Communication Device and Method

Abstract

The first communication device is configured to operate as an initiator and to communicate with a second communication device configured to operate as a responder, the first communication device comprising: circuitry configured to connect to the second communication device via at least two links, including a non-millimeter wave link and a millimeter wave link; transmit a beam-forming (BF) request frame to the second communication device via the non-millimeter wave link; conduct beam-forming training (BFT) with the second communication device by sequentially transmitting multiple sector sweep (SSW) frames and training fields in different transmit sectors via the millimeter wave link; and receive a BFT feedback frame from the second communication device via the non-millimeter wave link upon completion of the BFT if the first communication device is not busy upon completion of the BFT.

Description

[Technical Field]

[0001] The present disclosure relates to first and second communication devices used as an initiator and a responder. The present disclosure also relates to corresponding first and second communication methods.

[0002] The IEEE 802.11 standard requires beamforming (BF) before transmitting data over a millimeter wave link to establish a link of sufficient quality. Although a wide variety of BFs are available, these known BFs generally consume a significant amount of time, making them undesirable for low-latency and high-throughput applications.

[0003] The "Background" discussion provided herein is intended to generally provide a context for the present disclosure. The work of the currently named inventor(s) (to the extent described in the Background section) and aspects of the description that may not be admitted as prior art at the time of filing this application are not admitted, expressly or impliedly, as prior art to the present invention. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2022 / 158790 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to reduce the time required to establish a link between two communication devices for the data exchange required in low latency and high throughput applications, and to provide a corresponding communication device and method, as well as a corresponding computer program and non-transitory computer-readable recording medium for implementing the communication method. [Means for solving the problem]

[0006] According to one aspect, a first communication device configured to operate as an initiator and to communicate with a second communication device configured to operate as a responder, the first communication device comprising: connecting to the second communication device via at least two links including a non-millimeter wave link and a millimeter wave link; transmitting a beam-forming (BF) request frame to the second communication device over the non-millimeter wave link; performing beam-forming training (BFT) with a second communication device by sequentially transmitting a plurality of sector sweep (SSW) frames and training fields in different transmit sectors over the millimeter wave link; If the BFT is not busy at the end of the BFT, receive a BFT feedback frame from the second communication device via the non-millimeter wave link at the end of the BFT. The circuit section is configured to A first communication device is provided.

[0007] According to a further aspect, a second communication device configured to operate as a responder and to communicate with a first communication device configured to operate as an initiator, the second communication device comprising: connecting to the first communication device via at least two links including a non-millimeter wave link and a millimeter wave link; receiving a beam-forming (BF) request from the first communication device over the non-millimeter wave link; performing beam-forming training (BFT) with the first communication device by sequentially receiving a plurality of sector sweep (SSW) frames and training fields at different transmit sectors via the millimeter wave link, wherein different receive sectors are used during reception of the training fields; If the BFT is not busy at the end of the BFT, then at the end of the BFT, transmit a BFT feedback frame to the first communication device via the non-millimeter wave link. The circuit section is configured to A second communication device is provided.

[0008] According to another further aspect, there is provided a computer program comprising program means which, when executed on a computer, causes the computer to perform the steps of the methods disclosed herein, and a non-transitory computer readable recording medium storing a computer program product which, when executed by a processor, causes the computer to perform the methods disclosed herein.

[0009] Embodiments are defined in the dependent claims. It is to be understood that the disclosed communication method, the disclosed computer program, and the disclosed computer-readable recording medium have further embodiments similar and / or identical to the claimed communication devices and as defined in the dependent claims and / or disclosed herein.

[0010] One aspect of the present disclosure is based on the recognition that beamforming over asymmetric links is time-consuming and not useful for use cases requiring low latency and high throughput because the conventional initiator (also referred to herein as the “first communication device”) needs to wait for a certain period of time at different receiving sectors during the feedback phase. The present disclosure applies a faster and more efficient beamforming technique in multi-link operation (MLO) using a non-millimeter wave link (e.g., a sub-7 GHz link) and a millimeter wave link (e.g., a link using 45 GHz, 60 GHz, or 70 GHz). The proposed beamforming is hereinafter also referred to as multi-link-assisted beamforming. One of the elements of the present disclosure is that, to shorten the beamforming period, it is desirable to transmit beamforming feedback information over a non-millimeter wave link at the end of beamforming training (BFT).

[0011] Hereinafter, the term "sector" refers to one of the predetermined beam patterns of a communication device. The term "TX sector" refers to a sector used for transmission by a communication device, and the term "RX sector" refers to a sector used for reception by a communication device. A transmitter uses a TX sector, and a receiver uses an RX sector to obtain sufficient link quality. The term "beamforming (BF)" refers to the process of determining the optimal TX / RX sector(s) for a link before data transmission. The term "BF training" refers to the training process in beamforming.

[0012] It is to be understood that both the foregoing general description and the following detailed description are exemplary of the present technology and are not restrictive thereof. The described embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings, in which:

[0013] The present disclosure and many of the attendant advantages thereof will be readily appreciated as the same becomes better understood by reference to and consideration of the following detailed description, when taken in conjunction with the accompanying drawings, in which: [Brief explanation of the drawings]

[0014] [Figure 1] 1 shows a diagram of an example of conventional beamforming for asymmetric links. [Figure 2] 1 shows a diagram of an embodiment of the proposed beamforming for the first case for asymmetric links utilizing MLO. [Figure 3] 1 illustrates a first embodiment of a BFT feedback frame. [Figure 4] 10 illustrates a second embodiment of a BFT feedback frame. [Figure 5] 1 illustrates one embodiment of a BFT acknowledgement frame. [Figure 6] 1 shows a diagram of a first embodiment of the proposed Option A for asymmetric links utilizing beamforming and MLO according to the first case. [Figure 7]1 shows a diagram of a second embodiment of Option A for asymmetric links utilizing the proposed beamforming and MLO according to the first case. [Figure 8] 1 shows a diagram of a third embodiment of the proposed Option A for asymmetric links utilizing beamforming and MLO according to the first case. [Figure 9] 10 shows a diagram of a fourth embodiment of the proposed option A for asymmetric links utilizing beamforming and MLO according to the first case. [Figure 10] 10 shows a diagram of a fifth embodiment of the proposed option A for asymmetric links utilizing beamforming and MLO according to the first case. [Figure 11] 1 shows a diagram of a first embodiment of the proposed Option B for asymmetric links utilizing beamforming and MLO according to the first case. [Figure 12] 1 shows a diagram of a second embodiment of Option B for asymmetric links utilizing the proposed beamforming and MLO according to the first case. [Figure 13] 1 shows a diagram of an embodiment of the proposed beamforming for Case 2 for asymmetric links utilizing MLO. [Figure 14] 10 shows a diagram of one embodiment of Option A for asymmetric links utilizing the proposed beamforming and MLO according to Case 2. [Figure 15] 10 shows a diagram of one embodiment of Option B for asymmetric links utilizing the proposed beamforming and MLO according to Case 2. [Figure 16] 1 shows a flowchart of one embodiment of a first communication method according to the present disclosure. [Figure 17] 10 shows a flowchart of one embodiment of a second communication method according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] Future applications, such as virtual reality (VR), where console devices and head-mounted displays are wirelessly connected, may require both low latency and high throughput. In the IEEE 802.11ad and 802.11ay standards, a sector sweep (SSW) is performed before transmitting data. Two types of beamforming functions can be performed during the SSW phase: (1) transmit sector sweep (TXSS) and (2) receive sector sweep (RXSS). TXSS and RXSS can be performed for the beamforming initiator sector and the beamforming responder sector, respectively. Typically, in the initiator's TXSS, the initiator transmits training signals using different TX sectors, and the responder receives the signals in a quasi-omnidirectional pattern. After transmitting the training signals, the responder feeds back the best transmitting sector (or multiple best transmitting sectors) to the initiator, and vice versa in the initiator's RXSS.

[0016] IEEE802.11ay also standardizes beamforming for communication devices with antenna reciprocity. Regarding antenna reciprocity, the TX sector and the RX sector are usually not identical because the TX / RX circuitry in each communication device is not perfect. However, through calibration, the communication device can correct this mismatch so that the TX sector and the RX sector have the same beam pattern.

[0017] One of the beamforming techniques that utilizes antenna reciprocity in IEEE 802.11ay is called "beamforming for asymmetric links," which means that the link quality from the initiator to the responder is superior to the link quality from the responder to the initiator during the SSW phase. This asymmetric link essentially arises from the difference in sector gain between the initiator and the responder. For example, if the initiator is a station (STA) with a high TX sector gain and the responder is a station with a low TX sector gain, the training signal from the initiator to the responder can be correctly decoded, but the training signal from the responder to the initiator cannot be correctly decoded. This is because the device must configure a quasi-omnidirectional pattern during SSW. The initiator's feedback on the TXSS cannot be decoded even on the initiator side because the initiator configures a quasi-omnidirectional pattern to receive the feedback. Based on this, the initiator and responder configure sectors for asymmetric link beamforming during the SSW phase.

[0018] Referring to the figures (like reference numbers throughout the several figures indicate identical or corresponding parts in multiple figures), Figure 1 shows a diagram of an example of conventional beamforming for an asymmetric link. In this example, the initiator's TXSS is performed as part of the beacon signaling.

[0019] In a beacon transmission from an initiator, multiple beacon frames, each of which can have a training field (TRN-R), are transmitted using different TX sectors. The responder can set and switch RX sectors while receiving each TRN-R, so that it can train which combination of <initiator's TX sector ID, responder's RX sector ID> is the best (or better). In Figure 1, the responder sets the RX sector from RX sector #1 to RX sector #m when receiving each TRN-R. Each communication device predetermines the sector with a sector ID.

[0020] Since the initiator does not know which initiator's RX sector should be configured to receive the feedback signal from the responder, the feedback phase transmits the best (or better) set of <initiator's TX sector, responder's RX sector>. In the feedback phase, the responder transmits the feedback in the scheduled time slot, using the initiator's RX sector estimated by the responder as the best TX sector. The schedule information for the feedback phase (e.g., which initiator's RX sector is configured in which time slot) is included in the beacon frame. Whether the link is asymmetric or not is determined by the responder by estimating the link quality using 1) parameters included in the beacon frame from the initiator and 2) the RSSI (Received Signal Strength Indicator) of the received beacon frame on the responder's side.

[0021] As shown in Figure 1, at the end of the beacon transmission, the best pair of <initiator's TX sector ID, responder's RX sector ID> is assumed to be <initiator's TX sector #N, responder's RX sector #1>. In the feedback phase, the initiator allocates different time periods, each with a different RX sector, as indicated in the beacon frame. The responder transmits feedback frame(s) (SSW frame(s) in this case) within the time periods in which the initiator configured RX sector #N.

[0022] In conventional communication systems, BF over asymmetric links is time-consuming and largely inapplicable because the initiator needs to wait for a certain time in different RX sectors during the feedback phase. The technique disclosed herein proposes an efficient BF utilizing MLO using mmWave and non-mmWave links. Each proposed BF is hereinafter referred to as a multi-link-assisted BF. One of the elements of this disclosure is that BF feedback information is preferably transmitted over a non-mmWave link to shorten the BF duration.

[0023] In the following, we consider two main cases, assuming that the BFT signal is transmitted over a mmWave link. In case 1, the transmission of the training signal is not interrupted during the BFT. In case 2, the transmission of the training signal can be interrupted during the BFT.

[0024] FIG. 2 shows a diagram of a first embodiment of the proposed beamforming for Case 1 for asymmetric links utilizing MLO. Two STAs are associated with each other, with STA1 acting as the initiator and STA2 acting as the responder. As shown in FIG. 2, STA1 and STA2 each have two links, one of which is a millimeter wave link 10 and the other is a non-millimeter wave link 11 (e.g., a sub-7 GHz link having a center frequency less than 7.125 GHz), e.g., a sub-7 GHz link. Although the non-millimeter wave link will be referred to as a sub-7 GHz link hereinafter, it is essentially a link that does not require beamforming for association and / or control message exchange, and other non-millimeter wave links may be used instead of the sub-7 GHz link.

[0025] During the MLO setup phase 20, STA1 and STA2 exchange their capabilities and establish an association with each other. The capability exchange is typically performed over a sub-7 GHz link. This is because beamforming is required before information exchange occurs over millimeter wave links, particularly asymmetric links. Through the MLO setup, STA1 and STA2 learn the capabilities they support (e.g., beamforming for asymmetric links, number of TX / RX sectors, etc.) and can then perform initial configuration, such as which links to use. An example of capability exchange using MLO is the exchange of STA profile subelements. Assume that STA1 and STA2 are configured to use at least one sub-7 GHz link and one millimeter wave link for data transmission through the following MLO setup. The MLO setup may also include assigning a specific channel to the sub-7 GHz link to prevent other communication devices from interfering with the link. The link used for MLO setup may be different from the sub-7 GHz link over which beamforming requests and responses are exchanged.

[0026] After the MLO is set up, a BFT request and response step 21 is performed. STA1 transmits a BF request (BF request frame 210 in FIG. 2 ) to STA2 over the sub-7 GHz link 11. After receiving the BF request frame, STA2 transmits an optional response to the request (BFT response frame 211 in FIG. 2 ) to STA1. An exchange of a Request-To-Send (RTS) frame 212 and a Clear-To-Send (CTS) frame 213 over the sub-7 GHz link 11 (not shown in FIG. 2 ) may additionally be performed to obtain a Transmission Opportunity (TXOP) before transmitting the BF request frame. The RTS frame 212 over the sub-7 GHz link 11 may be identical to an RTS frame conforming to the IEEE 802.11 standard, and the CTS frame 213 over the sub-7 GHz link 11 may be identical to a CTS frame conforming to the IEEE 802.11 standard.

[0027] The BF request frame 210 may include an indication of the number of TX sectors of STA1 that will be trained in a subsequent BFT stage 22 on the mmWave link 10 and the number of TX antennas of STA1 that will be trained in a subsequent BFT stage 22 on the mmWave link 10. The BF response frame to the BF request is sent as an acknowledgment and indicates the number of RX sectors of STA2 that will be trained in a BFT stage 22 (N RX_Sector ) and the number of RX antennas of STA2 trained in BFT stage 22 (N RX_ant ) request.

[0028] Due to the nature of MLO, how TXOP can be obtained on both links is described below. Three exemplary signaling options on the mmWave link are described below. Each signaling is performed simultaneously with the exchange of BF request 210 and BFT response 211. The RTS frame 212 on the mmWave link can be the same as the RTS frame or DMG-RTS frame conforming to the IEEE 802.11 standard, and the CTS frame 213 on the mmWave link can be the same as the CTS frame or DMG-CTS frame conforming to the IEEE 802.11 standard.

[0029] According to the first option, the exchange of RTS / CTS frames on the millimeter wave link 10 is performed as shown in FIG. 2. STA1 transmits an RTS frame 212 to STA2 on the millimeter wave link 10 to obtain a TXOP on the millimeter wave link. In transmitting the RTS frame, at least one of the following conditions may be satisfied: (a) the BF request frame also includes an indication that the RTS frame will be transmitted on the millimeter wave link; (b) the RTS frame on the millimeter wave link is transmitted simultaneously with the transmission of the BF request; and (d) the PPDUs (Physical Data Protocol Data Units) of the RTS frame and the BF request on the millimeter wave link have substantially the same length, for example, by padding. After receiving the BF request frame 210 from STA1, STA2 transmits a CTS frame 213 on the millimeter wave link. In transmitting the CTS frame 213 over the mmWave link, at least one of the following conditions may be met: (a) the CTS frame over the mmWave link is transmitted simultaneously with the response to the BF request, and (b) each PPDU of both the response and the CTS frame has substantially the same length, e.g., due to padding. If the interframe spacing (IFS) between the RTS and CTS frames over the mmWave link is different from the IFS between the BF request and response frames over the sub-7 GHz link, no RTS / CTS frame exchange is performed.

[0030] According to a second option, STA1 on the mmWave link 10 (not shown in FIG. 2) transmits a CTS frame simultaneously with the BF request frame to obtain a TXOP on the mmWave link. In this case, STA1 can include in the BF request frame an indication that STA1 will transmit a CTS frame on the mmWave link.

[0031] According to the third option, no frame exchange occurs on the mmWave link (not shown in Figure 2). That is, STA1 does not transmit frames on the mmWave link. In this case, STA1 can include an indication in the BF request frame that STA1 will not transmit frames on the mmWave link.

[0032] After exchanging BFT requests and BFT responses over the sub-7 GHz link, a BFT step 22 is performed in which STA1 and STA2 perform BFT for their TX / RX sectors on the mmWave link in the TXOP established in the BFT request and response step 21. As shown in Figure 2, STA1 transmits SSW frames 220a to 220N with TRN fields 221a to 221N respectively.

[0033] A common TX sector is used for transmitting the SSW frame and the attached TRN field, but different TX sectors can be used for different SSW frames. Each SSW frame can contain one or more of the following indications: Control frame: An indication of which frame the frame is. Length: The number of bits or octets in the frame. · RA (receiving STA address): An indication of the MAC address of the communication device to which the frame is being sent. · TA (Sending STA Address): An indication of the MAC address of the communication device that sends the frame. · CDOWN: A down counter indicating the number of SSW frame transmissions remaining until the end of the training phase. · Sector ID: Indication of the TX sector ID used to transmit the SSW frame. Antenna ID: An indication of the mmWave antenna the transmitter is currently using for transmission. Frame Check Sequence (FCS): Additional bits for error detection.

[0034] Each TRN field may contain identical TRN subfields, but all TRN subfields within a TRN field must be transmitted via a common TX sector and mmWave antenna. These TX sectors and mmWave antennas are indicated and used for the prepended SSW frame. The number of TRN subfields is N. RX_ant ×N RX_Sector where N RX_ant and N RX_Sector is defined as above.

[0035] Typically, a known field is added to the beginning of any frame to perform AFC (Automatic Frequency Correction), AGC (Automatic Gain Control), channel estimation, etc. This allows the receiver to decode the frame, and the TRN subfield may be identical to the known field for channel estimation, and STA2 must know the TRN subfield.

[0036] When receiving each SSW frame 220, STA2 sets the sector to a quasi-omnidirectional pattern, but when receiving each additional TRN field, STA2 sets a different RX sector for each TRN subfield in the TRN field so that it can estimate the optimal Rx sector(s). As shown in Figure 2, STA2 changes the Rx sector from #1 to #m while receiving the TRN.

[0037] After the BFT stage 22, a feedback stage 23 is performed. As shown in Figure 2, STA2 transmits a BFT feedback frame 230 to STA1, and STA1 transmits a BFTAck frame 231 as an acknowledgment in response to the BFT feedback frame 230, both over the sub-7 GHz link 11. Typically, a separate TXOP is established over the sub-7 GHz link 11.

[0038] An embodiment of a BFT feedback frame 230a is shown in Figure 3. In general, the BFT feedback frame 230 may include one or more of the following indications: Control frame 2301: An indication of which frame the frame in question is. Length 2302: The number of bits or octets in the frame. RA (receiving STA address) 2303: An indication of the MAC address of the communication device to which the frame is to be sent. TA (Sending STA Address) 2304: An indication of the MAC address of the communication device that sends the frame. · Decoding flag 2305: An indication of whether the SSW frame transmitted using the TX sector specified in the TX sector selection field in the BFT feedback was correctly decoded at STA2. · Tx Sector Select 2306: Indication of whether the best quality SSW frame was received at STA2 during the BFT phase. Antenna Select 2307: Indication of the initiator's antenna ID of the SSW frame received with the best quality during the BFT phase. RSSI / SNR Report 2308: Indication of the SNR (Signal to Noise Ratio) of the selected TX sector, estimated from the received TRN field of that TX sector that was best received during the BFT phase if the decoding flags field indicates that the SSW frame was correctly decoded. Alternatively, an indication of the RSSI (Received Signal Strength Indicator) of the selected TX sector, estimated from the received TRN field that was best received during the BFT phase. Frame Check Sequence (FCS) 2309: Additional bits for error detection.

[0039] Another embodiment of BFT feedback frame 230b is shown in Figure 4. The main difference from BFT feedback frame 230a is that in this case, multiple sets 2310 of <Decoding Flag, Tx Sector Select, Antenna Select, RSSI / SNR Report> are shown to inform STA1 of alternative initiator sector and antenna sets. In this embodiment, BFT feedback frame 230b includes a Decoding Flag field 2303, a Tx Sector field 2306, an Antenna Select field 2307, and an RSSI / SNR Report field 2308 (preferably within each set). In addition, the following fields are included: Tx Sector Select Number 2311: Indication of the number of pairs 2310 consisting of <decoding flag, Tx sector select, antenna select, RSSI / SNR report> in the frame.

[0040] After receiving the BFT feedback frame 230, STA1 transmits a BFTAck frame 231 to indicate the Tx sector and antenna ID to use in the next transmission. Figure 5 shows one embodiment of the BFTAck frame 231, which may include one or more of the following indications: Control frame 2310: An indication of which frame the frame is. Length 2311: The number of bits or octets in the frame. RA (receiving STA address) 2312: An indication of the MAC address of the communication device to which the frame is to be sent. TA (Sending STA Address) 2313: An indication of the MAC address of the communication device that sends the frame. · Tx Sector Select 2314: Indication of the initiator's sector to use in the next transmission. · Antenna Select 2315: Indication of the initiator's Antenna ID value to be used in the next transmission. Frame Check Sequence (FCS) 2316: Additional bits for error detection.

[0041] As shown in FIG. 2, the BFT feedback frame 230 and the BFTAck frame 231 are transmitted over the sub-7 GHz link 11, although several options are possible. According to a first option A (shown in FIGS. 6 to 10), STA1 transmits data to STA2 over the sub-7 GHz link 11 during the BFT phase. According to a second option B (shown in FIGS. 11 and 12), the sub-7 GHz link 11 is busy with other transmissions at least during the feedback phase. In other words, according to the present disclosure, at the end of the BFT, if the BFT is not busy at the end of the BFT, the BFT feedback is transmitted over the non-mmWave link 11.

[0042] FIG. 6 shows a diagram of a first embodiment of Option A for the proposed asymmetric link utilizing beamforming and MLO for the first case. The MLO setup phase 20 is not shown in this figure. According to this embodiment, data frames 223 and 224 (PPDUs in this example) are transmitted from STA1 to STA2 over the sub-7 GHz link 11. The final PPDU 224 ends simultaneously with the BFT phase 22. If the data size of the PPDUs 223 and 224 is very large and the transmission time is estimated to exceed the end time of the BFT phase 22, STA1 transmits a portion of the data so that BFT feedback frames and BFT Ack frames can be exchanged over the sub-7 GHz link 11 immediately after the BFT phase ends. Reception of the data frames 223 and 224 is acknowledged by STA2 by transmitting an acknowledgement (Ack) frame 225. An acknowledgment for at least the last PPDU 224 may be transmitted separately (not shown) or in combination with the BFT feedback frame 230a, for example, as part of the BFT feedback frame (as shown in FIG. 6) or attached to the BFT feedback frame.

[0043] FIG. 7 shows a diagram of a second embodiment of Option A for the asymmetric link utilizing the proposed beamforming and MLO according to the first case. The main difference from the second embodiment shown in FIG. 6 is that STA1 obtains TXOP 24 by the end of the feedback stage 23 on the sub-7 GHz link 11 through the exchange of RTS and CTS frames 214, 215 before transmitting the BF request frame 210. This case can be considered based on the following assumption: data is already queued before the RTS frame 214 is transmitted on the sub-7 GHz link 11. Furthermore, the data size is large enough to result in a transmission time substantially equal to or greater than the BFT stage 22 using the worst-case code rate of the candidate MCS (Modulation and Coding Scheme). Furthermore, due to the low latency requirement, TXOP 24 needs to be reserved for the feedback stage 23.

[0044] According to this embodiment, the RTS frame 214 and / or the CTS frame 215 indicate that the TXOP 24 has a duration that covers at least the estimated feedback stage 23. To fix the time of the feedback stage 23 before the transmission of the BF request, the BF request frame 210 can indicate at least one of (a) the number of RX sectors and antennas of STA2 to be trained in the BFT stage 22, (b) an indication indicating that the response frame 211 to the BF request frame 210 does not include a request for the number of RX sectors and antennas of STA2 to be trained in the BFT stage 22, and (c) an indication indicating that STA1 will not consider the request for the number of RX sectors and antennas of STA2 to be trained in the BFT stage 22.

[0045] 8 shows a diagram of a third embodiment of Option A for an asymmetric link utilizing the proposed beamforming and MLO according to the first case. According to this embodiment, separate TXOPs are obtained. For example, there are two TXOPs 25 and 26, where the first TXOP 24 covers the period from the RTS / CTS exchange to the end of the BFT phase 22, and the second TXOP 25 covers the feedback phase 23. In this case, as shown in FIG. 8, another RTS / CTS exchange can occur just before the feedback phase 23, exchanging an RTS frame 232 and a CTS frame 233.

[0046] According to another embodiment, the first TXOP 25 may cover the transmission of the Ack+BFT feedback frame 230a, and the second TXOP 26 may cover only the BFT Ack transmission 231. This is illustrated in Figure 9, which shows a fourth embodiment of Option A for the proposed asymmetric link utilizing beamforming and MLO according to the first case.

[0047] While the above embodiment assumes that PPDUs are transmitted during the BFT phase 22, it is also possible that STA1 does not have enough traffic and the PPDU(s) transmitted on the sub-7 GHz link 11 do not occupy this link until the end of the BFT phase 22. A diagram of a fifth embodiment of Option A for the proposed asymmetric link utilizing beamforming and MLO for the first case is shown. According to this embodiment, PPDU(s) 223 are transmitted during the BFT phase 22, but the PPDUs do not occupy the entire duration of the BFT phase 22. In this case, another RTS / CTS exchange can be performed, exchanging an RTS frame 226 and a CTS frame 227, to ensure that the BFT feedback 230 is transmitted after the end of the BFT phase 22. The end time of the CTS frame 227 can be aligned with the end time of the last TRN field 221N.

[0048] The CTS frame 227 is received after the last TRN field 221N (T IFS +T CTS-T1) before. Here, as shown in Figure 10, IFS is the interframe spacing (IFS) between the CTS frame 227 and the BFT feedback frame 230, and T CTS is the duration of the CTS frame 227, and T1 is the duration between the reception of the last TRN field 221N and the transmission of the BFT feedback frame 230. IFS may be the same as SIFS (Short IFS) defined in the IEEE802.11 standard.

[0049] 11 shows a diagram of a first embodiment of Option B for an asymmetric link utilizing the proposed beamforming and MLO according to the first case. According to this embodiment, STA2 determines that the channel of the sub-7 GHz link 11 is busy with other transmissions at least during the feedback phase 23. Therefore, STA2 cannot transmit a BFT feedback frame to STA1 during the busy state, and transmits a BFT feedback frame 230a after determining that the channel is clear.

[0050] FIG. 12 shows a diagram of a second embodiment of Option B for asymmetric links utilizing the proposed beamforming and MLO according to the first case. According to this embodiment, BFT feedback 230 is transmitted over the mmWave link. In an asymmetric link scenario, STA1 cannot decode the signal from STA2 unless both STA1 and STA2 are configured with the optimal sector. Therefore, a feedback step 23 is performed for asymmetric links as defined in IEEE 802.11ay, "BF for Asymmetric Links." This allows STA1 to configure a specific RX sector for a given timeslot.

[0051] STA1 and STA2 decide whether to perform this process. After STA1 transmits the last TRN field to STA2, STA2 transmits the TRN field to STA1 for a certain period of time. thrIf STA1 does not receive a signal within a certain period of time, STA2 determines that the channel is busy. thr To determine that the busy state continues, STA2 attempts to transmit a BF feedback frame 230 to STA1 over the millimeter wave link 10.

[0052] In the embodiment shown in FIG. 12, STA2<Txセクタ#2、Rxセクタ#1> of<TxセクタID、RxセクタID> and the BFT feedback is transmitted by Tx sector #1 of STA2 in the time slot where STA1 sets Rx sector #2. After receiving the BFT feedback, STA1 transmits a BFTAck to STA2, and the feedback stage 23 ends. Although the number of time slots of the Tx sector of each STA1 is shown as one, the number of time slots of the Rx sector of each STA1 may be one or more.

[0053] The BF request frame 210 may include (a) an indication of potential scheduling information for a time slot, and / or (b) a time slot for the thr The scheduling information in the BF request 210 may include (a) the duration and start time of each timeslot, and / or (b) the initiator's Rx sector ID and antenna ID to be used in each timeslot.

[0054] Different embodiments of Case 1 in which the transmission of the training signal is not interrupted during BFT have been described with reference to Figures 2 to 12. Below, different embodiments of Case 2 in which the transmission of the training signal can be interrupted during BFT will be described with reference to Figures 13 to 15.

[0055] 13 shows a diagram of an embodiment of the proposed beamforming for Case 2 for asymmetric links utilizing MLO. According to this embodiment, the BFT transmission is suspended in BFT stage 22. The main difference from the embodiment according to Case 1 is that the BFT is suspended after STA1 receives a BFT feedback indication 230 from STA2 on the sub-7 GHz link 11.

[0056] In the MLO setup step 120, STA1 and STA2 exchange their capabilities and establish an association with each other. This step is similar or identical to the MLO setup step 20 in Case 1, but STA1 and STA2 can exchange their capabilities as follows: First, STA1 has a certain link quality.<STA1のTXセクタID、STA2のRXセクタID> If STA2 receives an indication that STA2 estimates at least one of the set of STA1, the BFT may be aborted. STA2 may then send feedback information to STA1 during the BFT transmission on the sub-7 GHz link 11. The feedback information may also be preliminary feedback and an indication that STA1 may stop the BFT.

[0057] After setting up the MLO, in a BF request and response stage 21, if STA1 obtains a TXOP on the sub-7 GHz link 11, it sends a BFT request 210 to STA2 on the sub-7 GHz link 11. STA2 sends a response 211 in response to the BF request frame 210. Thus, the BF request and response stage 21 is similar or identical to the BF request and response stage 21 in Case 1, but may include additional information as described below.

[0058] To allow STA2 to estimate the link quality, the BF request frame 210 may include one or more of the following indications: STA2 has a constant link quality S link qualityhave<STA1のTXセクタID、STA2のRXセクタID> When STA2 sends an indication that it estimates at least one of the sets, it can abort the corresponding BFT. A parameter of certain link quality above that may indicate either a required minimum RSSI, a required minimum estimated SNR for the link from STA1 to STA2, or a required estimated SNR for the link from STA2 to STA1. Constant link quality link quality is intended to be either the required RSSI estimated by STA2, the required SNR for the link from STA1 to STA2, or the required SNR for the link from STA2 to STA1.

[0059] If the BF request frame 210 includes the above indication (a) or (b), STA2 estimates the RSSI of the received SSW frame 220 or the SNR of the received SSW frame 220 during the BFT stage 22. If the BF request frame 210 includes the above indication (c), the method by which STA2 calculates the estimated SNR of the link from STA2 to STA1 is as follows.

[0060]

number

[0061] where SNR est is the estimate of the expected SNR by STA2 when its transmission is received by STA1, and P STA2 and G STA2-TX is the transmit power and antenna gain of the expected STA2 transmission, RSSI is the power measured by STA2 during reception of the TRN field in the BFT stage 22, and C is the value contained in the SSW frame 220 received during the BFT stage. The indicated value C can be set as follows:

[0062]

number

[0063] where P STA1 and G STA1-Tx are the transmit power and antenna gain used for SSW frame transmission, and P Noise is the noise power level estimated by STA1. The units of the above parameters are dB or dBm.

[0064] After exchanging BF requests and responses over the sub-7 GHz link 11, STA1 and STA2 perform BF training for the TX / RX sectors in BFT stage 122. The BFT may be similar to or identical to BFT stage 22 in Case 1. That is, STA1 transmits SSW frames 220a to 220K+1 with TRN fields 221a to 221K+1 added, respectively. The SSW frames and TRN fields may be similar to or identical to Case 1, but the SSW frames may additionally include the parameter C described above.

[0065] In the BFT stage 122, STA2 estimates the link quality of the content indicated in the BF request frame 210, i.e., RSSI, SNR of the link from STA1 to STA2, or SNR of the link from STA2 to STA1. The estimated link quality is compared to a threshold S link quality If so, STA2 transmits a BFT feedback frame 230 to STA1. As an exemplary case, FIG. 13 shows that K+1 SSW frames are transmitted by STA1, but STA2 does not receive a BFT feedback frame 230 if at least one of the sector IDs #1 to #K used in the first K SSW frames has a link quality of S or higher. link quality This indicates that the candidate is estimated to satisfy the above conditions. If STA2 receives SSW frames after transmitting the BFT feedback frame 230, STA2 does not need to decode these SSW frames.

[0066] Although not shown in Figure 13, STA1 can stop transmitting the (K+1)th SSW frame 220K+1 with the TRN field 221K+1 added while transmitting the frame in which STA1 receives the BFT feedback frame 230.

[0067] In the feedback stage 123, STA1 may transmit a BFT completion frame 234 on the sub-7 GHz link 11d, which includes the Tx sector and antenna ID to be used in the next transmission and an indication that the BFT stage 122 on the mmWave link 10 has ended. A Contention Free (CF) completion frame (not shown in FIG. 13) may be transmitted on the sub-7 GHz link 11d after the BFT completion frame 234 or may be included in the BFT completion frame 234.

[0068] STA2 may also transmit a CF End frame 235 on the mmWave link 10 simultaneously with the BFTAck frame (not shown in FIG. 13) or after transmitting the current SSW frame to notify the end of the TXOP on the mmWave link 10. The CF End frame may be similar or identical to that specified in the IEEE 802.11 standard.

[0069] As shown in Figure 13, the BFT feedback and BFT end frames are transmitted on the sub-7GHz link 11, but if the sub-7GHz link is occupied by another transmission, several options are possible: According to option A, STA1 transmits data to STA2 on the sub-7GHz link during the BFT phase 122, and according to option B, the sub-7GHz link 11 is busy due to other transmissions at least during the feedback phase 123.

[0070] FIG. 14 shows a diagram of one embodiment of Option A for an asymmetric link utilizing the proposed beamforming and MLO according to Case 2. According to this embodiment, data frames 223 and 224 are transmitted from STA1 to STA2 over the sub-7 GHz link 11. FIG. 14 also shows that the final PPDU 225 ends when or after the Nth SSW frame 220N over the mmWave link 10 is completely transmitted. In this case, STA2 transmits a BFT feedback frame 230a to STA1 after the PPDU transmission. An Ack frame for the PPDU(s) may be transmitted separately (as Ack frame 225) or together with the BFT feedback frame 230a.

[0071] STA1 may include a Reverse Direction Grant (RDG) in the PPDUs 223 and 224 on the sub-7 GHz link 11 during the BFT phase 122 so that STA2 can transmit a BFT feedback frame 230a on the sub-7 GHz link 11 while STA1 obtains a TXOP on the sub-7 GHz link 11. The RDG may be similar or identical to that described in the IEEE 802.11 standard.

[0072] If the data size is very large and the transmission time is estimated to exceed the end time of the transmission of the maximum number of SSW frames transmitted in the BFT stage, the Mth SSW frame (M is the maximum number of SSW frames transmitted in the BFT stage), STA1 can transmit only a portion of the data so that the BFT feedback frame 230a is transmitted on the sub-7GHz link 11 after the Mth SSW transmission.

[0073] STA2 determines whether STA2 has the required link quality.<STA1のTxセクタID、STA2のRxセクタID> Even if we have already estimated at least one of the sets of , we can still decode the SSW frame and estimate the link quality until the BFT feedback transmission.

[0074] FIG. 15 shows a diagram of one embodiment of Option B for the asymmetric link utilizing the proposed beamforming and MLO according to Case 2. According to this embodiment, the sub-7 GHz link of STA2 is busy with other transmissions at least during the feedback phase 123. STA2 cannot transmit the BFT feedback frame 230 to STA1 during the busy state and transmits the BFT feedback frame 230 after determining that the channel of the sub-7 GHz link 11 is normal. After receiving the BFT feedback frame 230 from STA2, STA1 transmits a BFT completion frame 234 on the sub-7 GHz link 11 and, optionally, a CF completion frame 235 on the mmWave link 10. As another exemplary case, the BFT feedback frame 230 is transmitted on the mmWave link 10. This case is similar or identical to that described above with reference to Case 1.

[0075] FIG. 16 shows a flowchart of an embodiment of a first communication method 300 that may be performed by a first communication device (STA1) acting as an initiator and communicating with a second communication device (STA2) acting as a responder. In a first step 301, the first communication device connects to the second communication device via at least two links, including a non-millimeter wave link and a millimeter wave link. In a second step 302, the first communication device transmits a BF request frame to the second communication device via the non-millimeter wave link. In a third step 303, the first communication device performs BF training with the second communication device by sequentially transmitting multiple SSW frames and training fields in different transmission sectors via the millimeter wave link. In a fourth step 304, the first communication device receives a BFT feedback frame from the second communication device via the non-millimeter wave link at the end of the BFT, if the non-millimeter wave link is not busy at the end of the BFT.

[0076] FIG. 17 shows a flowchart of an embodiment of a second communication method 400 performed by a second communication device (STA2) operating as a responder. In a first step 401, the second communication device connects to the first communication device via at least two links, including a non-millimeter wave link and a millimeter wave link. In a second step 402, the second communication device receives a BF request from the first communication device via the non-millimeter wave link. In a third step 403, the second communication device performs BF training with the first communication device by sequentially receiving multiple SSW frames and training fields via different transmit sectors via the millimeter wave link. Here, different receive sectors are used when receiving the training fields. In a fourth step, if the non-millimeter wave link is not busy at the end of the BFT, the second communication device transmits a BFT feedback frame to the first communication device via the non-millimeter wave link.

[0077] In summary, this disclosure is directed to fast beamforming for multi-link operation using non-mmWave (e.g., sub-7 GHz) and mmWave links. To establish links for data communication of sufficient quality without consuming excessive time, mechanisms exist to reduce beamforming time utilizing MLO, especially for asymmetric links in mmWave, especially for low latency and high throughput applications.

[0078] Accordingly, the foregoing discussion discloses and describes merely exemplary embodiments of the present invention. As will be understood by those skilled in the art, the present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The disclosure of the present invention, as well as the remaining claims, is hereby intended to be illustrative and not limiting of the scope of the disclosure. This disclosure defines in part the scope of the preceding claim terms, including readily discernible variations of the teachings herein, so that the inventive subject matter is not dedicated to the public.

[0079] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. A single element or other part may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0080] To the extent that embodiments of the present disclosure are described as being implemented at least in part by a software-controlled data processing apparatus, it will be understood that non-transitory machine-readable media, such as optical disks, magnetic disks, semiconductor memories, etc., that store such software also qualify as embodiments of the present disclosure. Furthermore, such software may be distributed in other forms, such as via the Internet or other wired or wireless communications telecommunications systems.

[0081] The elements of the disclosed devices, apparatus, and systems may be implemented by corresponding hardware and / or software elements, such as appropriate circuits. A circuit is a structural collection of electronic components, including conventional circuit elements, integrated circuits, including application-specific integrated circuits, standard integrated circuits, application-specific standard products, and field-programmable gate arrays. A circuit also includes a central processing unit, a graphics processing unit, and a microprocessor that are programmed or configured according to software code. A circuit includes the aforementioned hardware that executes software, but does not include pure software.

[0082] Below is a list of further embodiments of the disclosed subject matter. (1) A first communication device (STA1) configured to operate as an initiator and to communicate with a second communication device (STA2) configured to operate as a responder, connecting (20) to the second communication device via at least two links including a non-millimeter wave link (11) and a millimeter wave link (10); transmitting (21) a beam-forming (BF) request frame (210) to the second communication device over the non-millimeter wave link; performing (22) Beam-Forming Training (BFT) with a second communication device (STA2) by sequentially transmitting a plurality of sector sweep (SSW) frames (220A...220N) and training fields (221A...221N) in different transmitting sectors over the millimeter wave link; If not busy at the end of the BFT, receive (23) a BFT feedback frame (230) from the second communication device over the non-millimeter wave link at the end of the BFT. The circuit section is configured to A first communication device (STA1). (2) The first communication device according to any one of the above embodiments, The circuitry is configured to use the same beam pattern for transmitting and receiving over the millimeter wave link, and a particular beam pattern defines a transmitting and receiving sector. A first communication device. (3) The first communication device according to any one of the above embodiments, The circuitry is configured to include a plurality of training subfields in a training field. A first communication device. (4) The first communication device according to any one of the above embodiments, The circuitry is configured to transmit a BFT acknowledgment frame to the second communication device over the non-millimeter wave link in response to the BFT feedback frame received from the second communication device over the non-millimeter wave link. A first communication device. (5) The first communication device according to any one of the above embodiments, The circuit unit includes: a control frame indication that the frame is a BFT acknowledgement frame; a length indication indicating the number of bits or octets of the BFT acknowledgment frame; a destination indication indicating the communication device to which the BFT acknowledgment frame is addressed; a source indication indicating the first communication device; a sector selection indication indicating a transmission sector to be used in a next transmission over the millimeter wave link; an antenna selection indication indicating which antenna will be used for a subsequent transmission over the mmWave link; and Frame Check Sequence (FCS) used for error detection and configured to include one or more of the following in the BFT acknowledgement frame: A first communication device. (6) The first communication device according to any one of the above embodiments, The circuit unit includes: a control frame indication indicating that the frame is an SSW frame; A length indication indicating the number of bits or octets of the SSW frame; A destination indication indicating the communication device to which the SSW frame is addressed; a source indication indicating the first communication device; A counter indication indicating the number of remaining SSW frames to be transmitted until the end of the BFT; A sector selection indication indicating the transmission sector used to transmit the SSW frame; an antenna selection indication indicating the antenna used to transmit the SSW frame; and Frame Check Sequence (FCS) used for error detection configured to include one or more of the following in the SSW frame: A first communication device. (7) The first communication device according to any one of the above embodiments, The circuitry is configured to use a sub-7 GHz link having a center frequency less than 7.125 GHz as the non-millimeter wave link. A first communication device. (8) The first communication device according to any one of the above embodiments, the circuitry is configured to transmit one or more data frames to the second communication device over the non-millimeter wave link during the BFT; The transmission of the data frame ends at the latest at the end of the BFT. A first communication device. (9) A first communication device according to embodiment 8, The circuit unit includes: i) Do not send an RTS (Ready-To-Send) frame, or ii) RTS frame before sending said BF request, and / or before receiving the BFT feedback frame, during receiving the BFT feedback frame, and / or after receiving the BFT feedback frame, and / or During the BFT, configured to transmit over the non-millimeter wave link A first communication device. (10) The first communication device according to any one of the above embodiments, The circuitry may transmit to the second communication device, prior to the BFT, particularly as part of the BF request frame: Clearance period information indicating the clearance period used by the second communication device to determine whether to transmit the BFT feedback frame over the mmWave link if the non-millimeter wave link does not become idle within a clearance period; and / or Link quality information indicating a link quality threshold used by the second communication device to determine whether to transmit the BFT feedback frame during the BFT. configured to send A first communication device. (11) The first communication device according to any one of the above embodiments, The circuitry is configured to interrupt the BFT if the BFT feedback frame is received during the BFT. A first communication device. (12) A second communication device (STA2) configured to operate as a responder and communicate with a first communication device (STA1) configured to operate as an initiator, connecting (20) to the first communication device via at least two links including a non-millimeter wave link (11) and a millimeter wave link (10); receiving (21) a beam-forming (BF) request (210) from the first communication device via the non-millimeter wave link; performing (22) beam-forming training (BFT) with the first communication device by sequentially receiving a plurality of sector sweep (SSW) frames (220A...220N) and training fields (221A...221N) at different transmit sectors via the millimeter wave link, wherein different receive sectors are used during reception of the training fields; If the BFT is not busy at the end of the BFT, then at the end of the BFT, a BFT feedback frame (230) is transmitted (23) to the first communication device via the non-millimeter wave link. The circuit section is configured to A second communication device (STA2). (13) The second communication device according to embodiment 12, The circuitry is configured to use the same beam pattern for transmitting and receiving over the millimeter wave link. A second communication device. (14) The second communication device according to any one of embodiments 12 and 13, The circuitry is configured to transmit a BF response to the first communication device over the non-millimeter wave link in response to the BF request received from the first communication device over the non-millimeter wave link. A second communication device. (15) The second communication device according to any one of the 12th to 14th embodiments, The circuitry is configured to receive a plurality of training subfields included in a training field, each training subfield being received by a different receiving sector. A second communication device. (16) The second communication device according to any one of the 12th to 15th embodiments, The circuit unit includes: a decoding flag indicating whether the transmitted SSW frame was correctly decoded by the second communication device; and / or two or more decoding flag fields indicating two or more alternative transmission sectors used by the first communication device; configured to include in the BFT feedback frame A second communication device. (17) The second communication device according to embodiment 16, The circuit unit includes: a control frame indication indicating that the frame is a BFT feedback frame; a length indication indicating the number of bits or octets of the BFT feedback frame; a destination indication indicating the communication device to which the BFT feedback frame is addressed; a source indication indicating the second communication device; a decoding flag indicating whether the transmitted SSW frame indicated in the corresponding sector selection indication was correctly decoded by the second communication device; A sector selection indication indicating the SSW frame received with the highest quality at the second communication device during the BFT phase; An antenna selection indication indicating the antenna from which the SSW frame was received with the highest quality in the BFT step; A RSSI / SNR report indication indicating the signal-to-noise ratio (SNR) or received signal strength indicator (RSSI) of the best transmitting sector in the BFT stage; and Frame Check Sequence (FCS) used for error detection in the BFT feedback frame. A second communication device. (18) The second communication device according to any one of embodiments 12 to 17, The circuit unit transmits a CTS (Clear-to-send) frame in response to an RTS (Ready-To-Send) frame from the first communication device. before sending said BF request, and / or before receiving the BFT feedback frame, during receiving the BFT feedback frame, and / or after receiving the BFT feedback frame, and / or During the BFT, configured to transmit over the non-millimeter wave link A second communication device. (19) The second communication device according to any one of embodiments 12 to 18, The circuitry transmits the BFT feedback frame over the non-millimeter wave link as soon as the non-millimeter wave link becomes idle if the non-millimeter wave link is busy at the end of the BFT, or over the millimeter wave link after the clearance period if the non-millimeter wave link does not become idle within the clearance period. It is configured as follows: A second communication device. (20) The second communication device according to embodiment 19, If the non-millimeter wave link is busy at the end of the BFT and does not become idle within the clearance period, the circuit unit: estimating a best combination of a best transmitting sector of the first communication device and a best receiving sector of the second communication device; and transmitting the BFT feedback frame during the clearance period via the millimeter wave link using a transmission sector estimated as the best receiving sector of the second communication device in a time slot in which the first communication device receives using a receiving sector estimated as the best transmitting sector of the first communication device. It is configured as follows: A second communication device. (21) A second communication device according to any one of embodiments 12 to 20, The circuitry is configured to transmit the BFT feedback frame during the BFT if the estimated link quality is greater than or equal to a link quality threshold. A second communication device. (22) The second communication device according to any one of embodiments 12 to 21, The circuitry is configured to transmit the BFT feedback frame when the non-millimeter wave link is busy due to transmission of a data frame by the first communication device to the second communication device or due to other traffic on the non-millimeter wave link, as soon as a last data frame is transmitted by the first communication device or the non-millimeter wave link becomes idle. A second communication device. (23) A first communication method for a first communication device configured to operate as an initiator and to communicate with a second communication device configured to operate as a responder, comprising: connecting to the second communication device via at least two links including a non-millimeter wave link and a millimeter wave link; transmitting a beam-forming (BF) request frame to the second communication device over the non-millimeter wave link; performing beam-forming training (BFT) with a second communication device by sequentially transmitting a plurality of sector sweep (SSW) frames and training fields in different transmit sectors over the millimeter wave link; If the BFT is not busy at the end of the BFT, receive a BFT feedback frame from the second communication device via the non-millimeter wave link at the end of the BFT. The first communication method. (24) A second communication method for a second communication device configured to operate as a responder and to communicate with a first communication device configured to operate as an initiator, comprising: connecting to the first communication device via at least two links including a non-millimeter wave link and a millimeter wave link; receiving a beam-forming (BF) request from the first communication device over the non-millimeter wave link; performing beam-forming training (BFT) with the first communication device by sequentially receiving a plurality of sector sweep (SSW) frames and training fields at different transmit sectors via the millimeter wave link, wherein different receive sectors are used during reception of the training fields; If the BFT is not busy at the end of the BFT, then at the end of the BFT, transmit a BFT feedback frame to the first communication device via the non-millimeter wave link. Second communication method. (25) A non-transitory computer-readable recording medium storing a computer program product that, when executed by a processor, causes the method according to embodiment 23 or embodiment 24 to be performed. (26) A computer program comprising program code means for causing a computer to perform the steps of the method according to embodiment 23 or embodiment 24 when the computer program is executed on the computer.

Claims

1. A first communication device configured to act as an initiator and to communicate with a second communication device configured to act as a responder, connecting to the second communication device via at least two links including a non-millimeter wave link and a millimeter wave link; transmitting a beam-forming (BF) request frame to the second communication device over the non-millimeter wave link; performing beam-forming training (BFT) with a second communication device by sequentially transmitting a plurality of sector sweep (SSW) frames and training fields over the millimeter wave link in different transmit sectors; receiving a BFT feedback frame from the second communication device over the non-millimeter wave link at the end of the BFT if the second communication device is not busy at the end of the BFT; The circuit section is configured to A first communication device.

2. 10. The first communication device of claim 1, The circuitry is configured to use the same beam pattern for transmitting and receiving on the millimeter wave link, with a particular beam pattern defining a transmitting and receiving sector, and / or to abort the beam forwarding (BFT) if the BFT feedback frame is received during the BFT. A first communication device.

3. 10. The first communication device of claim 1, The circuitry is configured to include a plurality of training subfields in a training field. A first communication device.

4. 10. The first communication device of claim 1, the circuitry is configured to transmit a BFT acknowledgement frame to the second communication device over the non-millimeter wave link in response to the BFT feedback frame received from the second communication device over the non-millimeter wave link; and / or a control frame indication that the frame is a BFT acknowledgement frame; a length indication indicating the number of bits or octets of the BFT acknowledgment frame; a destination indication indicating the communication device to which the BFT acknowledgment frame is addressed; a source indication indicating the first communication device; a sector selection indication indicating a transmission sector to be used in a next transmission over the millimeter wave link; an antenna selection indication indicating which antenna will be used for a subsequent transmission over the mmWave link; and Frame Check Sequence (FCS) used for error detection configured to include one or more of the following in the BFT acknowledgement frame: A first communication device.

5. 10. The first communication device of claim 1, The circuit unit includes: a control frame indication indicating that the frame is an SSW frame; a length indication indicating the number of bits or octets of the SSW frame; a destination indication indicating the communication device to which the SSW frame is addressed; a source indication indicating the first communication device; a counter indication indicating the number of SSW frames remaining to be transmitted until the end of the BFT; a sector selection indication indicating a transmission sector used to transmit the SSW frame; an antenna selection indication indicating the antenna used to transmit the SSW frame; and Frame Check Sequence (FCS) used for error detection configured to include in the SSW frame one or more of A first communication device.

6. 10. The first communication device of claim 1, The circuitry is configured to use a sub-7 GHz link having a center frequency less than 7.125 GHz as the non-millimeter wave link. A first communication device.

7. 10. The first communication device of claim 1, the circuitry is configured to transmit one or more data frames to the second communication device over the non-millimeter wave link during the BFT; The transmission of the data frame ends at the latest at the end of the BFT. A first communication device.

8. 8. A first communication device according to claim 7, The circuit unit includes: i) not sending a Ready-To-Send (RTS) frame, or ii) RTS frame before sending the BF request, and / or before receiving the BFT feedback frame, during receiving the BFT feedback frame, and / or after receiving the BFT feedback frame; and / or During the BFT, configured to transmit over the non-millimeter wave link A first communication device.

9. 10. The first communication device of claim 1, The circuitry may transmit to the second communication device, prior to the BFT, particularly as part of the BF request frame: clearance period information indicating the clearance period used by the second communication device to determine whether to transmit the BFT feedback frame over the mmWave link if the non-mmWave link does not become idle within the clearance period; and / or link quality information indicative of a link quality threshold used by the second communication device to determine whether to transmit the BFT feedback frame during the BFT; configured to send A first communication device.

10. a second communication device configured to operate as a responder and to communicate with a first communication device configured to operate as an initiator, connecting to the first communication device via at least two links including a non-millimeter wave link and a millimeter wave link; receiving a beam-forming (BF) request from the first communication device via the non-millimeter wave link; performing beam-forming training (BFT) with the first communication device by sequentially receiving a plurality of sector sweep (SSW) frames and training fields over the millimeter wave link at different transmitting sectors, wherein different receiving sectors are used during reception of the training fields; If the BFT is not busy at the end of the BFT, transmitting a BFT feedback frame to the first communication device over the non-millimeter wave link at the end of the BFT. The circuit section is configured to A second communication device.

11. 11. A second communication device according to claim 10, The circuitry is configured to use the same beam pattern for transmitting and receiving over the millimeter wave link, and / or to transmit a beamforming response to the first communication device over the non-millimeter wave link in response to the beamforming request received from the first communication device over the non-millimeter wave link. A second communication device.

12. 11. A second communication device according to claim 10, The circuitry is configured to receive a plurality of training subfields included in a training field, each training subfield being received by a different receiving sector. A second communication device.

13. 11. A second communication device according to claim 10, The circuit unit includes: a decoding flag indicating whether the transmitted SSW frame was correctly decoded by the second communication device; and / or two or more decoding flag fields indicating two or more alternative transmission sectors used by the first communication device; configured to include in the BFT feedback frame A second communication device.

14. 14. A second communication device according to claim 13, The circuit unit includes: a control frame indication indicating that the frame is a BFT feedback frame; a length indication indicating the number of bits or octets of the BFT feedback frame; a destination indication indicating the communication device to which the BFT feedback frame is addressed; a source indication indicating the second communication device; a decoding flag indicating whether the transmitted SSW frame indicated in the corresponding sector selection indication was correctly decoded by the second communication device; a sector selection indication indicating an SSW frame received with the highest quality at the second communication device during the BFT phase; an antenna selection indication indicating an antenna from which the SSW frame was received with the highest quality in the BFT step; a signal-to-noise ratio (SNR) or received signal strength indicator (RSSI) report indication of the best transmitting sector during the BFT phase; and Frame Check Sequence (FCS) used for error detection in the BFT feedback frame. A second communication device.

15. 11. A second communication device according to claim 10, The circuit unit transmits a CTS (Clear-to-send) frame in response to an RTS (Ready-To-Send) frame from the first communication device. before sending the BF request, and / or before receiving the BFT feedback frame, during receiving the BFT feedback frame, and / or after receiving the BFT feedback frame; and / or During the BFT, configured to transmit over the non-millimeter wave link A second communication device.

16. 11. A second communication device according to claim 10, The circuitry is configured to: transmit the BFT feedback frame over the non-millimeter wave link as soon as the non-millimeter wave link becomes idle if the non-millimeter wave link is busy at the end of the BFT; or transmit the BFT feedback frame over the millimeter wave link after the clearance period if the non-millimeter wave link does not become idle within a clearance period, particularly if the non-millimeter wave link is busy at the end of the BFT and does not become idle within the clearance period. estimating a best combination of a best transmitting sector of the first communication device and a best receiving sector of the second communication device; and transmitting the BFT feedback frame during the clearance period via the millimeter wave link using a transmission sector estimated as the best receiving sector of the second communication device in a time slot in which the first communication device receives using a receiving sector estimated as the best transmitting sector of the first communication device. It is configured as follows: A second communication device.

17. 11. A second communication device according to claim 10, The circuit unit includes: (a) during the BFT if the estimated link quality is greater than or equal to a link quality threshold; and / or (b) if the non-millimeter wave link is busy due to transmission of a data frame by the first communication device to the second communication device or due to other traffic on the non-millimeter wave link, as soon as the last data frame is transmitted by the first communication device or the non-millimeter wave link becomes idle; configured to transmit the BFT feedback frame. A second communication device.

18. 1. A first communication method for a first communication device configured to act as an initiator and to communicate with a second communication device configured to act as a responder, the method comprising: connecting to the second communication device via at least two links including a non-millimeter wave link and a millimeter wave link; transmitting a beam-forming (BF) request frame to the second communication device over the non-millimeter wave link; performing beam-forming training (BFT) with a second communication device by sequentially transmitting a plurality of sector sweep (SSW) frames and training fields over the millimeter wave link in different transmit sectors; receiving a BFT feedback frame from the second communication device over the non-millimeter wave link at the end of the BFT if the second communication device is not busy at the end of the BFT; First communication method.

19. A second communication method for a second communication device configured to operate as a responder and to communicate with a first communication device configured to operate as an initiator, the method comprising: connecting to the first communication device via at least two links including a non-millimeter wave link and a millimeter wave link; receiving a beam-forming (BF) request from the first communication device via the non-millimeter wave link; performing beam-forming training (BFT) with the first communication device by sequentially receiving a plurality of sector sweep (SSW) frames and training fields over the millimeter wave link at different transmitting sectors, wherein different receiving sectors are used during reception of the training fields; If the BFT is not busy at the end of the BFT, transmitting a BFT feedback frame to the first communication device over the non-millimeter wave link at the end of the BFT. A second communication method.

20. A non-transitory computer readable storage medium storing a computer program product which, when executed by a processor, causes the method of claim 18 or 19 to be performed.

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