3804 of the User Info field 3704 and the RU Allocation subfields 3814 of the User Info fields 3706 indicates the RU (e.g., RU2) as the RU for LL data transmission, and the LL RU Flag subfields 3806, 3816 are set to 1 to specify LL data transmission to STA 1 and STA 2, respectively.

[0104] Returning to Figure 36, after the Relay transmits the Trigger frame (TF) 3602, STA1 then transmits an UHR PPDU with non-LL data on non-LL RU to the Relay, and with LL RU reserved for LL data, i.e. , no data is transmitted on the LL RU if no LL data for the AP arrives.

[0169]

[0105] In this example, LL data first arrives at STA1 and then another LL data arrives at STA2 during the ongoing data transmission of the UHR PPDU 3604 by the STA1 . When LL data first arrive at STA1 , STA1 will determine whether the remaining frequency-time resource is enough for transmitting the LL data to the Relay. If the remaining frequency-time resource is enough for transmitting the LL data, STA1 may start transmitting the LL data on the LL RU (RU2) immediately after receiving the LL data (not shown); if, however, the remaining frequency-time resource is not enough for transmitting the LL data, STA1 may only transmit an LL indication 3604 on the LL RU (RU2) to the Relay, as shown in Figure 36. Similarly, when LL data arrives at the third-party STA (STA2) during the ongoing data transmission of the UHR PPDU 3604 by the STA1 , STA2 will determine whether the remaining frequency-time resource is enough for transmitting the LL data to the Relay. If the remaining frequency-time resource is enough for transmitting the LL data, STA2 may start transmitting the LL data on the LL RU (RU2) immediately after receiving the LL data (not shown); if, however, the remaining frequency-time resource is not enough for transmitting the LL data, STA2 may only transmit an LL indication 3608 on the LL RU (RU2) to the Relay, as shown in Figure 36. After the Relay receives the non-LL data, the Relay will first transmit a BA frame to confirm receipt of the LL data, and then a trigger frame to solicit the LL data. STA1 and STA2 then simultaneously transmit the LL data in different Rus to the Relay. The Relay will transmit a BA frame to acknowledge receipt of the LL data and transmit the LL data to the AP. The AP will transmit a BA frame back to the Relay to confirm receipt of the LL data. The Relay then transmits the non-LL data after the LL data transmission, and the AP will transmit a BA frame back to the Relay to confirm receipt of the non-LL data.

[0170]

[0106] A third embodiment of the present disclosure is described. In the third embodiment, a PPDU (herein may be referred to as “large PPDU”) is divided into multiple smaller PPDUs (herein may be referred to as “small PPDU”) with a pre-empted time gap introduced therebetween to allow LL data or LL indication to be transmitted from a non-AP STA to the Relay.

[0171]

[0107] Figure 39 shows an exemplary schematic diagram 3900 illustrating an UL data transmission procedure involving an AP, a Relay and a non-AP STA (STA1) according to the third embodiment of the present disclosure. In this embodiment, a PPDU (not shown) may be divided into three smaller PPDUs (TB PPDU 1 / 3, TB PPDU 2 / 3 and TB PPDU 3 / 3). The small PPDUs, TB PPDU 1 / 3, TB PPDU 2 / 3 and TB PPDU 3 / 3, are transmitted in sequence with a pre-configured time gap separating each adjacent small PPDU. The pre-configured gap between the small PPDUs is XIFS (PIFS, SIFS or SIFS+ a ps).

[0172]

[0108] In this example, LL traffic arrives during an ongoing transmission of the PPDU, specifically, after TB PPDU 1 / 3 has been transmitted and when TB PPDU 2 / 3 currently is being transmitted by STAI . STA1 may wait for the transmission of the current small PPDU (i.e., TB PPDU 2 / 3) to finish, and then after a pre-configured or pre-emption time gap, transmits the LL data to the Relay. The time gap between the LL data and small PPDU is SIFS or other IFS shorter than the pre-configured time gap. During SIFS, STA1 will determine whether the medium is idle, i.e., there is no other transmission to the Relay. If STA1 senses the medium is idle, it may start transmitting the LL data in SIFS. In this case, the non-AP STA may refrain the transmission of the remaining part of the PPDU, i.e., TB PPDU 3 / 3.

[0173]

[0109] The Trigger frame (TF) 3902 soliciting small PPDU contains the transmission parameters of both non-LL data and LL data. The TB PPDUs contain signalling that pre-emption is allowed, and no immediate BA from Relay is needed.

[0174]

[0110] The Relay may send a BA frame to STA1 for acknowledging successful receipt of LL data and then forwards the LL data to the AP. The AP sends BA to Relay after receiving the LL data, and then the Relay may send another Trigger frame to STA1 to solicit unfinished small PPDU transmission. STA1 may then transmit the unfinished small PPDU, i.e., TB PPDU 3 / 3, to the Relay.

[0111] Figure 40 shows an exemplary format of a Trigger frame 4000 according to the third embodiment of the present disclosure. The Trigger frame 4000 may solicit small PPDU, in particular its User Info fields. The Trigger frame 4000 may be used as the Trigger frame 3902 in the UL transmission procedure illustrated in Figure 39, and comprise a Frame Control field, a Duration field, a RA field, a TA field, a Common Information field, two User Information fields (User Info 1 field 4002, User Info 2 field 4004), a Padding field and a FCS field. The User Info 1 field 4002 of the Trigger frame 4000 is configured for STA1 to transmit non-LL data while the User Info field 4004 is configured for STA1 to transmit LL data.

[0175]

[0112] Each of the User Info fields 4002, 4004 comprises a AID12 subfield which is set to the AID of STA1 , a RU Allocation subfield, a UL FEC Coding Type subfield, a UL UHR MCS subfield, a LL Flag subfield, a SS Allocation subfield, a UL Target Receive Power subfield, a PS160 subfield and a Trigger Dependent User Info subfield. The LL Flag subfield of the User Info 1 field 4002 may be set to 0 to indicate that the User Info field is for non-LL data transmission parameters whereas the LL Flag subfield of the User Info 2 field 4004 may be set to 1 to indicate that the User Info field is for LL data transmission parameters. Such LL Flag was originally reserved.

[0176]

[0113] Figure 41 shows an exemplary format of a Common Info field 4100 of the Trigger frame 4000 of Figure 40 according to the third embodiment of the present disclosure. The Common Info field 4000 comprises a Trigger Type subfield, a UL Length subfield, a More TF subfield, a CS Required subfield, a UL BW subfield, a Guard Interval (Gl) And High Efficiency / Extremely High Throughput Long Training Field (HE / EHT-LTF) Type / Triggered TXOP Sharing Mode subfield, a Preemption Enable subfield 4102, a Number Of HE / EHT-LTF Symbols subfield, a LDPC Extra Symbol Segment subfield, an AP Tx Power subfield, a Pre-FEC Padding Factor subfield, a PE Disambiguity subfield, an UL Spatial Reuse subfield, a HE / EHT P160 subfield, a Special User Information Field Flag subfield, a EHT Reserved subfield, and a Trigger Dependent Common Information subfield. The new Preemption Enable subfield 4102 was changed from Reserved field, and may be set to 1 to indicate the STA to divide long non-LL PPDU into small PPDUs to enable Preemption and may be set to 0 to indicate otherwise.

[0177]

[0114] Figure 42 shows an exemplary small TB PPDU 4200 according to an embodiment of the present disclosure. The PPDU 4200 may include a Legacy Short Training Field (L-STF), a Legacy

[0178] Long Training Field (L-LTF), a Legacy SIGNAL (L-SIG) field, a Repeated L-SIG (RL-SIG) field, a Universal SIGNAL (U-SIG) field 4202 , a Ultra High Reliability SIGNAL (UHR-SIG) field, a UHR Short Training Field (UHR-STF), a UHR Long Training Field (UHR-LTF) and a Data field. There are two parts in the U-SIG field (U-SIG-1 and U-SIG-2).

[0179]

[0115] Table 2 shows bits and their exemplary corresponding fields in the two parts of U-SIG field of U-SIG field 4202 of the small TB PPDU 4200.

[0180] Table 2

[0181]

[0116] B20 and B21 of U-SIG 1 are changed from Disregard field to Pre-emption Enable field and End PPDU Flag field, respectively. The Pre-emption Enable field is set to 1 to indicate that the Preemption is enabled and is set to 0 otherwise. The End PPDU Flag field is set to 1 to indicate that the PPDU is the last small PPDU divided from the large PPDU and is set to 0 otherwise.

[0182]

[0117] Figure 43 shows another exemplary schematic diagram 4300 illustrating an UL data transmission procedure involving an AP, a Relay, a non-AP STA (STA1 ) and a third-party STA (STA2) according to the third embodiment of the present disclosure. After the Relay Setup phase, the Relay may transmit a new type of Trigger frame 4302 to STA1 and STA2. The format of the new Trigger frame is illustrated in Figure 44, which enables STA1 to send small TB PPDUs (e.g., TB PPDU 1 / 3, TB PPDU 2 / 3 and TB PPDU 3 / 3), and enables STA2 to send only when LL data arrives. The small PPDUs, for example TB PPDU 1 / 3, TB PPDU 2 / 3 and TB PPDU 3 / 3, are transmitted in sequence with a pre-emption time gap separating each adjacent small PPDU. The pre-configured gap between the small PPDUs is XIFS (PIFS, SIFS or SIFS+ a ps). The TB PPDU contains signaling that preemption is allowed, and no immediate BA from the Relay is needed.

[0183]

[0118] Figure 44 shows an example format of a Trigger frame 4400 according to the third embodiment of the present disclosure. The Trigger frame 4400 may be used as the Trigger frame 4302 in the UL relay transmission procedure illustrated in Figure 43.

[0184]

[0119] Returning to Figure 43, after STA1 transmits one small PPDU (e.g., TB PPDU 1 / 3), the STA1 will check if there is any signal transmission within XIFS time gap in the medium. If STA1 does not detect signal transmission within XIFS time gap in the medium, STA1 then continue to send the subsequent small PPDU (e.g., TB PPDU 2 / 3). If STA1 detect signal transmission within XIFS time gap in the medium (e.g., STA2 transmits LL data in SIFS or other IFS that is shorter than the XIFS after transmitting the small PPDU), then the STA1 refrains from transmitting the next small PPDU.

[0120] In this example, LL traffic arrives at the third-party STA (STA2) during an ongoing transmission of the PPDU by STA1 , specifically, after TB PPDU 1 / 3 has been transmitted and when TB PPDU 2 / 3 currently is being transmitted by STA1 . STA2 may wait for the transmission of the current small PPDU (i.e., TB PPDU 2 / 3) to finish, and then after a pre-configured time gap, transmits a LL indication to indicate the arrival of the LL data to the Relay. The time gap between the LL data and small PPDU is SIPS, which is shorter than XIFS.

[0185]

[0121] During SIPS, STA2 will determine whether the medium is idle, i.e., there is no other transmission to the Relay. If STA2 senses the medium is idle, it may start transmitting the LL indication to the Relay after SIFS is introduced. The format of the LL indication may be similar to CTS. In this case, STA1 may detect there is signal transmission within XIFS, and the medium is busy, thus refrain the transmission of the remaining part of the PPDU, i.e., TB PPDU 3 / 3, and waits for BA from the Relay.

[0186]

[0122] The Trigger frame soliciting small PPDU contains the transmission parameters of both non- LL data and LL data. The TB PPDUs contain signalling that pre-emption is allowed, and no immediate BA from Relay is needed.

[0187]

[0123] The Relay may send a BA frame to STA1 to confirm successful reception of the TB PPDU (part of the TB PPDU) after receiving the LL indication from STA2 and then transmits a Trigger frame to STA2 to solicit the UL LL data from STA2. STA2 then transmits the LL Data to the Relay. After successful reception of LL data, the Relay transmits a BA frame and then forwards the LL data to the AP. The AP sends BA to Relay after receiving the LL data, and then the Relay may send another Trigger frame to solicit unfinished small PPDU transmission. STA1 may then transmit the unfinished small PPDU, i.e., TB PPDU 3 / 3, to the Relay.

[0188]

[0124] Figure 44 shows another exemplary format of a Trigger frame 4400 soliciting UL transmission from a non-AP STA and specifying LL data transmission parameters to be used by the non-AP STA according to the third embodiment of the present disclosure. No new trigger type is defined. The Trigger frame 4400 may be similar to that shown in Figure 27, which comprises a Frame

[0189] Control field, a Duration field, a RA field, a TA field, a Common Information field, one or more User

[0190] Information field (in this example, User Info 1 field 4402 specify the LL data transmission parameters), a Padding field and a FCS field. Each User Info field comprises a AID12 subfield, a RU Allocation subfield, a UL FEC Coding Type subfield, a UL UHR MCS subfield, a Pre-emption Flag subfield 4404, a SS Allocation subfield, a UL Target Receive Power subfield, a PS160 subfield and a Trigger Dependent User Info subfield. The Pre-emption Flag subfield 4404 was changed from Reserved field, and is set to 1 to indicate the STA which AID matches the AID12 subfield divides the long PPDU into mall PPDUs to enable Pre-emption and it set to 0 to indicate the STA which AID matches the AID12 is a potential receiver of LL data and the STA does not send data immediately and waits for LL data and send LL indication instead.

[0191]

[0125] According to the following paragraphs, a fourth embodiment of the present disclosure is described, where a LL indication is transmitted by a non-AP STA to the Relay to indicate the arrival of LL data and a Trigger frame is transmitted by a Relay to solicit the LL data from the non-AP STA.

[0192]

[0126] Figure 45 shows an exemplary schematic diagram 4500 illustrating an UL data transmission procedure involving an AP, a Relay and a non-AP STA (STA1 ) according to the fourth embodiment of the present disclosure. After Relay Setup phase, a Data Relay Phase 1 between the Relay and STA1 is carried out. The Relay transmits a Trigger frame 4502 to solicit UL transmission, and STA1 transmits an PPDU 4504 comprising data to the Relay. During the ongoing transmission by STA1 , LL data for AP arrives and an LL indication is inserted into the PPDU 4504 through any of the embodiments described above. The Relay transmits a BA frame 4506 to STA1 to acknowledge receipt of the data and then transmits another Trigger frame 4508 to solicit a LL UHR TB PPDU comprising the LL data from STA1 . Such Trigger frame type may be a Basic Trigger frame and may contain information about solicited UL LL PPDU length and specify the transmission parameters of LL UHR TB PPDU to be used by the STA. STA1 upon receipt the Trigger frame 4508 transmits a LL UHR TB PPDU 4510 comprising the LL data. The preamble of the LL UHR TB PPDU 4510 contains indication of LL data so that the AP can differentiate it with non-LL PPDU 4504. After which, a Data Relay Phase 2 between the Relay and AP is carried out.

[0193]

[0127] Figure 46 shows an exemplary format of a Trigger frame 4600 for soliciting an LL UHR TB PPDU according to the fourth embodiment of the present disclosure. The Trigger frame 4600 may be used as the Trigger frame 4508 in the UL transmission procedure illustrated in Figure 48 to solicit an LL UHR TB PPDU from STA1 after receiving an LL indication in the PPDU 4504. The Trigger frame 4600 comprises a Frame Control field, a Duration field, a RA field, a TA field, a Common Info field 4602, a User Info field 4604, a Padding field and a FCS field.

[0194]

[0128] The User Info field 4604 comprises a AID12 subfield, a RU Allocation subfield, a UL FEC Coding Type subfield, a UL UHR-MCS subfield, a SS Allocation / RA-RU Information subfield, a UL Target Receive Power subfield, a PS160 subfield and a Trigger Dependent User Info subfield.

[0195]

[0129] Figure 47 shows an exemplary format of a Common Info field 4700 of the Trigger frame 4600 in Figure 46. The Common Info field 4700 comprises a Trigger Type subfield, a UL Length subfield, a More TF subfield, a CS Required subfield, a UL BW subfield, a Guard Interval (Gl) And High Efficiency / Extremely High Throughput Long Training Field (HE / EHT-LTF) Type / Triggered TXOP Sharing Mode subfield, a LL Flag subfield 4702, a Number Of HE / EHT-LTF Symbols subfield, a LDPC Extra Symbol Segment subfield, an AP Tx Power subfield, a Pre-FEC Padding Factor subfield, a PE Disambiguity subfield, an UL Spatial Reuse subfield, a UHR P160 subfield 4704, a Special User Information Field Flag subfield, a UHR Reserved subfield, and a Trigger Dependent Common Information subfield. The new LL Flag subfield 4702 is set to 1 to indicate soliciting the LL data and is set to 0 otherwise. The LL Flag subfield 4702 was originally reserved. The UL Length subfield 4704 indicates the LL PPDU length, and the AID12 subfield 4606 in the User Info field 4604 is set to the AID of the STA that sent the LL indication.

[0196]

[0130] Figure 48 shows an exemplary LL UHR TB PPDU 4800 according to the fourth embodiment of the present disclosure. The LL UHR TB PPDU 4800 may include a L-STF, a L-LTF, a L-SIG field, a RL-SIG field, a U-SIG field 4802, a UHR-SIG field, a UHR-STF, a UHR-LTF, a Data field and a PE field. There are two parts in the U-SIG field (U-SIG 1 and U-SIG 2).

[0197]

[0131] Table 3 shows bits and their exemplary corresponding fields in the two parts of U-SIG field in the U-SIG field 4802 of the LL UHR TB PPDU 4800.

[0198] Table 3

[0132] The LL Flag subfield as indicated in B20 of the U-SIG-1 of U-SIG field was originally reserved. The non-AP STA uses full bandwidth (as indicated in B3-B5 of the U-SIG-1 of U-SIG field) to transmit LL PPDU, and set LL Flag field (as indicated in B20 of the U-SIG-1 of U-SIG field) to indicate that it is a LL PPDU, and 0 otherwise. This helps AP to differentiate between non-LL PPDU and LL PPDU. The Relay prioritizes LL PPDU transmission over non-LL PPDU transmission.

[0133] Figure 49 shows another exemplary schematic diagram 4900 illustrating a UL data transmission procedure involving an AP, a Relay and a non-AP STA according to the fourth embodiment of the present disclosure. After Relay Setup phase, a Data Relay Phase 1 between the Relay and STA1 is carried out. The Relay transmits a Trigger frame 4902 to solicit UL transmission, and STA1 transmits an PPDU 4904 comprising data to the Relay. During the ongoing transmission by STA1 , LL data for AP arrives and an LL indication is inserted into the PPDU 4904 through any of the embodiments described above. In this example, when receiving LL indication, the Relay may transmit a single PPDU 4906 containing a BA frame and a Trigger frame to STA1 to acknowledge receipt of the data and to solicit a LL UHR TB PPDU comprising the LL data from STA1 . A-MPDU containing a BA frame and a Trigger frame may be used. If MU cascading sequence is supported, the MU cascading structure multiplexing BA and a Trigger frame may be used. STA1 sends the LL data after receiving the single PPDU 4904. After which, a Data Relay Phase 2 between the Relay and AP is carried out.

[0199]

[0134] Alternatively, instead of a single PPDU, a BA frame may be modified with Basic Trigger function so that the BA and basic T rigger frame are combined. Figure 50 shows a schematic diagram 5000 illustrating yet another UL data transmission procedure involving an AP, a Relay and a non-AP STA according to the fourth embodiment of the present disclosure. In this example, when receiving LL indication, the Relay may transmit a BA frame 5006 with basic trigger function (herein may be referred to as “BlockAck + Trigger frame”) to acknowledge receipt of the data and to solicit a LL UHR TB PPDU comprising the LL data from STAI . STA1 sends the LL data after receiving the BA + Trigger frame 5006.

[0200]

[0135] Figure 51 shows an exemplary format of a frame 5100 according to the fourth embodiment of the present disclosure. The frame 5100 may be BlockAck + Trigger frame 5100, which may be used as the BlockAck + Trigger frame 5006 to acknowledge receipt of the data and to solicit a LL UHR TB PPDU comprising the LL data from STAI . The BlockAck + Trigger frame 5100 may comprise a Frame Control field, a Duration field, a RA field, a TA field, a BA Control field, a BA Information field and a FCS field. The BA Control field comprises a Trigger Flag field, a BA Type field, a No Memory Kept field, a Memory Configuration Tag field, a Management Ack field and a TID INFO field. The Trigger Flag field was changed from reserved. The Trigger Flag field is set to 1 so that the BA frame has Trigger function, which reuses the same information as previous Basic Trigger. The Non-AP STA receives such BA + Trigger frame 5100 will send TB PPDU the same was as being triggered by Basic Trigger frame. If Trigger Flag is set to 0, the BA frame becomes a normal BA frame without Trigger function.

[0201]

[0136] According to the following paragraphs, a fifth embodiment of the present disclosure relating to a Data Relay Phase 2 subsequent to the Relay Setup phase and Data Relay Phase 1 between a non-AP Sta and the Relay, during which LL data are transmitted by a Relay to the AP, is described.

[0202]

[0137] In this embodiment, after the Relay receives both LL data and non-LL data, the Relay may differentiate the LL data by signaling in the PPDU preamble, and forwards the LL data prior to or concurrent with non-LL data. After successfully sending both LL data and non-LL data, the Relay my decide whether to send a Trigger frame to STA1 soliciting remaining unsent non-LL data or discard the unsent non-LL data.

[0203]

[0138] Figure 52 shows an exemplary schematic diagram 5200 illustrating a UL data transmission procedure involving an AP, a Relay and a non-AP STA (STA1 ) according to the fifth embodiment of the present disclosure. After Relay Setup Phase and Data Relay Phase 1 where the Relay has received both LL data and non-LL data, the Relay forwards a PPDU comprising the LL data to the AP, prior to non-LL data. A SIFS is introduced before the AP transmits a BA frame to acknowledge receipt of the LL data, and subsequent to another SIFS, the Relay then transmits the non-LL data to the AP. The AP transmits another BA frame to acknowledge receipt of the non-LL data.

[0204]

[0139] After yet another SIFS is ensued, the Relay then sends a Trigger frame to solicit UL transmission, e.g., unsent non-LL data, from STA1 .

[0140] Figure 53 shows an exemplary schematic diagram 5300 illustrating a Relay Setup Phase of an UL data transmission procedure involving an AP, a Relay and a non-AP STA (STA) according to the fifth embodiment of the present disclosure. Prior to the Data Relay Phases, during Relay Setup Phase, TXOP sharing may be used to share TXOP. When the AP obtains the TXOP, the AP transmits a MU-RTS TXS frame after a CS-to-self frame to the Relay to share the TXOP to the Relay. The term “Relay Setup Phase” may be used interchangeably with “TXOP Sharing Phase”.

[0205]

[0141] Figure 54 shows an exemplary format of a MU-RTS TXS frame 5400 according to the fifth embodiment of the present disclosure. The MU-RTS TXS frame 5400 may be used in the Relay Setup Phase illustrated in Figure 53 to share TXOP. The MU-RTS TXS frame 5400 comprises a Frame Control field, a Duration field, a RA field, a TA field, a Common Info field, a User Info field 5402, a Padding field and a FCS field. The User Info field comprises a AID12 subfield, a RU Allocation subfield, an Allocation Duration subfield, a LL Pre-emption Enable subfield 5404 and a PS160 subfield. The Common field comprises a TXOP Sharing Mode subfield (not shown) which was Reserved. The TXOP Sharing Mode subfield may be set to 0 to indicate a MU-RTS that does not initiate TXS procedure; 1 to indicate MU-RTS that initiates TXS procedure wherein a scheduled STA can only transmit MPDU(s) addressed to its associated AP; 2 to indicate MU-RTS that initiates TXS procedure wherein a scheduled STA can transmit MPDU(s) addressed to its associated AP or addressed to another STA; and 3 to indicate MU-RTS that initiates TXS procedure wherein a scheduled STA ca transmit MPDU(s) addressed to its associated AP or addressed to other STAs. Returning to Figures 53 and 54, the TXOP Sharing Mode subfield of the Common Info field of the MU-RTS TXS is set to 3 to indicate MU-RTS that initiates TXS procedure wherein a scheduled STA can transmit MPDU(s) addressed to its associated AP or addressed to other STAs, so that the Relay can transmit to both AP and non-AP STA(s). In the User Info field 5402, the LL Pre-emption Enabled subfield 5404 was changed from reserved and is set to 1 to indicate the Relay device relay LL data prior to or concurrent with non-LL data.

[0142] Alternatively or additionally, the Relay may be notified of the STA(s)’s AID by the AP using a new information element (e.g., Relay notification element) during the TXOP Sharing Phase.

[0206]

[0143] Figure 55 shows another exemplary schematic diagram 5500 illustrating a UL data transmission procedure involving an AP, a Relay and a non-AP STA (STA1 ) according to the fifth embodiments of the present disclosure. In this implementation, after a CS-to-self frame is transmitted and before the MU-RTS TXS frame is transmitted by the AP to the Relay to share the TXOP during the Relay Setup Phase (or TXOP Sharing phase), the AP may transmit a Relay notification element 5502 to the Relay to notify the Relay of STATs AID, and the Relay may sends an Ack frame back to the AP to acknowledge receipt of the information element 5502.

[0207]

[0144] Figure 56 shows an exemplary format of a Relay notification element 5600 according to the fifth embodiment of the present disclosure. The Relay notification element 5600 may be used the one 5502 used in the UL data transmission procedure illustrated in Figure 55 to notify the Relay of the non-AP STA’s AID. The Relay notification element 5600 comprises an Element ID field, a Length field, an Element ID Extension field and one or more STA AID fields. The Element ID field may be set to 255, Element ID Extension field may be set to 1 17, which was Reserved element. Each of the one or more STA AID fields indicates the AID of one non-AP STA.

[0208]

[0145] Figure 57 shows yet another exemplary schematic diagram 5700 illustrating a UL data transmission procedure involving an AP, a Relay and a non-AP STA (STA1 ) according to the fifth embodiment of the present disclosure. The UL data transmission procedure consists of a Relay Setup Phase, a Data Relay Phase 1 and Data Relay Phase 2, and are carried out within the AP’s TXOP 5702. The procedure may start by AP transmitting a CTS-to-self frame and a MU-RTS TXS frame to the Relay to share a part 5704 of its TXOP (herein referred to as “shared TXOP”). The Relay is configured to complete the relay of the UL transmission from the non-AP STA to the AP including the transmission of LL data (if any) within the shared TXOP.

[0146] The shared TXOP 5704 may start after the AP transmits the MU-RTS TXS frame and the Relay transmits a CTS frame back to the AP. Subsequently, the Relay transmits a Trigger frame to STA1 to solicit UL transmission. Following a SIFS, STA1 then transmits a PPDU comprising (non- LL) data to the Relay. During the ongoing transmission, LL data for the AP may arrive at STA1 . STA1 may check if the remaining transmission time (resource) is enough for LL data transmission. If the remaining transmission time (resource) is enough, STA1 insert the LL data to the PPDU to the Relay so that the LL data is sent directly. Once the PPDU with the LL data is transmitted, subsequent to a SIFS, the Relay sends a BA frame to acknowledge receipt of the (non-LL) data. After another SIFS is ensued, the Relay prioritizes the transmission of the LL data and forwards the LL data first to the AP. Following another SIFS, the AP transmits a BA frame to acknowledge receipt of the LL data. Subsequently, after receiving acknowledgement of successful reception, the Relay then sends the original non-LL data to the AP after another SIFS is ensued, all within or by the end of the shared TXOP 5604.

[0209]

[0147] Figure 58 shows yet another exemplary schematic diagram 5800 illustrating an UL data transmission procedure involving an AP, a Relay and a non-AP STA (STA1 ) according to the fifth embodiment of the present disclosure. In this example, STA1 may check and determine that the remaining transmission time (resource) is not enough for LL data transmission, and insert an LL indication, as opposed to the LL data, to indicate the arrival of the LL data in the PPDU to the Relay. Following a SIFS, the Relay sends a BA frame to STA1 to acknowledge receipt of the (non-LL) data. Subsequent to another SIFS, the Relay then transmits a Trigger frame to solicit the LL data from STA1 , and STA1 transmits the LL data after a SIFS ensues upon receipt of the Trigger frame. The Relay sends another BA frame to STA1 to acknowledge receipt of the LL data. Following another SIFS, the Relay prioritizes the transmission of the LL data and forwards the LL data first to the AP. subsequent to a SIFS, the AP transmits a BA frame to the Relay to acknowledge receipt of the LL data. Subsequently, after receiving acknowledgement of successful reception, the Relay then sends the original non-LL data to the AP after another SIFs is ensued, all within or by the end of the shared

[0210] TXOP.

[0148] According to the present disclosure, an A-MPDU may consist of a sequence of one or more A-MPDU subframes and a variable amount of EOF Padding. Each A-MPDU subframe may consist of an MPDU delimiter optionally followed by an MPDU. Figure 59 shows an exemplary A-MPDU frame structure 5900 according to an embodiment of the present disclosure. The A-MPDU frame may comprise n A-MPDU subframes and a EOF padding field 5902. Each of the A-MPDU subframe may comprise a MPDU delimiter subfield, a MPDU subfield and a Padding field. The MPDU Delimiter subfield further comprises an EOF subfield, a MPDU Length subfield, a ORC subfield and a Delimiter Signature subfield. The EOF Padding field 5902 comprises EOF Padding subframes subfield 5904 and EOF Padding Octets. The EOF Padding subframes subfield 5904 contains zero or more EOF padding subframes. Figure 60 shows an exemplary EOF Padding subframe 6000 of an EOF Padding subframes subfield of an EOF Padding field in the A-MPDU frame in Figure 59. The EOF Padding subframe 6000 has a similar format as a A-MPDU subframe shown in Figure 60 except that the EOF Padding subframe 6000 is an A-MPDU subframe with 0 in the MPDU Length field and 1 in the EOF field.

[0211]

[0149] Figure 61 shows an exemplary format of an EHT Trigger frame 6100 according to an embodiment of the present disclosure. This EHT Trigger frame may be used in as one of the Trigger frames described in the above embodiments. The EHT Trigger frame 6100 comprises a Frame Control field, a Duration field, a RA field, a TA field, a Common Info field 6102, a User Info List field 6104, a Padding field and a FCS field. The User Info List may comprise a EHT variant User Info field and / or a Special User Info field.

[0212]

[0150] Figure 62A shows an exemplary format of a EHT variant User Info field 6200 that is applicable to User Info List in Figure 61. The EHT variant User Info field 6200 may comprise a AID12 subfield, a RU Allocation subfield, a UL FEC Coding Type subfield, a UL EHT-MCS subfield, a SS Allocation / RA-RU Information subfield, a UL Target Receive Power subfield, a PS160 subfield and a Trigger Dependent User Info subfield. Figure 62B shows another exemplary format of a Special User Info field 6210 that is applicable to User Info List in Figure 61 . The Special User Info field 6210 may comprise a AID12 subfield, a RPHY Version Identifier subfield, a UL BW Extension subfield, a EHT Spatial Reuse 1 subfield, a EHT Spatial Reuse 2 subfield, a U-SIG Disregard And Validate subfield and a Trigger Dependent User Info subfield.

[0213]

[0151] Figure 63 shows an exemplary format of a Common Info field 6300 that is applicable to Common Info in Figure 61. The Common Info field 6300 comprises a Trigger Type subfield, a UL Length subfield, a More TF subfield, a CS Required subfield, a UL BW subfield, a Gl And HE / EHT- LTF Type / Triggered TXOP Sharing Mode subfield, a LL Flag subfield, a Number Of HE / EHT-LTF Symbols subfield, a LDPC Extra Symbol Segment subfield, an AP Tx Power subfield, a Pre-FEC Padding Factor subfield, a PE Disambiguity subfield, an UL Spatial Reuse subfield, a HE / EHT P160 subfield, a Special User Information Field Flag subfield, a EHT Reserved subfield, and a Trigger Dependent Common Info subfield.

[0214]

[0152] 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.

[0153] 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.

[0215]

[0154] 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.

[0216]

[0155] 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)”.

[0217]

[0156] The communication may include exchanging data through, for example, a cellular system, a wireless LAN system, a satellite system, etc., and various combinations thereof.

[0218]

[0157] 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.

[0219]

[0158] 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.

[0159] 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.

[0220]

[0160] In the following paragraphs, certain exemplifying embodiments are explained with reference to terms related to wireless communication and the present disclosure regarding communication apparatuses and methods for uplink low latency transmission in relay operation, namely:

[0221] 1 . A first communication apparatus comprising: circuitry, which in operation, is configured to detect a receipt of data of a first traffic type during a transmission of a signal comprising one or more frames of a second traffic type to a second communication apparatus on a first resource of a plurality of resources allocated for the transmission of the signal; and a transmitter, which in operation, transmits one of (i) the data of the first traffic type and (ii) an indication of the receipt of the data of the first traffic type to the second communication apparatus on a second resource of the plurality of resources.

[0222] 2. The first communication apparatus of example 1 , wherein the receipt of the data of the first traffic type is detected during a transmission of a first frame of the signal, and the circuitry is configured to further determine whether a first remaining resource of the plurality of resources after the transmission of the first frame is sufficient for transmitting the data of the first traffic type; and the transmitter transmits the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type on the first remaining resource in response to a result of the determination.

[0223] 3. The first communication apparatus of example 3, wherein the circuitry is configured to further: refrain a second frame of the second traffic type of the signal subsequent to the first frame from transmitting to the second communication apparatus on the first remaining resource after the transmission of the first frame; and insert a third frame comprising the one of (i) the data of first traffic type and (ii) the indication of the receipt of the data of the first traffic type into the signal such that the transmitter transmits the third frame through the signal after the transmission of the first frame.

[0224] 4. The first communication apparatus of example 4, wherein the circuitry is configured to further determine if a second remaining resource of the plurality of resources after the transmission of the third frame is sufficient for transmitting the second frame; and the transmitter transmits the second frame through the signal after the transmission of the third frame on the second remaining resource in response to determining that the second remaining resource is sufficient.

[0225] 5. The first communication apparatus of example 1, wherein the signal comprises two or more smaller signals, the two or more smaller signals being transmitted one after another after every first pre-configured time frame, and the receipt of the data of the first traffic type is detected during a transmission of one of the two or more smaller signals; the transmitter transmits a second signal comprising the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type on a third remaining resource of the plurality of resources after a second pre-configured time frame to the second communication apparatus based on the result of the detection.

[0226] 6. The first communication apparatus of example 5, wherein the circuitry is configured to detect whether there is a transmission of another signal to the second communication apparatus within the first pre-configured time frame after the one of the two or more smaller signals is transmitted, and refrain another one of the two or more smaller signals subsequent to the one of the two or more smaller signals from transmitting to the second communication apparatus after the first pre-configured time frame in response to the detection of the transmission of the another signal.

[0227] 7. The first communication apparatus of example 6, further comprising: a receiver, which in operation, receives a block acknowledgment frame from the second communication apparatus; wherein the transmitter transmits the another one of the two or more smaller signals after receiving the block acknowledgement frame.

[0228] 8. The first communication apparatus of example 1, further comprising: a receiver, which in operation, receives from the second communication apparatus a trigger frame comprising information of an allocation of the second resource prior to the transmission of the signal.

[0229] 9. The first communication apparatus of example 8, wherein the trigger frame further comprises transmission parameters of the data of the first traffic type, and the transmitter transmits the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type using the transmission parameters.

[0230] 10. The first communication apparatus of example 8, wherein the circuitry receives an information element comprising the information of the allocation of the second resource prior to the transmission of the signal; and the trigger frame comprises information signaling that the second resource allocated by the information element is enabled for transmitting the data of the first traffic type.

[0231] 11 . The first communication apparatus of any one of example 1-6, wherein the transmitter transmits the indication of the receipt of the data of the first traffic type on the second resource, the first communication apparatus further comprises: a receiver, which in operation, receives a trigger frame soliciting the data of the first traffic type, the trigger frame comprising transmission parameters of the data of the first traffic type; and the transmitter transmits a third signal comprising the data of the first traffic type to the second communication apparatus using the transmission parameters upon receiving the trigger frame.

[0232] 12. The first communication apparatus of example 11, wherein the receiver receives a fourth signal comprising the trigger frame and a block acknowledgement frame indicating a successful reception of the first signal; and the transmitter transmits the third signal upon receiving the fourth signal.

[0233] 13. A second communication apparatus comprising: a receiver, which in operation, receives, one of (i) data of a first traffic type and (ii) an indication of a receipt of the data of the first traffic type from a first communication apparatus on a second resource of a plurality of resources allocated for a signal after receiving at least a part of the signal on a first resource of the plurality of resources; circuitry, which in operation, is configured to process the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type.

[0234] 14. The second communication apparatus of example 13, wherein the circuity is configured to further determine that the indication of the receipt of the data of the first traffic type is received, and the second communication apparatus further comprises: a transmitter, which in operation, transmits a trigger frame soliciting the data of the first traffic type to the first communication apparatus.

[0235] 15. The second communication apparatus of example 14, wherein the transmitter transmits a fourth signal comprising the trigger frame and a block acknowledgement frame indicating a successful reception of the first signal.

[0236] 16. The second communication apparatus of example 13, further comprising: a transmitter, which in operation, transmits a second trigger frame comprising information of an allocation of the second resource or information signaling that the second resource allocated by an information element is enabled for transmitting the data of the first traffic type prior to the transmission of the signal.

[0237] 17. The second communication apparatus of example 16, wherein the trigger frame further comprises transmission parameters of the data of the first traffic type.

[0238] 18. The second communication apparatus of claim 16 or 17, wherein the trigger frame signals (i) a transmission of the first signal comprising two or more smaller signals, the two or more smaller signals being transmitted one after another after every first pre-configured time frame, and (ii) a transmission of the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type by the first communication apparatus after a second pre-configured time frame after one of the two or more smaller signals is transmitted if the first communication apparatus detects a receipt of the data of the first traffic type during a transmission of the one of the two or more smaller signals.

[0239] 19. The second communication apparatus of example 13, wherein the circuitry is configured to identify the data of the first traffic type from the first signal; the second communication apparatus further comprises: a transmitter, which in operation, transmits the data of the first traffic type prior to or concurrent with data of the first signal to a third communication apparatus.

[0240] 20. The second communication apparatus of example 19, wherein the receiver receives from the third communication apparatus a trigger frame comprising a first signal field signaling one of (i) a transmission of the data of the first traffic type prior to the data of the first signal and (ii) a transmission of the data of the first traffic type concurrent with the data of the first signal, and the transmitter performs the one of (i) the transmission of the data of the first traffic type prior to the data of the first signal and (ii) the transmission of the data of the first traffic type concurrent with the data of the first signal. 21 . The second communication apparatus of example 20, wherein the trigger frame further comprises a second signal field indicating an available time period shared by the third communication apparatus during which the second communication apparatus is allowed to transmit signals to the third communication apparatus and the first communication apparatus so as to receive the one of (i) the data of a first traffic type and (ii) the indication of a receipt of the data of the first traffic type from the first communication apparatus and to transmits the data of the first traffic type to the third communication apparatus.

[0241] 22. A communication method implemented by a first communication apparatus comprising: detecting a receipt of data of a first traffic type during a transmission of a signal comprising one or more frames of a second traffic type to a second communication apparatus on a first resource of a plurality of resources allocated for the transmission of the signal; and transmitting one of (i) the data of the first traffic type and (ii) an indication of the receipt of the data of the first traffic type to the second communication apparatus on a second resource of the plurality of resources.

[0242] 23. A communication method implemented by a second communication apparatus comprising: receiving one of (i) data of a first traffic type and (ii) an indication of a receipt of the data of the first traffic type from a first communication apparatus on a second resource of a plurality of resources allocated for a signal after receiving at least a part of the signal on a first resource of the plurality of resources; processing the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type.

[0243]

[0161] 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 first communication apparatus comprising: circuitry, which in operation, is configured to detect a receipt of data of a first traffic type during a transmission of a signal comprising one or more frames of a second traffic type to a second communication apparatus on a first resource of a plurality of resources allocated for the transmission of the signal; and a transmitter, which in operation, transmits one of (i) the data of the first traffic type and (ii) an indication of the receipt of the data of the first traffic type to the second communication apparatus on a second resource of the plurality of resources.

2. The first communication apparatus of claim 1 , wherein the receipt of the data of the first traffic type is detected during a transmission of a first frame of the signal, and the circuitry is configured to further determine whether a first remaining resource of the plurality of resources after the transmission of the first frame is sufficient for transmitting the data of the first traffic type; and the transmitter transmits the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type on the first remaining resource in response to a result of the determination.

3. The first communication apparatus of claim 3, wherein the circuitry is configured to further: refrain a second frame of the second traffic type of the signal subsequent to the first frame from transmitting to the second communication apparatus on the first remaining resource after the transmission of the first frame; and insert a third frame comprising the one of (i) the data of first traffic type and (ii) the indication of the receipt of the data of the first traffic type into the signal such that thetransmitter transmits the third frame through the signal after the transmission of the first frame.

4. The first communication apparatus of claim 4, wherein the circuitry is configured to further determine if a second remaining resource of the plurality of resources after the transmission of the third frame is sufficient for transmitting the second frame; and the transmitter transmits the second frame through the signal after the transmission of the third frame on the second remaining resource in response to determining that the second remaining resource is sufficient.

5. The first communication apparatus of claim 1 , wherein the signal comprises two or more smaller signals, the two or more smaller signals being transmitted one after another after every first pre-configured time frame, and the receipt of the data of the first traffic type is detected during a transmission of one of the two or more smaller signals; the transmitter transmits a second signal comprising the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type on a third remaining resource of the plurality of resources after a second pre-configured time frame to the second communication apparatus based on the result of the detection.

6. The first communication apparatus of claim 5, wherein the circuitry is configured to detect whether there is a transmission of another signal to the second communication apparatus within the first pre-configured time frame after the one of the two or more smaller signals is transmitted, and refrain another one of the two or more smaller signals subsequent to the one of the two or more smaller signals from transmitting to the second communication apparatus after the first pre-configured time frame in response to the detection of the transmission of the another signal.

7. The first communication apparatus of claim 6, further comprising: a receiver, which in operation, receives a block acknowledgment frame from the second communication apparatus; wherein the transmitter transmits the another one of the two or more smaller signals after receiving the block acknowledgement frame.

8. The first communication apparatus of claim 1 , further comprising: a receiver, which in operation, receives from the second communication apparatus a trigger frame comprising information of an allocation of the second resource prior to the transmission of the signal.

9. The first communication apparatus of claim 8, wherein the trigger frame further comprises transmission parameters of the data of the first traffic type, and the transmitter transmits the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type using the transmission parameters.

10. The first communication apparatus of any one of claims 1-6, wherein the transmitter transmits the indication of the receipt of the data of the first traffic type on the second resource, the first communication apparatus further comprises: a receiver, which in operation, receives a trigger frame soliciting the data of the first traffic type, the trigger frame comprising transmission parameters of the data of the first traffic type; and the transmitter transmits a third signal comprising the data of the first traffic type to the second communication apparatus using the transmission parameters upon receiving the trigger frame.

11. The first communication apparatus of claim 10, wherein the receiver receives a fourth signal comprising the trigger frame and a block acknowledgement frame indicating a successful reception of the first signal; andthe transmitter transmits the third signal upon receiving the fourth signal.

12. A second communication apparatus comprising: a receiver, which in operation, receives, one of (i) data of a first traffic type and (ii) an indication of a receipt of the data of the first traffic type from a first communication apparatus on a second resource of a plurality of resources allocated for a signal after receiving at least a part of the signal on a first resource of the plurality of resources; circuitry, which in operation, is configured to process the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type.

13. The second communication apparatus of claim 12, wherein the circuity is configured to further determine that the indication of the receipt of the data of the first traffic type is received, and the second communication apparatus further comprises: a transmitter, which in operation, transmits a trigger frame soliciting the data of the first traffic type to the first communication apparatus.

14. The second communication apparatus of claim 13, wherein the transmitter transmits a fourth signal comprising the trigger frame and a block acknowledgement frame indicating a successful reception of the first signal.

15. The second communication apparatus of claim 12, further comprising: a transmitter, which in operation, transmits a second trigger frame comprising information of an allocation of the second resource or information signaling that the second resource allocated by an information element is enabled for transmitting the data of the first traffic type prior to the transmission of the signal.

16. The second communication apparatus of claim 15, wherein the trigger frame signals (I) a transmission of the first signal comprising two or more smaller signals, the two or more smaller signals being transmitted one after another after every first pre-configured time frame, and (ii) a transmission of the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type by the first communication apparatus after a second pre-configured time frame after one of the two or more smaller signals is transmitted if the first communication apparatus detects a receipt of the data of the first traffic type during a transmission of the one of the two or more smaller signals.

17. The second communication apparatus of claim 12, wherein the circuitry is configured to identify the data of the first traffic type from the first signal; the second communication apparatus further comprises: a transmitter, which in operation, transmits the data of the first traffic type prior to or concurrent with data of the first signal to a third communication apparatus.

18. The second communication apparatus of claim 17, wherein the receiver receives from the third communication apparatus a trigger frame comprising a first signal field signaling one of (i) a transmission of the data of the first traffic type prior to the data of the first signal and (ii) a transmission of the data of the first traffic type concurrent with the data of the first signal, and the transmitter performs the one of (i) the transmission of the data of the first traffic type prior to the data of the first signal and (ii) the transmission of the data of the first traffic type concurrent with the data of the first signal.

19. A communication method implemented by a first communication apparatus comprising: detecting a receipt of data of a first traffic type during a transmission of a signal comprising one or more frames of a second traffic type to a second communicationapparatus on a first resource of a plurality of resources allocated for the transmission of the signal; and transmitting one of (i) the data of the first traffic type and (ii) an indication of the receipt of the data of the first traffic type to the second communication apparatus on a second resource of the plurality of resources.

20. A communication method implemented by a second communication apparatus comprising: receiving one of (i) data of a first traffic type and (ii) an indication of a receipt of the data of the first traffic type from a first communication apparatus on a second resource of a plurality of resources allocated for a signal after receiving at least a part of the signal on a first resource of the plurality of resources; processing the one of (i) the data of the first traffic type and (ii) the indication of the receipt of the data of the first traffic type.

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