Integrated circuit

Abstract

To handle transition periods for user equipment (UE), a base station, and respective transmission / reception methods of the UE and the base station in an NR unlicensed operation or a similar system.SOLUTION: In a communication system, UE, during operation, determines, based on a type of transmission, a time interval between an outer boundary of a transition period for power ramping to start or end transmission and a symbol on which a signal included in the transmission is transmitted, during operation, transmits the signal on the symbol, where the time interval and a time window for clear channel assessment (CCA) is non-overlapping, the signal transmitted on the symbol is a first signal, the transmission includes a second symbol having a lower service requirement than the first symbol, and to increase the time interval, determines a time interval between the outer boundary of the transition period and a symbol on which the first signal is to be transmitted by swapping symbol positions of the first and second signals.SELECTED DRAWING: Figure 13

Description

[Technical field]

[0001] The present disclosure relates to transmitting and receiving signals in a communication system, and more particularly to methods and apparatus for such transmission and reception. [Background technology]

[0002] The 3rd Generation Partnership Project (3GPP) is working on technical specifications for next-generation cellular technologies, also known as the fifth generation (5G), which include the “New Radio” (NR) radio access technology (RAT) that will operate in the frequency range from sub-1 GHz to the mmWave bands. NR is the successor to the technologies represented by Long Term Evolution (LTE) and LTE Advanced (LTE-A).

[0003] For systems such as LTE, LTE-A, and NR, further modifications and options may facilitate efficient operation of the communication system as well as certain devices associated with the system. Summary of the Invention

[0004] One non-limiting and illustrative embodiment facilitates transmission of reliable signals with high service demand in unlicensed spectrum.

[0005] In an embodiment, the techniques disclosed herein feature a user equipment (UE) having circuitry that, during operation, determines based on a type of transmission, an outer boundary of a transient period for ramping of power to start or end the transmission and a time interval between a symbol on which a signal included in the transmission is transmitted, and a transceiver that, during operation, transmits the signal on the symbol, wherein the time interval and a time window for Clear Channel Assessment (CCA) are non-overlapping.

[0006] It should be noted that the general or specific embodiments may be realized as a system, a method, an integrated circuit, a computer program, a storage medium, or any combination thereof.

[0007] Further benefits and advantages of the disclosed embodiments will become apparent from the specification and drawings, in which the benefits and / or advantages may be obtained individually from various embodiments and features of the specification and drawings, which need not all be provided in order to obtain one or more of such benefits and / or advantages. [Brief description of the drawings]

[0008] In the following, exemplary embodiments are explained in more detail with reference to the attached drawings. [Figure 1] 1 illustrates an example architecture for a 3GPP NR system, including example user and control plane architectures for LTE eNBs, gNBs, and UEs. [Diagram 2] 1 is a schematic diagram of frames, subframes and slots for different subcarrier spacings. [Diagram 3] 1 is a graph showing a specific example of a transient period in NR. [Figure 4] 1 is a graph showing a specific example of a transition period in LTE-LAA (License-Assisted Access). [Diagram 5] FIG. 2 is a schematic diagram of a schematic embodiment of CCA immediately prior to transmission. [Figure 6] 1 is a block diagram of a base station and a UE in accordance with some embodiments. [Figure 7] FIG. 2 is a block diagram showing a processing circuit of a base station. [Figure 8] FIG. 2 is a block diagram showing a processing circuit of the UE. [Figure 9] 1 is a flow chart of a transmission method for a communication device. [Figure 10] FIG. 13 is a schematic diagram of a transient period at the end and start of two subsequent transmissions. [Figure 11]Indicates the time interval (guard period) between the start / end of power ramping and the first / last symbol of the transmission. [Figure 12] Indicates the time interval (guard period) between the start / end of power ramping and the first / last symbol of the transmission. [Figure 13] Indicates the time interval (guard period) between the start / end of power ramping and the first / last symbol of the transmission. [Figure 14] FIG. 1 is a schematic diagram showing a failed CCA and guard period for a transmission. [Figure 15] FIG. 1 is a schematic diagram showing a successful CCA and guard period for a transmission. [Figure 16] 1 illustrates different guard periods for different types of signals. [Figure 17] 1 illustrates different guard periods for different types of signals. [Figure 18] 1 illustrates different guard periods for different types of signals. [Figure 19] 1 illustrates different guard periods for different types of signals. [Figure 20] 1 illustrates different guard periods for different types of signals. [Figure 21] 1 illustrates different guard periods for different types of signals. [Figure 22] 5 is a flowchart illustrating steps performed by a UE at the start of a transmission. [Diagram 23] 10 is a flowchart illustrating another embodiment of steps performed by a UE at the start of a transmission. [Figure 24A] 11 is a flow chart showing steps performed by a UE at the end of transmission. [Figure 24B] 11 is a flow chart showing steps performed by a UE at the end of transmission. [Diagram 25] 1 is a flowchart illustrating a communication method for a base station and a UE. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] FIG. 1 illustrates an exemplary embodiment of a communication system including a base station, a terminal, and a core network. Such a communication system may be a 3GPP system, such as NR, LTE, and / or UMTS. For example, as illustrated in FIG. 1, a base station (BS) may be a gNB (gNodeB, such as an NR base station) or an eNB (eNodeB, such as an LTE base station). However, the present disclosure is not limited to these 3GPP systems or any other systems. Even though the embodiments and example implementations are described using some terminology of a 3GPP system, the present disclosure is also applicable to any other communication system, in particular any cellular, wireless, and / or mobile system.

[0010] NR is planned to facilitate the provision of a single technical framework that addresses several defined usage scenarios, requirements and deployment scenarios, including, for example, enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), massive Machine Type Communication (mMTC), etc. For example, eMBB deployment scenarios may include indoor hotspots, dense urban, rural, urban macro and high speed, URLLC deployment scenarios may include industrial control systems, mobile healthcare (remote monitoring, diagnosis and treatment), real-time control of vehicles, wide area monitoring and control systems for smart grids, and mMTC may include scenarios with a large number of devices with non-time-critical data transfer, such as smart wearables and sensor networks. The services eMBB and URLLC are similar in that both require very high bandwidth, but differ in that URLLC services require ultra-low latency. In NR, the physical layer may support multiple antenna operation based on time-frequency resources (such as orthogonal frequency division multiplexing (OFDM), similar to LTE).

[0011] The terminal is called User Equipment (UE) in LTE and NR. It may be a mobile device such as a wireless phone, a smartphone, a tablet computer or a Universal Serial Bus (USB) stick with user equipment functionality. However, the term mobile device is not limited to this and in general a relay may have the functionality of such a mobile device and a mobile device may also function as a relay.

[0012] A base station is a network node forming part of a network for providing services to terminals, for example A base station is a network node that provides wireless access to terminals.

[0013] 3GPP is studying NR-based operation in unlicensed spectrum (NR-U) (see, e.g., 3GPP TR 38.889, Study on NR-based access to unlicensed spectrum, v16.0.0). NR-U may operate in sub-7 GHz bands at 5 GHz or 6 GHz. However, the present disclosure is not limited to a particular band and may also be applied to, for example, the 52 GHz mmWave band.

[0014] The Listen-Before-Talk (LBT) procedure is defined as a mechanism whereby a device, such as a base station or user equipment, applies a Clear Channel Assessment (CCA) check before using a channel. CCA uses at least energy detection to determine the presence or absence of other signals on the channel to determine whether the channel is occupied or clear, respectively. For example, European and Japanese regulations mandate the use of LBT in unlicensed bands. Apart from regulatory requirements, this carrier sensing via LBT is one method for fair sharing of unlicensed spectrum and is therefore considered to be a key feature for fair and friendly operation in unlicensed spectrum in a single global solution framework.

[0015] If the detected energy level exceeds the set CCA threshold (e.g., for Europe -73 dBm / MHz, see ETSI 301 893), the channel is considered occupied. Conversely, if the detected power level is below the set CCA threshold, the channel is considered free. If the channel is classified as free, the device is allowed to transmit immediately. The maximum transmission duration is limited to achieve fair resource sharing with other devices operating in the same band.

[0016] In unlicensed band operation, after acquiring a channel by LBT, an initiating device (e.g., a scheduling device such as an NR gNB or LTE eNB) can occupy the channel up to a maximum channel occupation time (COT). For example, depending on the LBT request, the maximum COT may be assumed to be 8 ms or 9 ms. For example, for a subcarrier spacing of 15 kHz, a COT of 8 ms corresponds to 8 slots, and for a subcarrier spacing of 30 kHz, it corresponds to 16 slots.

[0017] The initiator device (e.g., gNB) may share the acquired time-frequency resources with the responder device (e.g., one or more transmitting / receiving devices such as UEs). Sharing the acquired time-frequency resources can be achieved to enable flexible resource utilization between uplink (UL) and downlink (DL). For example, DL and UL resources can be reallocated based on traffic demand in each direction.

[0018] Furthermore, sharing of the acquired resources may be realized to enable UL transmission with one-shot LBT (without random backoff) in the gNB acquired COT. In particular, for the case where a UL transmission in a gNB initiated COT is not followed by other DL transmissions in the same COT, Cat-2-LBT is utilized to sense the channel before the UE performs a UL transmission, which means that the duration of time that the channel is sensed as idle before the UL transmission is deterministic, as captured in 3GPP TR 38.889, Study on NR-based access to unlicensed spectrum, v16.0.0, Table 7.2.1.3.1-3.

[0019] Furthermore, semi-statically configured or periodic reference signal, signaling or data transmissions may be enabled by sharing the acquired time-frequency resources. For example, if a semi-statically configured UL transmission configured by higher layers was within the COT of the gNB, but the UL resources were not shared by the gNB, the UL transmission needs to be dropped.

[0020] However, the COT can also be initiated by the UE instead of the gNB. In such a case, the UE needs to perform LBT to ensure that the channel is not occupied by other devices before acquiring the channel for transmission. Compared to when the UE performs LBT in a COT already initiated by the gNB, the chance of collision is higher. Thus, the LBT needs to consider more uncertainties. For example, as captured in 3GPP TR 38.889, Study on NR-based access to unlicensed spectrum, v16.0.0, Table 7.2.1.3.1-4, if the UE wants to transmit PUSCH as the initiating device of the COT, Cat-4 LBT needs to be performed, which means that the LBT with random backoff with variable size contention window is utilized (see the channel access scheme in Section 8.2 in 3GPP TR 38.889, Study on NR-based access to unlicensed spectrum, v16.0.). Basically, the UE draws a random number N within the contention window. The size of the contention window is specified by the minimum and maximum values ​​of N. The UE can change the size of the contention window when it picks the random number N. The random number N is used in the LBT procedure to determine the duration of time that the channel is sensed as idle before the UE can transmit.

[0021] The CCA (Clear Channel Assessment) may be performed at the end of the slot, and the COT may have the first symbol (OFDM symbol) of the slot following the slot where the CCA is performed. However, different opportunities or times at which the initiating device may acquire the channel may be considered. For example, the opportunities may be once per second symbol or twice per slot. Thus, the CCA may also be performed at symbols away from the end of the slot.

[0022] In slot-based scheduling or allocation, a slot corresponds to the timing granularity (transmission time interval (TTI)) for the scheduling allocation. In general, the TTI determines the timing granularity for the scheduling allocation. One TTI is the time interval in which a given signal is mapped to the physical layer. For example, conventionally, the TTI length is variable from 14 symbols (slot-based scheduling) to 2 symbols (non-slot-based scheduling). Downlink (DL) and uplink (UL) transmissions are specified to be organized into frames (10 ms duration) consisting of 10 subframes (1 ms duration). In slot-based transmission, the subframes are further divided into slots, the number of slots being dictated by the numerology / subcarrier spacing, as shown in FIG. 2. Specified values ​​range from 10 slots per frame (1 slot per subframe) at a subcarrier spacing of 15 kHz to 80 slots per frame (8 slots per subframe) at a subcarrier spacing of 120 kHz. The number of OFDM symbols per slot is 14 for normal cyclic prefix and 12 for extended cyclic prefix (see sections 4.1 (Overall frame structure), 4.2 (Numerology), 4.3.1 (Frames and subframes) and 4.3.2 (Slots) of 3GPP TS 38.211 V15.3.0, Physical channels and modulation, 2018-09). However, the allocation of time resources for transmission may also be non-slot based. In particular, a TTI in a non-slot based allocation may correspond to a mini-slot instead of a slot. That is, one or more mini-slots may be allocated to a requested transmission of data / control signaling. In a non-slot based allocation, the minimum length of a TTI may be, for example, 1 or 2 OFDM symbols.

[0023] When a transmitting device, such as a UE transmitting an UL burst, starts transmitting a burst in the unlicensed spectrum, it may need to change the transmitter's radio frequency (RF) state. The transient period is the time required for the transmitter to change its RF state, such as powering from OFF to ON and ON to OFF.

[0024] During the transition period, the transmit power changes, increasing or decreasing from / to a value below the OFF power request threshold to / from a value above the ON power request threshold. The value of the transmit power during the transition period is not specified in the standard specification.

[0025] Instead, the maximum allowable transient period length is specified in the standard specification. For example, in Frequency Range 1 (FR1), a UE can have a transient period of up to 10us (see User Equipment (UE) radio transmission and reception, Part 1: Range 1 Standalone (Release 15) in 3GPP TS 38.101-1 V15.5.0 (2019-03)). FR1 is the frequency range from 410MHz to 7125MHz, and uses subcarrier spacings (SCS) of 15kHz, 30kHz, and 60kHz for the data channel. As an example of a transient period of NR UL transmission, a typical ON / OFF time mask for NR UL transmission in FR1 is shown in Figure 3 (see Figure 6.3.3.2-1 in 3GPP 38.101-1).

[0026] Additionally, in FR2, the UE can have a transient period of up to 5us (see User Equipment (UE) radio transmission and reception, Part 2: Range 1 Standalone (Release 15) in 3GPPTS 38.101-1 V15.5.0 (2019-03)). FR2 is the frequency range from 24250MHz to 52600MHz, and utilizes SCS 60kHz and 120kHz for the data channel.

[0027] As mentioned above, for unlicensed operation, CCA needs to be performed in unlicensed operation. Moreover, in a typical scenario, the device needs to perform CCA before any transmission. For LTE-LAA (License-Assisted Access) system, a scheme for unlicensed operation is provided. LTE-LAA provides respective frame structures for licensed band operation and unlicensed band operation, namely, Type 1 and 2 (licensed band operation) and Type 3 (unlicensed band operation).

[0028] On the other hand, type 3 frame configurations are dedicated to unlicensed operation. The subframe TTI and the general ON / OFF time mask for frame configuration type 3 are shown in Figure 4 (see Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) radio transmission and reception, Fig. 6.3.4.1-1A of 3GPP TS 36.101 V16.1.0 (2019-03)). As can be seen from Figure 4 in the time mask for frame configuration type 3, the transient period is absorbed by the Tx (transmit / transmitter) burst (transmission in unlicensed spectrum) itself. Thus, the CCA can be performed outside the burst (e.g., in the period t p It can be performed between

[0029] On the other hand, licensed spectrum operation utilizes frame configuration type 1 or type 2, which are not applicable to unlicensed spectrum operation for the following reasons: Frame configuration type 1 is only applicable to Frequency Division Duplex (FDD) and therefore is not applicable to unlicensed spectrum operation based on Time Division Duplex (TDD).

[0030] Furthermore, frame configuration type 2 is applicable to TDD, but provides a configuration with a fixed uplink and downlink ratio. Also, such uplink-downlink configuration pattern is always specified for a duration of 10 subframes (see Table 4.2-2 Uplink-downlink configurations in 3GPP TS 36.211 v15.4.0). Therefore, type 2 is not suitable for unlicensed band operation (or unlicensed operation for short), where flexibility regarding the duration of channel occupancy is required, along with greater flexibility for the transmission positions, e.g., UL and DL bursts. Another important factor that makes frame configuration type 2 inapplicable to unlicensed band operation is the lack of a time gap for performing CCA. In contrast, as shown in Figure 4, at the beginning of a subframe, the untransmitted gap is limited by the parameter t p and CCA is generated by t p This can be done later, before the actual transmission.

[0031] If the time mask for frame configuration type 3 from LTE-LAA is reused in NR-U, the front and rear symbols of a Tx burst will be subject to transient effects. The impact of transient effects on these symbols may be particularly relevant for NR-U operating with a higher / wider SCS corresponding to shorter symbol durations, or for bursts starting and / or ending with high priority symbols requiring high reliability, such as reference symbols.

[0032] If the CCA succeeds at the beginning of a symbol boundary and the Tx burst starts immediately, the first symbol of the burst will be affected by a transient period, as shown in Figure 5. As a result, the first symbol (or the signal transmitted in the first symbol) will be corrupted (e.g., the transmit power did not reach a sufficient strength and cannot be recovered at the receiving end), affecting the reliability of transmission and reception in the communication system or the QoS of the communication system.

[0033] The present disclosure provides techniques for facilitating providing reliability of transmission and reception. Techniques are provided for handling transient periods for unlicensed operation in NR unlicensed or similar systems. Embodiments of the present disclosure feature communication devices, such as user equipment (UE), base stations (e.g., NR gNB), and respective transmission and reception methods for the UE and communication devices, such as base stations.

[0034] As shown in FIG. 6, a UE 660 is provided that includes a transceiver 670 (or "UE transceiver") and circuitry 680 (or "UE circuitry"), and a base station 610 is provided that includes a transceiver 620 (or "base station transceiver") and circuitry 630 (or "base station circuitry"). For example, the base station and the UE communicate with each other over a channel, such as a radio channel in a communications system, such as NR (or NR unlicensed). The UE 660 transmits and receives signals to the base station 610, and vice versa.

[0035] In the following, the terms "circuitry" and "transceiver" encompass the base station circuitry 630 and base station transceiver 620, as well as the UE circuitry 680 and UE transceiver 670, unless the context or implicit reference indicates otherwise. The circuitry 630, 680 is processing circuitry, such as a processor. The transceivers 620, 670 include hardware components, such as one or more antennas, and software components that control the operation of the hardware components.

[0036] In operation, the circuitry determines, based on the type of transmission, the time interval (length) between the outer boundary of the transient period during which the transceiver performs power ramping to start or end the transmission and the symbol (symbol to which the signal or data is mapped) on which the signal contained in the transmission is transmitted. In operation, the transceiver 620, 670 performs transmissions, where it transmits signals on (or within) the symbols. The time intervals and time windows for CCA (Clear Channel Assessment) do not overlap. The time interval or the length (duration) of the time interval depends on the type of transmission.

[0037] An "outer boundary" is a boundary of a transition period where the power value passes the threshold for an "OFF" request, i.e., an earlier boundary if the transmit power is switched from OFF to ON state at the beginning of a transmission, or a later boundary if the transmit power is switched from ON to OFF at the end of a transmission / burst. Thus, for an OFF to ON transition period, the distance between the outer boundary and a symbol is the distance between an earlier boundary of the transition period in time (beginning of the symbol) and an earlier symbol boundary. For an ON to OFF transition period, the distance between the outer boundary and a symbol is the distance between a later symbol boundary in time (end of the symbol) and a later boundary of the transition period.

[0038] A transmission may be a (Tx) burst in an unlicensed spectrum including one or more OFDM symbols, and a symbol is an OFDM symbol included in the transmission. As described, the CCA may be a CCA for a transmission (i.e., a current transmission performed by the UE 660 or the base station 610) or a subsequent transmission performed after a current transmission by the base station 610 (DL burst), the UE 660, or another UE different from the UE 660. In particular, in the case of an OFF-to-ON transition period, the CCA is a CCA for a current transmission, and in the case of an ON-to-OFF transition period, the CCA is a CCA for a subsequent transmission.

[0039] The time window of the CCA refers to the duration during which the channel is actually measured. For example, a slot duration T sf (which is 9 us) indicates that the eNB senses the channel during the slot duration and the power detected by the eNB for at least 4 us during the slot duration is greater than the energy detection threshold X ThreshIf it is less than T, it is considered idle. sf In other words, if the CCA is busy for only one slot of 9us, the duration T sf , the actual measurement window need only be 4 us. With this understanding, what is required to not overlap is between the specified time interval and the actual measurement window for the CCA, instead of the full duration of the CCA, e.g., 4 us duration in the above example.

[0040] Also, as will be further described, the type of transmission may include the type of signal, such as a control signal, a reference signal, a preamble or a data signal, the symbol position of the particular type of signal within the transmission, and / or numerological characteristics, such as the SCS and its associated symbol length / duration. The type of transmission may further include the duration of the transmission or burst.

[0041] An exemplary base station circuit 630 for determining the spacing between an outer boundary of a transition period and a symbol ("signal / boundary spacing determination circuit") is shown in FIG. 7. For example, the processing circuit 630 includes a spacing derivation circuit 732. The circuit 630 may further include a notification determination circuit 731. An exemplary signal / boundary spacing determination circuit 680 of a UE 660 is shown in FIG. 8. For example, the UE circuit 680 includes a spacing derivation circuit 882 and may further include a notification evaluation circuit 881.

[0042] Corresponding to the above-mentioned UE and base station, a transmission method and a reception method for a communication device such as a UE or a base station are disclosed as shown in Fig. 9. The transmission method for the UE or base station includes a step S940 of determining, based on a type of transmission, a time interval between an outer boundary of a power ramping transient period for starting or ending the transmission and a symbol on which a signal included in the transmission is transmitted. The transmission method further includes a step S970 of transmitting a signal on a symbol, where the time interval does not overlap with a time window for CCA. The reception method includes a step of receiving the transmission rather than a step S970 of performing the transmission.

[0043] In the following, exemplary embodiments of the above-mentioned UE, base station, and corresponding communication methods (transmission and reception methods of the base station and the UE) are described. Unless expressly stated or indicated by the context, the following description applies to the method and apparatus, the base station, and the UE.

[0044] In some embodiments, the symbol on which the signal is transmitted is located at the time boundary of the transmission, for example the signal is assigned to the first or last symbol of a Tx burst in the time direction.

[0045] For example, a "guard period" (or "offset" or "explicit transient period") is defined or provided before and after a Tx burst boundary (the time boundary of a transmission that is also the time boundary of the symbol on which a signal is transmitted if the signal is at the time boundary of the transmission). In the time interval (or guard period, offset), no CCA measurements are performed. In this disclosure, the term "guard period" refers to a period during which power ramping for a burst may be performed but no CCA (measurements) is performed, and is set to protect the CCA results from effects caused by power ramping and to allow a symbol strength strong enough to achieve successful transmission / reception of critical symbols that require high reliability, if necessary.

[0046] Examples of time intervals / guard periods include a frontguard period at the starting boundary of a transmission and a rearguard period at the ending boundary of a transmission.

[0047] On the other hand, a front guard period (or front offset / front explicit transient period) between the CCA for the (current) transmission and the start of the first symbol of the transmit / Tx burst is available to accommodate, at least in part, the OFF to ON power transient period (the OFF to ON transition period mentioned above).

[0048] On the other hand, a rearguard period (rear offset / rear explicit transient period) may be set between the end of the last symbol and the next (possible) CCA performed by a device in the communication system and is available to accommodate at least partially the ON-to-OFF power transient period (ON-OFF transient period).

[0049] An example where an ON to OFF transition period of a previous burst is followed by an OFF to ON transition period of an intended Tx burst is shown in Figure 10. As mentioned above, transmission of symbols that may contain important signals during the transition period may jeopardize successful transmission of the signal and depending on the importance of the signal such as a control or reference signal, may jeopardize successful transmission of the burst. To achieve successful transmission of the burst, a guard period at the beginning of the transmission where the power is ramped on can be defined / configured.

[0050] Furthermore, as shown in Figure 10, if the CCA before an intended transmission measures a certain amount of residual power due to a transient period of the previous transmission, the channel may be unnecessarily blocked due to a failed CCA. Thus, it can be seen that the transient period after a Tx burst, during which the transmit power is ramped off, may also affect the CCA performed for a subsequent transmission. Thus, a time interval or guard period between the last symbol of a transmission and the outer boundary of the ON-to-OFF transient period that does not overlap with a CCA period or window for subsequent / future transmissions may facilitate CCA for future transmissions.

[0051] As mentioned above, the time interval or guard period depends on the type of transmission. For example, the length (duration) of the front and rear guard periods (or offset or explicit transient periods) may be determined by the type of channel / signal transmitted at the beginning and end (first and / or last symbol) of a Tx burst, respectively. Examples of guard periods of different lengths are shown in Figures 11 to 13. That is, the illustrated guard periods (time intervals between the outer boundary of the transient period and the first / last symbol of a burst) range from zero to values ​​greater than the length of the transient period. Thus, flexibility regarding service requirements can be provided, as shown by the following examples:

[0052] First, if the guard period is zero as shown in Fig. 11, the transient period is absorbed by the Tx burst itself. On the other hand, in this case, no "transient overhead" is generated due to the transient period. However, due to the guard period being zero, the first and / or last symbols may be corrupted as described above.

[0053] Second, when the guard period is non-zero but smaller than the transient period as shown in Fig. 12, the transient period is partially absorbed by the Tx burst and partially accommodated by the guard period. The guard period was previously called the "explicit transient period", but in the example of Fig. 12, the explicit transient period is equal to the portion of the transient period accommodated by the guard period. Correspondingly, the remaining portion of the transient period that is absorbed by the burst may be called the "implicit transient period". A non-zero guard period that is smaller than the transient period may be associated with a moderate transient overhead and a moderate impact on the first / last symbols.

[0054] Third, if the guard period is equal to or greater than the transition period, the transition period will be completely outside the Tx burst, as shown in Figure 13. This creates the largest overhead among the examples in Figures 11-13, but at the same time, it may be easier to provide good protection for the first / last symbols of the burst.

[0055] In the following, the cases of successful and failed CCA before the start of the Tx burst are explained with reference to figures 14 and 15. On the other hand, if the CCA fails and the value of the time interval is greater than zero, the transceiver performs a new attempt of CCA during operation, which ends by the start time of the transition period, as shown in figure 14. The transmission of the Tx burst is postponed to the next transmission opportunity with the new CCA (new attempt) with the guard period remaining. Thus, the time interval or time window in which the new CCA attempt is performed still does not overlap with the guard period. The time window or time interval for the earlier attempt of CCA and the time interval / time window for the new attempt of CCA may be different.

[0056] However, if the CCA for a transmission succeeds with a symbol guard period, but the guard period is non-zero, the guard period still needs to be respected. Thus, in some embodiments, as illustrated by FIG. 15, if the CCA succeeds and the value of the time interval is greater than 0, the transmission (Tx burst) is postponed from the first transmission opportunity at or after the end of the CCA window to a second transmission opportunity (e.g., the next transmission opportunity), and the time distance from the end of the CCA window to the second transmission opportunity is greater than or equal to the guard period. Furthermore, in some cases, even if the first CCA is successful, a new CCA needs to be performed before the second transmission opportunity. The purpose is to ensure that the channel is still free after shifting the transmission opportunity. However, typically, the second CCA may have a deterministic duration without a random backoff value so that it can be performed before the guard period of the second transmission opportunity.

[0057] In the following, some criteria are described for determining the length of the guard period. For example, if the start or end symbol (the first and / or last symbol of a burst) is important (assigned an important signal), the guard period will have a longer duration for better protection. Otherwise, it may have a shorter duration to minimize or reduce overhead.

[0058] Here, a symbol may be "important" if it has a high demand for service, such as a reliability demand, e.g., the symbol contains information necessary for receiving, demodulating, and / or decoding the burst. Thus, in some embodiments, the above-mentioned type of transmission includes a service demand for the type of signal (or type of channel) transmitted on the symbol, where the guard period is longer if the service demand is higher and shorter if the service demand is lower.

[0059] For example, the service requirement is higher if the type of signal is a control signal or reference signal, and lower if the type of signal is a preamble or data signal. Thus, the service requirement is higher (and therefore the guard period is longer) for symbols requiring a higher quality of service (priority / reliability) than for symbols requiring a lower quality of service. Some examples of the relationship between the guard period and types of signals / channels with different service requirements are shown in Figures 16 to 20.

[0060] For example, as shown in Figures 16 and 17, if a Tx burst starts or ends with a control channel such as a PDCCH or PUCCH (Physical Downlink / Uplink Control Channel) that occupies the first or last symbol or more symbols at the start or end of a transmission, the frontguard and / or rearguard periods are determined to be large enough to accommodate the transient period, either completely or in a sufficiently large part.

[0061] Similarly, if the guard period is started or ended by a reference signal such as a frontloaded Demodulation Reference Signal (DMRS), Sounding Reference Signal (SRS) or Channel State Information Reference Signal (CSI-RS) for PDSCH or PUSCH (Physical Downlink / Uplink Shared Channel), the (front and / or rear) guard period is large enough to accommodate (fully or partially) the transient period, as can be seen from Figures 18 and 19. In these figures, a typical configuration of RSs in an NR system is shown, including a frontloaded DMRS at the beginning of a Tx burst. However, the present disclosure is also applicable to other RSs at the beginning and / or end of a burst than those shown in Figures 18 or 19, such as a CSI-RS or SRS at the beginning of a burst.

[0062] However, if the Tx burst is initiated by an NR-U preamble or a preamble-like signal, the front guard period may be, for example, zero (or a value smaller than the above case). One possible use case described is for automatic gain control (AGC) and / or synchronization adjustment, since the presence of a periodic signal such as SSB for the UE to keep track of AGC and synchronization is not guaranteed due to the uncertainty of the LBT. Such a preamble design can be based on existing NR signals such as primary synchronization sequence (PSS), secondary synchronization sequence (SSS), DMRS or CSI-RS with possible modifications or new signal designs. Even if the new preamble design is based on DMRS or CSI-RS, it is not expected to be used for channel estimation, since reception including channel estimation is not possible or reliable before the AGC and / or synchronization are correctly adjusted. With this understanding, the service requirements for such a new preamble are lower than for the reference signal used for channel estimation. Therefore, the guard period can be set to a smaller or zero value. This is illustrated in FIG. 20, where an OFF to ON transition occurs within a burst at the start of the first symbol, which carries a signal similar to the preamble.

[0063] As mentioned above, according to the present disclosure, a transient period at the beginning or end of a burst can be subdivided into an "explicit transient period" and an "implicit transient period". An implicit transient period is a portion of the transient period absorbed by one or more start or end symbols at the beginning or end of a burst, and the value of the implicit transient period is equal to the "transient period minus the guard period".

[0064] Due to the above-mentioned relationship between guard periods and service requirements, the implied transition periods are smaller for "important" symbols (such as control and reference signals) and larger for less important symbols (on which the success of the transmission does not depend), such as data or the preamble or preamble-like signals mentioned above (especially if sufficient redundancy is provided).

[0065] The above specific examples have been provided where the length of the guard period is based on service requirements such as the required reliability of transmission of a certain signal type. Additionally or alternatively, in some embodiments, the type of transmission includes the subcarrier spacing (SCS) of the resource on which the transmission including the signal is performed, and the time interval between the outer boundary and the symbol on which the signal is transmitted is shorter if the subcarrier spacing is narrower (smaller) and longer if the subcarrier spacing is wider. The reason is that, at a high level, the wider the SCS, the shorter the symbol duration. Consider the case where the specified time interval (or called guard period) is zero. As a result, the transient period will be absorbed by the symbol itself. Since the transient period does not change according to the SCS, for symbols with a shorter duration (in other words, a larger SCS), the proportion of the symbol duration that is damaged by the transient period will be larger compared to symbols with a longer duration (in other words, a smaller SCS). Thus, for the case of a larger SCS, a longer time interval (or guard period) is required.

[0066] Therefore, according to the above-mentioned relationship between SCS and guard period in some embodiments, the implicit transition period is larger for smaller SCS and smaller for larger SCS, and therefore a more reliable transmission of the start or end symbol of a Tx burst is also possible for numerologies with wide SCS with short symbol length.

[0067] Thus, the rules or criteria based on which the guard period and the implicit transient period are determined take into account the signal type and the transmission type including the service requirements for the SCS / numerology. These criteria may be combined or employed alone. For example, one criterion from the numerology criteria and the service requirement criteria is applied or these criteria (and possibly further criteria) are combined. When combining criteria, one criterion may be used as a preliminary criterion and the other criterion as a secondary criterion. For example, it may be specified or set for all SCSs above a certain threshold, which is sufficient to accommodate the entire transient period, but for smaller SCSs, a guard period value is used whose transient period depends on the signal type. Alternatively, the signal type may be employed as a preliminary criterion. In this case, the guard period accommodates the entire transient period whenever, for example, the first or last symbol of a burst is an important symbol to which a signal such as DMRS or PDCCH / PUCCH is mapped.

[0068] In the following Table 1, possible exemplary and non-limiting values ​​of the guard period are shown for several different combinations of frequency ranges (FR1 or FR2) and their associated symbol durations, respectively. For example, the example shown in Figure 21 corresponds to SCS=30 kHz in FR1, and PUSCH is mapped to symbols including the first symbol. Here, as an exemplary value, the guard period is determined to be 5 us (instead of 10 us). [Table 1]

[0069] As described above, the time boundary of the transmission may be the start boundary of the transmission. And, in some embodiments, the UE transceiver 670 further receives notification of the start boundary of the transmission during operation, e.g., in a grant (scheduling grant, e.g., scheduling Downlink Control Information (DCI) where the transmission is scheduled) or higher layer signaling (Radio Resource Control (RRC) signaling). During operation, the UE circuitry 680 first determines the length of the time interval (or guard period) and then determines the outer boundary of the transition period from the notified start boundary of the transmission and the length of the time interval. The UE transceiver 670 performs CCA on the transmission according to the above description of the CCA time window / interval, and then ramps power in the transition period that does not overlap with the CCA period / window to start the transmission. In this disclosure, "notification" refers to one or more indicators, such as a bitmap or bit field, representing a numerical value, e.g., a starting position of a burst.

[0070] In the following, it is explained how the UE can know the duration of the guard period. It is assumed that the rule set defined and disclosed above, including the above criteria of e.g. numerology and / or service requirements, is known to both the UE and the base station / gNB, e.g. by a standard or specification.

[0071] For example, to start transmitting a Tx burst, the UE knows from the scheduling information the starting (symbol) position of the Tx burst and other information such as the SCS and / or whether the first symbol is an important symbol (e.g. DMRS or PDCCH). According to known and previously defined rules, the UE derives the length of the guard period. It is the scheduler (or scheduling entity)'s responsibility to create a sufficient gap for the CCA where no transmission is performed.

[0072] Further details regarding an exemplary UE operation for starting a Tx burst including a PUSCH transmission are shown in FIG. 22. In step S2201, the UE receives an UL grant for PUSCH, including the starting (symbol) position of the Tx burst and a CCA request, e.g., a Cat-2 LBT (Category 2 Listen Before Talk) of 25us. According to a service request or a rule such as SCS / numerology, the UE derives a guard period length in step S2202. From the guard period length and the starting symbol position of the uplink grant, the UE can determine the outer boundary of the transition period. Then, the UE performs CCA (step S2203). If the CCA is successful, the UE ramps the transmit power starting from the outer boundary of the transition period until the ON request is reached, and then maintains the ON request (step S2204). During the power ramping up, it is checked whether the first complete symbol boundary is reached (step S2205). Here, the beginning of the transition period (the "outer boundary") is assumed to be located between two symbol boundaries. If the first complete symbol boundary has not yet been reached, the UE continues ramping up the power. However, if the first complete symbol boundary is reached, the UE starts transmitting a Tx burst (in this case a PUSCH transmission). Depending on the length of the guard period and the transition period, the UE may still continue in a PUSCH transmission. If the CCA is not successful, the transmission is abandoned and a new CCA attempt may be performed as described above.

[0073] In the example of Figure 22 above, it is assumed that the transmission is a PUSCH transmission and the first symbol is a PUSCH symbol. The PUSCH is scheduled by a scheduling grant received by the UE from the base station. For various transmissions, which may include transmissions that do not require a dynamic grant in the downlink control channel to be received, such as configured grant-based PUSCH transmissions, the starting symbol position may be indicated to the UE from higher layer (RRC) signaling received from the base station.

[0074] The above described method utilized at the start of a Tx burst, such as a PUSCH transmission, may be considered implicit since the start of the transient period is a rule known to the UE and is implicit from the start of the transmission / Tx burst.

[0075] The start of the transition period may also be signaled explicitly, for example in the scheduling information, in which case the CCA should be performed before the signaled start of the transition period.

[0076] Examples of explicit signaling of the start position of a transition period by Downlink Control Information (DCI) are provided in Table 2. In these examples, the first symbol of a slot ("Sym 0") is extracted as a reference where the beginning of a guard period is indicated by a two-bit code point. However, Table 2 only provides examples of explicit signaling and is in no way intended to limit the present disclosure to a particular start position of a burst or a transition period / guard period. In contrast, a burst may start at a transmission opportunity that may be different from the first symbol of a slot. Furthermore, the present disclosure is applicable to slot-based as well as non-slot-based allocations. [Table 2]

[0077] According to Table 2, when the UE is indicated as "00", the UE starts the first symbol of the Tx burst at symbol 0 of any slot. This means that the transient period is absorbed by symbol 0 itself. When the UE is indicated as "01", the UE starts the first (complete) symbol of the Tx burst at symbol 1 of any slot. The UE starts the transient period 16us after the symbol 0 boundary. When the UE is indicated as "10", the UE starts the first symbol of the Tx burst at symbol 1 of any slot. The UE starts the transient period 25us after the symbol 0 boundary. Finally, when the UE is indicated as "11", the UE starts the first (complete) symbol of the Tx burst at symbol 1 of any slot. The UE starts the transient period 25us+TimeAdvance value after the symbol 0 boundary. An exemplary flow chart illustrating the steps performed at the start of a transmission in the case of explicit notification is shown in FIG. 23, where steps S2301 and S2302 differ from FIG. 22. The remaining steps S2303 to S2307 are similar to the corresponding steps shown in FIG.

[0078] In addition to the above example where the time boundary is a start boundary, in some embodiments, the time boundary is an end boundary of the transmission (the current transmission in which the signal is included). In such a case, the CCA may refer to a CCA for a later transmission different from the current transmission, possibly but not necessarily transmitted by a different communication device in the communication system, such as another UE (e.g., UL transmission) or a base station (DL transmission). The UE transceiver 670 receives notification of the start boundary of the current transmission and the duration of the current transmission during operation, by grant or higher layer signaling. The UE circuitry 680 derives the end boundary of the current transmission from the notified start boundary and duration of the current transmission during operation, and determines an inner boundary of the transient period located at a distance from the end boundary of the current transmission, which is the difference between the length of the transient period and the time interval between the outer boundary of the transient period and the symbol.

[0079] Thus, in addition to signaling the starting boundary of the transmission (e.g. the position of the first symbol), the signaling also signals the duration of the transmission. For example, there are two indicators (e.g. bit fields) in the scheduling grant / scheduling DCI or in the higher layer signaling, one indicator indicating the starting boundary and the other indicator indicating the duration. Both indicators may be included in the grant. However, there may be cases, for example, where an indicator of the starting boundary of the transmission is included in the grant and an indicator of the duration is included in the higher layer signaling. Yet alternatively, a single bit field may represent both the starting position and the length.

[0080] Thus, in order to terminate the transmission of a Tx (uplink) burst (transmission including a signal), the UE knows where to start the transition period (i.e., where to start ramping down the power). In particular, based on the above-mentioned notification / indicator and the rules / criteria used to determine the length of the explicit guard period (or time interval), the UE can determine the start of the transition period. Furthermore, the length of the transition period is related to its own capabilities (such as the specific hardware and software of the UE) and is also known to the UE since standard specifications already set limits for such transition periods, for example according to the values ​​shown in Table 1. Then, the start of the guard period from ON to OFF can be determined as "start of transmission + length of transmission - implicit transition period", where the implicit transition period is equal to "transition period - guard period".

[0081] A specific example of steps performed by the UE at the end of UL transmission is shown in FIG. 24. First, in step S2401, the UE receives an UL grant for PUSCH including the PUSCH length and an indication of SCS (e.g., 15 kHz). As described above, the grant may further include an indication of the start of transmission. Then, in step S2402, the UE determines the length of the rearguard period according to a known rule. For example, as shown in FIG. 1, it is determined that there is no guard period for PUSCH and SCS of 15 kHz. In step S2403, the UE determines the start position of power ramping down to satisfy the guard period requirement. In this example, assuming that its transition period is 10 us and there is no guard period (0 guard period), the UE must start the transition period 10 us by the end of the last symbol. The UE performs the transmission of PUSCH. Until the start of the ON-to-OFF transition period, the UE transmits PUSCH with ON power requirement (S2404). If it is determined that the start of the transition period for ramping down the power has been reached (S2405), the UE ramps down the power (S2406) and transmits the remaining PUSCH symbols (which will overlap with the transition period if there is no guard period) in step S2407. If the UE power off state / request has been reached (S2408), the transmission is terminated (S2409).

[0082] In the above case, the UE operation in the case of uplink transmission from the UE to the base station has been described. For downlink transmission, the UE may receive a DL Tx burst from the beginning and follow the scheduling information informing the UE of the first complete symbol to start receiving the burst. Whether the first complete symbol includes a transition period or not (i.e., whether the transition period is before the first symbol or not) is transparent to the UE. Also, at the end of the DL transmission, the UE may follow the scheduling information informing the UE of the last (complete) symbol to receive a Tx burst at the end. Whether the last symbol includes a transition period or not is transparent to the UE.

[0083] According to the above-mentioned UE operation, it may be provided that no special mapping (from coded bits or reference signals to physical resources) is required for the first and last symbols, regardless of whether the first / last symbols include a transition period or not.No special handling of the first and last symbols at the receiver side may be required, regardless of whether the first / last symbols include a transition period or not.

[0084] Above was described an embodiment in which the time interval between the outer boundary of the transition period and the symbol on which the signal is transmitted corresponds to a guard period inserted before the first symbol or after the last symbol of a Tx burst. However, the present disclosure also covers an embodiment in which no guard period is inserted (the guard period is 0, independent of the transmission type). In such an embodiment, a sufficiently large time interval between the start of the transition period and the symbol on which the essential (important) signal / information is mapped can be achieved by not using the start and end symbols (first and last symbols of the burst) for carrying essential information such as reference signals or control information.

[0085] In the disclosure above, SCS / numerology and service requirements are named as the basis of rules based on which the guard period is determined. Other requirements or criteria for the transition period as may be applicable to the use of the licensed band may be applied in addition to, in combination with, or on top of the rules described above. Thus, in some embodiments, the type of transmission includes the duration of the transmission, and if the duration of the transmission is shorter, the guard period will be longer and if the duration of the transmission is longer, the guard period will be shorter. For example, if the transmission burst is short, it may be required that the transition period should be outside of the Tx burst.

[0086] Thus, in some embodiments, the signal transmitted on the symbol is a first signal, and the transmission includes a second symbol having a lower service requirement than the first symbol. The (UE or base station) circuit 630, 680 determines the time interval between the outer boundary of the transition period and the symbol on which the first signal is transmitted by swapping the symbol positions of the first and second signals, and lengthens the time interval. Thus, the interval between the outer boundary of the transition period and the symbol carrying the first signal is established by swapping (swaping / switching) the symbol positions, thereby moving the symbol carrying the first signal to an internal symbol position that is distant from or not adjacent to the outer boundary of the transition period. For example, for a data channel, if a Tx burst is originally intended to start or end with a mandatory reference signal on the first or last symbol, the start or end symbol is swapped with, for example, the second symbol (or the second last symbol).

[0087] For example, the UE receives a flag from the base station in a grant or higher layer signaling indicating whether the symbol positions should be swapped or not, and performs the symbol position swapping according to the flag if the transmission is an uplink transmission. For DL ​​transmission, the base station performs the swapping and the flag informs the UE which signals should be received (demodulated, decoded) at which symbols and in which order.

[0088] For example, the scheduling DCI includes a flag to instruct the UE to reshuffle, which may be a one-bit flag indicating whether reshuffle should be performed or there may be one bit for the start of a burst and one for the end of a burst, or there may be multiple bits to indicate which symbols, e.g. the start symbol and / or the end symbol, should be reshuffled.

[0089] Some embodiments may be based on an agreement that no control channel should be mapped to the start and / or end symbols, and the receiving device does not expect to receive and does not attempt to decode a control channel such as PDCCH or PUCCH. For example, the agreement may be made by the standard (e.g. no control channel at the start / end symbols of a particular SCS) or may be configured. In case of such an agreement, a dedicated flag to indicate the swap may not need to be signaled.

[0090] In this disclosure, FR1 and FR2 are referred to as exemplary frequency bands for unlicensed operation in NR, and requirements for SCS and transitional periods may be provided. However, the techniques disclosed herein may also be applied to other frequency ranges, such as higher frequency bands. In certain cases, it may occur that the transitional period has a duration longer than one symbol (e.g., in the case of a very large SCS). The techniques disclosed herein may also be applied to such cases. For example, for a large SCS, the guard period may be selected to be large enough so that sufficient reliability is provided even for the second or last second symbol in a Tx burst. Alternatively, when replacing a required symbol with another symbol, the first symbol may be repositioned, for example, by the third or fourth symbol in the burst, rather than the second symbol.

[0091] Several embodiments have been described in which the transmission is an uplink transmission from the UE to the base station. Exemplary method steps of an uplink transmission method are shown in FIG. 25. The base station determines (S2510) a notification of the start of a transmission, such as an uplink burst, and possibly the length of the transmission (e.g., number of symbols). The base station further transmits (S2520) the notification to the UE in a grant or higher layer signaling. The UE receives (S2530) the notification and, based on it and the rules for determining the guard period, determines the time interval between the signal in which the symbols are transmitted and the outer boundary, and accordingly performs (S2580) the transmission that is received by the base station (steps S940 and S970 in FIG. 9).

[0092] In general, the present disclosure is applicable to uplink as well as downlink transmissions. For downlink transmissions, the base station (transmitter) determines the boundaries of the transmission and the (inner and / or outer) boundaries of the guard period, sends notification of the start of the transmission and, if necessary, the duration of the transmission in higher layer signaling or scheduling DCI / assignment, performs CCA, and performs the transmission.

[0093] Furthermore, in this disclosure, any reference to performing a transmission (such as a burst, grant, signaling, etc.) by a transmitting device (UE or base station) means that the transmission can be received by a corresponding receiving device (base station or UE).

[0094] The present disclosure can be realized by software, hardware, or software interlocked with hardware. Each functional block used in the description of each embodiment above can be partially or entirely realized by an LSI such as an integrated circuit, and each process described in each embodiment can be partially or entirely controlled by the same LSI or a combination of LSIs. The LSI may be formed as an individual chip, or a single chip may be formed to include some or all of the functional blocks. The LSI may include data input / output coupled thereto. Here, the LSI may be called an IC, a system LSI, a super LSI, or an ultra LSI depending on the degree of integration. However, the technology for realizing an integrated circuit is not limited to an LSI, and may be realized using a dedicated circuit, a general-purpose processor, or a processor for a specific application. Furthermore, a field programmable gate array (FPGA) that can be programmed after the manufacture of an LSI or a reconfigurable processor that can reconfigure the connection and settings of circuit cells arranged inside the LSI may be used. The present disclosure can be realized as digital processing or analog processing. If future integrated circuit technologies replace LSI as a result of advances in semiconductor technology and other derived technologies, the functional blocks can be integrated using the future integrated circuit technologies. Biotechnology can also be applied.

[0095] The present disclosure may be implemented by any type of apparatus, device or system having communication capabilities, referred to as a communications apparatus.

[0096] Some non-limiting examples of such communications devices include telephones (e.g., mobile (cell) phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, netbooks), cameras (e.g., digital still / video cameras), digital players (digital audio / video players), wearable devices (e.g., wearable cameras, smart watches, tracking devices), game consoles, digital book readers, telehealth / telemedicine (remote health and remote medical) devices, and vehicles (e.g., automobiles, airplanes, ships) that provide communications capabilities, and various combinations thereof.

[0097] The communications apparatus is not limited to being portable or mobile, but may include any type of apparatus, device or system that is non-portable or fixed, such as smart home devices (e.g., appliances, lighting, smart meters, control panels), vending machines, and any other "thing" in an "Internet of Things (IoT)" network.

[0098] Communications may include, for example, exchanging data via cellular systems, wireless LAN systems, satellite systems, and the like, as well as various combinations thereof.

[0099] A communications apparatus may include devices such as a controller or a sensor coupled to the communications device to perform the communications functions described in this disclosure. For example, a communications apparatus may include a controller or a sensor that generates control or data signals used by the communications device to perform the communications functions of the communications apparatus.

[0100] The communications equipment may also include infrastructure facilities such as base stations, access points, and any other equipment, devices or systems that communicate with or control equipment such as those in the non-limiting examples above.

[0101] There is provided a user equipment (UE) comprising: circuitry that, during operation, determines based on a type of transmission, an outer boundary of a transient period for ramping of power to start or end the transmission, and a time interval between a symbol on which a signal comprised in the transmission is transmitted; and a transceiver that, during operation, transmits the signal on the symbol, wherein the time interval and a time window for Clear Channel Assessment (CCA) are non-overlapping.

[0102] In some embodiments, the symbols on which the signal is transmitted are at the time boundaries of the transmission.

[0103] For example, the type of transmission includes a service requirement for the type of signal, and the time interval is longer if the service requirement is higher and shorter if the service requirement is lower.

[0104] For example, the service requirement may be higher if the type of the signal is a control signal or a reference signal, and lower if the type of the signal is a preamble or a data signal.

[0105] In some embodiments, the type of transmission includes a subcarrier spacing of a resource over which a transmission including the signal is to be performed, and the time interval is shorter if the subcarrier spacing is narrower and longer if the subcarrier spacing is wider.

[0106] In some demonstrative embodiments, the time boundary of the transmission is a start boundary, and the transceiver receives notification of the start boundary of the transmission in a grant or higher layer signaling during operation, the circuitry determines an outer boundary of the transition period based on the notification and the time interval during operation, and the transceiver performs the CCA for the transmission during operation and ramps on the power in the transition period to start the transmission.

[0107] In some exemplary embodiments, the signal is included in a current transmission, the CCA is a CCA for a subsequent transmission, the time boundary is an end boundary of the current transmission, the transceiver receives notification of a start boundary of the current transmission and a duration of the current transmission in a grant or higher layer signaling during operation, the circuitry derives an end boundary of the current transmission from the notified start boundary and duration of the current transmission during operation, and determines an inner boundary of the transient period located at a distance from the end boundary of the current transmission that is a difference between a length of the transient period and the time interval. For example, if the CCA is successful and the value of the time interval is greater than zero, the transmission is postponed from a first transmission opportunity at an end of a window of the CCA to a second transmission opportunity, and the time distance from the end of the window of the CCA to the second transmission opportunity is greater than the time interval.

[0108] For example, if the CCA fails and the time interval value is greater than zero, the transceiver performs a new attempt of the CCA during operation that finishes by the start time of the transition period.

[0109] In some embodiments, the type of transmission includes a duration of the transmission, and the time interval is longer if the duration of the transmission is shorter and shorter if the duration of the transmission is longer.

[0110] For example, the signal transmitted on the symbol is a first signal, the transmission includes a second symbol having a lower service requirement than the first symbol, and the circuit determines the time interval between an outer boundary of the transition period and the symbol on which the first signal is to be transmitted by swapping symbol positions of the first signal and the second signal to increase the time interval during operation.

[0111] For example, the transceiver receives, during operation, in a grant or in higher layer signaling, a flag indicating whether the symbol positions should be swapped, and the circuitry performs the swapping of the symbol positions according to the flag.

[0112] There is provided a user equipment (UE) comprising: circuitry that, during operation, determines based on a type of transmission, an outer boundary of a transient period for ramping of power to start or end the transmission, and a time interval between a symbol on which a signal comprised in the transmission is transmitted; and a transceiver that, during operation, receives the signal on the symbol, wherein the time interval and a time window for Clear Channel Assessment (CCA) are non-overlapping.

[0113] In some embodiments, the symbol at which the signal is received is at a time boundary of the transmission.

[0114] For example, the type of transmission includes a service requirement for the type of signal, and the time interval is longer if the service requirement is higher and shorter if the service requirement is lower.

[0115] For example, the service requirement may be higher if the type of the signal is a control signal or a reference signal, and lower if the type of the signal is a preamble or a data signal.

[0116] In some embodiments, the type of transmission includes a subcarrier spacing of a resource over which a transmission including the signal is to be performed, and the time interval is shorter if the subcarrier spacing is narrower and longer if the subcarrier spacing is wider.

[0117] For example, the type of transmission includes the duration of the transmission, and the time interval is longer if the duration of the transmission is shorter and shorter if the duration of the transmission is longer.

[0118] For example, the signal received on the symbol is a first signal and the transmission includes a second symbol having a lower service requirement than the first symbol, and the circuit determines the time interval between an outer boundary of the transition period and the symbol at which the first signal is to be transmitted by swapping symbol positions of the first signal and the second signal to increase the time interval during operation.

[0119] For example, the transceiver may receive, during operation, in an assignment or higher layer signaling, a flag indicating whether the symbol positions should be swapped or not, and the signal is received with the symbol positions swapped in accordance with the flag.

[0120] There is further provided a base station comprising: circuitry that, during operation, determines based on a type of transmission, an outer boundary of a transient period for ramping of power to start or end said transmission, and a time interval between a symbol on which a signal comprised in said transmission is transmitted; and a transceiver that, during operation, receives or transmits said signal on said symbol, wherein said time interval and a time window for Clear Channel Assessment (CCA) are non-overlapping.

[0121] In some embodiments, the symbols on which the signal is transmitted are at the time boundaries of the transmission.

[0122] For example, the type of transmission includes a service requirement for the type of signal, and the time interval is longer if the service requirement is higher and shorter if the service requirement is lower.

[0123] For example, the service requirement may be higher if the type of the signal is a control signal or a reference signal, and lower if the type of the signal is a preamble or a data signal.

[0124] In some embodiments, the type of transmission includes a subcarrier spacing of a resource over which a transmission including the signal is to be performed, and the time interval is shorter if the subcarrier spacing is narrower and longer if the subcarrier spacing is wider.

[0125] In some exemplary embodiments, the time boundary of the transmission is a start boundary, and the transceiver determines during operation a notification of the start boundary of the transmission, based on which an outer boundary of the transition period can be derived, and the transceiver transmits during operation a notification of the start boundary of the transmission in a grant or higher layer signaling, and receives the transmission in accordance with the notification.

[0126] In some embodiments, the signal is included in a current transmission, the CCA is a CCA for a subsequent transmission, the time boundary is an end boundary of the current transmission, the transceiver determines during operation a start boundary of the current transmission and a duration of the current transmission, the transceiver sends a notification of the start boundary of the current transmission and the duration of the current transmission in a grant or higher layer signaling, and receives the transmission in accordance with the notification.

[0127] In some embodiments, the type of transmission includes a duration of the transmission, and the time interval is longer if the duration of the transmission is shorter and shorter if the duration of the transmission is longer.

[0128] For example, the signal transmitted on the symbol is a first signal, the transmission includes a second symbol having a lower service requirement than the first symbol, and the circuit determines the time interval between an outer boundary of the transition period and the symbol on which the first signal is to be transmitted by swapping symbol positions of the first signal and the second signal to increase the time interval during operation.

[0129] For example, the transceiver may, during operation, transmit in a grant, assignment or higher layer signaling a flag indicating whether the symbol positions should be swapped or not, and the transmission is received or performed with the symbol positions swapped in accordance with the flag.

[0130] In summary, there is provided a user equipment (UE), a base station and respective transmission / reception methods between the UE and the base station, the UE having a circuit for determining, during operation based on a type of transmission, an outer boundary of a transient period for ramping of power to start or end said transmission and a time interval between a symbol on which a signal included in said transmission is transmitted, and a transceiver for transmitting said signal on said symbol during operation, said time interval being non-overlapping with a time window for Clear Channel Assessment (CCA).

Claims

1. An integrated circuit for controlling a process in a user equipment (UE), the process comprising: determining, based on a type of transmission, an outer boundary of a transient period for ramping power to start or end said transmission and a time interval between a symbol in which a signal included in said transmission is transmitted; transmitting said signals on said symbols; Including, the time interval and a time window for a Clear Channel Assessment (CCA) are non-overlapping, the signal transmitted on the symbol is a first signal, the transmission including a second symbol having a lower service requirement than the first symbol; An integrated circuit, wherein the processing determines the time interval between an outer boundary of the transition period and the symbol at which the first signal is to be transmitted by swapping symbol positions of the first and second signals to increase the time interval.

2. The integrated circuit of claim 1 , wherein the symbols at which the signal is transmitted are at time boundaries of the transmission.

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