A method for transmitting an uplink signal, a user equipment

Abstract

This application discloses an uplink signal transmission method, a user equipment (UE), and a base station. The UE determines the LBT type of the current subframe and the starting point for signal transmission by combining the scheduling information of the previous, current, and subsequent subframes, the LBT type, and whether there is an interval between these subframes. This application allows the UE to avoid additional LBT or select an appropriate LBT method on consecutively scheduled subframes, enabling continuous transmission after the first subframe passes LBT, increasing the probability of signal transmission. It also allows the UE to perform appropriate LBT even when it fails to correctly receive some scheduling signaling, avoiding impact on other devices and ensuring its own transmission probability, thereby improving overall network efficiency.

Description

[0001] This application is a divisional application of the patent application No. 201610721162.3 with the title of "A method for transmitting uplink signal and user equipment", the filing date of which is August 24, 2016. TECHNICAL FIELD

[0002] The present application relates to the field of mobile communication technology, in particular, the present application relates to a method for transmitting uplink signal and user equipment. BACKGROUND

[0003] With the contradiction between the user's demand for high bandwidth wireless service and the scarcity of spectrum resources becoming increasingly sharp, mobile operators begin to consider using unlicensed frequency band as a supplement to licensed frequency band. Therefore, the research on deploying LTE in unlicensed frequency band is on the agenda. 3GPP has begun to study the efficient carrier aggregation between unlicensed frequency band and licensed frequency band, as shown in the following figure, how to effectively improve the spectrum utilization of the whole network under the premise of ensuring no significant impact on other technologies in unlicensed frequency band is a technical problem to be solved. Figure 1

[0004] Unlicensed frequency band is usually allocated for some other use, for example, radar or wireless fidelity (WiFi) of 802.11 series. Thus, in unlicensed frequency band, the interference level is uncertain, which leads to the fact that the quality of service (QoS) of LTE transmission is usually difficult to guarantee, but unlicensed frequency band can still be used for data transmission with low QoS requirement. Here, the LTE system deployed in unlicensed frequency band is called licensed assisted access system (LAA). In unlicensed frequency band, how to avoid the mutual interference between LAA system and other wireless systems such as radar or WiFi is a key problem.

[0005] Carrier sensing (CCA) is a commonly used mechanism to avoid conflict in unlicensed frequency band. A mobile station (STA) must detect the wireless channel before transmitting a signal, and only when the wireless channel is detected to be idle can the wireless channel be occupied to transmit a signal. This mechanism is called LBT mechanism (Listen-before-talk). LAA also needs to follow a similar mechanism to ensure less interference to other signals. A relatively simple method is that LAA device (base station or terminal user) dynamically switches according to the CCA result, that is, if the channel is detected to be idle, the signal is transmitted, and if the channel is busy, the signal is not transmitted.

[0006] ​In uplink transmission in unlicensed band, UE determines the subframes that can transmit uplink channels / signals, LBT type and related parameters, and resource allocation, etc. according to the received scheduling signaling (UL grant) of the base station.

[0007] In order to make full use of the resources occupied by UE after successfully completing LBT once, the base station can schedule consecutive uplink subframes for the same UE. In order to save signaling overhead, the base station can perform multi-subframe scheduling, that is, schedule multiple consecutive uplink subframes through one UL grant. Of course, multi-subframe scheduling will sacrifice some flexibility, such as the same resource allocation and HARQ scheduling flexibility for multiple subframes. Therefore, the base station can also perform single-subframe scheduling, that is, schedule multiple consecutive uplink subframes through multiple UL grants one by one. The multiple UL grants can be sent in the same downlink subframe or in different downlink subframes. Of course, the base station can also support multi-subframe and single-subframe scheduling at the same time to schedule multiple uplink subframes in a UL burst.

[0008] UE performs corresponding LBT detection in the scheduled uplink subframes according to the LBT type and parameters indicated by the base station. UE does not need to perform LBT between multiple uplink subframes in a UL burst and continuously transmits, but UE needs to perform corresponding LBT detection according to the information indicated by the base station in the starting subframe of the UL burst. Due to the existence of hidden terminals, UE may miss some UL grants, so that UE cannot determine the LBT in the corresponding uplink subframes only according to the received UL grant. At the same time, if the base station does not indicate the LBT type of the subframes in the UL burst through the UL grant, for example, the base station only indicates 25us or Cat-4 LBT, but the base station still hopes that UE does not need to perform LBT within the UL burst, then it is necessary to define a rule that the base station and UE understand consistently to realize the implicit indication of this LBT type.

[0009] In addition, in order to indicate the LBT type more flexibly, the base station can also use cell common signaling, such as Common PDCCH (C-PDCCH) scrambled by CC-RNTI, to indicate the LBT type or the change of the LBT type. Then, how does UE determine the LBT in the above described cases according to the LBT type indicated by the UL grant and / or the LBT type indicated by the C-PDCCH is also urgent to be solved.

[0010] It should be noted that the above introduction to the technical background is only for the convenience of clearly and completely describing the technical solutions of the present application and facilitating the understanding of those skilled in the art. The above technical solutions cannot be considered as known to those skilled in the art merely because they are described in the background of the present application. SUMMARY

[0011] The present application provides a method for transmitting uplink signals, a user equipment and a base station, which can solve the problem of how the UE determines LBT and the starting point of the uplink signal when the UE is scheduled by multiple scheduling signals for consecutive uplink subframes. This includes a method for how the UE determines the LBT type when at least one of the scheduling signals is missed, and a method for how the UE determines the LBT type when the scheduling signal is not missed. Through the method of the present application, the UE can continuously transmit without additional LBT on the continuously scheduled subframes, improve the probability of transmitting signals, and also enable the UE to perform appropriate LBT when it fails to correctly receive part of the scheduling signal, avoid affecting other devices, and also ensure the UE's own transmission probability, thereby improving the overall network efficiency.

[0012] To achieve the above object, the present application adopts the following technical solutions:

[0013] A method for transmitting uplink signals, comprising:

[0014] receiving scheduling signals for scheduling the current subframe, and / or signals containing LBT type indication;

[0015] determining the LBT type of the current subframe according to the received scheduling signals for scheduling the current subframe, and / or signals containing LBT type indication, and / or the received scheduling signals for scheduling the immediately preceding subframe, and / or the received scheduling signals for scheduling the immediately following consecutive subframes;

[0016] performing LBT on the current subframe according to the determined LBT type, and attempting to transmit uplink signals from the current subframe.

[0017] Preferably, the signals containing LBT type indication are scheduling signals UL grant for scheduling the current subframe and / or the previous subframe, and / or cell common control signals.

[0018] Preferably, when the signals containing LBT type indication are only UL grant, the UE determines the LBT type of the current subframe according to the received UL grant for scheduling the current subframe and the received UL grant for scheduling the previous subframe, and judges whether there is an interval between the current subframe and the previous subframe.

[0019] Preferably, if there is no gap between the current subframe and the previous subframe, and the UE has transmitted the scheduled signal in the previous subframe, the UE does not need to perform LBT in the current subframe, and directly transmits the scheduled signal from the beginning of the current subframe.

[0020] Preferably, if there is no gap between the current subframe and the previous subframe, and the UE has not transmitted the scheduled signal in the previous subframe, the LBT type of the current subframe is a predefined default LBT type if the LBT type indicated by the UL grant scheduling the current subframe is no LBT; and / or,

[0021] If the LBT type indicated by the UL grant scheduling the current subframe is LBT, the LBT type of the current subframe is the LBT type indicated by the UL grant scheduling the current subframe.

[0022] Preferably, if there is a gap between the current subframe and the previous subframe, the LBT type of the current subframe is the LBT type indicated by the UL grant scheduling the current subframe.

[0023] Preferably, when the signaling containing the LBT type indication is only the UL grant, the UE does not receive the UL grant scheduling the previous subframe, and the UE determines the LBT type of the current subframe according to the received UL grant scheduling the current subframe, including:

[0024] If the LBT type indicated by the UL grant scheduling the current subframe is no LBT, the UE determines the LBT type of the current subframe to be a predefined default LBT type, or the UE further determines whether the previous subframe of the current subframe is a downlink subframe, if the previous subframe is a downlink subframe, the current subframe does not need to perform LBT, otherwise the LBT type of the current subframe is a predefined default LBT type;

[0025] Or,

[0026] If the LBT type indicated by the UL grant scheduling the current subframe is LBT, the LBT type of the current subframe is the LBT type indicated by the UL grant scheduling the current subframe; or,

[0027] If the LBT type indicated by the UL grant scheduling the current subframe is not no LBT, the LBT type of the current subframe is the LBT type indicated by the UL grant scheduling the current subframe.

[0028] Preferably, the signaling containing the LBT type indication is scheduling signaling of the current subframe, and / or, scheduling signaling UL grant of the immediately following subframe, and / or, cell common control signaling.

[0029] Preferably, in multi-subframe scheduling, if one or more of the consecutive multiple uplink subframes starting from the current subframe has interval, the starting point of the one or more of the consecutive multiple uplink subframes with interval is fixed as the second symbol of the uplink subframe with interval.

[0030] Preferably, if the signaling containing the LBT type indication contains at least the cell common control signaling, the UE determines the LBT type of the current subframe and the starting point of the signal of the current subframe according to the received UL grant scheduling the current subframe, the received UL grant scheduling the immediately following subframe, and the LBT type indicated by the cell common control signaling.

[0031] Preferably, if the consecutive multiple uplink subframes starting from the current subframe without interval belong to the same LBT type indicated by the cell common control signaling, the LBT type of the current subframe is the LBT type indicated by the cell common control signaling.

[0032] Preferably, in multi-subframe scheduling, if one or more of the consecutive multiple uplink subframes starting from the current subframe has interval, and all the consecutive multiple uplink subframes without interval before the first interval belong to the same LBT type indicated by the cell common control signaling, the LBT type of the current subframe is the LBT type indicated by the cell common control signaling. Preferably, the starting point of the one or more of the consecutive multiple uplink subframes with interval is fixed as the second symbol of the uplink subframe with interval.

[0033] Preferably, if the consecutive multiple uplink subframes starting from the current subframe without interval belong to different LBT types indicated by the cell common control signaling, the LBT type of the current subframe is the LBT type indicated by the UL grant scheduling the current subframe, or,

[0034] the LBT type of the current subframe is a predefined default LBT type, or,

[0035] the LBT type of the current subframe is the most conservative LBT type of the consecutive multiple uplink subframes without interval.

[0036] Preferably, if one or more of the continuous multiple uplink subframes starting from the current subframe has interval, and all the continuous multiple uplink subframes without interval before the first interval belong to different LBT types indicated by the cell common control signaling, the LBT type of the current subframe is the LBT type indicated by the UL grant scheduling the current subframe. Preferably, the starting point of the one or more of the continuous multiple uplink subframes with interval is fixed as the second symbol of the uplink subframe with interval.

[0037] Preferably, if the signaling containing the LBT type indication contains at least the cell common control signaling, and the UE does not receive the UL grant scheduling the previous subframe, the LBT type of the current subframe is the LBT type indicated by the cell common control signaling.

[0038] Preferably, if the continuous multiple uplink subframes starting from the current subframe belong to different LBT types indicated by the cell common control signaling, the LBT type of the current subframe is the LBT type indicated by the cell common control signaling before the latest received cell common control signaling, or,

[0039] the LBT type of the current subframe is a predefined default LBT type, or,

[0040] the LBT type of the current subframe is the most conservative LBT type of the continuous multiple uplink subframes without interval.

[0041] Preferably, the predefined default LBT type is the fourth type Cat-4 LBT.

[0042] Preferably, when the user is scheduled by the signaling of the multiple subframe scheduling, if at least one of the continuous M1 subframes scheduled by the signaling exceeds the current maximum occupation time indicated by the cell common control information, if the subframe carrying the aperiodic CSI and / or the subframe transmitting SRS determined according to the M1 subframes scheduled exceeds the current maximum occupation time indicated by the cell common control information, the corresponding subframe can be abandoned, or the subframe carrying the aperiodic CSI and / or the subframe transmitting SRS is determined according to the M2 continuous subframes determined according to the maximum occupation time which can be transmitted.

[0043] Preferably, if the user receives the cell common control information and the time difference between the subframe carrying the aperiodic CSI and / or the subframe transmitting SRS determined according to the M2 continuous subframes determined according to the maximum occupation time which can be transmitted is not less than the minimum processing time delay of the uplink transmission of the user, the user can carry the subframe carrying the aperiodic CSI and / or transmit SRS in the newly determined subframe, otherwise the user cannot transmit.

[0044] The application also discloses a user equipment, comprising:

[0045] The first receiving module is used for receiving scheduling signaling, wherein the scheduling signaling at least contains LBT information indication;

[0046] The first uplink signal sending module is used for determining the LBT type of the current subframe according to the scheduling signaling of the current subframe and / or the scheduling signaling of the previous subframe, and sending uplink signals on the uplink carrier. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 A schematic diagram of the joint networking of the licensed frequency band and the unlicensed frequency band in the LAA system;

[0048] Figure 2 A flow chart of the uplink signal sending method in the first embodiment of the application;

[0049] Figure 3 A schematic diagram of the LBT type determination of the UE when the UE does not receive the UL grant of the previous subframe and the UL grant contains the LBT indication in the embodiment of the application;

[0050] Figure 4 Another schematic diagram of the LBT type determination of the UE when the UE does not receive the UL grant of the previous subframe and the UL grant contains the LBT indication in the embodiment of the application;

[0051] Figure 5 Still another schematic diagram of the LBT type determination of the UE when the UE does not receive the UL grant of the previous subframe and the UL grant contains the LBT indication in the embodiment of the application;

[0052] Figure 6 Yet another schematic diagram of the LBT type determination of the UE when the UE does not receive the UL grant of the previous subframe in the embodiment of the application;

[0053] Figure 7 A schematic diagram of the LBT type determination of the UE when the UE receives the UL grant of the previous subframe and the UL grant contains the LBT indication in the embodiment of the application;

[0054] Figure 8 Another schematic diagram of the LBT type determination of the UE when the UE receives the UL grant of the previous subframe and the UL grant contains the LBT indication in the embodiment of the application;

[0055] Figure 9For the embodiment of the present application, when the LBT indication is contained in the UL grant, the UE determines the LBT type according to the following another schematic diagram when the UE receives the UL grant of the previous subframe;

[0056] Figure 10 For the embodiment of the present application, when the LBT indication is contained in the UL grant, the UE determines the LBT type according to the following another schematic diagram when the UE receives the UL grant of the previous subframe;

[0057] Figure 11 For the embodiment of the present application, when the LBT indication is contained in the UL grant, the UE determines the LBT type according to the following another schematic diagram when the UE receives the UL grant of the previous subframe;

[0058] Figure 12 For the embodiment of the present application, when the LBT indication is contained in the C-PDCCH only, the UE determines the LBT type according to the following schematic diagram;

[0059] Figure 13 For the embodiment of the present application, when the LBT indication is contained in the C-PDCCH only, the UE determines the LBT type according to the following another schematic diagram;

[0060] Figure 14 For the embodiment of the present application, when the LBT indication is contained in the C-PDCCH only, the UE determines the LBT type according to the following another schematic diagram;

[0061] Figure 15 For the embodiment two of the present application, the flow chart of the method for sending the uplink signal is shown in the following figure;

[0062] Figure 16 For the embodiment two of the present application, when the multi-subframe scheduling is used, the UE determines the LBT type according to the following schematic diagram;

[0063] Figure 17 For the embodiment two of the present application, when the LBT indication is contained in the C-PDCCH, the UE determines the LBT type according to the following schematic diagram;

[0064] Figure 18 For the embodiment of the present application, the schematic diagram of the composition structure of the user equipment is shown in the following figure;

[0065] Figure 19 For the embodiment of the present application, the schematic diagram of the UE determining the starting point of the uplink subframe is shown in the following figure;

[0066] Figure 20 For the embodiment of the present application, the schematic diagram of the UE determining the A-CSI sending subframe is shown in the following figure;

[0067] Figure 21 For the embodiment of the present application, the schematic diagram of the UE determining the A-CSI sending subframe is shown in the following figure; DETAILED DESCRIPTION

[0068] To solve the problems in the prior art, the application provides a method for transmitting uplink signals, user equipment and a base station. More specifically, the application provides a method for determining LBT and a method for transmitting uplink signals.

[0069] In the unlicensed frequency band, in order to increase the channel occupation opportunities of the UE, the base station can schedule consecutive uplink subframes for the same UE. The UE only needs to perform LBT detection in the first uplink subframe of the multiple consecutive uplink subframes, and can continuously transmit the uplink subframes without performing LBT in the middle. The base station can schedule multiple consecutive uplink subframes through multi-subframe scheduling, for example, through one UL grant to schedule multiple consecutive uplink subframes; or through multiple UL grants to schedule multiple consecutive uplink subframes, for example, one UL grant schedules the first four consecutive subframes, and another UL grant schedules the next two consecutive subframes, and the six uplink subframes are consecutive; or through single-subframe scheduling, for example, through multiple UL grants to schedule multiple consecutive uplink subframes; or through joint multi-subframe and single-subframe scheduling, for example, through one UL grant to schedule the first four consecutive subframes, and through another UL grant to schedule the fifth subframe. For the convenience of description, the multiple consecutive uplink subframes are referred to as one uplink UL burst. There is no interval in the middle of the uplink subframes, for example, the first symbol of a certain middle subframe is not left out, or the last symbol of a certain middle subframe is not left out.

[0070] If it is multi-subframe scheduling, in addition to the above-described case that there is no interval in the middle of the scheduled consecutive subframes, there is another case that one or more subframes in the middle of the scheduled multiple consecutive uplink subframes are spaced. For example, the UL grant can dynamically indicate in combination with high-layer signaling configuration, or the system can be pre-defined rule, or the UL grant can dynamically indicate which one or more subframes of the multiple consecutive subframes are spaced. The size of the interval can be determined in one of the following two ways:

[0071] Method one: The size of the interval can be pre-defined, for example, the first SC-FDMA symbol of the corresponding subframe is left out, and the starting point is the second SC-FDMA symbol (#1 SC-FDMA symbol), and does not depend on the starting point of the first subframe of the multiple consecutive subframes indicated in the UL grant. For example, Figure 19As shown, the UL grant schedules 4 consecutive subframes, all within the MCOT. The starting point indicated by the UL grant is 25us, the LBT type is 25us LBT, and there is a gap between the 2nd and 3rd subframes among the 4 consecutively scheduled subframes. Then, the starting point of the 1st subframe is 25us after the start of the uplink subframe boundary, and the UE performs 25us LBT, and if the LBT passes, the UE can transmit the 1st and 2nd subframes consecutively. The 3rd subframe starts from the 2nd SC-FDMA symbol of the subframe, and the UE performs 25us LBT before the start of transmission.

[0072] In the second way, the size of the gap can be determined jointly according to the starting point indicated in the UL grant and a predefined threshold value. For example, the threshold value is defined as X microseconds (us), if the time difference between the starting point of the 1st subframe among the multiple consecutive subframes indicated in the UL grant and the uplink subframe boundary of the 1st subframe is greater than and / or equal to X us, then the starting point of the subframe with the gap among the multiple consecutive subframes is determined according to the starting point of the 1st subframe among the multiple consecutive subframes indicated in the UL grant, otherwise the starting point is the 2nd SC-FDMA symbol, or the starting point is a position X us later than the subframe boundary of the corresponding subframe. For example, the UL grant schedules 4 consecutive subframes, all within the MCOT. The starting point indicated by the UL grant is 25us, the LBT type is 25us LBT, and there is a gap between the 2nd and 3rd subframes among the 4 consecutively scheduled subframes. Assuming that the threshold X is 60us. Then, since the UL grant indicates 25us < 60us, the starting point of the 3rd subframe is the 60us position within the 1st symbol, or the starting point is the 2nd symbol.

[0073] The following embodiments of the present application are all for the case without a gap among consecutive subframes.

[0074] When the base station schedules different uplink subframes in one uplink UL burst with multiple UL grants, the base station can indicate no LBT, so that the UE does not need to perform LBT and continuously transmits in these subframes. However, if the UE misses the UL grant sent by the base station to indicate the first uplink subframe of the UL burst, the UE cannot perform the corresponding LBT according to the no LBT. For example, the base station sends two UL grants to schedule uplink subframe n and uplink subframe n+1, respectively, and indicates that the LBT type of subframe n is Cat-4 LBT and the LBT type of subframe n+1 is no LBT. If the UE does not detect the UL grant of subframe n, the UE cannot perform the corresponding LBT according to the no LBT of subframe n+1. For another example, the base station can not indicate no LBT, but indicates 25us or Cat4 LBT, but the base station also expects the UE to determine that the current subframe does not need to perform LBT according to a predefined rule. For example, the base station sends two UL grants to schedule uplink subframe n and uplink subframe n+1, respectively, and indicates that the LBT type of subframe n is Cat-4 LBT and the LBT type of subframe n+1 is also Cat4 LBT. At this time, if the UE misses the UL grant of subframe n, the UE can also perform LBT according to the LBT type indicated by the UL grant of subframe n+1. However, if the UE detects the UL grant of subframe n and also detects the UL grant of subframe n+1, and the base station expects no LBT between the continuous scheduling of subframe n and subframe n+1, a corresponding rule needs to be defined so that the UE can not perform LBT in subframe n+1.

[0075] In addition, if the base station can also indicate through cell common signaling that some uplink subframes belong to one LBT type and other uplink subframes belong to another LBT type according to the latest downlink transmission situation, the UE also needs to determine how to determine the LBT type of each uplink subframe and the starting point of the uplink signal of the uplink subframe when the scheduled continuous uplink subframes belong to different LBT types.

[0076] In the present application, specific solutions are given to solve the above problems.

[0077] In the present application, the transmission of the corresponding uplink signal is described. If it is not explicitly described that it can be directly transmitted without LBT, it means that it is transmitted after the required LBT is completed. If the LBT fails, it is not transmitted.

[0078] In the invention, the LBT performed in a certain subframe is not limited to the starting point of the LBT or the end position being at the boundary of the start of a certain subframe, but only indicates that the LBT is performed for the transmission of uplink signals in a certain subframe. The specific end position of the LBT is determined according to the starting point of the uplink channel / signal in a certain subframe.

[0079] Embodiment one:

[0080] Figure 2 The flowchart of the method for transmitting uplink signals in the embodiments of the present application includes:

[0081] Step 201: The UE receives scheduling signaling for scheduling uplink transmission and / or signaling containing LBT type indication.

[0082] Preferably, the scheduling signaling for scheduling uplink transmission can be UL grant.

[0083] Preferably, the scheduling signaling for scheduling uplink transmission can be single-subframe scheduling UL grant or multi-subframe scheduling UL grant.

[0084] Preferably, the scheduling signaling for scheduling uplink transmission can contain LBT type indication, such as 25us LBT or Cat 4 LBT, or no LBT, etc.

[0085] Preferably, the scheduling signaling for scheduling uplink transmission further includes LBT related information, such as LBT priority and / or contention window size adjustment (CWS) related information. The contention window size adjustment related information can be explicit, such as the base station indicating the size of the CW, or the contention window size adjustment related information can be implicit, such as the base station sending information that can indirectly / directly indicate ACK / NACK so that the UE can determine the size of the CW according to the information. The present invention does not make any limitation. The UE can determine the parameters of Cat-4 LBT through the information. The LBT related information and LBT type indication in the scheduling signaling can be independent bit indication or joint coding, and the present invention does not make any limitation.

[0086] Preferably, the signaling containing LBT type indication can be cell common signaling, such as C-PDCCH. The specific form of the cell common signaling indicating LBT type is not limited by the present invention.

[0087] Preferably, whether the LBT information is indicated in the C-PDCCH can be configured by higher layers or predefined by the system.

[0088] Step 202: Determine the LBT type of the current subframe, and the PUSCH starting point of the current subframe, according to the received scheduling signaling of the current subframe, and / or the signaling containing LBT type indication of the current subframe, and the scheduling signaling of the previous subframe.

[0089] Preferably, the LBT type information is contained in the UL grant, and the C-PDCCH does not contain the LBT type information.

[0090] Preferably, the LBT type information is contained in the UL grant, and the C-PDCCH contains the LBT type information.

[0091] Preferably, the LBT type information is not contained in the UL grant, and the C-PDCCH contains the LBT type information.

[0092] In this step, we will describe the two cases respectively, (1) the LBT type information is contained in the UL grant, and the C-PDCCH contains or does not contain the LBT type information, and (2) the LBT type information is not contained in the UL grant, and the C-PDCCH contains the LBT type information.

[0093] Preferably, the PUSCH starting point of the current subframe is determined according to the starting point indicated by the UL grant scheduling the current subframe. If it is multi-subframe scheduling, it can be considered that if it is the first subframe of multiple subframes, the starting point is the starting point indicated by the UL grant, and if it is not the first subframe of multiple subframes, the starting point is the first symbol of the subframe, i.e. symbol #0, or determined according to the starting point indicated by the UL grant. In the following description, it is collectively referred to as the starting point indicated by the UL grant.

[0094] (1) If the UL grant contains LBT indication, the UE can determine the LBT type and / or the starting point of the PUSCH of the current subframe according to the LBT information indicated by the UL grant, and / or the LBT information indicated by the C-PDCCH, and whether the UL grant of the previous subframe is received, and whether there is a gap between the previous subframe and the current subframe.

[0095] (1.1) If the UL grant of the previous subframe is not received, and no C-PDCCH containing LBT indication information is received thereafter,

[0096] If the LBT type that the UL grant can indicate contains No LBT, and the LBT type indicated by the UL grant of the current subframe is No LBT, the UE can determine the LBT type and the starting point position of the uplink channel / signal in one of the following two ways:

[0097] Method 1: Determine the LBT type of the current subframe as a predefined default LBT type, such as Cat-4 LBT. The UE can determine the Cat-4 LBT parameters based on the received UL grant. For example, the UE adjusts relevant information based on the LBT priority and contention window size (CWS) of the current subframe to determine the Cat-4 LBT parameters, such as generating a backoff counter (BO). The starting point of the PUSCH is determined based on the starting position indicated by the current subframe. The indicated starting position is indicated by the UL grant, determined by predefined rules, determined by higher-layer signaling and / or the UL grant, or determined by cell common / user group information. The indication information will not be elaborated further in this invention.

[0098] If the system does not support the first uplink subframe of a UL burst starting with no LBT, then when the UE receives an LBT type of No LBT in the UL grant indication, the UE can determine that the base station scheduled uplink transmission in the previous subframe, but the UE missed the corresponding UL grant. In this case, the UE performs LBT according to Cat-4. Because the UL grant indicates the LBT priority and CWS adjustment information, the UE can determine the Cat-4 LBT parameters based on this information. Figure 3 As shown, the base station sent a UL grant for scheduling uplink subframe #4 in downlink subframe #0, indicating that the LBT type is Cat-4. In downlink subframe #1, it sent UL grants for scheduling uplink subframes #5 to #7, indicating that the LBT type is No LBT. Furthermore, subframes #4 to #7 are consecutive without any gaps. The UE detects the UL grants for scheduling subframes #5 to #7, but does not detect the UL grant for scheduling subframe #4. Therefore, the UE performs a Cat-4 LBT in subframe #5.

[0099] Method 2: If the LBT type indicated by the UL grant in the current subframe is No LBT, and the system supports UL bursts starting with noLBT, then if the UE can determine that the previous subframe is a downlink subframe, the UE does not need to perform LBT, and the start point of PUSCH is determined according to the start position specified in the current subframe. If the UE cannot determine whether the previous subframe is a downlink subframe, then the UE determines the LBT type of the current subframe to be the predefined default LBT type, such as Cat-4 LBT, and determines the Cat-4 parameters according to the LBT priority and CWS adjustment information of the current subframe. The start point of PUSCH is determined according to the start position indicated by the current subframe.

[0100] If a system supports a no LBT for the first uplink subframe of a UL burst, e.g. if the time interval between a downlink subframe and an uplink subframe is no more than 16us, the UE can transmit without LBT detection before the corresponding uplink subframe. If the UE receives a no LBT indication in the UL grant of the current uplink subframe and does not detect an UL grant in the previous subframe, the UE can not be able to determine whether (a) the previous subframe is a downlink subframe and the current subframe is the first uplink subframe of a UL burst without LBT, or (b) the UE missed the UL grant of the previous uplink subframe. Therefore, if the UE can determine that the previous subframe is a downlink subframe, the UE does not need to perform LBT and directly transmit the scheduled uplink transmission in the current subframe. Preferably, the UE can determine that the previous subframe is a downlink subframe by detecting C-PDCCH signaling indicating that the previous subframe is a downlink subframe, and / or by detecting signaling (PDCCH) in the previous subframe scheduling the UE for downlink transmission in the previous subframe, and / or by CRS detection determining that the previous subframe is a downlink subframe, and / or by determining that the start of the PUSCH of the current subframe is TA (Timing advance) + 16us or 16us. If the UE cannot determine that the previous subframe is a downlink subframe, the LBT type of the current subframe is a predefined default LBT type, e.g. Cat-4 LBT. Because the UL grant indicates the LBT priority and CWS adjustment related information, the UE can determine the parameters of the Cat-4 LBT according to the information. As shown in FIG. 2, the base station transmits UL grants scheduling uplink subframes #4 and #5 in downlink subframes #0 and #1, respectively. The UE detects the UL grant scheduling subframe #5 but does not detect the UL grant scheduling subframe #4. Because the UE does not detect PDCCH in subframe #4, the UE cannot determine whether subframe #4 is a downlink subframe or the UE determines that subframe #4 is not a downlink subframe. Therefore, the UE performs Cat-4 LBT before subframe #5. As another example, as shown in FIG. 3, the base station transmits UL grants scheduling uplink subframes #4 and #5 in downlink subframes #0 and #1, respectively. The UE detects the UL grant scheduling subframe #5 but does not detect the UL grant scheduling subframe #4. Because the UE does not detect PDCCH in subframe #4, the UE cannot determine whether subframe #4 is a downlink subframe or the UE determines that subframe #4 is not a downlink subframe. Therefore, the UE performs Cat-4 LBT before subframe #5. Figure 4 As shown in FIG. 2, the base station transmits UL grants scheduling uplink subframes #4 and #5 in downlink subframes #0 and #1, respectively. The UE detects the UL grant scheduling subframe #5 but does not detect the UL grant scheduling subframe #4. Because the UE does not detect PDCCH in subframe #4, the UE cannot determine whether subframe #4 is a downlink subframe or the UE determines that subframe #4 is not a downlink subframe. Therefore, the UE performs Cat-4 LBT before subframe #5. As another example, as shown in FIG. 3, the base station transmits UL grants scheduling uplink subframes #4 and #5 in downlink subframes #0 and #1, respectively. The UE detects the UL grant scheduling subframe #5 but does not detect the UL grant scheduling subframe #4. Because the UE does not detect PDCCH in subframe #4, the UE cannot determine whether subframe #4 is a downlink subframe or the UE determines that subframe #4 is not a downlink subframe. Therefore, the UE performs Cat-4 LBT before subframe #5. Figure 5As shown, the base station sends UL grant scheduling subframe #5 in subframe #1, and the UE detects the UL grant. Subframe #4 is a downlink subframe, and the base station sends C-PDCCH in subframe #4. If the UE detects that #4 is a downlink subframe, such as detecting C-PDCCH, the UE determines that subframe #4 is a downlink subframe, and the UE does not perform LBT and directly sends PUSCH in #5. If the UE does not detect that #4 is a downlink subframe, such as missing C-PDCCH or inaccurate CRS detection, the UE still performs Cat-4 LBT in subframe #5. Since the base station sends downlink in subframe #4, the UE cannot detect through LBT, and thus cannot send PUSCH in subframe #5.

[0101] • If the UL grant can indicate LBT type contains No LBT, and the LBT type indicated by the UL grant of the current subframe is not No LBT, the LBT type of the current subframe is the LBT type indicated by the UL grant scheduling the current subframe.

[0102] In this case, it is explained that the base station expects the UE to perform LBT. For example, the base station schedules UE1 to send PUSCH in the previous subframe and the current subframe, and schedules UE2 to send PUSCH from the current subframe. Therefore, in order to enable the newly scheduled UE2 to be detected by CCA, a gap is reserved in the current subframe, so that the newly scheduled UE2 and the previously scheduled UE1 can simultaneously perform CCA detection. In this case, there is a gap between the previous subframe and the current subframe.

[0103] • If the UL grant can indicate LBT type does not contain No LBT, such as the UL grant only indicates 25us LBT or Cat-4 LBT with 1 bit, the UE determines that the LBT type of the current subframe is the LBT type indicated by the UL grant, and the start of PUSCH is determined according to the start indicated by the UL grant of the current subframe.

[0104] In this case, it can be considered that the base station does not support UL burst starting with no LBT, but the base station still supports that there is no LBT between consecutive uplink subframes. The base station does not explicitly indicate no LBT, but indirectly indicates by indicating that there is no gap between adjacent subframes. For specific ways, see the description in (1.3) and (1.4).

[0105] In this case, whether the UE misses the UL grant of the previous subframe or not, as long as the UE does not detect the UL grant of the previous subframe, the UE can perform LBT according to the LBT type indicated by the UL grant scheduling the current subframe.

[0106] (1.2) If the UE does not receive the UL grant of the previous subframe and receives the C-PDCCH containing the LBT indication information, the UE can determine the LBT type of the current subframe and the PUSCH starting point in at least one of the following three ways:

[0107] Way one: The UE determines the LBT type of the current subframe according to the LBT type indicated by the C-PDCCH (which can contain No LBT), and the PUSCH starting point of the current subframe is the PUSCH starting point indicated by the UL grant scheduling the current subframe.

[0108] Way two: The UE determines the LBT type of the current subframe according to the LBT type indicated by the C-PDCCH, and determines the PUSCH starting point of the current subframe according to the PUSCH starting point indicated by the UL grant scheduling the current subframe. If the LBT type of the subsequent subframe needs to be changed, see embodiment two.

[0109] (1.3) If the UE receives the UL grant of the previous subframe and does not receive the C-PDCCH containing the LBT indication information, then:

[0110] • If the LBT type that the UL grant can indicate contains No LBT, and the LBT type indicated by the UL grant of the current subframe is No LBT (a more reasonable case, the UL grant of the current subframe and the UL grant of the previous subframe indicate that there is no gap between the previous subframe and the current subframe), then: if the UE successfully transmits the PUSCH of the previous subframe, the UE does not need to perform LBT (the LBT type is No LBT), and the PUSCH starting point is the starting point indicated by the UL grant (i.e. #0 symbol); if the UE does not successfully transmit the PUSCH of the previous subframe, the LBT type is the default LBT type, for example Cat-4 LBT, and the UE needs to determine the parameters of Cat-4 according to the LBT priority of the current subframe and the CWS adjustment related information.

[0111] Because the UE has successfully received the UL grant of the previous subframe, the UE can determine that the previous subframe must be an uplink subframe, not a downlink subframe. Therefore, there is no problem that the UE cannot determine whether the previous subframe is an uplink or downlink subframe as described above.

[0112] As Figure 7As shown, the base station sends UL grant in subframe #0 to schedule uplink subframe #4, where the indicated LBT type is Cat-4 LBT. The base station sends UL grant in subframe #1 to schedule uplink subframes #5, #6, #7, where the indicated LBT type is No LBT. The base station indicates that these 4 subframes are consecutive without gap. That is, the base station expects the UE to transmit PUSCH in subframes #4~#7 consecutively. The UE detects UL grant in subframe #0 to schedule subframe #4, and detects UL grant in subframe #1 to schedule subframes #5 and #7. Then, the UE can determine that subframes #4~#5 are consecutive. Therefore, the UE performs LBT according to the Cat-4 indicated by the UL grant before subframe #4, and if the LBT passes, the UE can transmit PUSCH consecutively in subframes #4 and #5, i.e. subframe #5 does not need to perform LBT. Also, the UE performs LBT according to Cat-4 before subframe #7, and the Cat-4 parameters can be determined by the LBT priority and the related information of CWS adjustment in the UL grant. If the LBT before subframe #4 does not succeed, the UE performs LBT according to Cat-4 before subframe #5, and the Cat-4 parameters can be determined by the LBT priority and the related information of CWS adjustment in the UL grant.

[0113] • If the LBT type that the UL grant can indicate contains No LBT, and the LBT type indicated by the UL grant of the current subframe is not No LBT, the UE determines the LBT type according to the LBT indicated by the UL grant of the current subframe, and the start of PUSCH is determined according to the start indicated by the UL grant of the current subframe.

[0114] In this case, it is explained that the base station expects the UE to perform LBT. For example, the base station schedules UE1 to transmit PUSCH in the previous subframe and the current subframe, and also schedules UE2 to transmit PUSCH from the current subframe. Therefore, in order to enable the newly scheduled UE2 to pass the CCA detection, a gap needs to be reserved in the current subframe, so that the newly scheduled UE2 and the previously scheduled UE1 can perform CCA detection at the same time. In this case, the previous subframe and the current subframe are directly with a gap.

[0115] • If the LBT type indicated by UL grant does not contain No LBT, e.g. only 1 bit to indicate 25us LBT or Cat 4 LBT, then: If the UE can determine from the UL grant of the current subframe and the UL grant of the previous subframe that there is no gap between the previous subframe and the current subframe, and if the UE has successfully transmitted the PUSCH of the previous subframe, then the UE does not need to perform LBT (LBT type is No LBT), and the starting point of the PUSCH is the starting point indicated by the UL grant (i.e. symbol #0); If the UE has not successfully transmitted the uplink signal of the previous subframe or the UE can determine from the UL grant of the current subframe and the UL grant of the previous subframe that there is a gap between the previous subframe and the current subframe, then the UE needs to determine the LBT type, the LBT priority and the CWS adjustment related information according to the LBT type indicated by the UL grant, and determine the LBT parameters, and determine the starting point of the PUSCH according to the UL grant.

[0116] To save the overhead of LBT type indication, one implementation is that the LBT type indicated by UL grant does not contain No LBT. But this does not mean that when the base station schedules consecutive uplink subframes, the UE still has to perform LBT in the consecutive uplink subframes. The UE needs to determine whether to perform LBT according to whether there is a gap between the current subframe and the previous subframe. For example, the uplink transmission scheduled in the previous subframe occupies the last SC-FDMA symbol, and the uplink transmission scheduled in the current subframe starts from the first SC-FDMA symbol (#0 symbol), then the UE can determine that there is no gap between the two subframes. Therefore, if the UE has transmitted the previous subframe, then the current subframe can not perform LBT and directly transmit. For another example, the uplink transmission scheduled in the previous subframe occupies the last SC-FDMA symbol, and the uplink transmission scheduled in the current subframe starts from the second SC-FDMA symbol (#1 symbol), then the UE can determine that there is a gap between the two subframes. Therefore, the UE performs LBT according to the LBT information indicated by the UL grant before transmitting in the current subframe, and if the LBT passes, the UE can transmit the scheduled uplink signal in the current subframe.

[0117] As Figure 8As shown, the base station sends UL grant in subframe #0 to schedule uplink subframe #4, where the indicated LBT type is Cat-4 LBT. The base station sends UL grant in subframe #1 to schedule uplink subframes #5, #6, #7, where the indicated LBT type is Cat-4 LBT. The base station indicates that these 4 subframes are consecutive, without interval. That is, the base station expects the UE to transmit PUSCH in subframes #4~#7 consecutively. The UE detects UL grant in subframe #0 to schedule subframe #4, and detects UL grant in subframe #1 to schedule subframes #5 and #7. Then, the UE can determine that subframes #4~#5 are consecutive. Therefore, the UE performs LBT according to the Cat-4 indicated by the UL grant before subframe #4, and if the LBT is passed, the UE can transmit PUSCH consecutively in subframes #4 and #5, i.e. subframe #5 does not need to perform LBT, although the UL grant to schedule subframe #5 indicates LBT type. Also, the UE performs LBT according to the Cat-4 indicated by the UL grant before subframe #7. If the LBT before subframe #4 is not successful, the UE performs LBT according to the LBT indicated by the UL grant to schedule subframe #5 before subframe #5.

[0118] (1.4) If the UE receives UL grant of the previous subframe and receives C-PDCCH containing LBT indication information, then:

[0119] • If the LBT type indicated by the UL grant can be No LBT, and the LBT type indicated by the UL grant of the current subframe is No LBT, and if the current subframe and the previous subframe belong to the same set of subframes of the same LBT type, then,

[0120] If the UE successfully transmits PUSCH of the previous subframe, the UE does not need to perform LBT (LBT type is No LBT), and determines the starting point of PUSCH according to the UL grant;

[0121] If the UE does not successfully transmit PUSCH of the previous subframe, the UE can determine the LBT type of the current subframe according to one of the following methods:

[0122] Method one: the LBT type of the current subframe is the LBT type indicated by the C-PDCCH.

[0123] Method two: the LBT type of the current subframe is the LBT type indicated by the UL grant of the previous subframe.

[0124] Method three: the LBT type of the current subframe is the default subframe type, e.g. Cat-4 LBT.

[0125] Method 4: The UE needs to further determine whether there is an adjacent uplink subframe without gaps scheduled after the current subframe, see Example 2.

[0126] like Figure 9 As shown, the base station sends a UL grant for scheduling uplink subframe #4 in subframe #0, indicating the LBT type as Cat-4 LBT. The base station sends UL grants for scheduling uplink subframes #5 and #6 in subframe #1, indicating the LBT type as No LBT. That is, the base station expects the UE to continuously send PUSCH in subframes #4 to #6. The UE detects the UL grant in subframe #0, detects the UL grants for scheduling subframes #5 and #6 in subframe #1 (without an interval between these two subframes), and detects a C-PDCCH in downlink subframe #3, indicating that subframes #4 to #6 are a 25µs LBT subframe set, and #7 is a Cat-4 LBT subframe set. Therefore, the UE can determine that subframes #4 to #6 belong to the same LBT subframe set. The UE performs a 25µs LBT before subframe #4; if the LBT passes, it starts sending PUSCH from subframe #4 until subframe #6. The PUSCH of these three subframes is continuous, and no LBT is required in between.

[0127] • If the LBT type indicated by the UL grant includes No LBT, and the LBT type indicated by the UL grant of the current subframe is No LBT, and if the current subframe and the previous subframe do not belong to the same set of subframes with the same LBT type, then the UE can determine the LBT type of the current subframe in one of the following two ways:

[0128] Method 1: The UE does not change the LBT type of the uplink subframe immediately adjacent to the current subframe (without any gap) based on the LBT information indicated by the C-PDCCH. If the UE transmitted an uplink signal in the previous subframe, the UE does not need to perform LBT in the current subframe and transmits PUSCH according to the indicated PUSCH start point in the current subframe. If the UE fails to transmit the PUSCH of the previous subframe, the LBT type of the current subframe is the LBT type indicated by the C-PDCCH. Alternatively, the UE needs to further determine whether there is an adjacent uplink subframe without any gap scheduled after the current subframe. If there is such a subframe and the subsequent subframes belong to a different LBT type subframe set than the current subframe, the LBT type of the current subframe is the default LBT type, such as Cat-4 LBT. If there is such a subframe and the subsequent subframes belong to the same LBT type subframe set as the current subframe, the LBT type of the current subframe is the LBT type indicated by the C-PDCCH. The UE then transmits PUSCH according to the indicated PUSCH start point in the current subframe.

[0129] likeFigure 10 As shown, the base station sends UL grant in subframe #0 scheduling uplink subframe #4, where the indicated LBT type is Cat-4 LBT. The base station sends UL grant in subframe #1 scheduling uplink subframes #5, 6, where the indicated LBT type is No LBT. That is, the base station expects to schedule the UE to transmit PUSCH continuously in subframes #4~#6. The UE detects the UL grant in subframe #0, detects the UL grant scheduling subframes #5 and #6 in subframe #1 (there is no gap between these three subframes), and detects C-PDCCH in downlink subframe #3, where it indicates that subframes #4~#5 are a 25us LBT subframe set and #6 is a Cat-4 LBT subframe set. Then, the UE does not do 25us LBT before subframe #4, but does Cat-4 LBT as indicated in the UL grant. If the LBT passes, the UE starts transmitting PUSCH from subframe #4 until subframe #6. The PUSCH of these three subframes is continuous, and no LBT is needed in between. In this example, the current subframe is subframe #5, and the subframe 4 of the current subframe does not change the LBT type according to the C-PDCCH.

[0130] Method two: the LBT type of the current subframe is the LBT type indicated by the C-PDCCH, and

[0131] √ The start of the PUSCH is symbol #0.

[0132] √ The start of the PUSCH is symbol #1 (Cat-4 LBT). The PUSCH still does rate matching with the start at symbol #0, and then punctures symbol #0.

[0133] √ The start of the PUSCH is symbol #0 + 25us (Cat-2 LBT). The PUSCH still does rate matching with the start at symbol #0, and then punctures 25us.

[0134] • If the LBT type indicated by UL grant can contain No LBT, and the LBT type indicated by UL grant of the current subframe is not No LBT. In this case, the base station expects the UE to do LBT, and the current subframe and the previous subframe are not gap. Then the LBT type of the current subframe is the LBT type indicated by C-PDCCH, and the starting point of PUSCH is determined according to the starting point indicated by UL grant of the current subframe, or the UE further determines whether there is a contiguous uplink subframe after the current subframe, if there is such a subframe and the subsequent subframe belongs to a different LBT type subframe set with the current subframe, then the LBT type of the current subframe is the LBT type indicated by UL grant; if there is such a subframe and the subsequent subframe belongs to the same LBT type subframe set with the current subframe, then the LBT type of the current subframe is the LBT type indicated by C-PDCCH. And the starting point of PUSCH is determined according to the starting point indicated by UL grant of the current subframe.

[0135] • If the LBT type indicated by UL grant does not contain No LBT, for example, only 1 bit indicates 25us LBT or Cat 4 LBT, then: if the UE can determine that there is no gap between the previous subframe and the current subframe through the UL grant of the current subframe and the UL grant of the previous subframe, and if the UE successfully transmits the PUSCH of the previous subframe, then the UE does not need to do LBT, and the starting point of the previous subframe PUSCH is the starting point indicated by UL grant (#0 symbol); If the UE has not successfully transmitted the PUSCH of the previous subframe, or if the UE can determine that there is a gap between the previous subframe and the current subframe through the UL grant of the current subframe and the UL grant of the previous subframe, then: the LBT type of the current subframe is the LBT type indicated by C-PDCCH, or further determine whether there is a contiguous uplink subframe after the current subframe and whether it belongs to the same LBT type subframe set to determine whether to use the LBT indicated by UL grant or the LBT type indicated by C-PDCCH.

[0136] (2) If only C-PDCCH contains LBT indication, then the UE can determine the LBT type of the current subframe and / or the starting point of PUSCH according to the LBT information indicated by C-PDCCH, whether the UL grant of the previous subframe is received, and whether there is a gap between the previous subframe and the current subframe.

[0137] (1.1) If no UL grant is received from the previous subframe, the start point of the PUSCH of the current subframe is determined according to the start point indicated by the UL grant of the current subframe, and the LBT type of the current subframe can be determined by one of the following three methods:

[0138] Method 1: The LBT type of the current subframe is the LBT type indicated by the most recently received C-PDCCH.

[0139] Method 2: Similar to the method described above, further determine whether there are consecutive uplink subframes after the current subframe and whether they belong to the same LBT type subframe set to determine whether to use the LBT indicated by the previous C-PDCCH or the LBT type indicated by the latest received C-PDCCH, as in Example 2 (2).

[0140] Method 3: Similar to the method described above, the LBT type of the current subframe is determined according to the LBT indicated by the latest received C-PDCCH. If the LBT is successful, the scheduled uplink subframes without intervals can be continuously sent until the subframe set of another LBT type begins, and then proceed according to another LBT type, as in Example 2 (2).

[0141] like Figure 12 As shown, the base station sent a UL grant for scheduling uplink subframe #4 in subframe #0. The base station also sent UL grants for scheduling uplink subframes #5 and #6 in subframe #1. There is no gap between these three subframes, and the base station expects the UE to continuously send PUSCH in subframes #4 to #6. According to the LBT indicated by the previous C-PDCCH, subframes #4 to #6 all belong to the Cat-4 LBT subframe set. However, the base station sent a new C-PDCCH in subframe #3, indicating that subframes #4 to #5 belong to the 25us LBT subframe set, and subframe #6 belongs to the Cat4 subframe set. The UE did not detect a UL grant in subframe #0, detected the UL grants for scheduling subframes #5 and #6 in subframe #1 (there is no gap between these two subframes), and detected the new C-PDCCH in downlink subframe #3. Therefore, before subframe #5, the UE does not perform the 25µs LBT as indicated by the newly received C-PDCCH, but instead performs the LBT according to the Cat-4 instruction of the previous C-PDCCH. If the LBT is successful, the UE starts sending PUSCH from subframe #5 until subframe #6. The PUSCHs in these two subframes are consecutive, and no LBT is needed in between. In this example, the current subframe is subframe #5.

[0142] For example Figure 13As shown, the base station sends UL grant in subframe #0 to schedule uplink subframe #4. The base station sends UL grant in subframe #1 to schedule uplink subframe #5, 6. There is no gap between these three subframes, and the base station expects the UE to transmit PUSCH continuously in subframe #4~#6. According to the LBT indicated by the previous C-PDCCH, subframe #4~#6 belong to Cat-4 LBT subframe set. But the base station sends new C-PDCCH in subframe #3, which indicates that subframe #4~ belong to 25us LBT subframe set, and subframe #5~#6 belong to Cat-4 subframe set. The UE does not detect UL grant in subframe #0, detects UL grant in subframe #1 to schedule subframe #5 and subframe #6 (there is no gap between these two subframes), and detects new C-PDCCH in downlink subframe #3. Then, the UE performs LBT according to Cat-4 LBT indicated by the newly received C-PDCCH in subframe #5. If LBT passes, the UE transmits PUSCH from subframe #5 to subframe #6. The PUSCH of these two subframes is continuous, and no LBT is needed in between. In this example, the current subframe is subframe #5.

[0143] (1.2) If UL grant of previous subframe is received, and it can be inferred from UL grant of previous subframe and current subframe that there is a gap between previous subframe and current subframe, then determine LBT type and PUSCH start of current subframe as (2.1).

[0144] (1.3) If UL grant of previous subframe is received, and it can be inferred from UL grant of previous subframe and current subframe that there is no gap between previous subframe and current subframe:

[0145] • If current subframe and previous subframe belong to the same LBT type subframe set, if the UE successfully transmits PUSCH of previous subframe, the UE can not perform LBT again, and the start of PUSCH is #0 symbol; if the UE does not successfully transmit PUSCH of previous subframe, then determine LBT type and PUSCH start of current subframe as (2.1).

[0146] As Figure 14As shown, the base station sends UL grant in subframe #0 to schedule uplink subframe #4. The base station sends UL grant in subframe #1 to schedule uplink subframe #5, 6. There is no gap between these three subframes, and the base station expects the UE to transmit PUSCH continuously in subframe #4~#6. According to the LBT indicated by the previous C-PDCCH, subframe #4~subframe #6 belong to Cat-4 LBT subframe set. However, the base station sends a new C-PDCCH in subframe #3, which indicates that subframe #4~subframe #6 belong to 25us LBT subframe set, and subframe #7 belong to Cat-4 subframe set. The UE detects UL grant in subframe #0, detects UL grant in subframe #1 to schedule subframe #5 and subframe #6 (there is no gap between these two subframes), and detects a new C-PDCCH in downlink subframe #3. Then, the UE performs 25us LBT before subframe #4 according to the new received C-PDCCH indication. If the LBT passes, the UE transmits PUSCH from subframe #4 to subframe #6. The PUSCH of these three subframes is continuous, and no LBT is needed in between. If the LBT in subframe #4 does not pass, the UE performs 25us LBT in subframe #5, and if it passes, the UE transmits PUSCH from subframe #5 to subframe #6. In this example, the current subframe is subframe #5.

[0147] • If the current subframe and the previous subframe belong to different LBT type subframe sets, the LBT type of the current subframe and the PUSCH starting point can be determined in one of the following three ways:

[0148] Way one: the UE does not change the LBT type of the uplink subframe immediately adjacent to the current subframe (with no gap in between) according to the LBT information indicated by the newly received C-PDCCH. If the UE has transmitted uplink signal in the previous subframe of the current subframe, the UE does not need to perform LBT in the current subframe, and the PUSCH starting point according to the UL grant is the starting point of the current subframe. If the UE has not successfully transmitted PUSCH in the previous subframe, the LBT type of the current subframe is the LBT type indicated by the C-PDCCH, and the PUSCH starting point according to the UL grant is the starting point of the current subframe.

[0149] Method two: UE further judges whether there is a non-interval uplink subframe immediately after the current subframe, if there is such a subframe and the subframe after that belongs to a different LBT type subframe set from the current subframe, the LBT type of the current subframe is the LBT type indicated by the C-PDCCH received before, if there is such a subframe and the subframe after that belongs to the same LBT type subframe set as the current subframe indicated by the newly received C-PDCCH, the LBT type of the current subframe is the LBT type indicated by the newly received C-PDCCH. And the starting point of PUSCH indicated by the UL grant is the starting point of the current subframe.

[0150] Method three: the LBT type of the current subframe is the LBT type indicated by the newly received C-PDCCH, regardless of whether the UE successfully sent the PUSCH of the previous subframe,

[0151] √ The starting point of PUSCH is #0 symbol.

[0152] √ The starting point of PUSCH is #1 symbol (Cat-4 LBT). The PUSCH still does rate matching with the starting point of #0, and then punctures the #0 symbol.

[0153] √ The starting point of PUSCH is #0 symbol + 25us (Cat-2 LBT). The PUSCH still does rate matching with the starting point of #0, and then punctures the 25us.

[0154] Step 203: performing LBT on the current subframe according to the determined LBT type, if the LBT passes, sending the PUSCH from the determined starting point of the PUSCH in the current subframe; if the LBT fails, not sending the PUSCH in the current subframe.

[0155] In the application, the examples given are all single subframe scheduling scenarios, but the application is also applicable to multi-subframe scheduling scenarios. For example, consecutive uplink subframes can also be indicated by one or more multi-subframe scheduling UL grants, such as the base station expecting to continuously schedule subframe #0-subframe #5, but the maximum length of multi-subframe scheduling is 4 subframes, then the base station can send two UL grants, one of which schedules subframe #0-subframe #3, and the other schedules subframe #4-subframe #5. The five subframes are consecutive and have no interval inside.

[0156] Embodiment two:

[0157] Figure 15 The flowchart of the method for transmitting uplink signals in the embodiments of the application comprises:

[0158] Step 1501: UE receives scheduling signaling scheduling uplink transmission, and / or signaling containing LBT type indication.

[0159] Preferably, the scheduling signaling scheduling uplink transmission can be UL grant.

[0160] Preferably, the scheduling signaling scheduling uplink transmission can be single-subframe scheduling UL grant or multi-subframe scheduling UL grant.

[0161] Preferably, the scheduling signaling scheduling uplink transmission can contain LBT type indication, such as 25us LBT or Cat 4 LBT, or no LBT, etc.

[0162] Preferably, the scheduling signaling scheduling uplink transmission further contains LBT related information, such as LBT priority, and / or contention window size adjustment (CWS) related information. The CWS related information can be explicit, such as the base station indicating the size of CW, or the CWS related information can be implicit, such as the base station sending information indirectly / directly indicating ACK / NACK so that the UE can determine the size of CW according to the information. The present application does not limit. The UE can determine the parameters of Cat-4 LBT through the information. The LBT related information and LBT type indication in the scheduling signaling can be independent bit indication or joint coding, which is not limited by the present application.

[0163] Preferably, the scheduling signaling scheduling uplink transmission can be a physical layer signaling, such as UL grant, containing the content of the existing UL grant and LBT related information and / or uplink signal transmission time information. It can also be two physical layer signaling, such as the first step is UL grant, containing the content of the existing UL grant and / or uplink signal transmission time information and / or LBT related information, and the second step is UL grant or user group scheduling / triggering signaling or cell common signaling.

[0164] Preferably, the signaling containing LBT type indication can be cell common signaling, such as C-PDCCH. The specific form of the cell common signaling indicating LBT type is not limited by the present application.

[0165] Preferably, whether the LBT information is indicated in the C-PDCCH can be configured by higher layer or predefined by system.

[0166] Step 1502: Determine the LBT type of the current subframe, and the PUSCH starting point of the current subframe, according to the received scheduling signaling scheduling the current subframe, and / or the signaling containing LBT type indication of the current subframe, and the scheduling signaling scheduling the next one or more subframes.

[0167] Preferably, the LBT type information is contained in the UL grant, and the C-PDCCH does not contain the LBT type information.

[0168] Preferably, the LBT type information is contained in the UL grant, and the C-PDCCH contains the LBT type information.

[0169] Preferably, the LBT type information is not contained in the UL grant, and the C-PDCCH contains the LBT type information.

[0170] In this step, we will describe the two cases respectively, (1) the LBT type information is contained in the UL grant, and the C-PDCCH contains or does not contain the LBT type information, and (2) the LBT type information is not contained in the UL grant, and the C-PDCCH contains the LBT type information.

[0171] Preferably, the PUSCH starting point of the current subframe is determined according to the starting point indicated by the UL grant scheduling the current subframe. If it is multi-subframe scheduling, it can be considered that if it is the first subframe of multiple subframes, the starting point is the starting point indicated by the UL grant, and if it is not the first subframe of multiple subframes, the starting point is the first symbol of the subframe, i.e. symbol #0, or determined according to the starting point indicated by the UL grant. In the following description, it is collectively referred to as the starting point indicated by the UL grant.

[0172] (1) If the LBT indication is contained in the UL grant, the UE can determine the LBT type and / or the PUSCH starting point of the current subframe according to the LBT information indicated by the UL grant, and / or the LBT information indicated by the C-PDCCH, and whether the UE receives the UL grant of the next one or more subframes, and whether there is a gap between the next one or more subframes and the current subframe.

[0173] (1.1) If the LBT indication is contained in the UL grant, and the UE receives the C-PDCCH containing the LBT indication information.

[0174] So, UE needs to determine whether there is a consecutive uplink subframe scheduled (UE detects the corresponding scheduling signaling) after the current subframe, if there is such a subframe and the following subframe belongs to a different LBT type subframe set with the current subframe, then the LBT type of the current subframe can be determined in one of the following ways, otherwise the LBT type of the current subframe is determined according to the LBT indicated by C-PDCCH.

[0175] Way one: the LBT type of the current subframe is determined according to the most conservative LBT type of these consecutive subframes, and the PUSCH starting point of the current subframe is the PUSCH starting point indicated by the UL grant.

[0176] An exception of way one, if the current subframe is No LBT (the interval between the previous downlink subframe and the current uplink subframe is less than 16us), and the following several subframes are 25us, then the LBT type of the current subframe is No LBT. In other cases, the most conservative one is used. For example, the current subframe is No LBT (the interval between the previous downlink subframe and the current uplink subframe is less than 16us), and the first subframe after it is 25us LBT, and the second subframe is Cat-4 LBT, then the current subframe applies Cat-4 LBT. For another example, the current subframe is 25us LBT, and the following two subframes are Cat-4 LBT, then the current subframe applies Cat-4 LBT.

[0177] Way two: the LBT type of the current subframe is determined according to the LBT type indicated by the UL grant scheduling the current subframe (if the indicated LBT type is not No LBT), and the PUSCH starting point of the current subframe is the PUSCH starting point indicated by the UL grant.

[0178] For way two, if the UL grant scheduling the current subframe does not indicate the LBT type, for example, the base station expects to schedule multiple consecutive subframes, and the current subframe is one of the multiple consecutive subframes, and the base station indicates No LBT, then a pre-defined default LBT type can be used, for example, Cat-4 LBT.

[0179] Way three: the LBT type of the current subframe is determined according to the indication of C-PDCCH, but the first subframe of the following subframes and the current subframe is not a subframe set of the same LBT type needs to be determined according to the indication of C-PDCCH, and the PUSCH starting point of this subframe is a pre-defined starting point, for example:

[0180] √ The starting point of PUSCH is #1 symbol (if the LBT type of this subframe is Cat-4 LBT). The PUSCH still does rate matching according to the starting point of #0, and then punctures the #0 symbol.

[0181] The start of PUSCH is #0 symbol + 25us (if the LBT type of this subframe is Cat-2 LBT). The PUSCH still rate matches with the start at #0, then punctures the 25us.

[0182] Preferably, the set of subframes of LBT type is determined by the indication of C-PDCCH. For example, the base station sends C-PDCCH in subframe #n, indicating that from subframe #n+1 to subframe #n+k is a set of 25us LBT subframes, and subframe #n+k+1 and the following subframes are a set of Cat-4 LBT subframes. Note that the subframes falling in the set of 25us or Cat-4 LBT subframes can be not LBT, for example, the middle subframes of the multiple consecutive subframes discussed in the embodiment, even if falling in the set of 25us or Cat-4 LBT subframes, it is also possible not to do LBT. The present application does not limit how C-PDCCH specifically indicates the set of subframes of LBT type.

[0183] An example of mode two, the current subframe UL grant indicates Cat-4 LBT, and the following two consecutive subframe UL grants indicate No LBT or both indicate Cat-4 LBT, wherein the current subframe falls in the set of 25us LBT subframes, and the following two subframes fall in the set of Cat-4 LBT subframes, then the LBT type is determined according to the Cat-4 LBT indicated by the UL grant of the current subframe. That is, in this case, although the current subframe falls in the set of 25us LBT subframes indicated by C-PDCCH, the UE does not use 25us LBT, but according to the Cat-4 LBT indicated by the UL grant received before scheduling the current subframe.

[0184] An example of mode one, the current subframe UL grant and the following two consecutive subframe UL grants both indicate No LBT, wherein the current subframe falls in the set of 25us LBT subframes, and the following two subframes fall in the set of Cat-4 LBT subframes, then the most conservative LBT type of these consecutive subframes is Cat-4 LBT.

[0185] In an example of Method 3, if the current subframe UL grant indicates Cat-4 LBT, and the following two consecutive subframes both indicate No LBT or both indicate Cat-4 LBT, and the current subframe falls within the 25µs LBT subframe set, while the following two subframes fall within the Cat-4 LBT subframe set, then the LBT type of the current subframe is the 25µs LBT indicated by the C-PDCCH. However, the next subframe cannot be transmitted directly without performing an LBT; the next subframe must perform a Cat-4 LBT according to the C-PDCCH indication. Although the base station does not reserve a gap between the current subframe and the next subframe during scheduling, the UE needs to allocate the first symbol in the next subframe for Cat-4 LBT.

[0186] like Figure 6 As shown, the base station sends a UL grant for scheduling uplink subframe #4 in subframe #0, indicating the LBT type as Cat-4 LBT. The base station sends UL grants for scheduling uplink subframes #5 and #6 in subframe #1, indicating the LBT type as No LBT. That is, the base station expects the UE to continuously send PUSCH in subframes #4 to #6. The UE does not detect the UL grant in subframe #0, detects the UL grants for scheduling subframes #5 and #6 in subframe #1 (without an interval between these two subframes), and detects a C-PDCCH in downlink subframe #3, indicating that subframes #4 and #5 are 25µs LBT subframe sets, and #6 is a Cat-4 LBT subframe set. Therefore, the UE can determine that subframe #5 and subframe #6 belong to different LBT subframe sets. Thus, the UE cannot perform LBT on subframe #5 according to the 25us indicated by C-PDCCH, but should perform LBT on subframe #5 according to Cat-4. If LBT is successful, the UE can continuously send PUSCH for subframe #5 and subframe #6.

[0187] Similarly, if it is multi-subframe scheduling, such as Figure 16 As shown, the base station sends a UL grant for scheduling uplink subframes #4 to #6 in subframe #0, indicating the LBT type as Cat-4 LBT. These subframes have no gap. The UE detects the UL grant in subframe #0 and a C-PDCCH in downlink subframe #3, indicating that subframes #4 and #5 are 25µs LBT subframe sets, and #6 is a Cat-4 LBT subframe set. Therefore, the UE can determine that subframes #4, #5, and #6 belong to different LBT subframe sets. Thus, according to method two, the UE cannot perform LBT on subframe #4 according to the 25µs indicated by the C-PDCCH, but should instead perform LBT on subframe #4 according to Cat-4. If the LBT passes, the UE can continuously send PUSCHs for subframes #5 and #6.

[0188] As Figure 11 shown, the base station sends UL grant in subframe #0 to schedule uplink subframe #4, where the indicated LBT type is Cat-4 LBT. The base station sends UL grant in subframe #1 to schedule uplink subframe #5, 6. The UE detects UL grant in subframe #0, detects UL grant in subframe #1 to schedule subframe #5 and subframe #6 (there is no gap between these three subframes), and detects C-PDCCH in downlink subframe #3, where it is indicated that subframe #4~#5 is a 25us LBT subframe set, and #6 is a Cat-4 LBT subframe set. Then, according to the third approach, the UE performs LBT for 25us in subframe #4 according to the indication of C-PDCCH. If the LBT passes, the UE transmits PUSCH from subframe #4 to subframe #5. The PUSCH of these two subframes is continuous, and no LBT is needed in between. But subframe #6 needs to perform Cat-4 LBT, and the start of PUSCH is at symbol #1.

[0189] The fourth approach: the LBT type of the current subframe is determined according to the indication of C-PDCCH, but the UE gives up transmitting from the first subframe of a subframe set which is not of the same LBT type as the current subframe.

[0190] For example, the UE detects multi-subframe scheduling signaling in subframe n, which schedules four continuous uplink subframes (subframes n+8~n+11) with no gap in between, and the indicated LBT type is Cat-4 LBT. The UE also detects C-PDCCH in subframe n+7, which indicates that the MCOT ends at subframe n+9, i.e. subframe n+9 and the previous subframes belong to the current MCOT, while the subframes after subframe n+9 do not belong to the current MCOT. Then, the UE can perform 25us LBT before subframe n+8, and if the LBT passes, the UE can continuously transmit subframe n+8 and subframe n+9, while the UE gives up transmitting subframe n+10 and subframe n+11.

[0191] Preferably, if the interval between subframe n, in which the UE receives C-PDCCH which contains information indicating 25us or Cat-4 LBT, and the uplink subframe n+k that the UE wants to transmit is greater than or equal to the minimum processing delay k' of the uplink data of the UE, the UE can re-determine the subframes in which the UE transmits A-CSI, and / or SRS, and / or whether the last symbol is shortened, according to the number M2 of uplink subframes that the UE can transmit according to the C-PDCCH.

[0192] Further, assume that there are M1 uplink subframes scheduled by multi-subframe scheduling signaling, and UE determines that there are M2 uplink subframes that can be transmitted by C-PDCCH, where M1 >= M2. Assume that there are I1 subframes determined by M1 to transmit A-CSI. If subframe I1 is after the M2 subframes that can be transmitted, for example, M1 = 4, M2 = 2, and subframe I1 is the second last subframe of M1 = 4 subframes, then subframe I1 is after M2 = 2 subframes, and UE cannot transmit. In this case, subframe I2 to transmit A-CSI can be determined by one of the following methods:

[0193] Method one: if M2 = 2, then A-CSI is transmitted in the second subframe. If M2 > 2, then A-CSI is transmitted in the second last subframe, for example, M2 = 3, then A-CSI is transmitted in the second subframe. If M2 = 1, then A-CSI is transmitted in the first subframe.

[0194] Method two: if M2 = 2, then A-CSI is transmitted in the second subframe. If M2 > 2, then A-CSI is transmitted in the second last subframe, for example, M2 = 3, then A-CSI is transmitted in the second subframe. If M2 = 1, then A-CSI is not transmitted.

[0195] Method three: if M2 > 0, then A-CSI is transmitted in the last subframe of M2 subframes.

[0196] Method four: if M2 > 1, then A-CSI is transmitted in the last subframe of M2 subframes. If M2 = 1, then A-CSI is not transmitted.

[0197] Note that the above four methods are all based on the assumption that the time difference between the newly determined subframe I2 to transmit A-CSI and the subframe in which the C-PDCCH is received is greater than or equal to the minimum processing delay k' of UE. If the time difference is less than the minimum processing delay, then UE can only give up transmitting A-CSI, and the transmission of PUSCH within the M2 subframes is still generated based on the assumption that there is no A-CSI. Generally, the minimum processing delay k' = 4.

[0198] As Figure 20As shown, UE receives the multi-subframe scheduling signaling in subframe 0, which indicates scheduling uplink in subframes 4~7 with no gap in between, triggering aperiodic A-CSI transmission, i.e. in the third subframe (subframe 6). Then, M1=4. UE also receives C-PDCCH in subframe 2 / 3, which indicates subframes starting from subframe 4 as uplink subframes, and MCOT ends in subframe 5, then M2=2. UE performs 25us LBT before subframe 4 starts, and after LBT succeeds, it transmits subframe 4 and subframe 5 consecutively, and does not transmit subframe 6 and subframe 7. The subframe 6 determined by M1 for transmitting A-CSI cannot be transmitted. According to the third approach, the subframe for transmitting A-CSI determined by M2 is subframe 5. But since the delay from subframe 2 to subframe 5 after receiving C-PDCCH = 3 is less than the minimum delay 4, UE does not transmit A-CSI. The PUSCH in subframes 4, 5 is determined according to the scheduling signaling received in subframe 0, i.e. without considering the impact of transmitting A-CSI.

[0199] As shown, UE receives the multi-subframe scheduling signaling in subframe 0, which indicates scheduling uplink in subframes 4~7 with no gap in between, triggering aperiodic A-CSI transmission, i.e. in the third subframe (subframe 6). Then, M1=4. UE also receives C-PDCCH in subframe 2 / 3, which indicates subframes starting from subframe 4 as uplink subframes, and MCOT ends in subframe 5, then M2=2. UE performs 25us LBT before subframe 4 starts, and after LBT succeeds, it transmits subframe 4 and subframe 5 consecutively, and does not transmit subframe 6 and subframe 7. The subframe 6 determined by M1 for transmitting A-CSI cannot be transmitted. According to the third approach, the subframe for transmitting A-CSI determined by M2 is subframe 5. But since the delay from subframe 2 to subframe 5 after receiving C-PDCCH = 3 is less than the minimum delay 4, UE does not transmit A-CSI. The PUSCH in subframes 4, 5 is determined according to the scheduling signaling received in subframe 0, i.e. without considering the impact of transmitting A-CSI. Figure 21 As shown, UE receives the multi-subframe scheduling signaling in subframe 0, which indicates scheduling uplink in subframes 4~7 with no gap in between, triggering aperiodic A-CSI transmission, i.e. in the third subframe (subframe 6). Then, M1=4. UE also receives C-PDCCH in subframe 2 / 3, which indicates subframes starting from subframe 4 as uplink subframes, and MCOT ends in subframe 5, then M2=2. UE performs 25us LBT before subframe 4 starts, and after LBT succeeds, it transmits subframe 4 and subframe 5 consecutively, and does not transmit subframe 6 and subframe 7. The subframe 6 determined by M1 for transmitting A-CSI cannot be transmitted. According to the third approach, the subframe for transmitting A-CSI determined by M2 is subframe 5. But since the delay from subframe 2 to subframe 5 after receiving C-PDCCH = 3 is less than the minimum delay 4, UE does not transmit A-CSI. The PUSCH in subframes 4, 5 is determined according to the scheduling signaling received in subframe 0, i.e. without considering the impact of transmitting A-CSI.

[0200] If the MCS of the PUSCH containing A-CSI needs to be adjusted, e.g. unchanged or reduced according to predefined rules, the MCS adjustment is performed on the newly determined PUSCH containing A-CSI.

[0201] Further, assume that there are M1 uplink subframes scheduled by multi-subframe scheduling signaling, and UE determines that there are M2 uplink subframes that can be transmitted by C-PDCCH, where M1 >= M2. Assume that the subframes I1 for transmitting SRS are determined by M1. If the subframes I1 are after the M2 subframes that can be transmitted, for example, M1 = 4, M2 = 2, and the offset of the subframes for SRS configured by high layer is 3, then the subframes I1 for SRS determined by M1 are the fourth subframes, which are after the M2 = 2 subframes that can be transmitted. In this case, the subframes I2 for transmitting SRS, i.e., the first subframes, can be determined by taking the modulus of M2 of the subframes for SRS configured by high layer.

[0202] Note that this way assumes that the time difference between the newly determined subframes I2 for transmitting SRS and the subframes for receiving the C-PDCCH is greater than or equal to the minimum processing delay k' of the UE. If the time difference is less than the minimum processing delay, the UE can only give up transmitting SRS, and the transmission of PUSCH in the M2 subframes is still generated according to the assumption without SRS.

[0203] Further, assume that there are M1 uplink subframes scheduled by multi-subframe scheduling signaling, and UE determines that there are M2 uplink subframes that can be transmitted by C-PDCCH, where M1 > M2. The last symbol of the M2th subframe can be determined according to the following two ways,

[0204] Way one: the last symbol is not left empty. That is, whether the last symbol indicated in the multi-subframe scheduling signaling is left empty or not, the last symbol of the M2th subframe is not left empty. If the last symbol of the M2th subframe is indicated for SRS, then the PUSCH also needs to be left empty in the last symbol for SRS transmission. If the last symbol of the M2th subframe is not indicated for SRS, then the last symbol is also used for PUSCH mapping.

[0205] Way two: the last symbol is determined according to whether the last symbol indicated in the multi-subframe scheduling signaling is left empty. That is, if the last symbol indicated in the multi-subframe scheduling signaling is left empty, then the last symbol of the M2th subframe needs to be left empty and cannot transmit any PUSCH. Whether it can be used for SRS transmission is determined according to the SRS indication.

[0206] Note that in multi-subframe scheduling, it is shown in the scheduling signaling whether the last symbol of the last subframe of the scheduled multiple subframes needs to be left empty. When the number of subframes that can actually be transmitted by the UE M2 < the number of subframes M1 that are scheduled, then it is determined according to way one and way two.

[0207] Note that the second way is based on the assumption that the time difference between the last subframe I2 that can be transmitted according to the C-PDCCH and the subframe in which the C-PDCCH is received is greater than or equal to the minimum processing delay k' of the UE. If the time difference is less than the minimum processing delay, the UE still determines the PUSCH according to the last symbol non-empty way.

[0208] (1.2) If the LBT indication is contained in the UL grant and the UE does not receive the C-PDCCH containing the LBT indication information.

[0209] Then, the UE determines the LBT type and the start of the uplink signal of the current subframe only according to the UL grant scheduling the current subframe.

[0210] (2) If only the LBT indication is contained in the C-PDCCH, the UE can determine the LBT type and / or the start of the PUSCH of the current subframe according to the LBT information indicated by the C-PDCCH, whether the UL grant of the next one or more subframes is received, and whether there is a gap between the next subframe and the current subframe.

[0211] The UE can receive multiple C-PDCCHs indicating the LBT type of the current subframe in sequence. For example, a C-PDCCH is received in subframe #n indicating that subframe #n+k belongs to the Cat-4 LBT type subframe set, and a C-PDCCH is received in subframe #n+k1(k1

[0212] Then, similar to (1), the UE needs to determine whether there is a consecutive uplink subframe scheduled (the UE detects the corresponding scheduling signaling) after the current subframe, and if there is such a subframe and the subframe after the current subframe belongs to a different LBT type subframe set, the LBT type of the current subframe can be determined according to one of the following ways, otherwise the LBT type of the current subframe is determined according to the LBT indicated by the latest received C-PDCCH.

[0213] The first way: the LBT type of the current subframe is determined according to the most conservative LBT type of these consecutive subframes, and the start of the PUSCH of the current subframe is the start of the PUSCH indicated by the UL grant.

[0214] The same as the first way in (1), there is also an exception.

[0215] Method 2: The LBT type of the current subframe is determined according to the LBT type indicated by the C-PDCCH prior to the latest C-PDCCH, and the PUSCH start point of the current subframe is the PUSCH start point indicated by the UL grant.

[0216] Method 3: The LBT type of the current subframe is determined according to the indication of the latest received C-PDCCH. However, the first subframe of the subsequent subframe set that is not of the same LBT type as the current subframe also needs to be determined according to the indication of the latest received C-PDCCH, and the PUSCH start point of this subframe is a predefined start point. As in Method 3 of (1) of this embodiment.

[0217] like Figure 18 As shown, the base station sent a UL grant for scheduling uplink subframe #4 in subframe #0. The base station also sent UL grants for scheduling uplink subframes #5 and #6 in subframe #1. There is no gap between these three subframes, and the base station expects the UE to continuously send PUSCH in subframes #4 to #6. According to the LBT indicated by the previous C-PDCCH, subframes #4 to #6 all belong to the Cat-4 LBT subframe set. However, the base station sent a new C-PDCCH in subframe #3, indicating that subframes #4 to #5 belong to the 25µs LBT subframe set, and subframe #6 belongs to the Cat4 subframe set. The UE detected a UL grant in subframe #0, detected UL grants for scheduling subframes #5 and #6 in subframe #1 (without a gap between these two subframes), and detected a new C-PDCCH in downlink subframe #3. Therefore, in subframe #4, the UE does not perform the 25us LBT as indicated by the latest received C-PDCCH, but instead performs the LBT according to the Cat-4 indicated by the previous C-PDCCH. If the LBT is successful, the UE starts sending PUSCH from subframe #4 until subframe #6. The PUSCHs in these two subframes are consecutive, and no LBT is needed in between. The same principle applies to multi-subframe scheduling.

[0218] Step 1503: Perform LBT on the current subframe according to the determined LBT type. If LBT passes, start sending PUSCH from the determined PUSCH start point in the current subframe; if LBT fails, do not send PUSCH in the current subframe.

[0219] It is worth noting that, in this invention, the multiple consecutive, uninterrupted uplink subframes starting from the current subframe refer to subframes whose corresponding UL grants have been correctly demodulated by the UE before performing LBT for the current subframe. For example, if the base station expects to schedule subframes #n to #n+4, but the UE has only demodulated the UL grants for scheduling subframes #n to #n+3 before sending subframe #n, then when determining the LBT for subframe #n, the UE only considers subframes #n to #n+3.

[0220] Corresponding to the above-mentioned embodiments, the present application respectively provides corresponding user equipment, which is described below in conjunction with the accompanying drawings.

[0221] The constituent structure of the user equipment is shown in Figure 18 The user equipment comprises a first receiving module and a first uplink signal sending module, wherein:

[0222] The first receiving module is used for receiving scheduling signaling, wherein the scheduling signaling at least contains LBT information.

[0223] The first uplink signal sending module is used for determining the LBT type of the current subframe according to the scheduling signaling of the current subframe, and / or the scheduling signaling of the previous subframe, and / or the scheduling signaling of the next subframe, and sending uplink signals on the uplink carrier. Before sending the uplink signals, if the determined LBT type requires the UE to perform CCA, the UE performs CCA detection; if the CCA detection passes, the uplink signals are sent, otherwise the sending is abandoned. Before sending the uplink signals, if the determined LBT type does not require the UE to perform CCA, the UE directly sends the uplink signals.

Claims

1. A method performed by a user equipment, comprising: receiving, from a base station, an uplink grant (UL grant) scheduling an uplink transmission, wherein the UL grant comprises an indication of a first listen-before-talk (LBT) type; receiving, from the base station, downlink control information comprising a channel occupancy time (COT) associated with a second LBT type; performing, for an uplink transmission of the uplink transmission within the COT, a second LBT procedure of the second LBT type.

2. The method of claim 1, wherein, The downlink control information is comprised in user group common signaling. 3.A method performed by a base station, comprising: transmitting, to a user equipment, an uplink grant (UL grant) scheduling an uplink transmission, wherein the UL grant comprises an indication of a first listen-before-talk (LBT) type; transmitting, to the user equipment, downlink control information comprising a channel occupancy time (COT) associated with a second LBT type; wherein, for an uplink transmission of the uplink transmission within the COT, a second LBT procedure of the second LBT type is performed.

4. The method of claim 3, wherein, The downlink control information is comprised in user group common signaling.

5. A user equipment, comprising: comprising: a transceiver; a processor coupled to the transceiver and configured to perform the method of any one of claims 1-2.

6. A base station, characterized by comprising: a transceiver; a processor coupled to the transceiver and configured to perform the method of any one of claims 3-4.

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