• 专利附录
  • 专利说明
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    • 专利摘要:
    According to an example aspect of the present invention, there is provided a method comprising starting a transmission burst (435) to occupy a channel on an unlicensed frequency band for a channel occupancy time, transmitting a trigger to a user equipment (110), the trigger triggering at least one channel availability measurement to be performed on the channel by the user equipment (110) during the channel occupancy time, determining, during the channel occupancy time, whether the channel is available based at least on a response of the user equipment (110) and continuing the transmission burst or starting a new transmission burst (435), wherein the continuation of the transmission burst (435) or start of the new transmission burst (435) depends on whether the channel is determined as available during the channel occupancy time.
    公开号:FI20205098A1
    申请号:FI20205098
    申请日:2020-01-31
    公开日:2021-08-01
    发明作者:Kari Juhani Hooli；Esa Tapani Tiirola；Timo Erkki Lunttila；Klaus Hugl；Karol Schober
    申请人:Nokia Technologies Oy；
    IPC主号:
    专利说明:

    [0001] [0001] Various example embodiments relate in general to cellular communication devices and more specifically, to channel access on unlicensed frequency bands by such devices.BACKGROUND
    [0002] [0002] Scarcity of available freguency spectrum is an issue for various wireless communication networks, such as for cellular communication networks operating according to Long Term Evolution, LTE, and/or 5G radio access technology. 5G radio access technology may also be referred to as New Radio, NR, access technology. Since its inception, LTE has been widely deployed and 3rd Generation Partnership Project, 3GPP, — still develops LTE. Similarly, 3GPP also develops standards for SG/NR. One of the topics in the 3GPP discussions is related to increasing available freguency spectrum by using unlicensed freguency bands for communication on top of or as alternative for licensed freguency bands. According to the discussions there is a need to provide improved methods, apparatuses and computer programs for channel access on unlicensed freguency — bands by cellular communication devices.O
    [0005] [0005] According to a first aspect of the present invention, there is provided an apparatus, such as a base station, comprising one or more processors, and memory storing instructions that, when executed by the one or more processors, cause the apparatus to start a transmission burst to occupy a channel on an unlicensed frequency band for a channel occupancy time, transmit a trigger to a user equipment, the trigger triggering at least one channel availability measurement to be performed on the channel by the user equipment during the channel occupancy time, determine, during the channel occupancy time, whether the channel is available based at least on a response of the user equipment and continue the transmission burst or start a new transmission burst , wherein the continuation — of the transmission burst or start of the new transmission burst depends on whether the channel is determined as available during the channel occupancy time.
    [0006] [0006] Embodiments of the first aspect may comprise at least one feature from the following bulleted list: e The trigger may be a command transmitted to the user equipment, the command commanding the user eguipment to perform the at least one channel availability measurement on the channel during the channel occupancy time. In some embodiments, the command may be transmitted on a group common physical downlink control channel or on a unicast physical downlink control channel. e Said one or more processors, and memory storing instructions that, when executed by the one or more processors, may further cause the apparatus to perform at least one channel availability measurement on the channel during the channel occupancy time and determine, during the channel occupancy time, S whether the channel is available based on the at least one channel availability N measurement of the apparatus and the response of the user eguipment. In some > 25 embodiments, the at least one channel availability measurement to be & performed on the channel by the user eguipment and the at least one channel E availability measurement performed by the apparatus may take place at most a 3 predetermined number of slots or symbols apart.
    [0007] [0007] According to a second aspect of the present invention, there is provided an apparatus, such as a user equipment or a relay, comprising one or more processors, and memory storing instructions that, when executed by the one or more processors, cause the apparatus to receive a trigger from a base station, the trigger triggering at least one channel availability measurement to be performed by the apparatus on a channel on an unlicensed frequency band during a channel occupancy time, perform the at least one channel availability measurement on the channel during the channel occupancy time, transmit a response to the base station during the channel occupancy time, wherein the response is based on the at least one channel availability measurement, and detect that a transmission burst is continuing or a new transmission burst is starting.
    [0008] [0008] In some embodiments of the second aspect, the trigger may be a command received from the base station, the command commanding the user equipment to perform the at least one channel availability measurement on the channel during the channel occupancy time.
    [0009] [0009] According to a third aspect, there is provided a first method, for a base station for example, comprising starting a transmission burst to occupy a channel on an unlicensed frequency band for a channel occupancy time, transmitting a trigger to a user equipment, the trigger triggering at least one channel availability measurement to be performed on the channel by the user equipment during the channel occupancy time, determining, during the — channel occupancy time, whether the channel is available based at least on a response of the user eguipment and continuing the transmission burst or starting a new transmission burst , wherein the continuation of the transmission burst or start of the new transmission S burst depends on whether the channel is determined as available during the channel O occupancy time. O 25 [0010] According to a fourth aspect, there is provided a second method, for a user O eguipment or a relay for example, comprising receiving a trigger from a base station, the E trigger triggering at least one channel availability measurement to be performed by the 2 apparatus on a channel on an unlicensed freguency band during a channel occupancy time, 2 performing the at least one channel availability measurement on the channel during the O 30 channel occupancy time, transmitting a response to the base station during the channel occupancy time, wherein the response is based on the at least one channel availability measurement, and detecting that a transmission burst is continuing or a new transmission burst is starting.
    [0011] [0011] According to a fifth aspect of the present invention, there is provided non- transitory computer readable medium having stored thereon a set of computer readable 5 instructions that, when executed by at least one processor, cause an apparatus to at least perform the first method. According to an sixth aspect of the present invention, there is provided non-transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least perform the second method.
    [0012] [0012] According to a seventh aspect of the present invention, there is provided a computer program configured to perform the first method. According to an eight aspect of the present invention, there is provided a computer program configured to perform the second method.BRIEF DESCRIPTION OF THE DRAWINGS
    [0013] [0013] FIGURE 1 illustrates an exemplary network scenario in accordance with at least some example embodiments;
    [0014] [0014] FIGURE 2 illustrates flexible beam operation in accordance with at least some embodiments;
    [0015] [0015] FIGURE 3 illustrates an example apparatus capable of supporting at least S some embodiments; & - [0016] FIGURE 4 illustrates timing of channel availability measurements and
    [0019] [0019] FIGURE 7 illustrates a flow graph of a second method in accordance with at least some embodiments.EMBODIMENTS
    [0020] [0020] Channel access on unlicensed frequency spectrum by cellular communication devices may be improved by the procedures described herein. For instance, a collision may be detected and acted upon also during a Channel Occupancy Time, COT. In addition, flexible beam operation may be enabled by allowing re-assessment of availability of a channel on an unlicensed frequency band. In the beginning, a Base Station, BS, may occupy the channel for the COT, wherein the COT may be for a transmission burst. After that, one or more User Equipments, UEs, may measure the channel during the COT and transmit a response to the BS during the COT as well. Upon receiving the results, the BS may decide about continuation of the transmission burst or start of a new transmission burst. For instance, the BS may decide to continue the transmission burst or to start the —new transmission burst during the COT if the channel is still determined as available. On the other hand, the BS may decide to stop the transmission burst during the COT if the channel is determined as occupied upon re-assessment and continue the transmission burst or start the new transmission burst later on.
    [0021] [0021] FIGURE 1 illustrates an exemplary network scenario in accordance with at — least some embodiments. According to the example scenario of FIGURE 1, there may be a cellular communication system, which comprises one or more UEs 110, one or more Base Stations, BS, 120, and core network element 130. UE 110 may be connected to BS 120 via S air interface using beams 115 on unlicensed frequency spectrum. That is to say, the cellular — communication network may be a beam-based system and UE 110 and BS 120 may be = 25 — cellular communication devices operating on unlicensed freguency spectrum. = [0022] UE 110 may comprise, for example, a smartphone, a cellular phone, a 2 Machine-to-Machine, M2M, node, machine-type communications node, an Internet of 3 Things, IoT, node, a car telemetry unit, a laptop computer, a tablet computer or, indeed, O any kind of suitable wireless terminal. In the example system of FIGURE 1, UE 110 may communicate wirelessly with BS 120, or a cell of BS 120, via at least one beam 115. Beams 115 may be referred to as transmit beams, transmitted by BS 120. BS 120 may be considered as a serving BS for UEs 110. Air interface between UE 110 and BS 120 may be configured in accordance with a Radio Access Technology, RAT, which both UE 110 and BS 120 are configured to support.
    [0023] [0023] Examples of cellular RATs include Long Term Evolution, LTE, New Radio, NR, which may also be known as fifth generation, 5G, radio access technology and MulteFire. For example, in the context of LTE, BS 120 may be referred to as eNB while in the context of NR, BS 120 may be referred to as gNB. In any case, embodiments of the present invention are not restricted to any particular wireless technology. Instead, embodiments may be exploited in any cellular communication network, ie., for any — cellular RAT, operating on unlicensed frequency bands.
    [0024] [0024] BS 120 may be connected, directly or via at least one intermediate node, with core network 130 via interface 125. Core network 130 may be, in turn, coupled via interface 135 with another network (not shown in FIGURE 1), via which connectivity to further networks may be obtained, for example via a worldwide interconnection network. BS 120 may be connected with at least one other BS as well via an inter-base station interface (not shown in FIGURE 1), even though in some embodiments the inter-base station interface may be absent. BS 120 may be connected, directly or via at least one intermediate node, with core network 130 or with another core network.
    [0025] [0025] In some embodiments of the present invention, the exemplary network — scenario may comprise a relay instead of, or in addition to UE 110. Relaying may be used for example when operating on millimeter-wave freguencies. One example of the relay may be an Integrated Access and Backhaul, IAB, node. The IAB node may be referred to S as a self-backhauling relay as well. Another example of a relay may be an out-band relay. N In general, the relay may comprise two parts: > S 25 1) Distributed Unit, DU, part which may facilitate functionalities of BS 120, such as a enB + 2) Mobile Termination, MT, part which may facilitate functionalities of UE 110, i.e, a & backhaul link which may be the communication link between a parent node (DU) N and the relay, such as an IAB node. In some embodiments, the MT part may be N 30 referred to as a IAB-UE as well, i.e, the relay may correspond to UE 110 partly and perform similar operations as UE 110.
    [0026] [0026] Using 5G/NR as an example, embodiments of the present invention may be exploited for example for operation on frequency spectrum beyond 52.6 GHz. Ranges, use cases, deployment scenarios and requirements for such frequency spectrum are being discussed in 3rd Generation Partnership Project, 3GPP, Radio Access Network, RAN, meetings. Objectives discussed in the meetings comprise waveform design for operation beyond 52.6 GHz and study of physical layer design for above 52.6 GHz. The design should take into consideration at least efficient transceiver design, including power efficiency and complexity, improvement of coverage to cope with extreme propagation loss and inheriting physical layer channel design for below 52.6 GHz from NR Rel-15 whenever applicable.
    [0027] [0027] Even though the present invention is not limited to any specific frequency bands, other potential high mm-wave bands for 5G and beyond systems comprise at least 70/80/92-114 GHz. For instance, there are wide global unlicensed freguency bands available on the frequency range of 57-71 GHz (in some regions 57-66 GHz), making the unlicensed operation at mm-wave bands interesting option for future development of NR.
    [0028] [0028] Operation on unlicensed spectrum may be regulated by certain channel access or spectrum sharing rules that target at fair spectrum usage among different RATs on the same shared unlicensed spectrum. Typically, the channel access rules reguire use of Listen-Before-Talk, LBT, type channel access. Further, in case of beam-based systems, the LBT operation may be performed for the intended transmit direction. That is to say, a transmitter, such as BS 120, may perform channel sensing using the beam it intends to use for the scheduled/planned transmission. Thus, in some embodiments of the present invention, it is assumed that channel sensing is performed per beam and that there is also a S channel sensing process per beam. O 25 [0029] Regarding channel access procedures, the channel access procedures may O need to comply with regulations. The channel access procedures may therefore need to be E adapted for particular freguency ranges. For instance, the channel access procedures D considered for 5 GHz as well as tentatively for 6 GHz unlicensed NR operation may be 3 found from 3GPP Technical Report 38.889. On the other hand, regulatory landscape for O 30 channel access on 60 GHz spectrum may be found from 3GPP Technical Report 38.805. In addition, there are wide range of channel access or spectrum sharing mechanisms for unlicensed freguency spectrum, including e.g. low duty cycle per carrier (in combination e.g. with frequency hopping), dynamic frequency selection, and automatic transmit power control. In general, it is foreseen that NR-U should support sufficient coverage as well as high cell and UE throughput.
    [0030] [0030] When considering channel sensing in a beam-based system, channel sensing both on transmitter and receiver may be more important than with omnidirectional antennas. For instance, a transmitter, such as BS 120, may perform channel sensing prior to its transmission and sometimes detect a transmission, e.g., from another BS. However, sometimes the transmitter may not be able to detect the transmission, but in such a case a receiver, such as UE 110, may perform channel sensing and detect transmission from — another BS.
    [0031] [0031] Embodiments of the present invention address various challenges related to channel access by cellular communication devices on unlicensed frequency bands. For instance, on higher frequencies such as 60 GHz, it may be assumed that coexistence problem is less severe than at lower frequency bands. The higher spatial isolation due to — narrow beam and higher attenuation alleviates the coexistence problem when compared to e.g. 24 GHz or 5 GHz bands. In addition, implementation impact of channel access is emphasized. Channel bandwidths can be extremely wide, in order of couple of GHz. This implies very high sampling, symbol and data rates, causing significant challenges for device implementation.
    [0035] [0035] Hence, flexible beam operation as illustrated in FIGURE 2 appears attractive at least for 60 GHz band. FIGURE 2 illustrates following steps: a) BS 120 may measure a vacant channel in a first beam direction; b) BS 120 may transmit an uplink scheduling grant to UE 110 in the first beam direction; c) BS 120 may measure a vacant channel in a second beam direction; d) BS 120 may transmit Physical Downlink Shared Channels, PDSCH(s), for another UE 112 in the second beam direction; e) BS 120 may switch back to the first beam direction to receive the scheduled PUSCH from UE 110; f) BS 120 may switch to the second beam direction to continue the PDSCH(s) transmissions for another UE 112 without performing channel measurements again.
    [0036] [0036] Some embodiments of the present invention therefore allow brief gaps for transmissions with reasonable implementation efforts. Thus, flexible beam operation may be made attractive by exploiting embodiments of the present invention. Some
    [0040] [0040] Device 300 may comprise memory 320. Memory 320 may comprise random- access memory and/or permanent memory. Memory 320 may comprise at least one RAM chip. Memory 320 may comprise solid-state, magnetic, optical and/or holographic memory, for example. Memory 320 may be at least in part accessible to processor 310. Memory 320 may be at least in part comprised in processor 310. Memory 320 may be means for storing information. Memory 320 may comprise computer instructions that processor 310 is configured to execute. When computer instructions configured to cause processor 310 to perform certain actions are stored in memory 320, and device 300 overall is configured to run under the direction of processor 310 using computer instructions from memory 320, processor 310 and/or its at least one processing core may be considered to be configured to perform said certain actions. Memory 320 may be at least in part comprised — in processor 310. Memory 320 may be at least in part external to device 300 but accessible to device 300.
    [0041] [0041] Device 300 may comprise a transmitter 330. Device 300 may comprise a receiver 340. Transmitter 330 and receiver 340 may be configured to transmit and receive, respectively, information in accordance with at least one cellular or non-cellular standard. Transmitter 330 may comprise more than one transmitter. Receiver 340 may comprise more than one receiver. Transmitter 330 and/or receiver 340 may be configured to operate in accordance with Global System for Mobile communication, GSM, Wideband Code Division Multiple Access, WCDMA, 5G, Long Term Evolution, LTE, IS-95, Wireless Local Area Network, WLAN, Ethernet and/or Worldwide Interoperability for Microwave — Access, WIMAX, standards, for example.
    [0042] [0042] Device 300 may comprise a Near-Field Communication, NFC, transceiver
    [0044] [0044] Device 300 may comprise or be arranged to accept a user identity module
    [0045] [0045] Processor 310 may be furnished with a transmitter arranged to output information from processor 310, via electrical leads internal to device 300, to other devices comprised in device 300. Such a transmitter may comprise a serial bus transmitter arranged to, for example, output information via at least one electrical lead to memory 320 for — storage therein. Alternatively to a serial bus, the transmitter may comprise a parallel bus transmitter. Likewise processor 310 may comprise a receiver arranged to receive information in processor 310, via electrical leads internal to device 300, from other devices comprised in device 300. Such a receiver may comprise a serial bus receiver arranged to, for example, receive information via at least one electrical lead from receiver 340 for — processing in processor 310. Alternatively to a serial bus, the receiver may comprise a parallel bus receiver.
    [0046] [0046] Device 300 may comprise further devices not illustrated in FIGURE 3. For example, where device 300 comprises a smartphone, it may comprise at least one digital camera. Some devices 300 may comprise a back-facing camera and a front-facing camera, wherein the back-facing camera may be intended for digital photography and the front- facing camera for video telephony. Device 300 may comprise a fingerprint sensor arranged to authenticate, at least in part, a user of device 300. In some embodiments, device 300 S lacks at least one device described above. For example, some devices 300 may lack a NFC O transceiver 350 and/or user identity module 370. O 25 = [0047] Processor 310, memory 320, transmitter 330, receiver 340, NFC transceiver O 350, UI 360 and/or user identity module 370 may be interconnected by electrical leads E internal to device 300 in a multitude of different ways. For example, each of the D aforementioned devices may be separately connected to a master bus internal to device 3 300, to allow for the devices to exchange information. However, as the skilled person will O 30 appreciate, this is only one example and depending on the embodiment various ways of interconnecting at least two of the aforementioned devices may be selected without departing from the scope of the embodiments.
    [0048] [0048] FIGURE 4 illustrates timing of channel availability measurements and reporting in accordance with at least some embodiments. With reference to FIGURE 1, FIGURE 4 may illustrate operation of UE 110 and BS 120, such as a gNB. In the beginning, BS 120 may configure channel availability measurements and reporting resources to UE 110. More specifically, channel availability measurements may take place on resources allocated for downlink transmissions, such as Zero Power - Channel State Information — Reference Signal, ZP-CSI-RS, resources and related reporting may be done on resources allocated for uplink transmissions, such as Physical Uplink Control Channel, PUCCH and/or Uplink Control Information, UCI, on PUSCH.
    [0050] [0050] In some embodiments, the channel may be measured and determined as — vacant at a considered beam. Moreover, channel access may be performed for a certain beam and channel access on non-overlapping beams may be independently determined. For instance, BS 120 may determine the channel as available for the certain beam. UE 110 or BS 120 capable of multi-panel transmission and reception may also perform channel access concurrently on multiple beams.
    [0053] [0053] A longer gap between the measurement and start of transmission burst 435 may also increase the probability that another transmitter determines the channel as available. Thus, said another transmitter may start its own transmission as well, which would increase the probability of collision. Further, BS 120 may start transmission burst 435 without knowing whether the channel is determined to be vacant also by UE 110. This also may increase the probability of channel access collision. Embodiments of the present invention may be used to mitigate the probability of collisions by performing channel — availability measurements and assessment of the availability of the channel during the COT, e.g, for a certain beam. In some embodiments of the present invention, it may be assumed that data arrives to transmitters sufficiently random so that multiple transmitters do not access the channel too freguently at the same time at the same spatial area.
    [0054] [0054] BS 120 may transmit indication 430 about the start of transmission burst 435, ie. start of the COT, to occupy the channel. Indication 430 about the start of transmission burst 435 may be transmitted on the channel, on the unlicensed frequency band. In some embodiments, indication 430 about the start of transmission burst 435 may be transmitted in a beginning of transmission burst 435, in a first slot of the COT for example. Moreover, in some embodiments, indication 430 about the start of transmission burst 435 may be — transmitted in Downlink Control Information, DCI.
    [0055] [0055] In some embodiments of the present invention, BS 120 may start a transmission of transmission burst 435 to UE 110 upon transmitting indication 430. In S some embodiments, BS 120 may transmit indication 430 and start transmission of N transmission burst 435 within a certain time from measuring the channel as available. The O 25 transmission of transmission burst 435 by BS 120 may trigger a start of the COT, ie, O occupy the channel for the COT. Transmission burst 435 may comprise both, downlink E and uplink resources. In some embodiments, for example uplink resources may occur at 3 most y slots apart. N [0056] Indication 430 about the start of transmission burst 435 or the start of N 30 transmission burst 435 by BS 120 may be a trigger triggering at least one channel availability measurement to be performed by UE 110 and/or UE 112 during the COT. In some embodiments, the trigger may be a command transmitted to UE 110 and/or UE 112 by BS 120, the command commanding UE 110 and/or UE 112 to perform the at least one channel availability measurement on the channel during the COT.
    [0057] [0057] In some embodiments, BS 120 may transmit a trigger, such as indication 430 or start of transmission burst 435, the trigger triggering the at least one channel availability measurement to be performed by UE 110 and/or UE 112 on downlink resources allocated for the duration of the COT and UE 110 and/or UE 112 may perform the at least one channel availability measurement accordingly on said downlink resources. For instance, said allocated resources may be periodic and semi-statically configured to UE 110.
    [0061] [0061] In some embodiments of the present invention, BS 120 may measure availability of the channel and receive response 450, such as a measurement report from UE 110, and possibly from another UE 112 as well, at most a predetermined number y slots apart. Timing of uplink resources used for responding/reporting, such as PUCCH, — may be determined relative to a start of the COT, e.g., with a configured time offset and periodicity. Alternatively, the start of the COT may be indicated on a group common downlink control channel, such as GC PDCCH, possibly with a timing indicator. As another option, the start of the COT may be signalled to each reporting UE separately. As yet another option, the uplink resources may be pre-configured and the uplink resource — used for responding/reporting may be the next resource after the channel availability measurement and measurement processing time.
    [0062] [0062] In some embodiments of the present invention, response 450, such as a channel availability report transmitted by UEs to BS 120, may contain a bit field or fields, such as selection of a reference signal sequence and/or PUCCH resource. The sequence or — resource selection may indicate whether the channel is available or not. Alternatively, UE 110 may transmit a reference signal sequence on PUCCH if UE 110 measures the channel as available. S [0063] In some embodiments, BS 120 may also measure availability of the channel N during the COT, e.g., during resources allocated for uplink transmissions during the COT. O 25 For instance, BS 120 may leave some of said resources allocated for uplink transmissions O empty by not scheduling transmissions for said resources. UE 110 may also leave E predefined resource elements of the scheduled freguency and time resource unused. & [0064] BS 120 may thus re-assess availability of the channel during the COT, e.g., N based on the measurements performed by BS 120 and/or response 450 received from UE N 30 110. That is to say, BS 120 may determine during the COT whether the channel is still available. Upon determining whether the channel is available, BS 120 may continue transmission burst 435 to UE, wherein the continuation of transmission burst 435 depends on whether the channel is determined as available during the COT.
    [0065] [0065] For instance, if response 450 of UE 110 and the at least one channel availability measurement performed by BS 120 indicate that the channel is still available, BS 120 has a need to continue transmission burst 435 and a duration of transmission burst 435 is less than a maximum COT, BS 120 may transmit an indication to UE 110. The indication may signal a further continuation of the transmission burst by z/ slots (or symbols), or less, for example. In other words, BS 120 may continue transmission burst 435 during the COT responsive to determining that the channel is still available and duration of transmission burst 435 is smaller than the maximum COT.
    [0066] [0066] Alternatively, BS 120 may start a new transmission burst, to occupy the channel for a new COT for example. In other words, in some embodiments, BS 120 may decide to start the new COT instead of continuing the existing COT. UE 110 may detect that the transmission burst is continuing or the new transmission is starting for example based on the received indication or receiving a beginning of the new transmission burst.
    [0067] [0067] Alternatively, if response 450 of UE 110 or the at least one channel availability measurement performed by BS 120 indicate that the channel is occupied, BS 120 has a need to continue transmission burst 435 and the duration of transmission burst 435 is less than the maximum COT, BS 120 may determine a deferral time for the continuation of the transmission of transmission burst 435 and transmission of transmission burst 435 may continue after the deferral time. Alternatively, BS 120 may start a new transmission burst after the deferral time, to occupy the channel for a new COT 3 for example. — [0068] In some embodiments, BS 120 may determine the deferral time by drawing a 7 25 pseudo-random value from a value range that depends on a value x. BS 120 may then = transmit an indication, e.g., on a group common downlink control channel, the indication * indicating that the COT ends earlier than originally indicated. In other words, the & indication indicating that the COT ends earlier than originally indicated may indicate N suspension of transmission burst 435, as shown by 460 in FIGURE 4. After the indication, N 30 BS 120 and UE 110 may be suspended from the considered beam for example. BS 120 may then stop the transmission of transmission burst 435 in z2 slots (or symbols). In addition, or alternatively, BS 120 may transmit the deferral time to UE 110. In some embodiments, BS 120 may transmit an indication of a deferral time to UE 110 responsive to determining that the channel is not available, i.e., BS 120 may defer the continuation of the transmission burst or the start of the new transmission burst by the deferral time responsive to determining that the channel is not available.
    [0069] [0069] The deferral time may be determined pseudo-randomly so that simultaneous re-entering to the channel can be avoided. As channel availability may be measured up to x us before starting the transmission, a value range for the pseudo-random transmission deferral time may be considerably larger than x and hence, the deferral time may depend on x.
    [0070] [0070] Alternatively, if response 450 of UE 110 or the at least one channel availability measurement performed by BS 120 indicate that the channel is occupied, BS 120 has a need to continue transmission burst 435 and the duration of transmission burst 435 is less than the maximum COT, BS 120 may select an option from the following actions: e Option A: BS 120 may determine the deferral time by drawing a pseudo-random value from a value range that depends on a value x. BS 120 may then transmit an indication, e.g, on a group common downlink control channel, the indication indicating that the COT ends earlier than originally indicated. BS 120 may then stop the transmission of transmission burst 435 in z2 slots (or symbols). In addition, or alternatively, BS 120 may transmit the deferral time to UE 110.
    [0071] [0071] That is to say, BS 120 may determine, during the COT, that the channel is occupied and select an action from at least two options, such as options A and B above, wherein said at least two options comprise stopping a transmission of transmission burst 435 and continuing the transmission of transmission burst 435. In both options A and B, BS 120 may transmit for a limited period of time, despite measuring the channel as occupied.
    [0072] [0072] In some embodiments of the present invention, both or all colliding devices may detect a collision and stop transmissions. The COT may then be restarted simultaneously, which would lead to another collision. To avoid further collisions, random — selection between options A and B may be introduced. That is to say, for example BS 120 may randomly select option A or option B upon detecting that the channel is not available.
    [0073] [0073] The deferral time may be determined in various ways. As a first example, the deferral time may be a random number within a range [Tcor/a, Tcor+p], wherein Tcor is a maximum duration of the COT and a and B may be design parameters. Value of a may be 20r4for example and value of P may be k times x. The maximum duration of the COT may be incorporated to determination of the deferral time, because in case of a collision, another wireless device may continue occupying the channel until the maximum duration of the COT.
    [0074] [0074] As a second example, upon determining the channel as available again BS — 120 may draw the deferral time randomly from range [0, vy], wherein y may be & times x us. If the derived deferral time is less than a threshold, BS 120 may start a transmission right away. If the deferral time is larger than the threshold, BS 120 may wait for the deferral N time before repeating a channel availability measurement.
    [0077] [0077] Phases 530 — 570 may be performed during the COT. At phase 530, BS 120 may trigger UE 110, and possibly another UE 112, to perform at least one channel availability measurement on the channel during the COT, for example on downlink resources during the COT. At phase 540, BS 120 may measure availability of the channel and receive a response, such as a channel availability report, from UE 110 at most y slots — apart, and possibly from another UE 112 as well if another UE 112 is configured to perform measurements. The response(s) may comprise at least one measurement result or an indication indicating whether the channel is determined as available by the UE in guestion.
    [0078] [0078] At phase 550, BS 120 may re-assess availability of the channel, e.g., based on — the at least one measurement performed by BS 120 and/or a response received from UE 110, and possibly from another UE 112 as well. At phase 560, BS 120 may determine whether the channel is available or not. For instance, BS 120 may determine whether the channel is still available based at least on the response of UE 110.
    [0079] [0079] If the channel is determined as occupied, i.e., not available, the process may — proceed to phase 562, wherein BS 120 may determine a deferral time, such as a pseudo- random deferral time for continuation of the transmission burst or for starting a new transmission burst. BS 120 may also transmit an indication to UE 110, the indication S indicating suspension of the transmission burst. For instance, BS 120 may transmit an N updated group common downlink control channel, such as GC PDCCH, indicating that the O 25 COT ends in 22 slots. Alternatively, or in addition, BS 120 may transmit the deferral time O to UE 110. At phase 564, BS 120 may stop transmission of the transmission burst in z2 E slots (or symbols)) and continue the transmission burst or start the new transmission burst x after the deferral time.O
    [0081] [0081] Embodiments of the present invention therefore provide improvements for spectrum sharing on unlicensed freguencies, e.g., for a beam-based system. According to some embodiments, a collision may be detected and acted upon also during the COT. Conseguently, simplified implementation is enabled, wherein also a signal for first — transmission slots of a transmission burst may be prepared at least partially after the channel is determined to be available at a transmitter, such as BS 120. Brief gaps in the transmission are also enabled, thereby allowing flexible beam operation. In some embodiments, measurements, of a receiver such as UE 110, are also incorporated to mitigate the hidden node problem without increasing overhead or delay of the channel — access (e.g., due to RTS/CTS handshake prior to the transmission).
    [0082] [0082] FIGURE 6 is a flow graph of a first method in accordance with at least some embodiments. The phases of the illustrated first method may be performed by BS 120, or by a control device configured to control the functioning thereof, possibly when installed therein. — [0083] The first method may comprise, at step 610, starting a transmission burst to occupy a channel on an unlicensed freguency band for a channel occupancy time. At step 620, the first method may comprise transmitting a trigger to a user eguipment, the trigger S triggering at least one channel availability measurement to be performed on the channel by N the user eguipment during the channel occupancy time. At step 630, the first method may O 25 — comprise determining, during the channel occupancy time, whether the channel is available O based at least on a response of the user eguipment. Finally, at step 640, the first method E may comprise continuing the transmission burst or starting a new transmission burst, D wherein the continuation of the transmission burst or start of the new transmission burst 3 depends on whether the channel is determined as available during the channel occupancy O 30 time.
    [0084] [0084] FIGURE 7 is a flow graph of a second method in accordance with at least some embodiments. The phases of the illustrated second method may be performed by UE
    [0085] [0085] The second method may comprise, at step 710, receiving a trigger from a base station, the trigger triggering at least one channel availability measurement to be performed by the apparatus on a channel on an unlicensed frequency band during a channel occupancy time. At step 720, the second method may comprise performing the at least one channel availability measurement on the channel during the channel occupancy time. At step 730, the second method may comprise transmitting a response to the base station during the channel occupancy time, wherein the response is based on the at least one — channel availability measurement. Finally, at step 740, the second method may comprise detecting that a transmission burst is continuing or a new transmission burst is starting.
    [0086] [0086] It is to be understood that the embodiments disclosed are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.
    [0087] [0087] Reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Where reference is made to a numerical value using a term such as, for example, about or S substantially, the exact numerical value is also disclosed.O
    [0089] [0089] In an exemplary embodiment, an apparatus, such as, for example, UE 110, a relay or BS 120, may comprise means for carrying out the embodiments described above and any combination thereof.
    [0090] [0090] In an exemplary embodiment, a computer program may be configured to cause a method in accordance with the embodiments described above and any combination thereof. In an exemplary embodiment, a computer program product, embodied on a non- transitory computer readable medium, may be configured to control a processor to perform — a process comprising the embodiments described above and any combination thereof.
    [0091] [0091] In an exemplary embodiment, an apparatus, such as, for example, UE 110, a relay or BS 120, may comprise at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform — the embodiments described above and any combination thereof.
    [0092] [0092] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the preceding description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or S described in detail to avoid obscuring aspects of the invention. O [0093] While the forgoing examples are illustrative of the principles of the n 25 embodiments in one or more particular applications, it will be apparent to those of ordinary = skill in the art that numerous modifications in form, usage and details of implementation 2 can be made without the exercise of inventive faculty, and without departing from the 3 principles and concepts of the invention. Accordingly, it is not intended that the invention O be limited, except as by the claims set forth below. — [0094] The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor reguire the existence of also un-recited features. The features recited in depending claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of "a" or "an", that is, a singular form, throughout this document does not exclude a plurality.INDUSTRIAL APPLICABILITY
    [0095] [0095] At least some embodiments find industrial application in cellular communication networks, wherein it is desirable to enable flexible beam operation, such as in networks operating according to 3GPP standards. For instance, embodiments of the present invention may be applied for 3GPP RAN standardization.ONO
    N > ™
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    ACRONYMS LIST 3GPP 3rd Generation Partnership Project ASIC Application-Specific Integrated Circuit BS Base Station COT Channel Occupancy Time DCI Downlink Control Information DU Distributed Unit FPGA Field-Programmable Gate Array GC PDCCH Group Common PDCCH GSM Global System for Mobile communication IAB Integrated Access and Backhaul IoT Internet of Things LBT Listen-Before-Talk LTE Long-Term Evolution M2M Machine-to-Machine MT Mobile Termination N NFC Near-Field Communication
    N 5 NR New Radio > NR-U NR Unlicensed
    T 2 20 PDCCH Physical Downlink Control Channel 3 PDSCH Physical Downlink Shared Channel
    O N PUCCH Physical Uplink Control Channel PUSCH Physical Uplink Shared Channel
    RAN Radio Access Network RAT Radio Access Technology SCS Subcarrier Spacing SIM Subscriber Identity Module UCI Uplink Control Information UE User Equipment Ul User Interface WCDMA Wideband Code Division Multiple Access WiMAX Worldwide Interoperability for Microwave Access WLAN Wireless Local Area NetworkONO
    N > ™
    I a a coOOLOONON
    REFERENCE SIGNS LIST Another User Equipment 300 — 370 Structure of the apparatus of FIGURE 3 410 — 460 Actions of BS and UE in FIGURE 4 510 — 570 Steps of the process of FIGURE 5 610 — 640 Phases of the first method in FIGURE 6 710 — 740 Phases of the second method in FIGURE 7 oO
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    N OoN
    权利要求:
    Claims (15)
    [1] 1. An apparatus, comprising one or more processors, and memory storing instructions that, when executed by the one or more processors, cause the apparatus to: — start a transmission burst to occupy a channel on an unlicensed frequency band for a channel occupancy time; — transmit a trigger to a user equipment, the trigger triggering at least one channel availability measurement to be performed on the channel by the user equipment during the channel occupancy time; — determine, during the channel occupancy time, whether the channel is available based at least on a response of the user equipment; and — continue the transmission burst or starting a new transmission burst, wherein the continuation of the transmission burst or start of the new transmission burst depends on whether the channel is determined as available during the channel occupancy time.
    [2] 2. An apparatus according to claim 1, wherein the trigger is a command transmitted to the user equipment, the command commanding the user equipment to perform the at least one channel availability measurement on the channel during the channel occupancy time.
    [3] 3. An apparatus according to claim 2, wherein the command is transmitted on a group common physical downlink control channel or on a unicast physical downlink control channel.
    [4] S S 4. An apparatus according to any of the preceding claims, wherein said one or more processors, and memory storing instructions that, when executed by the one or more 5 processors, further cause the apparatus to: E — perform at least one channel availability measurement on the channel during the o channel occupancy time; and 3 — determine, during the channel occupancy time, whether the channel is available O based on the at least one channel availability measurement of the apparatus and the response of the user eguipment.
    [5] 5. An apparatus according to claim 4, wherein the at least one channel availability measurement to be performed on the channel by the user equipment and the at least one channel availability measurement performed by the apparatus take place at most a predetermined number of slots or symbols apart.
    [6] 6. An apparatus according to any of the preceding claims, wherein said one or more processors, and memory storing instructions that, when executed by the one or more processors, further cause the apparatus to: — continue the transmission burst during the channel occupancy time responsive to determining that the channel is still available and a duration of the transmission burst is smaller than a maximum channel occupancy time.
    [7] 7. An apparatus according to any of the preceding claims, wherein said one or more processors, and memory storing instructions that, when executed by the one or more processors, further cause the apparatus to: — transmit an indication responsive to determining that the channel is still available, the indication indicating continuation of the transmission burst during the channel occupancy time or start of the new transmission burst.
    [8] 8. An apparatus according to any of the preceding claims, wherein said one or more processors, and memory storing instructions that, when executed by the one or more processors, further cause the apparatus to: — defer the continuation of the transmission burst or the start of the new transmission o burst by a deferral time responsive to determining that the channel is not available.
    [9] N & = 9. An apparatus according to any of the preceding claims, wherein said one or more = processors, and memory storing instructions that, when executed by the one or more x processors, further cause the apparatus to: © — transmit an indication of a deferral time responsive to determining that the channel 3 is not available, wherein the deferral time is determined pseudo-randomly based on ä a maximum duration of the channel occupancy time.
    [10] 10. An apparatus according to any of the preceding claims, wherein said one or more processors, and memory storing instructions that, when executed by the one or more processors, further cause the apparatus to: — transmit an indication during the channel occupancy time responsive to determining that the channel is not available, the indication indicating suspension of the transmission burst.
    [11] 11. An apparatus, comprising one or more processors, and memory storing instructions that, when executed by the one or more processors, cause the apparatus to: — receive a trigger from a base station, the trigger triggering at least one channel availability measurement to be performed by the apparatus on a channel on an unlicensed frequency band during a channel occupancy time; — perform the at least one channel availability measurement on the channel during the channel occupancy time; — transmit a response to the base station during the channel occupancy time, wherein the response is based on the at least one channel availability measurement; and — detect that a transmission burst is continuing or a new transmission burst is starting.
    [12] 12. An apparatus according to claim 11, wherein the trigger is a command received from the base station, the command commanding the user equipment to perform the at least one channel availability measurement on the channel during the channel occupancy time.
    [13] 13. A method for a base station, comprising: o — starting a transmission burst to occupy a channel on an unlicensed frequency band a for a channel occupancy time; — transmitting a trigger to a user equipment, the trigger triggering at least one channel n availability measurement to be performed on the channel by the user eguipment E during the channel occupancy time; 00 — determining, during the channel occupancy time, whether the channel is available 3 based at least on a response of the user equipment; and O — continuing the transmission burst or starting a new transmission burst, wherein the continuation of the transmission burst or start of the new transmission burst depends on whether the channel is determined as available during the channel occupancy time.
    [14] 14. A method for a user equipment or a relay, comprising: — receiving a trigger from a base station, the trigger triggering at least one channel availability measurement to be performed by the apparatus on a channel on an unlicensed frequency band during a channel occupancy time; — performing the at least one channel availability measurement on the channel during the channel occupancy time; — transmitting a response to the base station during the channel occupancy time, wherein the response is based on the at least one channel availability measurement; and — detecting that a transmission burst is continuing or a new transmission burst is starting.
    [15] 15. A computer program configured to perform a method according to claim 13 or 14.
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    同族专利:
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    FI129272B|2021-10-29|
    WO2021151719A1|2021-08-05|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    CN108574953B|2017-03-09|2020-06-09|华为技术有限公司|Channel access method, device and computer storage medium|
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    PCT/EP2021/051013| WO2021151719A1|2020-01-31|2021-01-19|Improved channel access on unlicensed frequency bands by cellular communication devices|
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