KR20210050455A - Method for uplink transmission, and apparatus for the same - Google Patents

Abstract

Provided is an uplink transmission method in an unlicensed band which can improve wireless resource use efficiency. The uplink transmission method in an unlicensed band comprises the steps of: receiving a set of a physical uplink shared channel (PUSCH) resource and a physical uplink control channel (PUCCH) resource from a serving base station; performing a first listen-before-talk (LBT) procedure for transmitting a PUSCH in the PUSCH resource; multiplexing and transmitting uplink control information (UCI) to the PUSCH in the PUSCH resource if the first LBT procedure is successful; performing a second LBT procedure for transmitting the UCI in the PUCCH resource if the first LBT procedure fails; and transmitting the UCI through a PUCCH in the PUCCH resource if the second LBT procedure is successful.

Description

Uplink transmission method and apparatus for same in unlicensed band [Method for uplink transmission, and apparatus for the same]

The present invention relates to an uplink transmission method and apparatus in a mobile communication system, and more particularly, to a method and apparatus for transmitting uplink control information and uplink data in an unlicensed band.

3GPP is currently discussing a frame structure for NR (New Radio), a channel modulation and coding scheme (MCS), and a waveform & multiple access scheme for research on the next-generation/5G radio access technology. Such NR requires a design capable of satisfying various conditions including an improved data rate compared to LTE/LTE-Advanced. In particular, eMBB (Enhancement Mobile BroadBand), mMTC (massive MTC) and URLLC (Ultra Reliable and Low Latency Communications) are proposed as representative scenarios of NR. It is necessary to design a flexible frame structure.

The terminal requests scheduling from a serving base station through a licensed band, receives an uplink (UL) grant, and transmits a UL data channel. Alternatively, the terminal receives downlink (DL) assignment information (DL assignment) through the licensed band and receives a DL data channel. However, when a terminal always transmits and receives a data channel through a licensed band, a problem of excessive use of limited licensed band resources may occur.

An object of the present invention for solving the above problems is to provide a method of transmitting uplink control information and uplink data in an unlicensed band.

Another object of the present invention for solving the above problems is to provide an apparatus for transmitting uplink control information and uplink data in an unlicensed band.

The present invention for achieving the above object is a method for transmitting uplink control information (UCI) in an unlicensed band, a physical uplink shared chanenl (PUSCH) resource and a physical uplink (PUCCH) resource from a serving base station. control channel) receiving a resource setting-the PUSCH resource and the PUCCH resource at least partially overlap in a time domain, and the PUSCH resource is temporally preceded by the PUCCH resource; Performing a first listen-before-talk (LBT) procedure for transmitting a PUSCH in the PUSCH resource; If the first LBT procedure is successful, multiplexing the UCI to the PUSCH in the PUSCH resource and transmitting the multiplexed signal; If the first LBT procedure fails, performing a second LBT procedure for transmitting the UCI in the PUCCH resource; And when the second LBT procedure is successful, transmitting the UCI through PUCCH in the PUCCH resource.

According to embodiments of the present invention, the efficiency of using radio resources can be improved by mapping (multiplexing) uplink control information and uplink data to an uplink channel of an unlicensed band and transmitting them.

1 is a conceptual diagram illustrating a situation in which a PUCCH time resource precedes a PUSCH time resource when time resources of a PUCCH and a PUSCH overlap.
FIG. 2 is a conceptual diagram illustrating a situation in which a PUSCH time resource precedes a PUCCH time resource when time resources of a PUCCH and a PUSCH overlap.
3 is a conceptual diagram illustrating a UCI transmission method according to success or failure of an LBT in a situation in which a PUSCH time resource precedes a PUCCH time resource when time resources of PUCCH and PUSCH overlap.
4 is a conceptual diagram illustrating a situation in which UCI is mapped to any one of a plurality of PUSCHs when a PUCCH overlaps a plurality of PUSCHs.
5 is a conceptual diagram illustrating a situation in which UCI is mapped to two or more PUSCHs among a plurality of PUSCHs when a PUCCH overlaps a plurality of PUSCHs.
6 is a conceptual diagram illustrating a case in which a PUSCH is allocated to several slots.
7 to 10 are conceptual diagrams for explaining examples in which 3 TBs are allocated and transmitted twice.
11 is a conceptual diagram for explaining an example in which an okion having an arbitrary length longer than a slot length is repeated twice.
12 is a conceptual diagram illustrating an example of instructing to repeatedly transmit 3 TBs 4 times in one DCI.
13 is a conceptual diagram illustrating an embodiment of a timing in which a conventional MAC CE is applied to activation/deactivation of a serving cell.
14 is a block diagram illustrating a configuration of an apparatus for performing methods according to embodiments of the present invention.

In the present invention, various modifications may be made and various embodiments may be provided, and specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to a specific embodiment, it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention. In describing each drawing, similar reference numerals have been used for similar elements.

Terms such as first, second, A, and B may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. The term "and/or" includes a combination of a plurality of related described items or any of a plurality of related described items.

When a component is referred to as being "connected" or "connected" to another component, it is understood that it may be directly connected or connected to the other component, but other components may exist in the middle. It should be. On the other hand, when a component is referred to as being "directly connected" or "directly connected" to another component, it should be understood that there is no other component in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof does not preclude in advance.

Unless otherwise defined, all terms used herein including technical or scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in the present application. Does not.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate an overall understanding, the same reference numerals are used for the same elements in the drawings, and duplicate descriptions for the same elements are omitted.

UCI and PUSCH multiplexing method

The UE may be allocated resources of a physical uplink shared channel (PUSCH) dynamically or semi-persistent from a serving base station. When semi-statically allocating PUSCH resources, the serving base station may configure (and activate) a UL semi-persistent scheduing (SPS) to the terminal. In this case, the terminal may be configured with two types of UL SPS.

In the first type of UL SPS, the UE may receive time resources, frequency resources, and other configuration parameters for transmitting the PUSCH through radio resource control (RRC) signaling. In the second type of UL SPS, the UE may be instructed by some of the configuration parameters for the resource for transmitting the PUSCH through RRC signaling, and the remaining configuration parameters may be indicated (activated) through downlink control information (UL-DCI). The UL-SPS may be used complementarily with transmission of a PUSCH (ie, dynamic scheduling of a PUSCH) by a UL grant indicated by a UL-DCI transmitted by a serving base station.

In addition, the UE may receive an indication of a resource of a physical uplink control channel (PUCCH) to transmit uplink control information (UCI) from a serving base station. UCI means scheduling request (SR), hybrid automatic repeat request (HARQ)-acknowledgement (ACK), channel state information (CSI), and the like. The resource of the PUCCH for transmitting UCI may be indicated to the UE by RRC signaling and/or DCI. In this case, there may be a case where the time resource instructed to transmit the UL-SCH (uplink shared channel) and the time resource instructed to transmit the UCI overlap each other and do not overlap with each other.

If the time resources of the PUSCH and the PUCCH at least partially overlap, the UE may map UCI (and/or UL-SCH) to the PUSCH. Through this, it is possible to reduce the peak-to-average power ratio/cubic metric (PAPR/CM) experienced by the terminal. In order for the UE to map the UCI (and/or UL-SCH) to the PUSCH, a predetermined processing time is required, and the serving base station embodiably secures this and can allocate sufficient time to the UE. For example, if the base station indicates a time resource (e.g., a slot, a minislot, a subslot) for feedback (feedback) of the HARQ-ACK and a time resource for transmitting a PUSCH, the base station may perform the processing capability of the terminal ( processing capability).

When UL SPS is configured/activated, if there is no UL-SCH to be transmitted, the UE may not transmit the PUSCH. Accordingly, the serving base station may determine whether the UE actually transmits or does not transmit a PUSCH in the corresponding resource by detecting a PUSCH demodulation reference signal (DM-RS) in the PUSCH resource indicated to the UE. If the PUSCH DM-RS is detected, the base station determines that the UE has transmitted the PUSCH, and if the PUSCH DM-RS is not detected, the base station may determine that the UE has not transmitted the PUSCH. On the other hand, in the case of dynamically instructing to transmit the PUSCH using the UL grant, the serving base station always transmits the UL-SCH (or aperiodic/semi-persistent CSI) in the resource indicated by the UL grant. By detecting the RS, it may be determined whether discontinuous transmission (DTX) has occurred to the terminal.

Meanwhile, when the UE multiplexes UCI and UL-SCH (or aperiodic/semi-persistent CSI), the number of cases to be detected by the serving base station may increase. That is, the base station must determine whether the UE transmits PUCCH or PUSCH (or aperiodic/semi-persistent CSI) in the corresponding resource. Accordingly, the serving base station must first detect the existence of a transmitted UL transmission by comparing the time resource of the PUCCH and the time resource of the PUSCH.

Considering the case where one PUCCH and one PUSCH overlap each other, a procedure of mapping UCI to PUSCH may be performed as described above. On the other hand, considering the case where one PUCCH overlaps two or more PUSCHs, the UCI may be mapped to the first indicated PUSCH. Hereinafter, a case where a PUCCH overlaps with one PUSCH (ie,'one PUSCH case') and a case where a PUCCH overlaps with two or more PUSCHs (ie,'multiple PUSCH case) are considered.

(One) One PUSCH case

1 is a conceptual diagram illustrating a situation in which a PUCCH time resource precedes a PUSCH time resource when time resources of a PUCCH and a PUSCH overlap.

Referring to FIG. 1, when time resources are indicated so that the PUCCH is transmitted before the PUSCH (FIG. 1 (a)), the serving base station detects the PUCCH DM-RS and may determine whether the UE transmits the PUCCH ( Fig. 1(b)). If it is determined that the UE has transmitted the PUCCH, the serving base station decodes the UCI and determines that there is no UL-SCH (or aperiodic/semi-persistent CSI) (in the case of UL SPS), or the UE has not received the UL grant. It can be interpreted as (in the case of a dynamically allocated PUSCH). On the other hand, if it is determined that the UE has not transmitted the PUCCH, since the UCI has not been transmitted through the PUCCH, the serving base station generates a DTX to the UE or the UCI is multiplexed with the UL-SCH (or aperiodic/semi-persistent CSI) to transmit the PUSCH. It can be interpreted as being transmitted through. When the serving base station detects the PUSCH DM-RS in the PUSCH resource indicated to the terminal, it may determine that the terminal has transmitted the PUSCH (FIG. 1 (c)). If the PUSCH DM-RS is not detected in the PUSCH resource, the serving base station may interpret that the UE has not transmitted UL-SCH and does not transmit UCI. Accordingly, the serving base station can interpret that DTX has occurred in the terminal. The serving base station assumes that the UL-SCH (or aperiodic/semi-persistent CSI) is always mapped to the PUSCH, and additionally determines whether the UCI is multiplexed on the PUSCH, and may determine whether DTX has occurred in the terminal.

FIG. 2 is a conceptual diagram illustrating a situation in which a PUSCH time resource precedes a PUCCH time resource when time resources of a PUCCH and a PUSCH overlap.

Referring to FIG. 2, when time resources are indicated so that PUSCH is transmitted prior to PUCCH (FIG. 2(a)), the serving base station may detect a PUSCH DM-RS and determine whether the UE actually transmitted the PUSCH. . If it is determined that the UE transmits the PUSCH, the serving base station may interpret that the UE multiplexes UCI and UL-SCH (or aperiodic/semi-persistent CSI) in the PUSCH (FIG. 2(b)). If it is determined that the UE has not transmitted the PUSCH, the serving base station may determine that there is no UL-SCH to be transmitted to the UE (in the case of UL SPS), or may determine that the UE has not received the UL grant (dynamic allocation Occation). In addition, the serving base station may determine that UCI is transmitted through PUCCH or that DTX has occurred to the terminal. The serving base station may then detect the PUCCH DM-RS and determine whether or not the PUCCH is transmitted (FIG. 2(c)). If it is determined that the PUCCH is transmitted, the serving base station can decode the UCI. If it is determined that the PUCCH is not transmitted, the serving base station may interpret that DTX has occurred to the terminal.

When UL SPS is configured (and activated), at least two time resources for the UE to transmit UCI may be given. PUSCH transmission by the UL grant can also be interpreted as well. The difference is that the number of cases to be determined by the serving base station may be somewhat reduced because the UE always has a UL-SCH (or aperiodic/semi-persistent CSI) to be transmitted. Therefore, in the case of PUSCH transmission by the UL grant, a maximum of two time resources for the UE to transmit UCI (ie, a PUSCH resource or a PUCCH resource) may be given. Accordingly, in a system operating in a licensed band, UCI can be decoded by detecting only two time resources in the serving base station.

Meanwhile, in a system operating in an unlicensed band, there may be a case in which the serving base station needs to check two or more time resources. When all terminals and base stations transmitting in the unlicensed band measure the channel state according to a predetermined rule, and determine that other terminals and base stations do not perform transmission on the corresponding channel (i.e., listen-before-talk (LBT)). Transmission can only be initiated (success), otherwise (i.e. LBT failure) does not transmit. This procedure is called CCA (clear channel assessment) or LBT. The UE can perform UL transmission (ie, PUCCH, SRS, PUSCH, PRACH transmission) only when LBT is successful.

According to the conventional technical standard, when there are UCI and UL-SCH to be transmitted, the UE must transmit the UCI and UL-SCH by multiplexing it on the PUSCH at all times. Otherwise, it is limited to a case in which the UE cannot know whether the UCI or UL-SCH exists. For example, when a DTX not receiving DL-DCI for transmitting UCI occurs or a DTX not receiving UL-DCI for transmitting UL-SCH occurs, the UE transmits only UCI using PUCCH, or Only UL-SCH can be transmitted using PUSCH.

This can be applied in a licensed band, and similarly, it can be applied in an unlicensed band, but improvement is needed. This is because the UE performs UL transmission only after LBT is successful. In the case of LBT failure, since the UE cannot transmit PUCCH or PUSCH, there is a new room for the serving base station to interpret the reason why the UCI was not transmitted as LBT failure along with the occurrence of DTX.

In the proposed method, when the UE needs to transmit UCI in PUSCH, if LBT fails, the UE does not transmit PUSCH and may not transmit UCI. That is, the UE can transmit UCI if LBT is successful, but does not transmit UCI if LBT fails. The serving base station expects the UE to transmit the PUSCH and attempts to decode, but if it does not detect the presence of the PUSCH (for example, by detecting the presence of the PUSCH DM-RS), the UE performs the UCI (and/or the UL-SCH). ) Are not expected to be sent. Accordingly, the serving base station can interpret the reasons for not detecting the PUSCH in various ways. That is, it can be interpreted that the UE transmits the PUSCH, but the serving base station does not detect it, the UE fails the LBT, or the UE misses both the instruction to transmit the UCI and the instruction to transmit the PUSCH. This method is simple to implement because the UE executes the LBT only once in order to transmit the PUSCH, but it is preferable to apply another procedure for transmitting the UCI.

In another proposed method, when the UE needs to transmit UCI on the PUSCH, if the LBT fails, the UE can transmit the UCI on the PUCCH. It can be applied to the case where the PUSCH and the PUCCH overlap each other, and the PUCCH transmitted later than the PUSCH is indicated to the terminal (ie, FIG. 2A). In this case, since the terminal may attempt LBT two or more times to transmit UCI, the probability of transmitting UCI increases.

FIG. 3 is a conceptual diagram illustrating a UCI transmission method according to success or failure of an LBT in a situation where a PUSCH time resource precedes a PUCCH time resource when time resources of PUCCH and PUSCH overlap.

Referring to FIG. 3, a case in which time resources of the PUSCH and the PUCCH overlap each other and is allocated so that the PUSCH is transmitted before the PUCCH is considered. According to the conventional method, PUCCH and PUSCH are multiplexed, and UCI can be mapped to PUSCH. If operating in the unlicensed band, the UE may perform LBT before transmitting the PUSCH. If the UE succeeds in LBT, since it can transmit the PUSCH, the UCI can be mapped to the PUSCH (FIG. 3 (a)). On the other hand, if the terminal fails in the LBT, it cannot transmit the PUSCH.

In the proposed method, if the UE fails in LBT (ie, LBT for PUSCH transmission), the UE may map UCI to PUCCH. The UE may perform LBT before transmitting the PUCCH, and may transmit the PUCCH if the LBT is successful. If the UE fails in LBT, it does not transmit PUCCH. Accordingly, since the terminal has two LBT opportunities for transmitting UCI, the probability of UCI transmission may increase.

The coding procedure applied when the UE transmits UCI on the PUSCH may be different from the coding procedure applied when the UE transmits UCI on the PUCCH. Specifically, when the UCI is multiplexed on the PUSCH and transmitted, the polar code rate can be obtained by applying an offset (ie, beta offset) to the standard modulation/demodulation rate (ie, MCS). Here, the modulation/demodulation rate as a reference may be dynamically indicated through a UL grant or may be given from a serving base station through RRC signaling. Here, the offset may be selected using an index in which one of the values given by RRC signaling is dynamically indicated through the UL grant, or may be given by RRC signaling. For example, different offsets may be given for a PUSCH given as a UL SPS to the UE and a PUSCH given as a UL grant to the UE. Alternatively, another offset may be indicated according to the format of the UL grant.

Since the same UCI is given as an information word, the UE can perform rate matching according to the indicated extreme code rate after obtaining a codeword. These extreme code words are selected as many as appropriate to the number of resource elements (REs) indicated to be occupied by the corresponding UCI in the PUSCH or PUCCH, are modulated, and mapped to the corresponding REs. In this case, the extreme code word generated by the terminal may be generated differently according to the number of REs. That is, if the number of REs is in a specific range, there is a characteristic of generating the same polar code word.

Therefore, if the terminal has the same extreme code word when mapping UCI to PUSCH and when mapping UCI to PUCCH, it is sufficient for the terminal to perform only code rate adjustment for the same extreme code word. The extra time to run is minimized.

On the other hand, when the extreme code word when mapping UCI to PUSCH and the extreme code word when mapping UCI to PUCCH are different (that is, when the number of REs are significantly different), the terminal is required to perform the extreme code procedure again. I need time. Therefore, in order to perform the proposed method, it is desirable to be able to generate all of the extreme code words in case the terminal fails in LBT. Alternatively, the serving base station implemenably allocates the number of REs of the corresponding UCI in the PUCCH and PUSCH so that the number of REs is similar, so that the UE can generate only one extreme code word. This is the scheduling that the serving base station should preferably perform. The reason is that, since UCI is assigned the number of REs similarly to each other, the effective extreme code rate is similar to each other regardless of whether the UE transmits UCI through PUSCH or PUCCH.

(2) Multiple PUSCH case

One PUCCH may overlap with two or more PUSCHs. This is because the time resource of the PUCCH and the time resource of the PUSCH are indicated independently of each other in a given slot (or mini-slot or sub-slot). Here, it is assumed that the time resources of two or more PUSCHs do not overlap with each other. By applying priority to time resources of two or more PUSCHs according to an indication of the serving base station or the UE determines, the UE can transmit UCI by selecting only one PUSCH. This priority may be given to the UE through RRC signaling, or may be given by a combination of RRC signaling and an index included in the UL grant.

According to the conventional technical standard, a PUCCH may be multiplexed with a PUSCH indicated first among a plurality of PUSCHs. If there is no UL-SCH to be transmitted to the UE (ie, in the case of a PUSCH configured (and activated) as UL SPS), the UE may not transmit the corresponding PUSCH. Accordingly, UCI may be multiplexed on the first PUSCH desired to be transmitted by the UE. In the case of operating in the unlicensed band, since the UE can transmit the PUSCH only when the LBT is successful, if the UCI is mapped only on the first PUSCH to be transmitted, the chance of transmitting the UCI to the serving base station is only one time. When operating in an unlicensed band, the success and failure of the LBT should be considered.

If the previously proposed method (i.e., a method of mapping UCI to PUCCH and transmitting) is applied and PUCCH is transmitted, it cannot be applied as it is because other PUSCH overlapping with PUCCH cannot be transmitted, and UCI is mapped to PUSCH and transmitted. desirable.

(2-1) Mapping of singular number

4 is a conceptual diagram illustrating a situation in which UCI is mapped to any one of a plurality of PUSCHs when a PUCCH overlaps a plurality of PUSCHs.

In the proposed method, only one of the PUSCHs overlapping with the PUCCH is selected and the UCI is mapped to the selected PUSCH, and other PUSCHs may not be selected. Implementation is simple because the terminal can perform the extreme coding procedure only once to map the UCI, and implementation is simple because the serving base station reduces the number of cases for detecting UCI. This example is shown in Fig. 4(a). Hereinafter, when a time resource of one PUCCH is indicated to overlap with two or more PUSCHs, a method of selecting one PUSCH and mapping UCI to the selected PUSCH for transmission is described.

A method of selecting one PUSCH may be determined in the technical standard or may be indicated to the UE through RRC signaling. In FIG. 4(b), UCI is mapped to the second PUSCH among three PUSCHs. In order for the UE to transmit UCI, since it must be able to transmit the second PUSCH, it must succeed by attempting two LBTs. That is, the LBT must succeed in the first PUSCH, or the LBT must fail in the first PUSCH and succeed in the second PUSCH.

If two or more PUSCHs are temporally overlapped with the PUCCH, if the criterion for selecting which PUSCH is not clear, the first or last PUSCH may be selected.

In the proposed method, UCI may be mapped only to the PUSCH for which transmission is attempted for the first time (FIG. 4(c)). It is similar to the operation performed in the licensed band, so it is easy to implement in the system. However, since the PUSCH transmitting the UCI is the most advanced, the PUSCH to which the UCI is mapped can be transmitted only when the LBT is successful only once. Among the schemes (b) to (d) shown in FIG. 4, the probability of transmitting UCI is the lowest.

In another proposed method, UCI may be mapped to the last PUSCH attempted (FIG. 4(d)). Since the PUSCH to which the UCI is mapped is the third, the UE may attempt LBT three times, and thus the probability of transmitting the UCI is highest. That is, if any one of the LBT for the first PUSCH, the LBT for the second PUSCH, and the LBT for the third PUSCH succeeds, the third PUSCH can be transmitted, so the third PUSCH has the highest transmission probability.

Finally, in order to map the UCI in the PUSCH that overlaps the last, a procedure for mapping the UCI to the PUSCH in the conventional technical standard must be changed. That is, the PUSCH to which the last symbol of the PUCCH belongs is selected, and the UCI must be mapped in the corresponding PUSCH. However, according to the method presented above, since UCI is mapped to the PUSCH only once, it is preferable that the UCI transmission opportunity is given multiple times in order to improve the performance of the system.

(2-2) Multiple mapping

5 is a conceptual diagram illustrating a situation in which UCI is mapped to two or more PUSCHs among a plurality of PUSCHs when a PUCCH overlaps a plurality of PUSCHs.

According to the conventional technical standard, when a PUSCH and a PUCCH are multiplexed, the first symbol is used as a reference, so the UCI can be mapped to the first PUSCH to be transmitted by the UE.

In the proposed method, the UCI may be mapped to the first PUSCH that the UE can actually transmit according to the result of the LBT. If the UE fails in LBT, the UCI (and/or UL-SCH) is not transmitted in the corresponding PUSCH, but the UE maps the UCI and performs LBT in the subsequent PUSCH. That is, the UE may remap UCI according to the LBT result.

The UE maps the UCI to the PUSCH, but cannot know in advance whether the LBT will succeed or fail. Accordingly, the UE may map UCI to PUSCH on the assumption that LBT succeeds. If the LBT is successful, the UE may transmit UCI in the first PUSCH (FIG. 5 (a)).

If the LBT fails, the UE must transmit UCI in the PUSCH indicated thereafter. Accordingly, the UE may map the UCI according to a conventional technical standard in consideration of UL transmissions thereafter except for the first PUSCH. That is, the UE can map the UCI to the second PUSCH (FIG. 5(b)). In order to transmit the second PUSCH, the UE must succeed in LBT. If the LBT is successful, the UE transmits the UCI in the PUSCH, but if the LBT fails, the UCI may be transmitted in the subsequent PUSCH.

In consideration of subsequent UL transmissions excluding UL transmissions that cannot be transmitted due to LBT failure, UCI is mapped according to a conventional technical standard. Since the PUCCH is still multiplexed when it temporally overlaps the PUSCH, the UE can map the UCI to the third PUSCH (FIG. 5(c)).

According to the method proposed above, the UE can newly map the PUSCH each time LBT is performed. UCI is punctured in the RE to which the UL-SCH codeword is mapped, or the codeword of the UL-SCH is code rate adjusted and mapped to the RE. Therefore, after performing the LBT, it is preferable that the UE maps the PUSCH to be transmitted next. Since the UE knows the size of a transport block (TB) to be applied to the PUSCH in advance, it can generate a codeword for the UL-SCH in advance. You may be performing.

The extreme code rate applied when UCI is mapped may be given to the UE as an offset using the UL grant field or may be given by RRC signaling. When an offset is given using a field of a UL grant, a UL grant for a PUSCH through which UCI is transmitted may include only an offset for one PUSCH. The UE may determine which PUSCH to transmit for one offset.

example

The serving base station may dynamically allocate multiple PUSCHs to the terminal using DCI, or set (and/or activate) resources of the PUSCH using higher layer signaling (and/or DCI).

When operating in an unlicensed band, the serving base station may allocate multiple PUSCHs in order to increase the transmission probability of the terminal. Although it is possible to instruct the UE to allocate traffic to only one PUSCH, since the LBT may fail, it is desirable to allow the UE to attempt several LBT by dividing the traffic into multiple TBs and mapping them to each PUSCH. Do.

However, if PUSCH is allocated only to mapping type B (i.e., mapping type B or mini-slot-based data allocation), since each PUSCH corresponds to the HARQ process one-to-one, the terminal is assigned multiple PUSCHs, but is allocated to mapping type B. If so, several HARQ processes are required. To reduce this, the PUSCH is initially allocated to the PUSCH mapping type B, and after that, the PUSCH mapping type B or PUSCH mapping type A having a larger number of symbols (ie, mapping type A or slot-based data allocation) is used. Allocating a PUSCH can use a small number of HARQ processes.

Therefore, when allocating a PUSCH over several slots to a terminal, a PUSCH is allocated to one or more PUSCH mapping type B in the first slot, and one PUSCH mapping type B or PUSCH mapping type A is allocated in subsequent slots. It is desirable.

6 is a conceptual diagram illustrating a case in which a PUSCH is allocated to several slots.

6, PUSCHs are allocated to four slots, and three PUSCHs are allocated to mapping type B in the first slot, but one PUSCH is allocated to mapping type B or PUSCH mapping type A in the remaining slots. Able to know. If the UE needs to transmit the PUCCH, it may take into account a case of partially overlapping the PUSCH in time.

(Case 1)

If the PUCCH overlaps with one PUSCH in the slot, the UE may map the UCI to the corresponding PUSCH. If the UE can transmit the corresponding PUSCH (ie, successively transmitting the corresponding PUSCH immediately after transmitting the previous PUSCH, or if LBT is successful to transmit the corresponding PUSCH), the UE may transmit UCI. However, if the UE cannot transmit the corresponding PUSCH, the UE must succeed in LBT for new UL transmission. Limited to the case where the first symbol of the PUCCH is located behind the first symbol of the corresponding PUSCH, the UE may attempt LBT in order to transmit UCI on the PUCCH. If the terminal succeeds in LBT, it can transmit UCI using PUCCH.

This case may occur in all slots of FIG. 6. In the first slot, the symbols of the PUCCH belong to only one mapping type B PUSCH and do not belong to the other PUSCH mapping type B PUSCH at all. In other slots, since the PUSCH is assigned to the PUSCH mapping type B or the PUSCH mapping type A, the PUCCH may always overlap one PUSCH.

(Case 2)

If the PUCCH overlaps with two or more PUSCHs in the slot, the UE may map the UCI to any one of these PUSCHs. Among these, the UE may transmit a PUCCH in the first PUSCH that succeeds in LBT. Alternatively, the UE may map the UCI to the first PUSCH overlapping the PUCCH. Alternatively, the UE may map the UCI to the last PUSCH overlapping the PUCCH.

Allocation method of multiple data channels

The serving base station can allocate two or more TBs using one DCI. The UE may know the time resource of the PUSCH(s) (or PDSCH(s) or PSSCH(s)) from a field indicating the time domain of the DCI set by RRC signaling (time domain resource allocation, TDRA). If one index representing the TDRA allocates n TBs, n new data indicators (NDIs) and n redundancy versions (RVs) are provided in DCI. Each time resource, each NDI, and each RV are applied to each TB, but HARQ processes may be assigned adjacent indices. The DCI includes the HARQ process identifier only for the TBs scheduled the fastest in time, and the HARQ process identifiers of the TBs scheduled thereafter may be derived from the first HARQ process identifier.

Since the size of the DCI must be able to simultaneously schedule the number of TBs that the TDRA can represent, it may be set by RRC signaling to have the maximum size. The terminal can know the number of TBs from the index of the TDRA, and can use only some bit strings among the fields included in the DCI for scheduling of TBs.

In DCI, the number of bits of NDI and RV varies according to the maximum number of TBs. Accordingly, NDI may be expressed as n bits, and RV may be expressed as 2*n bits (or n bits). This can be applied to both cases where two or more TBs are allocated in a licensed band or an unlicensed band. Hereinafter, a PUSCH is described, but the following embodiments can be applied to the PDSCH and the PSSCH in the same manner.

(One) DCI field interpretation method according to BWP transformation

According to the technical standard, information elements for configuring a serving cell include information elements for configuring a bandwidth part (BWP). The information element for setting the PUSCH is included in the information element for setting the BWP. The information element for configuring the PUSCH includes a TDRA and a slot aggregation factor. Therefore, when the terminal receives the DCI and is instructed to change the BWP, if the BWP is different, the TDRA may be set to be the same or different.

In the proposed method, even if the terminal is instructed to switch BWP, it can be assumed that the maximum number of TBs that DCI can schedule is the same. The serving base station may indicate different TDRAs according to the BWP, but must instruct the UE so that the maximum number of TBs indicated by the TDRA index does not change. Accordingly, the size of the NDI field and the size of the RV field are the same. The UE may assume that the field of the NDI and the field of NV have the same size despite the change of the BWP. Here, the field of the NDI and the field of the RV may be configured as a field by dividing NDI and RV, or may be configured by concatenating several pairs by forming a pair of NDI and RV. In this case, only bits corresponding to NDI may be defined as an NDI field, and only bits corresponding to RV may be defined as an RV field. For example, when K TBs are allocated, the DCI may include a bit string consisting of only RV i for TB i (i=1,2, ...,K) and a bit string consisting of only NDI i. Alternatively, in DCI, a bit stream composed of RV i and NDI i for TB i may be concatenated to form a bit stream (ie, RV 1, NDI 1, RV 2, NDI 2, ...). Here, i may be the order of the first symbol of the PUSCH allocated by the DCI or vice versa.

Meanwhile, according to different settings, the maximum number of TBs may be given differently for each BWP. The serving base station can reset the TDRA without any restrictions on the BWP. This means that the size of the NDI field may vary and the size of the RV may vary. The NDI field and the RV field must be interpreted differently in DCI according to the BWP conversion.

According to the technical standard, when the size of a DCI field decreases according to the change of the BWP, the bit string corresponding to the field is interpreted as a new value from the LSB to the required size. On the other hand, when the size of a field of DCI increases, 0 is added to the MSB as much as a required size in the bit string corresponding to the field and interpreted as a new value. For convenience of explanation, the serving base station instructs the terminal to change from BWP1 to BWP2, and the TDRA field for BWPi (i=1,2) indicates TDRAi, the NDI field indicates NDIi, and the RV field indicates RVi. I assume it does. TDRAi means a time resource for the maximum Ki TBs.

If K1 is larger than K2, RV1 has a longer bit string than RV2, and NDI1 has a longer bit string than NDI2. Accordingly, a bit stream excluding MSBs in RV1 may mean RV2, and a bit stream excluding MSBs in NDI1 may mean NDI2. Since this can represent all cases for RV2 and NDI2, the UE can generate the PUSCH by encoding the TB according to the information indicated by the DCI.

On the other hand, if K1 is smaller than K2, RV1 has a shorter bit string than RV2, and NDI1 has a shorter bit string than NDI2. Accordingly, in RV1, a bit string in which 0 is added to the MSB may mean RV2, and in NDI1, a bit string in which 0 is added to the MSB can mean NDI2. Therefore, RV and NDI for (K2-K1) TBs in DCI are fixed to 0, and a method for the terminal to interpret this is required.

In the proposed method, the UE may assume scheduling only for (K2-K1) TBs. The serving base station can schedule only (K2-K1) TBs. The terminal may interpret only bit strings corresponding to lengths of RV1 and NDI1 in fields corresponding to RV2 and NDI2. That is, each field is interpreted as having the same structure as RV1 and NDI1 without adding 0. Alternatively, the UE can interpret the corresponding field from the LSB.

In another proposed method, the UE may assume scheduling for K2 TBs. The terminal may add 0 to RV1 and 0 to NDI1. The terminal can interpret that RV2 is given as 00 (or 0). This may imply a restriction on scheduling to the serving base station. However, for (K2-K1) TBs in NDI2, the NDI is fixed to 0.

For the HARQ process identifier in which the NDI is fixed to 0, even if NDI is not received, it can be distinguished whether the UE allocates a PUSCH for initial transmission of a new TB or a PUSCH for retransmission of an existing TB.

The serving base station operating in the unlicensed band may transmit the HARQ-ACK for the PUSCH to the terminal for the HARQ process identifier. The terminal can know the HARQ-ACK for the HARQ process identifier by receiving a separate DCI including downlink feedback information (DFI). If the terminal receives the ACK in the DFI, since it can be assumed that the serving base station does not transmit the DCI to retransmit the same TB, even if the NDI is fixed to 0 and the NDI cannot be toggled, the scheduling for the corresponding HARQ process identifier is It can be regarded as an initial transmission for a new TB. If the terminal receives the NACK in the DFI, since it can be assumed that the serving base station does not transmit DCI to initially transmit a new TB, even if the NDI is fixed to 0 and the NDI cannot be toggled, scheduling for the corresponding HARQ process identifier Can be regarded as retransmission for the same TB.

Therefore, in the proposed method, the UE can distinguish between initial transmission and retransmission according to the HARQ-ACK for the HARQ process identifier received from the DFI. If the terminal does not receive the DFI, this method cannot be applied. When the UE initially transmits a new TB in the corresponding HARQ process identifier, it must be retransmitted using an ARQ procedure rather than an HARQ procedure, so the UE may regard it as retransmission for the same TB. Since the serving base station performs the LBT procedure to transmit the DFI, it is possible to know whether or not the DFI has been transmitted to the terminal. Since the serving base station allocates DCI so that the DFI has a sufficiently low error rate, the above method assumes that the terminal receives the DFI when the serving base station transmits the DFI.

However, when the UE detects the DFI and there is an error, the transmission of the PUSCH has a problem different from that of the serving base station, and thus retransmission may be performed using an ARQ procedure rather than an HARQ procedure. Therefore, in another proposed method, regardless of the reception of the DFI, the terminal can retransmit the same TB even if the NDI is not toggled to 0.

In the case of the PDSCH, based on the HARQ-ACK, even if there is no NDI, it is possible to know whether the TB included in the PDSCH is regarded as a new TB or the same TB. If the HARQ-ACK bit most recently transmitted by the UE is ACK, it may be regarded as a new TB, and if it is NACK, it may be regarded as the same TB. In the case of PUSCH, even if there is no NDI, it may be determined whether to transmit a new TB or retransmit the same TB using DFI.

In another proposed method, for the HARQ process identifier in which the NDI of DCI is set to 0, it may be determined in the technical standard so that the terminal performs only initial transmission or retransmission. For example, the terminal may assume only the initial transmission. For the newly added HARQ process identifier, the UE may re-encode the new TB in order to empty the HARQ buffer and transmit the new TB.

In another proposed method, for the HARQ process identifier in which the NDI of the DCI is set to 0, the NDI that the terminal already has is compared with 0, and if the NDI is not toggled, it is regarded as retransmission of the same TB. , If it is determined that the NDI is toggled, it may be regarded as transmission of a new TB. Therefore, if the terminal considers that the toggle has not been performed as the NDI is maintained at 0, the serving base station can receive the same TB from the terminal even if it has already successfully decoded the TB. The serving base station may minimize the value of SLIV in order to minimize resource waste at this time.

However, the terminal may not have an NDI value for the corresponding HARQ process identifier. For example, since the corresponding serving cell is activated, scheduling for the corresponding HARQ process identifier may not have been received. In this case, even if the value of the NDI is not toggled, the UE may consider that a new TB is transmitted by receiving 0 from the DCI.

(2) How to interpret channel access

According to the technical standard, repeated PUSCH can be transmitted by reusing a value of a field indicated by DCI (eg, an LBT type and an extension length of a CP CP extension). The terminal may perform LBT as many as the number of PUSCHs indicated in the TDRA. When performing LBT before transmitting the first PUSCH, values of the fields indicated by DCI (ie, LBT type and CP length) may be applied. If LBT is successful, the UE transmits all PUSCHs allocated in DCI.

In the proposed method, if the LBT fails, the UE performs LBT before transmitting the second PUSCH, and the values of the fields indicated in DCI (ie, LBT type and CP length) can be applied. This can be repeated as many times as the remaining number of PUSCHs. Here, the terminal may use the value indicated by the DCI as it is for at least the LBT type. As the value of the CP length (or the extended length of the CP), a value indicated in DCI may not be used. Accordingly, the UE may apply the CP length to only the first PUSCH and may not apply the CP length thereafter. That is, since the UE does not apply the extended length of the CP, it may start from a symbol in which the second PUSCH is scheduled.

In another proposed method, the serving base station and the terminal may determine a default value of a field indicated in DCI (ie, LBT type and CP length) using RRC signaling or DCI. If the UE fails in the first LBT when the time resources of UL transmission (ie, PUSCH or PUCCH or SRS or PRACH) are consecutively allocated, the LBT type to be applied when performing LBT in the second UL transmission to be transmitted is the corresponding default. It derives from the value.

In one example, although the serving base station instructs the terminal to perform C2 LBT in the DCI field, the terminal may fail the C2 LBT. The reason for this failure is that the LBT has failed because the energy received by the terminal exceeds the threshold. When a signal from an adjacent base station or a terminal or another type of signal (eg, a WLAN signal) is transmitted, excessive energy may be measured in the terminal. In this case, it is difficult to interpret that the corresponding radio resource is no longer secured by the serving base station. In order to perform the second UL transmission, it is not preferable that the UE reuses the DCI field as it is and uses the C2 LBT. In this case, the terminal can use the LBT type given by default. For example, by using the C4 LBT, the UE can self-secur time resources for UL transmission.

In another example, although the serving base station instructs the terminal to perform C4 LBT in a field of DCI, the terminal may fail in C4 LBT. In order to perform the second UL transmission, the UE may attempt C4 LBT by reusing the DCI field as it is.

In another example, the UE may be instructed from the serving base station to transmit the PUSCH but to transmit in one type of C2 LBT (eg, type 2B or type 2C). In this case, if the C2 LBT for transmission of the first PUSCH fails, the UE may apply the type 2C C2 LBT to transmit the subsequent PUSCH. Here, type 2C corresponds to a kind of default value.

Analysis method for multi-PUSCH (or multi-PDSCH) and slot aggregation

According to the technical standard, the information elements for setting the BWP include information elements for setting the PUSCH (or PDSCH), and the information elements for setting the PUSCH include the TDRA and the aggregate number of slots (L). The UE may be configured with TDRA and L through RRC signaling. The UE may transmit the PUSCH (or PDSCH) by repeating the time resource indicated by the TDRA L times per slot. In this case, a codeword may be generated by applying different RVs of the same TB. This repetitive transmission has the purpose of reducing the error rate of the PUSCH (or PDSCH), and has an effect of lowering the effective code rate of the TB.

If the amount of data the UE has is large while reducing the error rate of the PUSCH (or PDSCH), it is necessary to configure the aggregation of slots while scheduling several TBs.

(One) How to allocate time resources

In the proposed method, the UE may repeatedly transmit all PUSCHs (or PDSCHs) indicated by the TDRA in the next slot. This is a method in which one PUSCH (or PDSCH) is repeated at intervals of slots, so that even if one or more PUSCHs (or PDSCHs) are scheduled, each PUSCH (or PDSCH) may be repeated at intervals of slots. have.

In the proposed method, the serving base station can schedule such that time resources of all PUSCHs (or PDSCHs) are equal to or smaller than one slot (ie, 14 symbols in normal CP, 12 symbols in extended CP). have. Even if the UE repeatedly transmits each PUSCH (or PDSCH), it may be assumed that other PUSCHs (or PDSCHs) and time resources do not overlap with each other. Here, each PUSCH (or PDSCH) may be composed of the same number of symbols or may be composed of a different number of symbols, and it may be assumed that each PUSCH (or PDSCH) is arranged consecutively. The base station can signal only the PUSCH (or PDSCH) arranged at the front in one slot. In this case, the mapping type of the PUSCH (or PDSCH) may be indicated to be the same in all PUSCHs (or PDSCHs) belonging to the slot.

If the PUSCHs (or PDSCHs) indicated by the TDRA are repeated in a slot period, they may not be transmitted in consecutive symbols. In a system operating in an unlicensed band, if the last symbol of the PUSCH (or PDSCH) indicated by the TDRA and the first symbol of the repeated PUSCH (or PDSCH) are separated by 14 symbols (or 12 symbols) from each other, the UE performs a separate LBT procedure. Without it, PUSCH (or PDSCH) may be continuously transmitted. However, when 13 symbols or less (or 12 symbols or less) is separated, the UE must transmit repeated PUSCHs (or PDSCHs) through the LBT procedure.

7 to 10 are conceptual diagrams for explaining examples in which 3 TBs are allocated and transmitted twice.

In FIGS. 7 to 10, three TBs constitute one occassion, and occassions composed of PUSCHs (or PDSCHs) are arranged at slot intervals. In each case, PUSCHs are repeatedly transmitted while changing TB for the same RV (TB cycling) or repeated transmission while changing RV for the same TB (RB cycling). I can.

Referring to FIG. 7, all of the PUSCHs (or PDSCHs) constituting the okay are included in one slot. Meanwhile, referring to FIGS. 8 and 9, the OK may cross the boundary of the slot. That is, each PUSCH (or PDSCH) does not cross the boundary of the slot, but the okay can be allocated over two slots. Here, the start time of the PUSCH (or PDSCH) transmitted in the second slot may be the first symbol of the slot as in the case of FIG. 8. However, the start time of the PUSCH (or PDSCH) transmitted in the second slot may be a time after not the first symbol of the slot as in the case of FIG. 9. In a system operating in TDD, consecutive symbols including the first symbol of a slot may be allocated as a DL symbol or a flexible (FL) symbol. In this case, the PUSCH cannot be transmitted in the corresponding symbols. Alternatively, consecutive symbols including the first symbol of the slot may be allocated as UL symbols or FL symbols. In this case, the PDSCH cannot be transmitted in the corresponding symbols. In addition, when the system operates in an unlicensed band, the time already secured by the LBT procedure may be shared with other terminals (or base stations). In this case, the corresponding terminal (or base station) cannot perform transmission at the corresponding time. In this way, when an invalid symbol exists between TBs, TBs are not continuously allocated.

Referring to FIG. 10, the time resource of the okay is allocated to one slot (ie, 14 symbols or 12 symbols), and may be continuously transmitted with the successively transmitted OK. In this allocation, when operating in an unlicensed band, since there is no need to additionally perform an LBT procedure between OKs, the probability of transmitting an OK increases.

In one embodiment, the base station may instruct the terminal to repeat the time resources of these PUSCHs (or PDSCHs). The UE may repeatedly transmit PUSCHs (or PDSCHs) for the indicated period. In the case of FIG. 7, it may represent a form in which PUSCHs (or PDSCHs) are transmitted within one period.

Depending on the setting of the TDRA, one ok can consist of more symbols than one slot. In this case, the above-described methods cannot be applied.

In the proposed method, if the okay is indicated to be longer than the length of one slot, the first PUSCH (or PDSCH) belonging to the okay may be given not by one slot, but by an interval of an integer number of slots. That is, a plurality of TBs are allocated to form one ok, and the interval between the oks may be given by an integer multiple of the slot. In addition, the number of times the okay is repeated may be given by RRC signaling or DCI.

11 is a conceptual diagram for explaining an example in which an okion having an arbitrary length longer than a slot length is repeated twice.

Referring to FIG. 11, an interval between first symbols constituting okays is set in units of slots, and may be given as 2 or more.

(2) TB allocation method

According to the technical standard, the UE may receive a repetition transmission type A or a repetition transmission type B indication by RRC signaling. Repetitive transmission type A was introduced to reduce the error rate of the data channel, and the data channel is repeatedly transmitted, and the interval of adjacent data channels is given in units of slots. Repetitive transmission type B was introduced to reduce both the error rate and delay time of the data channel, and the data channel is repeatedly transmitted, and adjacent data channels are continuously allocated. One TB is repeatedly transmitted, and at this time, the TB mapped in the data channel may be repeated while having different RVs.

The number of repetitions of the repetitive transmission type A may be derived from the TDRA included in the DCI. The number of repetitions may not be included in the TDRA, and in this case, the data channel is repeatedly transmitted according to the number of repetitions given by RRC signaling. If the number of repetitions is not indicated by RRC signaling, the data channel is transmitted only once. The number of repetitions of the repetitive transmission type B can be derived from the TDRA included in the DCI.

On the other hand, in order to obtain a higher transmission amount, a TDRA included in the DCI may be instructed to transmit multiple TBs consecutively using one DCI. In this case, it is necessary to distinguish between a repetitive transmission type A/B and a method of continuously transmitting a plurality of TBs.

The TDRA may allocate one or more data channels, and the number of data channels (L), time resources for L data channels (i.e., the number of start symbols and symbols of the data channels), and data The mapping type (ie, type A or type B) of channels may be indicated. Here, a start symbol may be indicated for the first data channel, but the start symbols for data channels positioned thereafter may not be explicitly indicated.

In the proposed method, it is possible to receive one TDRA and derive the number of TBs allocated to the data channels (L) and the number of repetitions of the L data channels. When the number of repetitive transmissions is not set by RRC signaling to the UE, when the number of times expressed by the TDRA is given as L, it may be interpreted as L different TBs. Accordingly, L data channels are successively transmitted, and different TBs may be mapped to each data channel. Each of the RVs and NDIs applied to the L TBs may be indicated in the DCI.

If the number of repetitions (K) is indicated to the terminal by RRC signaling, when the number of times expressed by TDRA is given as L, data channels through which L different TBs are transmitted are consecutively arranged, and they maintain an interval in units of slots. It can be interpreted as being repeatedly transmitted K times. RVs and NDIs applied to each of the L TBs may be indicated in the DCI. When repeated K times, different RVs may be applied to TBs mapped to data channels.

In an example applied to the NR system, K may correspond to repK or pdsch-AggregationFactor or pusch-AggregationFactor.

12 is a conceptual diagram illustrating an example of instructing to repeatedly transmit 3 TBs 4 times in one DCI.

Referring to FIG. 12, when TB cycling is applied first and RV cycling is applied later (FIG. 12(a)) and RV cycling is applied first and TB cycling is applied later (FIG. 12(b) ) Is shown. Here, K is given as 4 and is indicated by RRC signaling. L is given by 3 and is indicated by the TDRA. DCI can independently indicate the RV and NDI of the three TBs. The DCI includes only the HARQ process identifier for the data channel to be mapped first, and the HARQ process identifier for the data channel mapped thereafter is given as a value obtained by adding 1 to the previous identifier. The three data channels are arranged consecutively in time, and these data channels have an interval of n slots. In this case, the value of n is indicated to correspond to the fastest slot in which the data channel to which the first TB is mapped may have the same start symbol among integer values including 1. Here, it can be further divided into a configuration in which the TB is changed for the same RV (FIG. 12 (a)) and a configuration in which the RV is changed for the same TB (FIG. 12 (b)).

When the TB is repeated in the same RV, the base station can receive the systematic bit first, so that the decoding of the TBs can be successfully completed according to the state of channel fading. On the other hand, if decoding of a TB fails due to channel fading, soft combining is required, and thus a longer time is required to receive a data channel for another RV.

When the RV is repeated in the same TB, since the base station performs decoding for each TB including association, it is easier to predict the time at which the decoding of a specific TB ends successfully.

How to interpret the timing of activation/deactivation of the serving cell

The serving base station may indicate to the terminal the type of the HARQ codebook through RRC signaling. The size of the T1 HARQ codebook (type 1 HARQ-ACK codebook) is given by RRC signaling. More specifically, all time points (ie, slots or subslots) at which the UE receives the PDSCH and feeds back HARQ-ACK for it are given by RRC signaling, and one view is indicated in DCI. The T1 HARQ codebook includes bits for all time points given by RRC signaling, and indicates a HARQ-ACK bit (ie, a HARQ-ACK bit obtained by decoding a PDSCH) only at a position corresponding to a time point indicated by DCI. Meanwhile, the size of the T2 HARQ codebook (type 2 HARQ-ACK codebook) is given by DCI. More specifically, the terminal may derive the size of the T2 HARQ codebook from specific field(s) of DC.

On the other hand, the T3 HARQ codebook (type 3 HARQ-ACK codebook) is given a size by RRC signaling, but has a different principle from the T1 HARQ codebook. More specifically, in the case of the T1 HARQ codebook, HARQ-ACK bits are generated only for candidate positions of the PDSCH that can be fed back at the same time, but in the case of the T3 HARQ codebook, HARQ- ACK bits are generated. This difference can occur when the NR system operates in the unlicensed band. The PUSCH or PUCCH for the UE to transmit the HARQ-ACK may be transmitted only after success by attempting LBT. However, if the LBT fails, since PUSCH and PUCCH cannot be transmitted, the serving base station cannot receive the HARQ-ACK. Therefore, in order not to retransmit all of the PDSCH, a more improved HARQ codebook is required. To this end, a T3 HARQ codebook in which HARQ-ACK (or HARQ-ACK and NDI) bits are arranged in the order of HARQ processes has been introduced.

When the terminal is instructed by RRC signaling to generate the T3 HARQ codebook, the serving base station may instruct the terminal to transmit the T3 HARQ codebook through the PUCCH in a specific field of the DL-DCI. When frequency aggregation is indicated to the UE by RRC signaling, the UE includes HARQ-ACK (or HARQ-ACK and NDI) bits for the HARQ process configured with RRC signaling in each serving cell for all serving cells. You can generate codebooks.

The number of HARQ processes is indicated by RRC signaling for each serving cell. Therefore, even if the serving cell is activated or deactivated, there is no effect on the size of the T3 HARQ codebook. However, since a specific BWP of a specific serving cell may vary while the serving cell is activated or deactivated, the value of the HARQ-ACK bit (or HARQ-ACK bit and NDI) for a specific HARQ process of the T3 HARQ codebook is also affected.

The serving cell may instruct the UE to activate/deactivate a specific serving cell by using a MAC control element (MAC CE). Alternatively, when the timer set in the terminal expires, deactivation of the corresponding serving cell is performed.

For the serving cell activated by the MAC CE, the UE transmits the SRS, CSI reporting, monitoring the PDCCH for the serving cell, monitoring the PDCCH received from the serving cell, and transmitting the PUCCH as a reference BWP (e.g. For example, in case of DL BWP, it can be performed in firstActiveDownlinkBWP, in case of UL BWP, firstActiveUplinkBWP). Meanwhile, for a serving cell deactivated by the MAC CE, the terminal stops the timer for the corresponding serving cell, stops the timer for the BWP, stops transmission and reception of all data channels indicated by DCI or RRC signaling, and transmits to the corresponding serving cell. All related HARQ buffers are emptied.

In this case, the time when the UE applies activation/deactivation when the serving cell is activated/deactivated is defined in the technical standard. That is, the serving cell is activated/deactivated after a predetermined time offset based on the time when the MAC CE for activating/deactivating the serving cell is received or the time when the deactivation timer expires.

13 is a conceptual diagram illustrating an embodiment of a timing in which a conventional MAC CE is applied to activation/deactivation of a serving cell.

으로 제시된다. 여기서

은 MAC CE를 포함한 PDSCH에 대한 HARQ-ACK를 전송하는 슬롯 옵셋으로 주어지고, 이는 PDSCH를 스케줄링하는 DCI에서 지시된다. 만일 비활성화 타이머가 고려되는 경우에는,

을 0으로 간주할 수 있다.

은 PUCCH를 전송하는 부반송파의 간격에서, 1개의 서브프레임에 속한 슬롯의 개수로 주어진다. Referring to FIG. 13, when a PDSCH including MAC CE is received by a UE in slot n, it is reflected from a predetermined time (k slot). In addition, activation/deactivation is reflected in advance of the minimum time given in the technical specification. Here, the value of k is

Is presented as. here

Is given as a slot offset for transmitting the HARQ-ACK for the PDSCH including the MAC CE, which is indicated in the DCI scheduling the PDSCH. If a deactivation timer is considered,

Can be regarded as 0.

Is given as the number of slots belonging to one subframe in the interval of subcarriers transmitting the PUCCH.

As an exception to the technical standard, in the case of CSI reporting, it is reflected in slot n+k. For HARQ-ACK, the time during which the corresponding serving cell is activated/deactivated is given as a period rather than one time point. If the T3 HARQ codebook is instructed to the UE, the UE must determine which serving cell to derive HARQ-ACK for in the process of activation/deactivation of a specific serving cell.

In the proposed method, one time point at which the serving cell is activated/deactivated (ie, slot n+t) may be determined according to a technical standard. The UE may generate a T3 HARQ codebook using HARQ-ACK bits of HARQ processes for an existing serving cell (ie, existing BWP) that is not changed up to slot n+t-1. From subsequent slots including slot n+t, a T3 HARQ codebook may be generated using HARQ-ACK bits of HARQ processes for a changed serving cell (changed BWP (ie, firstActiveDownlinkBWP)). In one example, the value of t may be k described above.

In the NR system operating in the unlicensed band, the PUCCH or PUSCH that feeds back HARQ-ACK is transmitted only when the LBT procedure is successful. If the LBT procedure fails, the HARQ-ACK cannot be fed back, so the serving base station may indicate a time point at which the HARQ-ACK is fed back to the UE as a non-numerical value. Therefore, the HARQ-ACK bit of a specific HARQ process may not be fed back indefinitely, and when generating the T3 HARQ codebook, it is preferable not to empty the HARQ buffer for the deactivated serving cell.

Meanwhile, when a HARQ-ACK bit for a corresponding serving cell is derived not only in the T3 HARQ codebook but also in the T1 HARQ codebook, an interpretation problem for activation/deactivation occurs. The NR system operating in the licensed band may receive feedback at the point of instructing HARQ-ACK. An event in which the MAC CE is transmitted to the terminal or the timer expires can be expected by the serving base station, and in particular, in the case of deactivating the corresponding serving cell by transmitting the MAC CE, after already receiving all the HARQ-ACK feedback from the corresponding serving cell, MAC CE can be transmitted. Therefore, the problem of interpretation of the T1 HARQ codebook and the problem of emptying the HARQ buffer by the terminal may be embodiedly avoided or ignored. However, in the case of generating the T1 HARQ codebook in the NR system operating in the unlicensed band, since the above-described problems still exist, the timing of activation/deactivation of the serving cell or emptying the HARQ buffer is clarified, and the HARQ- The ACK bits have to be determined.

ULCI's scope of application for PUSCH

The serving base station can support both URLLC traffic and eMBB traffic. Since URLLC traffic should have higher reliability, it is preferable not to allocate eMBB traffic that can act as interference in order to reduce the size of the interference.

After the serving base station allocates the PDSCH including the eMBB traffic, the PDSCH including the URLLC traffic may be transmitted. In this case, the resource of the PDSCH including the URLLC traffic may be transmitted by puncturing the resource of the PDSCH including the eMBB traffic. Therefore, to a terminal that needs to receive eMBB traffic, the serving base station may indicate a downlink preemption indication (DLPI) including a punctured shape in a separate DCI format (eg, DCI format 2_1). The UE may not perform soft combining on the received PDSCH by using the bitmap included in the DLPI.

After the serving base station allocates the PUSCH including eMBB traffic, in order to allocate the PUSCH including URLLC traffic, a separate DCI format (e.g., DCI format 2_4) is transmitted to the terminal, and the eMBB traffic is included. It can be instructed to cancel transmission of the PUSCH. Using the bitmap included in this ULCI (uplink cancellation indication), the UE may not transmit the PUSCH. Here, the UE may receive a search space set for receiving a DCI format (eg, DCI format 2_4) from the serving base station as higher layer signaling.

Meanwhile, the UE does not apply ULCI to all PUSCHs. When the terminal performs initial access, the terminal has not yet established an RRC connection, and thus the search space set and RNTI (eg, INT-RNTI) for receiving ULCI cannot be configured from the serving base station. In this case, since the UE cannot receive ULCI, it transmits Msg 3 PUSCH depending only on the RAR UL grant.

If the serving base station sets the search space set and INT-RNTI for receiving ULCI to the terminal, a 2-stage random access (Type-2 RACH) can be performed. -RNTI can be set. The terminal may transmit Msg A to the serving base station. In this case, MsgA is composed of a PRACH preamble and a PUSCH. When both ULCI and Type-2 RACH are configured for the UE, the UE may not apply ULCI in the PUSCH (MsgA PUSCH) constituting the MsgA.

Accordingly, when the UE identifies PUSCHs to which ULCI is applied, the scrambling sequence is initialized with a specific RNTI (e.g., C-RNTI, MCS-C-RNTI, CS-RNTI) or CRC masking with a specific RNTI. PUSCH scheduled on the PDCCH can be applied. That is, ULCI may not be applied to PUSCH related to RNTI other than that.

Alternatively, the UE may not apply ULCI to all PUSCHs related to RACH. In this case, ULCI may be applied to all PUSCHs not related to RACH.

If not only the UL BWP is activated in the same UL carrier, but also the sidelink BWP (SL BWP) may be activated. If for a specific terminal, the serving base station may schedule sidelink transmission/reception and PUSCH. Here, among the resources belonging to the SL BWP, a sidelink resource pool means a specific set of time and frequency resources, and this set of resources may appear periodically. The serving base station may indicate the sidelink resource pool to the corresponding terminal through higher layer signaling. Accordingly, a UE supporting both the sidelink and the PUSCH may receive not only the RNTI related to the PUSCH, but also the RNTI related to the sidelink (i.e., SL-RNTI, SLCS-RNTI, SL SPS V-RNTI) from the serving base station.

Since the bitmap included in ULCI is a group common DCI broadcast to a plurality of unspecified terminals from the serving base station, it may be defined regardless of the pattern of the sidelink resource pool. Therefore, the time and frequency resources that one bit means in the bitmap included in ULCI may be a time and frequency resource belonging to the sidelink resource pool. Since the PUSCH including URLLC traffic can be scheduled or configured to be orthogonal to the sidelink resource pool in the serving base station, the ULCI bitmap may not have any effect on time and frequency resources belonging to the sidelink resource pool. Therefore, when the terminal performs sidelink transmission/reception, it is preferable not to apply this to sidelink transmission/reception even if INT-RNTI is indicated and ULCI is observed.

14 is a block diagram illustrating a configuration of an apparatus for performing methods according to embodiments of the present invention.

The apparatus illustrated in FIG. 14 may be a communication node (eg, a terminal or a base station) for performing a method according to embodiments of the present invention.

Referring to FIG. 14, a communication node 1400 may include at least one processor 1410, a memory 1420, and a transmission/reception device 1430 connected to a network to perform communication. In addition, the communication node 1400 may further include an input interface device 1440, an output interface device 1450, and a storage device 1460. Each of the components included in the communication node 1400 may be connected by a bus 1470 to communicate with each other.

The processor 1410 may execute a program command stored in at least one of the memory 1420 and the storage device 1460. The processor 1410 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 1420 and the storage device 1460 may be configured with at least one of a volatile storage medium and a nonvolatile storage medium. For example, the memory 1420 may be composed of at least one of read only memory (ROM) and random access memory (RAM).

The methods according to the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and usable to those skilled in computer software.

Examples of computer-readable media include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language codes such as those produced by a compiler, as well as high-level language codes that can be executed by a computer using an interpreter or the like. The above-described hardware device may be configured to operate as at least one software module to perform the operation of the present invention, and vice versa.

Although described with reference to the above embodiments, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention described in the following claims. I will be able to.

Claims (1)

As a method for transmitting uplink control information (UCI) in an unlicensed band,
Receiving setting of a physical uplink shared channel (PUSCH) resource and a physical uplink control channel (PUCCH) resource from a serving base station-the PUSCH resource and the PUCCH resource at least partially overlap in a time domain, and the PUSCH resource is temporally greater than the PUCCH resource antecedence;
Performing a first listen-before-talk (LBT) procedure for transmitting a PUSCH in the PUSCH resource;
If the first LBT procedure is successful, multiplexing the UCI to the PUSCH in the PUSCH resource and transmitting the multiplexed signal;
If the first LBT procedure fails, performing a second LBT procedure for transmitting the UCI in the PUCCH resource; And
If the second LBT procedure is successful, comprising the step of transmitting the UCI through the PUCCH in the PUCCH resource,
UCI transmission method.

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