REFERENCE SIGNAL CONFIGURATION

Description

TECHNICAL FIELD

[0001] This patent document is directed generally to wireless communications.BACKGROUND

[0002] The mobile communication technologies are moving the world toward an increasingly connected and networked society. In comparison with the existing wireless networks, the next generation systems and wireless communication techniques will need to support a much wider range of use-case characteristics and provide a much more complex range of network access techniques.

[0003] Qualcomm Incorporated: "Discussion on QCL"; 3GPP Draft; R1-1711176, ZTE et al: "Remaining details on TRS"; 3GPP Draft; R1-1715452, Catt: "Discussion on DL beam management"; 3GPP Draft, R1-1707475 are related prior art documents.SUMMARY OF PARTICULAR EMBODIMENTS

[0004] This patent document relates to techniques, systems, and devices for reference signal configuration in wireless communications. The invention is specified by the independent claims. Preferred embodiments are defined in the dependent claims. In the following description, although numerous features may be designated as optional, it is nevertheless acknowledged that all features comprised in the independent claims are not to be read as optional.

[0005] In one exemplary aspect, a method for wireless communication is provided as defined by the independent claim 1.

[0006] In yet another exemplary embodiment, a method for wireless communication is defined as provided by the independent claim 5.

[0007] In yet another exemplary embodiment, an apparatus for wireless communication is provided as defined by the independent claim 9.

[0008] In yet another exemplary embodiment, an apparatus for wireless communication is provided as defined by the independent claim 10.

[0009] In yet another exemplary embodiment, a non-transitory computer readable program storage medium is provided as defined by the independent claim 14.

[0010] The above and other aspects and their implementations are described in greater detail in the drawings, the descriptions, and the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 shows an example of a base station and UEs in wireless communication, in accordance with some examples of the presently disclosed technology. FIG. 2 shows an example of reference signal resource configuration information that includes cell indicator(s) or BWP indicator(s), in accordance with some examples of the presently disclosed technology. FIG. 3 shows an example of selecting one or more reference signal resources, cells, and / or BWPs based on reference signal resource configuration, in accordance with some examples of the presently disclosed technology. FIG. 4 shows an example of reference signal resource set (or subset) configuration information that includes cell indicator(s) or BWP indicator(s), in accordance with some examples of the presently disclosed technology. FIG. 5 shows an example of a method for triggering one or more reference signal resource subsets, in accordance with some embodiments of the presently disclosed technology. FIG. 6 is a block diagram representation of a portion of a radio station, in accordance with some embodiments of the presently disclosed technology. DETAILED DESCRIPTION

[0012] The rapid growth of wireless communications and advances in technology is partly to satisfy the demand for greater capacity and higher data rates. Other aspects, such as energy consumption, device cost, spectrum resource allocation, and latency are also factors in the success of future networks.

[0013] To achieve higher data transfer rate in wireless communications, wireless communication nodes can use multiple antennas to send and / or receive data. Multiple-input and multiple-output (MIMO) is a method for multiplying the capacity of a radio link using multiple transmitting and receiving antennas to exploit multipath propagation. MIMO can use some features of the communication channel to form a multi-layer transmission that matches the channel characteristics, so as to effectively improve communication system performance without increasing the bandwidth and / or power consumption.

[0014] Illustratively, a transmitting end sends a reference signal via a channel, and a receiving end calculates the channel state information (CSI) by measuring the received reference signal and feeds back the CSI via the channel to the transmitting end, which can perform precoding or beamforming that matches corresponding channel characteristics. In some embodiments, transmission of a reference signal is not periodic. That is, the transmitting end triggers (or activates) the transmission of the reference signal by signaling, and the receiving end receives and measures the reference signal according to the signaling, and reports CSI. Specifically, the transmit end configures reference signal resource set(s) that are available for selection via first signaling, and indicates selection of reference signal resource(s) or reference signal resource subset(s) from the reference signal resource set(s) via second signaling. The transmitting end triggers transmission of reference signal(s) using the selected reference signal resource(s) or reference signal resource subset(s). The receiving end receives the first and second signaling, and based thereon, the receiving end receives corresponding reference signal(s), takes measurements, and reports CSI.

[0015] In the 5G wireless communication technology, a transmitting end can perform data transmission in multiple cells, multiple bandwidth parts (BWPs), and / or multiple spatial quasi-co-location (QCL) parameters. Accordingly, it is desirable for the transmitting end to transmit reference signals in multiple cells, multiple BWPs, and / or multiple spatial QCL parameters to obtain corresponding CSIs. Therefore, more resources for the reference signal may need to be transmitted, the triggering of reference signals can lead to a larger signaling overhead, and in some cases, the timing relationship between the trigger signaling and the reference signal transmission may need redesigning. The presently disclosed technology addresses these issues.

[0016] FIG. 1 shows an example of a base station and UEs in wireless communication, in accordance with some examples of the presently disclosed technology. The base station (120) can transmit signaling (140a-140c) and reference signals (150a-150c) to the plurality of UEs (110a-110c). The UEs (110a-110c) can transmit corresponding CSIs (130a-130c) to the base station (120). The presently disclosed technology provides various examples of reference signal configuration, related signaling, and corresponding CSI transmission in wireless communications between the base station and the UEs.First Example

[0017] Reference signal transmission can be performed in various ways. In cases of periodic reference signal transmission, a base station configures the period and the time offset for sending a reference signal through high layer signaling, and a UE receives a reference signal at a time point determined from the period and time offset information. In cases of triggered reference signal transmission, a base station configures selectable reference signal resource(s) through higher layer signaling, and triggers transmission of the reference signal via base station signaling.

[0018] For triggered reference signal transmission, the base station can configure reference signal resource set(s) by using first signaling, where the first signaling is generally high layer signaling. The base station can select reference signal resource(s) and / or reference signal resource subset(s) from the configured reference signal resource set(s) by using second signaling. The UE can receives a reference signal using the selected reference signal resource(s) and / or reference signal resources subset(s). Illustratively, the second signaling can be Layer 1 (L1) signaling, Layer 2 (L2) signaling, or a combination of L1 signaling and L2 signaling. For example, L2 signaling can indicate a selection of a first subset of reference signal resources from the configured reference signal resource set(s), and then L1 signaling can indicate a further selection of a second subset of reference signal resources from the first subset. The UE can receive the reference signal using reference signal resource(s) included in the second subset.

[0019] In a New Radio (NR) communication system, multiple cells (e.g., cells in carrier aggregation) can exist. Illustratively, a cell can correspond to a component carrier (CC) or a group of CCs with one or more BWPs. Different cells or BWPs can have different reference signal resource requirements, thus it is desirable for the configuration of reference signal(s) to reflect corresponding cell(s) and / or BWP(s). When more cells and / or BWPs are considered, more reference signal resources and / or reference signal resource subsets need to be configured, which can lead to greater L1 / L2 signaling overhead. The presently disclosed technology includes the following methods to address these problems.

[0020] In some examples, configuration information of each individual reference signal resource can include cell or BWP information associated with the reference signal resource. FIG. 2 shows an example of reference signal resource configuration that includes cell indicator(s) or BWP indicator(s), in accordance with some examples of the presently disclosed technology.

[0021] In this way, each reference signal resource configuration includes corresponding cell indicator(s) and / or BWP indicator(s). When selecting a reference signal resource or a reference signal resource subset by using the second signaling, the base station can select cell(s) or BWP(s) by using signaling. FIG. 3 shows an example of selecting one or more reference signal resources, cells, and / or BWPs based on reference signal resource configuration, in accordance with some examples of the presently disclosed technology.

[0022] Illustratively, as discussed above, the base station can select reference signal resource(s) and / or reference signal resource subset(s) from configured reference signal resource set(s) or subset(s) by using second signaling 302. The base station can also select candidate cell indicator group(s) and / or candidate BWP indicator group(s) based on configuration information of individual reference signal resources using third signaling 303. In some examples, the third signaling is L2 signaling.

[0023] In some examples, the base station can optionally further select cell indicator group(s) and / or BWP indicator group(s) from the candidate group(s) using fourth signaling 304. Each selected cell indicator group can include one or more cell indicators, and each selected BWP indicator group can include one or more BWP indicators. In some examples, the fourth signaling is L2 signaling or L1 signaling.

[0024] The UE can receive reference signal(s) on selected cell(s) and / or BWP(s). Further, the UE can receive reference signal(s) on the selected cell(s) and / or BWP(s) using their associated reference signal resource(s). In some examples, the UE only receives reference signals both (1) on the selected cell(s) and / or BWP(s) and (2) using selected reference signal resource(s). In other words, if a selected reference signal resource is not associated with any selected cell or BWP, then the UE does not use the resource to receive reference signal. Also, if a selected cell or BWP is not associated with any selected reference signal resource, then the UE does not receive reference signal on the cell or BWP.

[0025] In some examples, the UE can determine frequency domain information (e.g., the maximum bandwidth, the frequency domain granularity of partial bandwidth configuration, or the like) of the selected reference signal resource(s) based on the selected cell and / or BWP information and the reference signal resources included in the selected reference signal resource subset.

[0026] In some examples, configuration information of each reference signal resource set and / or subset can include associated cell or BWP information. FIG. 4 shows an example of reference signal resource set (or subset) configuration that includes cell indicator(s) or BWP indicator(s), in accordance with some examples of the presently disclosed technology. Illustratively, when configuring multiple reference signal resource sets, each set can include one or more corresponding cell indicator(s) and / or one or more corresponding BWP indicators. Alternatively or in addition, when configuring multiple reference signal resource subsets, each reference signal resource subset can include one or more corresponding cell indicator(s) and / or one or more corresponding BWP indicators. For example, different reference signal resource sets can each correspond to a different cell, and within each set, different reference signal resource subsets can each correspond to a different BWP.

[0027] Accordingly, when the base station indicates a reference signal resource subset through the second signaling, the base station can indicate a first subset through L2 signaling. The first subset can include reference signal resource subsets within multiple, different reference signal resource sets. In this case, corresponding reference signal resource set and / or subset configuration information can include multiple cell indicators and / or BWP indicators. Similar to the cell and / or BWP selection as discussed above, the base station can select, using third signaling, one or more candidate cell indicator groups and / or one or more candidate BWP indicator groups. In some examples, the base station can further select cell(s) and / or BWP(s) from the foregoing candidate group(s) by using fourth signaling. Illustratively, the third signaling can be L1 signaling and / or L2 signaling, and the fourth signaling can be L1 signaling.

[0028] The UE can receive reference signal(s) on selected cell(s) and / or BWP(s). Further, the UE can receive reference signal(s) on the selected cell(s) and / or BWP(s) using their associated reference signal resource(s). In some examples, the UE only receives reference signals both (1) on the selected cell(s) and / or BWP(s) and (2) using selected reference signal resource(s). In other words, if a selected reference signal resource is not associated with a selected cell or BWP, then the UE does not use the resource to receive reference signal. Also, if a selected cell or BWP is not associated with a selected reference signal resource, then the UE does not receive reference signal on the cell or BWP.

[0029] In some examples, the UE can determine frequency domain information (e.g., the maximum bandwidth, the frequency domain granularity of partial bandwidth configuration, or the like) of the selected reference signal resource(s) based on the selected cell and / or BWP information and the reference signal resources included in the selected reference signal resource subset.First Embodiment

[0030] For triggered reference signal transmission, the base station configures reference signal resource set(s) by using the first signaling, where the first signaling is generally high layer signaling. The base station selects reference signal resource(s) and / or reference signal resource subset(s) from the configured reference signal resource set(s) by using the second signaling. The UE can receive a reference signal using the selected reference signal resource(s) and / or reference signal resources subset(s). Illustratively, the second signaling can be L1 signaling, L2 signaling, or a combination of L1 signaling and L2 signaling. For example, L2 signaling can indicate a selection of a first subset of reference signal resources from the configured reference signal resource set(s), and then L1 signaling can indicate a further selection of a second subset of reference signal resources from the first subset. The UE can receive the reference signal using reference signal resource(s) included in the second subset.

[0031] When the base station needs to trigger multiple reference signal resource sets or reference signal resource subsets at a time, the base station can achieve it via signaling notification. FIG. 5 shows an example of a method for triggering one or more reference signal resource subsets, in accordance with some embodiments of the presently disclosed technology.

[0032] Illustratively, the base station uses signaling 502 to select, from a plurality of reference signal resource subsets, a number of reference signal resource subsets to form one or more candidate groups of reference signal resource subsets. For example, N reference signal resource subsets can be configured with one or more N-bit bitmaps, and reference signal resource subsets that correspond to value "1" in the bitmap(s) are included in corresponding candidate subset group(s) while reference signal resource subsets that correspond to value "0" in the bitmap(s) are filtered out. The signaling 502 can be high layer signaling, such as Layer 3 (L3) signaling and / or L2 signaling. In some embodiments, the signaling can be a combination of L3 signaling and L2 signaling. For example, L N-bit bitmaps are indicated in L3 to form L candidate groups of reference signal resource subsets. L2 signaling is used to select M candidate group of reference signal resource sets from the L candidate groups of reference signal resource subsets indicated in the L3 signaling. In some embodiments, this L2 signaling maps the associated L1 signaling states (e.g., codepoints), if any, to a subset of the L candidate groups of reference signal resource subsets indicated in the L3 signaling.

[0033] The base station can notify the UE by another signaling 504, to further select final reference signal resource subset group(s) from the candidate subset group(s). The signaling 504 can be L2 signaling or L1 signaling. The UE can receive reference signal(s) using reference signal resource(s) corresponding to the selected final reference signal resource subset group(s). When triggering transmission of multiple reference signal resource sets and / or reference signal resource subsets, the base station indicates to the UE a time gap between the triggering signaling and the actual transmission of the corresponding reference signal resource set or subset. The time gap can be configured with respect to individual reference signal resource sets or subsets (e.g., the reference signal resources in a same reference signal resource set or subset are associated with a same time gap). The indication of the time gap is achieved via signaling or predefined rules. The predefined rules for indicating the time gap includes determining the time gap based on (1) whether the L1 signaling that triggers reference signal includes corresponding spatial QCL parameter information, or (2) whether the spatial QCL parameter information in the L1 signaling is consistent with the spatial QCL parameter of a default or high level configuration.Second Example

[0034] As discussed above, a UE can determine the cell and / or BWP information corresponding to the triggered reference signal resource(s). The signaling that triggers the transmission of reference signal can also be used to trigger CSI feedback. Illustratively, a base station can notify a UE of the transmission of reference signal resource(s) and the request for CSI reporting simultaneously, by using the first and / or second signaling. Accordingly, the UE can generate corresponding CSI by measuring the triggered reference signal resources, and reports the CSI to the base station. The frequency domain resource(s) corresponding to the generated CSI can be determined in various ways.

[0035] In some examples, the base station uses fifth signaling to notify the UE of the cell and / or BWP information for reporting the CSI. Illustratively, the cell(s) configured for CSI reporting can be a subset of the cell(s) determined based on the reference signal configuration information, and / or, the BWP(s) configured for CSI reporting can be a subset of the BWP(s) determined based on the reference signal configuration information. In some cases, the cell(s) configured for CSI reporting is the same as the cell(s) determined based on the reference signal configuration information, and / or the BWP(s) configured for CSI reporting is the same as the BWP(s) determined based on the reference signal configuration information.

[0036] In some examples, the UE determines cell(s) for CSI feedback according to the cell(s) determined via the reference signal configuration information, and / or determines BWP(s) for CSI feedback according to the BWP(s) determined via the reference signal configuration information. Further, the UE can determine, according to the cell or BWP information determined based on the reference signal configuration information, (1) subband size for CSI reporting and / or (2) frequency-domain location of the subband associated with the CSI reporting.Second Embodiment

[0037] When a base station transmits the reference signal, the receiving end (e.g., a UE) of the reference signal can improve reception quality of the signal by changing spatial QCL parameter(s) for signal reception. In general, the spatial QCL parameter(s) can be determined by indication(s) included in L2 control signaling or L1 control signaling, so as to adapt to the rapid change of communication channel(s). The spatial QCL parameter indication(s) can be transmitted in the same control signaling format as the control signaling that triggers reference signal. After the UE receives the indication(s) of the spatial QCL parameter(s), it can take a certain amount of time for the UE to adjust its receiving mode or function. Therefore, the time gap between the control signaling for triggering the reference signal and the actual transmission of the reference signal can be determined according to the indication(s) of the spatial QCL parameter(s).

[0038] In some embodiments, if the control signaling format of the signaling (e.g., signaling that indicates a selection of reference signal resource subset(s) and / or reference signal resource(s)) for triggering transmission of reference signal(s) does not include corresponding spatial QCL parameter(s), then the reference signal resource subset(s) and / or reference signal resource(s) are transmitted in the same time slot as the signaling for triggering the reference signal(s).

[0039] In some embodiments, if the control signaling format of the signaling for triggering the reference signal(s) includes spatial QCL parameter(s) corresponding to the reference signal resource subset(s) and / or reference signal resource(s), the UE can determine the time gap between the time slot in which the reference signal(s) is transmitted and the time slot in which the signaling that triggers the reference signal(s) is transmitted, by using predefined rules and / or based on control signaling.

[0040] Illustratively, the predefined rules can include a rule of -- if the control signaling format of the signaling for triggering the reference signal(s) includes spatial QCL parameter(s) corresponding to the reference signal resource subset(s) and / or reference signal resource(s), then the reference signal(s) is transmitted in an immediate next time slot after a time slot in which the signaling that triggers the reference signal(s) is transmitted.

[0041] As for control signaling based time gap determination, illustratively, (1) indication information for the time gap between the slot in which the reference signal(s) is transmitted and the slot in which the signaling that triggers the reference signal(s) is transmitted and (2) indication information for the spatial QCL parameter(s) can be jointly indicated. In some embodiments, the joint indicating signaling includes a state indicating that QCL parameter(s) and time gap parameter(s) are nonexistent, unavailable, or absent. Illustratively, in this case, the reference signal(s) is transmitted in a slot in which the second signaling is transmitted. In some embodiments, the control signaling includes joint coding of (1) the spatial QCL parameter(s) and (2) parameter(s) indicating the time gap.Third Example

[0042] An individual reference signal resource or a group of reference signal resources may include multiple reference signal ports. These ports may have different transmission or reception configurations. Therefore, these ports may have different configurations of QCL parameters. Based on predefined or configured mode(s), a base station can configure different QCL parameters for different reference signal ports. Illustratively, the ports in a same group can have same QCL parameters, and the QCL parameters of different groups may be different. More specifically, N CSI-RS ports can be divided into D port groups. Ports in each group have the same QCL parameters, and QCL parameters for different groups can be respectively indicated using the following methods.

[0043] Method 1: Ports on a same symbol or symbol group are included in a same group. For example, FDM ports on a same time-domain symbol can be grouped into a same group. As another example, ports associated with a same symbol group by time-domain CDM multiplexing can be grouped into a same port group.

[0044] Method 2: Ports within a same component or component group are included in a same group. Illustratively, in a reference signal configuration, a component is a basic unit of a multi-port reference signal configuration (e.g., configuration of a 2-port or 4-port reference signal), and reference signals with more ports can be formed by aggregation of multiple components. Therefore, component can serve as a basic unit for reference signal port grouping, that is, the ports in a same component or component group are grouped into a same port group.

[0045] Method 3: Ports with port indices separated by an interval of M are grouped into a same group. Illustratively, the value of M can be determined in various ways. For example, the value of M is N / 2, that is, ports separated by an interval of N / 2 other ports are grouped into a same group. Further, individual port indices can be divided by N / 2. If the division results in a remainder value that is smaller than a threshold T, then the corresponding port can be included in a same group. All other ports can be included in another group. As another example, the value of M is N / K, and K is the number of CDM groups included in the reference signal resource(s). Further, individual port indices can be divided by N / K. If the division results in a remainder value that is smaller than a threshold T, then the corresponding port can be included in a same group. And other ports can be grouped into another group. As yet another example, the value of M is the number of ports included in each CDM group. Alternatively or in addition, the value of M can be determined via base station signaling. For example, the value of M can be determined by associated codebook configuration parameter(s). More specifically, the value of M can be determined based on parameter(s) of port group interval(s) and / or the number of precoding vectors that are combined as indicated by codebook index.

[0046] Method 4: Ports with S consecutive port indices are grouped into a same group. For example, S can be the number of ports in a component, the number of ports in each CDM group, or the number of ports in multiple consecutive CDM groups. As another example, the value of S is N / K, and K is the number of CDM groups included in the reference signal resource(s). Alternatively or in addition, the value of S can be determined via base station signaling. For example, the value of S can be determined by associated codebook configuration parameter(s). More specifically, the value of S can be determined based on parameter(s) of port group interval(s) and / or the number of precoding vectors that are combined as indicated by codebook index.

[0047] FIG. 6 is a block diagram representation of a portion of a radio station, in accordance with some embodiments of the presently disclosed technology. A radio station 605, such as a base station or a wireless device (or UE), can include processor electronics 610 such as a microprocessor that implements one or more of the techniques presented in this document. The radio station 605 can include transceiver electronics 615 to send and / or receive wireless signals over one or more communication interfaces such as antenna(s) 620. The radio station 605 can include other communication interfaces for transmitting and receiving data. Radio station 605 can include one or more memories (not explicitly shown) configured to store information such as data and / or instructions. In some implementations, the processor electronics 610 can include at least a portion of the transceiver electronics 615. In some embodiments, at least some of the disclosed techniques, modules or functions are implemented using the radio station 605.

[0048] Some of the embodiments described herein are described in the general context of methods or processes, which may be implemented in one embodiment by a computer program product, embodied in a computer-readable medium, including computer-executable instructions, such as program code, executed by computers in networked environments. A computer-readable medium may include removable and non-removable storage devices including, but not limited to, Read Only Memory (ROM), Random Access Memory (RAM), compact discs (CDs), digital versatile discs (DVD), etc. Therefore, the computer-readable media can include a non-transitory storage media. Generally, program modules may include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. Computer- or processor-executable instructions, associated data structures, and program modules represent examples of program code for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps or processes.

[0049] Some of the disclosed embodiments can be implemented as devices or modules using hardware circuits, software, or combinations thereof. For example, a hardware circuit implementation can include discrete analog and / or digital components that are, for example, integrated as part of a printed circuit board. Alternatively, or additionally, the disclosed components or modules can be implemented as an Application Specific Integrated Circuit (ASIC) and / or as a Field Programmable Gate Array (FPGA) device. Some implementations may additionally or alternatively include a digital signal processor (DSP) that is a specialized microprocessor with an architecture optimized for the operational needs of digital signal processing associated with the disclosed functionalities of this application. Similarly, the various components or sub-components within each module may be implemented in software, hardware or firmware. The connectivity between the modules and / or components within the modules may be provided using any one of the connectivity methods and media that is known in the art, including, but not limited to, communications over the Internet, wired, or wireless networks using the appropriate protocols.

[0050] Only a few implementations and examples are described and other implementations, enhancements and variations can be made based on what is described and illustrated in this patent document.

Claims

1. A method for wireless communication, comprising: receiving, by a receiving end (110a), a first signaling (140a) from a transmitting end configuring one or more sets of reference signal resources for a reference signal associated with channel state information; receiving, by the receiving end, a second signaling (502) from the transmitting end (120) that indicates a selection of a subset of the one or more sets of reference signal resources from the one or more sets of reference signal resources; and receiving, by the receiving end, a third signaling (504) from the transmitting end triggering a transmission using a final set of reference signal resources selected from the subset of the one or more sets of reference resources for the transmission, wherein a time gap between a first slot in which the third signaling is received and a second slot in which the transmission is to occur is determined based on whether a spatial quasi-co-location, QCL, parameter for the one or more sets of reference signal resources is indicated by the transmitting end.

2. The method of claim 1, wherein the first slot and the second slot are the same slot in case the spatial QCL parameter for the one or more sets of reference signal resources is not indicated.

3. The method of claim 1, wherein the time gap is determined based on configuration by the transmitting end in case the spatial QCL parameter for the one or more sets of reference signal resources is indicated.

4. The method of claim 1, wherein the time gap is configured with respect to at least one of the one or more sets of reference signal resources.

5. A method for wireless communication, comprising: transmitting, by a transmitting end (120), a first signaling (140a) to a receiving end (110a) indicating one or more sets of reference signal resources for a reference signal associated with channel state information; transmitting, by the transmitting end, a second signaling (502) to the receiving end that indicates a selection of a subset of the one or more sets of reference signal resources from the one or more sets of reference signal resources; and transmitting, by the transmitting end, a third signaling (504) to the receiving end triggering a transmission by the terminal end using a final set of reference signal resources selected from the subset of the one or more sets of reference resources, wherein a time gap between a first slot in which the third signaling is received and a second slot in which the transmission is to occur is determined based on whether a spatial quasi-co-location, QCL, parameter for the one or more sets of reference signal resources is indicated by the transmitting end.

6. The method of claim 5, wherein the first slot and the second slot are the same slot in case the spatial QCL parameter for the one or more sets of reference signal resources is not indicated.

7. The method of claim 5, wherein the time gap is determined based on configuration by the transmitting end in case the spatial QCL parameter for the one or more sets of reference signal resources is indicated.

8. The method of claim 7, wherein the time gap is configured with respect to at least one of the one or more sets of reference signal resources.

9. An apparatus (110a) for wireless communication, comprising: a processor (610), and a memory including processor executable code, wherein the processor executable code upon execution by the processor configures the processor to: receive a first signaling (140a) from a transmitting end (120) configuring one or more sets of reference signal resources for a reference signal associated with channel state information; receive a second signaling (502) from the transmitting end indicating a selection of a subset of the one or more sets of reference signal resources from the one or more sets of reference signal resources; receive a third signaling (504) from the transmitting end triggering a transmission using a final set of reference signal resources from the subset of the one or more sets of reference resources wherein a time gap between a first slot in which the third signaling is received and a second slot in which the transmission is to occur is determined based on whether a spatial quasi-co-location, QCL, parameter for the one or more sets of reference signal resources is indicated by the transmitting end.

10. An apparatus (120) for wireless communication, comprising: a processor (610), and a memory including processor executable code, wherein the processor executable code upon execution by the processor configures the processor to: transmit a first signaling (140a) to a receiving end (110a) configuring one or more sets of reference signal resources for a reference signal associated with channel state information; transmit a second signaling (502) to the receiving end indicating a selection of a subset of the one or more sets of reference signal resources from the one or more sets of reference signal resources; transmit a third signaling (504) to the receiving end triggering a transmission using a final set of reference signal resources selected from the subset of the one or more sets of reference resources, wherein a time gap between a first slot in which the third signaling is received and a second slot in which the transmission is to occur is determined based on whether a spatial quasi-co-location, QCL, parameter for the one or more sets of reference signal resources is indicated by the transmitting end.

11. The apparatus of claim 9 or 10, wherein the first slot and the second slot are the same in case the spatial QCL parameter for the one or more sets of reference signal resources is not indicated.

12. The apparatus of claim 9 or 10, wherein the time gap is determined based on a configuration by the transmitting end in case the spatial QCL parameter for the one or more sets of reference signal resources is indicated.

13. The apparatus of claim 12, wherein the time gap is configured with respect to at least one of the one or more sets of reference signal resources.

14. A non-transitory computer readable program storage medium having code stored thereon, the code, when executed by a processor (610), causing the processor to implement the method recited in claims 1 to 4 or the method recited in claims 5 to 8.