Method and apparatus for wireless communication between a base station and a user equipment

Abstract

A method and apparatus for wireless communication between a base station and a user equipment are provided. A base station apparatus includes a transceiver and a processor configured to transmit, via the transceiver, a control message configured for a user equipment to the user equipment and receive, via the transceiver, a sounding reference signal (SRS) from the user equipment based on the control message. The control message indicates a trigger time slot offset and an available time slot for SRS transmission to the user equipment.

Description

[0001] This application is based on and claims priority to U.S. Provisional Patent Application No. 17 / 329,735, filed May 25, 2021, U.S. Provisional Patent Application No. 63 / 162,805, filed March 18, 2021, U.S. Provisional Patent Application No. 63 / 133,585, filed January 4, 2021, U.S. Provisional Patent Application No. 63 / 062,772, filed August 7, 2020, U.S. Provisional Patent Application No. 63 / 062,508, filed August 7, 2020, and U.S. Provisional Patent Application No. 63 / 056,926, filed July 27, 2020, each of which is incorporated by reference herein in its entirety. TECHNICAL FIELD

[0002] The present disclosure relates generally to New Radio (NR) Multiple Input Multiple Output (MIMO) enhancements, and more particularly, to enhancing the capacity and coverage of sounding reference signal (SRS) transmission by SRS time bundling, increased SRS repetition, and partial sounding across frequencies. BACKGROUND

[0003] As 5th-Generation (5G) NR MIMO moves towards commercialization, various aspects have been identified that still need further enhancements from the perspective of real deployment scenarios. One such aspect includes enhancements for SRS transmission for different frequency ranges.

[0004] For example, facing the increased demand for SRS resources for multi-panel transmission and due to the use of SRS for various scenarios, SRS should be further enhanced at least for flexibility, capacity, and coverage. In addition, with the increase in the number of user equipment (UE) antennas, additional procedures are needed for antenna switching configuration for downlink (DL) channel state information (CSI) acquisition. SUMMARY

[0005] Accordingly, the present disclosure is designed to address at least the above-mentioned problems and / or disadvantages, and to provide at least the advantages described below.

[0006] An aspect of the present disclosure is to provide a method and apparatus that facilitates more flexible triggering and downlink control information (DCI) overhead reduction.

[0007] Another aspect of the present disclosure is to provide different antenna switching configurations with an increased number of antennas (e.g., eight antennas).

[0008] Another aspect of the disclosure is to provide a mechanism for enhancing the capability and coverage of SRS transmission through SRS time bundling, increased SRS repetition, and partial sounding across frequencies.

[0009] According to an aspect of the disclosure, a base station device for wireless communication with a user equipment (UE) is provided. The base station device includes a transceiver; and a processor configured to transmit, via the transceiver, a control message configured for the UE to the UE, and receive, via the transceiver, a sounding reference signal (SRS) from the UE based on the control message. The control message indicates a trigger slot offset and available slots to the UE for SRS transmission.

[0010] According to another aspect of the disclosure, a user equipment (UE) device for wireless communication with a base station is provided. The UE device includes a transceiver; and a processor configured to receive, via the transceiver, a control message configured for the UE from the base station, and transmit, via the transceiver, a sounding reference signal (SRS) to the base station based on the control message. The control message indicates a trigger slot offset and available slots to the UE for SRS transmission. BRIEF DESCRIPTION OF DRAWINGS

[0011] The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0012] Figure 1 A method for transmitting SRS according to an embodiment is illustrated;

[0013] Figure 2 An example of aperiodic SRS time bundling on the same subcarriers according to an embodiment is illustrated; SRS SRS resource allocation with = 30;

[0014] Figure 3 An example of aperiodic SRS time bundling on the same subcarriers according to an embodiment is illustrated;

[0015] Figure 4 An example of periodic / semi-persistent SRS time bundling on the same subcarriers according to an embodiment is illustrated;

[0016] Figure 5 An example of SRS time bundling with additional companion SRS slot transmission according to an embodiment is illustrated; and

[0017] Figure 6 An electronic device in a network environment according to an embodiment is illustrated. DETAILED DESCRIPTION

[0018] Hereinafter, various embodiments of the present disclosure are described in detail with reference to the accompanying drawings. It should be noted that, although the same reference numerals are shown in different drawings, the same elements will be represented by them. In the following description, only specific details (such as detailed configurations and components) are provided in order to assist in a comprehensive understanding of embodiments of the present disclosure. Therefore, it will be apparent to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope of the present disclosure. Furthermore, descriptions of well-known functions and structures are omitted for clarity and conciseness. The terms described below are terms defined in consideration of the functions in the present disclosure, and the terms can differ according to users, user's intentions, or habits. Therefore, the definition of the terms should be determined based on the content throughout the specification.

[0019] The present disclosure can have various modifications and various embodiments, and the embodiments are described in detail below with reference to the accompanying drawings. However, it should be understood that the present disclosure is not limited to these embodiments, but includes all modifications, equivalents, and alternatives within the scope of the present disclosure.

[0020] Although terms including ordinal numbers such as first, second, etc. can be used to describe various elements, the structural elements are not limited by the terms. The terms are used only to distinguish one element from another element. For example, a first structural element can be referred to as a second structural element without departing from the scope of the present disclosure. Similarly, a second structural element can also be referred to as a first structural element. As used herein, the term "and / or" includes any and all combinations of one or more related items.

[0021] The terms used herein are only used to describe various embodiments of the present disclosure and are not intended to limit the present disclosure. The singular form is intended to include the plural form unless the context clearly dictates otherwise. In the present disclosure, it should be understood that the term "include" or "have" indicates the presence of features, numbers, steps, operations, structural elements, components, or combinations of features, numbers, steps, operations, structural elements, and components, and does not exclude the presence or addition of one or more other features, numbers, steps, operations, structural elements, components, or combinations of features, numbers, steps, operations, structural elements, and components.

[0022] Unless defined differently, all terms used herein have the same meaning as understood by those skilled in the art to which the present disclosure belongs. Terms such as those defined in a generally used dictionary should be interpreted as having the same meaning as the contextual meaning in the relevant art, and should not be interpreted as having an ideal or overly formal meaning unless explicitly defined in the present disclosure.

[0023] An electronic device according to an embodiment can be one of various types of electronic devices. The electronic devices can include, for example, a portable communication device (e.g., a smartphone), a computer, a portable multimedia device, a portable medical device, a camera, a wearable device, or a home appliance. According to an embodiment of the disclosure, the electronic devices are not limited to those described above.

[0024] The terms used in the present disclosure are not intended to limit the present disclosure, but are intended to include various changes, equivalents, or replacements of the terms in the corresponding technical field of the present disclosure. In describing the drawings, similar reference numerals can be used to refer to similar or related elements. Unless otherwise defined, the singular forms of terms can include one or more plural forms of the terms. As used herein, each of the phrases such as "A or B," "at least one of A and B," "at least one of A or B," "A, B, or C," "at least one of A, B, and C," and "at least one of A, B, or C" can include all possible combinations of the items in the corresponding phrase. As used herein, the terms such as "1st," "2nd," "first," and "second" can be used to distinguish one element from another element in the description. However, the terms are not intended to limit the scope of the disclosure. If an element (for example, a first element) is referred to as "operatively or communicatively coupled with / to" another element (for example, a second element), it can mean that the first element is directly coupled with / to the second element or indirectly connected with / to the second element via a third element.

[0025] As used herein, the term "module" can include a unit implemented in hardware, software, or firmware, and can interchangeably be used with other terms, for example, "logic", "logic block", "part", and "circuitry". The module can be a single integral component, or a minimum unit or part thereof, adapted to perform one or more functions. For example, a module can be implemented in a form of an application-specific integrated circuit (ASIC).

[0026] Figure 1 A method for transmitting an SRS according to an embodiment is illustrated. Specifically, Figure 1 A signal flow diagram illustrating processes performed between a UE and a gNB is illustrated.

[0027] Referring to Figure 1At step 101, the UE generates and sends a UE capability message to the gNB. For example, the UE capability message can indicate a transmit capability for each port of the UE, e.g., based on a per-port transmit capability. The UE capability message can indicate a number of ports of the UE, a number of antennas of the UE, a transmit capability for each port, etc. The UE capability report can indicate a number of transmit / receive paths of the UE.

[0028] At step 103, the gNB generates and sends a configuration message to the UE. The configuration message can be based at least in some aspects on the UE capability message. For example, the configuration message can indicate an uplink (UL) MIMO configuration for the UE, a number of spatial streams or layers for the UE to use for UL MIMO communications, a transmit configuration for the UE to use, etc.

[0029] Thereafter, at step 105, the UE generates and sends an SRS to the gNB based on the received configuration message.

[0030] In NR MIMO, key parameters for configuring the frequency domain location of the SRS are included within the freqHopping parameter structure (i.e., C SRS , B SRS , and b hop ), freqDomainPosition (i.e., n RRC ), FreqDomainShift (i.e., n shift ), and TransmissionComb (i.e., K TC , and ).

[0031] An example of the freqHopping parameter structure is provided in Table 1 below, where it is assumed that C SRS = 30.

[0032] Table 1

[0033]

[0034] In Table 1, the m SRS，b parameter defines the number of resource blocks (RBs) used for SRS transmission and ranges from 4 RBs to 272 RBs. For C SRS = 30, the maximum resource allocation is m SRS，b = 128 RBs (i.e., B SRS = 0). All possible resource allocations for C SRS = 30 are shown in Figure 2 .

[0035] In current specifications (e.g., 3rd Generation Partnership Project (3GPP) Technical Specification (TS) 38.211), the frequency domain starting position is defined as shown in Equation (1)

[0036]

[0037] In Equation (1), p i represents the port i, and the first part of Equation (1) can be derived as shown in Equation (2)

[0038]

[0039]

[0040] In Equation (2), n shift is a frequency domain shift to adjust the SRS allocation with respect to the reference point grid, and is included in the higher layer parameter freqDomainShift. Also, is the number of subcarriers in an RB. K TC is the transmission comb, and is the transmission comb offset included in the higher layer parameter transmissionComb. is the transmission comb cyclic shift included in the higher layer parameter transmissionComb. is the number of SRS ports given by the higher layer parameter nrofSRS-Ports.

[0041] Referring back to Equation (1), B SRS is a hopping parameter as shown in Figure 2 , which is included in the higher layer parameter freqHopping, and is the length of the SRS sequence given as Equation (3).

[0042]

[0043] In Equation (3), m SRS is derived using a lookup table given the freqHopping parameter C SRS and the freqHopping parameter B SRS，b as shown above and in Figure 2 . Thus, K TC corresponds to the total number of subcarriers included in the m SRS，b RBs used for SRS transmission.

[0044] In Equation (1), n b is the frequency location index defined based on the freqHopping parameter B SRS and the freqHopping parameter b hop . If b hop ≥ B SRS , frequency hopping is disabled and n b remains constant unless reconfigured. n b may be defined using Equation (4).

[0045]

[0046] In Equation (4), n RRC is given by the higher layer parameter freqDomainPosition, taking values from 0 to 67, and 4n RRC = 0,..., 271 means that up to 272 RBs can be used for SRS. However, Figure 2 the example shown in FIG. C SRS = 30 uses only 128 RBs for SRS.

[0047] A lookup table is used to derive N SRS for b = B b given the freqHopping parameter. N b corresponds to the total number of possible SRS locations within m SRS，b-1 RBs when m hop RBs are used for SRS transmission.

[0048] If b SRS < B b , frequency hopping is enabled and n b may be defined by Equation (5).

[0049]

[0050] In Equation (5), F SRS (n b ) can be defined using Equation (6).

[0051]

[0052] In Equation (6), N SRS does not depend on the value of n hop and n b is the count of the number of SRS transmissions. The first line in Equation (5) does not change over time, which means that the corresponding N hop for b ≤ b b does not change over time.No transition occurs between the possible positions. The transition occurs when b > b hop Multiple n b Within a defined set of RBs. That is, b hop This is a parameter indicating the transition range. The design of the nested structure and transition mode of SRS transmission is inspired by the possibility of orthogonal multiplexing of SRS transmissions from multiple users.

[0053] For aperiodic SRS, within a time slot, by Given n SRS , where l' is the SRS symbol index, and R is the repetition factor given by the repetitionFactor field contained in the higher-level parameter resourceMapping.

[0054] For periodic or semi-persistent SRS, n is given by equation (7). SRS .

[0055]

[0056] In equation (7), for those that satisfy The time slot is configured according to the higher-level parameter periodicityAndOffset-p or periodicityAndOffset-sp to indicate the periodicity of the SRS. SRS and T indicating time slot offset offset . Indicates the number of SRS symbols, and is given by the higher-level parameter nrofSymbols. It is the number of time slots in each frame with a subcarrier spacing of μ. It is the number of time slots within a frame with a subcarrier spacing of μ, and n f It represents the number of system frames.

[0057] Using equation (7), The number of consecutive symbols with an "R" in a symbol set maintains the same frequency position. A transition is applied across such a block of "R" symbols, and the frequency position of each instance transmitted periodically will change.

[0058] In summary, the first part of equation (1) depends on freqDomainShift (i.e., n shift ), which targets the reference point grid and the transmission comb offset configured in transmissionComb (i.e., To adjust the SRS allocation. The second part of equation (1) is a summation, which depends on transmissionComb (i.e., K). TC ), freqDomainPosition(i.e., nRRC ), the freqHopping parameter (i.e., C SRS , B SRS , and b hop ) and the count n SRS of the number of SRS transmissions.

[0059] Flexible SRS triggering and DCI overhead / usage reduction

[0060] According to embodiments of the present disclosure, to increase multiplexing capability, SRS transmission can be enhanced by a larger transmission comb or by a smaller transmission bandwidth (i.e., m SRS，b ):

[0061] • Transmitting SRS with a larger transmission comb size provides the benefit of increased multiplexing capability. However, it can degrade channel estimation performance to some extent, especially in frequency-selective fading scenarios.

[0062] • Transmitting SRS on a smaller bandwidth provides the benefit of increased multiplexing capability. For example, if a UE transmits SRS with 64 RBs instead of 128 RBs of bandwidth, the multiplexing capability can be doubled. However, a smaller SRS bandwidth results in multiple SRS transmissions with frequency hopping needed to have knowledge of the propagation channel over the entire BWP. For example, a UE would have to transmit SRS four times when using 32 resource blocks. This increases the latency and the risk of outdated measurements in fast fading scenarios.

[0063] • In addition, at the cell edge, UEs experience high path loss and can not have enough power to allow reliable detection of SRS transmissions on large bandwidths by the base station. These UEs can be allocated a smaller SRS bandwidth to increase the received power density. As mentioned above, if the UEs at the cell edge are high-speed UEs, the smaller SRS bandwidth increases the risk of latency and outdated measurements.

[0064] To handle the above tradeoff, the base station (e.g., gNB) should be allowed to configure more flexible frequency locations for SRS. That is, flexible SRS transmission with updated parameters such as transmissionComb and freqHopping can provide more knowledge of the propagation channel.

[0065] According to embodiments of the present disclosure, the MAC control element (CE) updates the transmissionComb parameter and the freqHopping parameter of SRS transmission more flexibly and more efficiently in terms of overhead.

[0066] Moreover, transmitting SRS with larger transmission comb size reduces the channel estimation granularity and performance, especially in frequency selective fading scenarios. However, aperiodic partial sounding on a specific part of the bandwidth part (BWP) can alleviate this issue.

[0067] The BWP part for sounding with partial aperiodic SRS transmission can change over time according to channel conditions. This can be effectively done by flexibly updating the parameters that affect the frequency domain starting position of the configured SRS transmission. As mentioned above, the frequency domain starting position depends on the transmissionComb value, the transmissionComb value, the freqDomainPosition value, and the FreqDomainShift value.

[0068] According to embodiments of the present disclosure, MAC CE updating the freqDomainPosition and / or FreqDomainShift parameters of SRS transmission is more flexible and more efficient in terms of overhead.

[0069] In current specifications, each SRS resource set is configured for a specific use case. However, if the usage of the configuration of SRS resource set can be flexibly updated, a lot of overhead can be avoided.

[0070] According to embodiments of the present disclosure, MAC CE updating the usage parameter of SRS transmission is more flexible and more efficient in terms of overhead.

[0071] Regarding sharing SRS resources between the two different usages of “codebook” and “antennaSwitching”, generally for mTnR scenarios, where mT denotes m transmit antennas and nR denotes n receive antennas, if m = n, SRS resource reuse between “codebook” and “antennaSwitching” has already been supported. However, if m < n, because current specifications allow the UE to perform different antenna virtualization for these two SRS resource sets, it is needed to identify which UE antennas in the SRS resources will be used for “antennaSwitching” for uplink (UL) CSI acquisition. Therefore, the following provides a method for ensuring that the UE will use the same virtualization and transmit (Tx) power as for UL CSI acquisition.

[0072] One method is to add a new option “antennaSwitching / codebook” as the usage parameter within the SRS-config IE. With this method, the UE will not perform different antenna virtualization for the shared SRS resource set between the two different usages of “antennaSwitching” and “codebook”.

[0073] Another approach is to utilize an implicit indication of the SRS resources in the set that can be shared with a new radio resource control (RRC) parameter SRS-PortIndex introduced for those SRS resources. This parameter is optional and can be configured for SRS resources that can be shared for "antenna switching" usage and "codebook" usage. An example of the parameter is shown in the SRS configuration (SRS-Config) information element in Table 2 below.

[0074] Table 2

[0075]

[0076] Since there are multiple SRS resources configured for mTnR antenna switching, when m < n, the UE needs to know which "antenna switching" resources should be reused for UL CSI acquisition.

[0077] One option is to always use a predetermined resource in the set for "codebook" usage. For example, the first resource in the set (i.e., according to resource identifier (ID) order) can be reused for "codebook" usage.

[0078] An alternative option is to add one or more resources in the set specifically for "codebook" usage purposes. For example, information about which SRS resource in the set corresponds to "codebook" usage can be explicitly indicated to the UE or implicitly determined by the UE.

[0079] An option for implicitly indicating the resource for "codebook" usage is to utilize associated quasi co-location (QCL) information. Here, it is reasonable to assume that all resources with "antenna switching" usage have the same associated QCL information. The resource for "codebook" usage can be the first resource among these resources. Another resource for "codebook" usage can be the remaining resource with different associated QCL information.

[0080] SRS Antenna Switching: UE sounding procedure for DL CSI acquisition

[0081] When a UE is configured with "antenna switching" in SRS-ResourceSet, the current specification only covers the configuration of SRS-TxPortSwitch for supported xTyR, where x = {1, 2, 4}, y = {1, 2, 4}.

[0082] In general, at most two sets are defined for each scenario of xTyR in order to cover the two possible periodic / semi-persistent resource type configurations or aperiodic resource type configuration. The number of resources is defined based on the number of antenna switching events. In each scenario of xTyR, the number of SRS ports for each resource is defined based on the number of available ports for transmission (i.e., x). If the SRS resources of a set are transmitted in the same slot, the UE is configured with a guard period of Y symbols in which the UE does not transmit any other signal. The guard period is in the middle of the SRS resources of a set. The values of Y are defined by Table 3 (Table 6.2.1.2-1 in TS 38.214). Specifically, Table 3 provides an example of the minimum guard period between two SRS resources of a SRS resource set for antenna switching.

[0083] As shown in Table 3 below, when the number of required antenna switching is three or more, more than one slot is needed to keep one symbol gap between switching events. That is, because SRS symbols can only be located within the last 6 symbols of a slot and with one symbol guard between every two SRS resources, at most three resources can fit in a slot. For example, in the 1T4R scenario, there are 4 antenna switching events, the transmission path switches across two slots. Because periodic / semi-persistent SRS configuration allows each resource in a set (through the higher layer parameter periodicityAndOffset-p or periodicityAndOffset-sp) to be configured with different slot offsets, this is only important for aperiodic SRS transmission, which is not possible for aperiodic SRS resources. Therefore, for the 1T4R scenario, because the antenna switching spans two different slots, aperiodic SRS transmission needs two resource sets.

[0084] Table 3

[0085] Δf = 2 μ · 15 [kHz] ] > Y [symbol] 0 15 1 1 30 1 2 60 1 3 120 2

[0086] Furthermore, TS 38.214 Section 6.2.1.2 specifies that:

[0087] - For 1T2R, at most two SRS resource sets are configured with different values of the higher layer parameter resourceType in SRS-ResourceSet, where each set has two SRS resources transmitted in different symbols, where each SRS resource in a given set consists of a single SRS port, and the SRS port of the second resource in a set and the SRS port of the first resource in the same set are associated with different UE antenna ports, or

[0088] - For 2T4R, up to two SRS resource sets are configured with different values of the higher layer parameter resourceType in SRS-ResourceSet set, where each SRS resource set has two SRS resources transmitted in different symbols, where each SRS resource in a given set consists of two SRS ports, and the SRS port pair of the second resource and the SRS port pair of the first resource are associated with different UE antenna port pairs, or

[0089] - For 1T4R, zero or one SRS resource set is configured with the higher layer parameter resourceType in SRS-ResourceSet set to have “periodic” or “semi-persistent”, where four SRS resources are transmitted in different symbols, where each SRS resource in a given set consists of a single SRS port, and the SRS port of each resource is associated with a different UE antenna port, and

[0090] - For 1T4R, zero or two SRS resource sets, each configured with the higher layer parameter resourceType in SRS-ResourceSet set to have “aperiodic”, where a total of four SRS resources are transmitted in different symbols of two different slots, and where the SRS port of each SRS resource in a given two sets is associated with a different UE antenna port. The two sets are each configured with two SRS resources, or one set is configured with one SRS resource and the other set is configured with three SRS resources.

[0091] - For 1T = 1R, or 2T = 2R, or 4T = 4R, up to two SRS resource sets, where each SRS resource set has one SRS resource, where the number of SRS ports for each resource is equal to 1, 2, or 4…

[0092] To increase the SRS antenna ports to 8, according to embodiments of the present disclosure, SRS resource set and resource definitions and additions for the new UE capability supportedSRS-TxPortSwitch, and a new configuration xTyR is added, where x = {1, 2, 4} and y = {6, 8}.

[0093] For xTyR:

[0094] • If the number of antenna switching events is less than or equal to n l = (max(l offset ) + 1) / 2, where l offset is the SRS symbol starting position from the end of the slot backwards in time domain:

[0095] - You should define up to two sets with different resourceTypes to cover both periodic / semi-persistent resource type configurations and aperiodic resource type configurations.

[0096] - Each set should be defined in Resources, wherein each resource in the set comprises x SRS ports that are different from the other resource ports. This is because (in the case of x transmit antennas and y receive antennas) there exists... There are several possible switching scenarios, so utilize One resource, and has in the set In the case of individual resources, it can cover For each of the following scenarios, since there are x ports available for transmission, the number of SRS ports for each resource is x.

[0097] ●Otherwise:

[0098] - Zero sets or one set have periodicity / semi-persistence, zero sets or The set is aperiodic because a one-symbol protection period is required between two switching events, and in order to cover all of the scenarios... One possible switching scenario is needed. One non-periodic SRS transmission.

[0099] - Total should be defined There are x resources, where each resource in the set includes x ports. This is because (in the case of x transmit antennas and y receive antennas) there exist... There are several possible switching scenarios, so utilize the total Individual resources. For scenarios involving non-periodic resource types, these... One resource in The distributions within each set can be different. That is, each set can be configured with n... i There are n SRS resources. i =1,...,n l , making Since there are x ports available for sending, the number of SRS ports for each resource is x.

[0100] - For the aperiodic resource type xTyR, because a one-symbol protection period is required between two switching events, and there is an overlay requirement. Each time slot There are various switching scenarios, so in total SRS resource transmission span Each time slot.

[0101] For xTyR scenarios, where x = {1, 2, 4} and y = {6, 8},

[0102] • If the number of antenna switching events is less than or equal to n l = (max(l offset ) + 1) / 2,

[0103] where l offset is the SRS symbol starting position from the end of the slot backwards in time domain:

[0104] At most two SRS resource sets are configured with different values of the higher layer parameter resourceType in SRS-ResourceSet for the higher layer parameter resourceType, where each SRS resource set has SRS resources transmitted in different symbols, and each SRS resource in a given set includes x SRS ports. If y mod x = 0, then one resource’s SRS ports and another resource’s SRS ports are associated with different UE antenna ports, otherwise some SRS ports can be shared between resources.

[0105] • Otherwise:

[0106] Zero or one SRS resource set is configured with the higher layer parameter resourceType in SRS-ResourceSet to have “aperiodic” or “semi-persistent” and where SRS resources are transmitted in different symbols, where each SRS resource in a given set includes x SRS ports. If y mod x = 0, then one resource’s SRS ports and another resource’s SRS ports are associated with different UE antenna ports, otherwise some SRS ports can be shared between resources, and

[0107] Zero or SRS resource sets, each SRS resource set is configured with the higher layer parameter resourceType in SRS-ResourceSet to have “aperiodic” and where SRS resources are transmitted in different symbols of consecutive slots, and where if y mod x = 0, then each SRS resource in a given set of i SRS resources has SRS ports associated with different UE antenna ports, otherwise some SRS ports can be shared between resources. Each set can be configured with n i = 1,..., nl such that

[0108] For 4T8R:

[0109] • At most two sets with different resourceType should be defined to cover periodic / semi-persistent resource type configuration or aperiodic resource type configuration, similar to the current specification for xTyR, where x = {1,2,4}, y = {1,2,4}.

[0110] • Two resources in each set should be defined, where each resource in a set includes four SRS ports that are different from other resource ports. Because there are two possible switching cases (in the case of 4 transmit antennas and 8 receive antennas), two resources are utilized, and with two resources in a set, both cases can be covered. Because there are four ports available for transmission, the number of SRS ports per resource is four.

[0111] According to embodiments of the present disclosure, for 4T8R, at most two SRS resource sets are configured with different values for the higher layer parameter resourceType in the SRS-ResourceSet set, where each SRS resource set has two SRS resources transmitted in different symbols, each SRS resource in a given set includes four SRS ports, and the SRS ports of the second resource and the SRS ports of the first resource are associated with different UE antenna ports.

[0112] For 4T6R:

[0113] • At most two sets with different resourceType should be defined to cover periodic / semi-persistent resource type configuration or aperiodic resource type configuration, similar to the current specification for xTyR, where x = {1,2,4}, y = {1,2,4}.

[0114] • Two resources in each set should be defined, where each resource in a set includes four SRS ports that can be the same as other resource ports. Because there are two possible switching cases (in the case of 4 transmit antennas and 6 receive antennas), two resources are utilized, and with two resources in a set, both cases can be covered. Because there are four ports available for transmission, the number of SRS ports per resource is four.

[0115] In this case, since y mod x ≠ 0, two different assumptions can be considered. First, this case can be considered as a special case of 4T8R with two receive antennas turned off. In the case of this assumption, as with 4T8R, there are two switching events that group the four antennas for transmission.

[0116] Therefore, according to embodiments of the present disclosure, for 4T6R, at most two SRS resource sets are configured with different values for the higher layer parameter resourceType in the SRS-ResourceSet set, where each SRS resource set has two SRS resources transmitted in different symbols, each SRS resource in a given set includes four SRS ports, and a pair of SRS ports of the second resource and the SRS ports of the first resource are associated with different UE antenna ports.

[0117] A second assumption for this case is that the switching events share two antenna ports. In the case of this assumption, a pair of antenna ports in the two SRS resources of a given set should be shared.

[0118] Therefore, according to embodiments of the present disclosure, for 4T6R, at most two SRS resource sets are configured with different values for the higher layer parameter resourceType in the SRS-ResourceSet set, where each SRS resource set has two SRS resources transmitted in different symbols, each SRS resource in a given set includes four SRS ports, and a pair of SRS ports of the second resource and the SRS ports of the first resource are associated with the same UE antenna port.

[0119] For 2T8R:

[0120] • Zero or one set has periodicity / semi-persistent, zero or two sets have aperiodic, since 1 symbol of guard period is needed between two switching events and to cover all four possible switching cases. In this scenario, assuming max(l offset ) = 5, two aperiodic SRS transmissions are needed.

[0121] • A total of four resources should be defined, where each resource in a set includes two ports. Since there are four possible switching cases (in the case of 2 transmit antennas and 8 receive antennas), a total of four resources are utilized. For the aperiodic resource type scenario, the distribution of these four resources between the two sets can be different (i.e., assuming max(l offset) = 5, either two SRS resource sets are configured with two SRS resources each, or one set is configured with one SRS resource and the other set is configured with three SRS resources). Because there are two ports available for transmission, the number of SRS ports per resource is two.

[0122] • For aperiodic resource type for 2T8R, the resources are transmitted in two slots because a 1 -symbol guard period is needed between two switching events and there are four switching cases to be covered, assuming max(l offset ) = 5, which requires two slots.

[0123] According to embodiments of the present disclosure, for 2T8R, zero or one SRS resource set is configured with higher layer parameter resourceType in SRS-ResourceSet to have "periodic" or "semi-persistent" with four SRS resources transmitted in different symbols, each SRS resource in a given set includes two SRS ports, and SRS ports per resource are associated with different UE antenna ports.

[0124] For 2T8R, assuming max(l offset ) = 5, either zero or two SRS resource sets are configured with higher layer parameter resourceType in SRS-ResourceSet to have "aperiodic" and a total of four SRS resources are transmitted in different symbols of two different slots, and each SRS resource in a given set includes two SRS ports, where SRS ports per SRS resource in a given four sets are associated with different UE antenna ports. Two sets are each configured with two SRS resources, or one set is configured with one SRS resource and the other set is configured with three SRS resources.

[0125] For 2T6R:

[0126] • A maximum of two sets with different resourceType should be defined to cover periodic / semi-persistent resource type configuration or aperiodic resource type configuration, similar to the current specification for xTyR, where x = {1, 2, 4}, y = {1, 2, 4}.

[0127] • Three resources in each set should be defined, where each resource in the set includes two SRS ports that are different from the other resource ports. Because there are three possible switching cases (in the case of 2 transmit antennas and 6 receive antennas), three resources are utilized, and with three resources in a set, the three cases are covered. The number of SRS ports per resource is two because there are two ports available for transmission.

[0128] According to embodiments of the present disclosure, for 2T6R, up to two SRS resource sets are configured with different values of the higher layer parameter resourceType in SRS-ResourceSet, where each SRS resource set has three SRS resources transmitted in different symbols, each SRS resource in a given set includes two SRS ports, and the SRS port pair of the second resource and the SRS port pair of the first resource are associated with different UE antenna port pairs.

[0129] For 1T6R:

[0130] • Zero or one set has periodicity / semi-persistent, zero or two sets have aperiodic, because a 1 symbol guard period is needed between every two switching events and all six possible switching cases are covered. In this case, assuming max(l offset ) = 5, two aperiodic SRS transmissions are needed.

[0131] • A total of six resources should be defined, where each resource in the set includes one port. Because there are six possible switching cases (in the case of 1 transmit antenna and 6 receive antennas), a total of six resources are utilized. For aperiodic resource type scenario, assuming max(l offset ) = 5, each set is configured with three SRS resources. The number of SRS ports per resource is one because there is one port available for transmission.

[0132] • For aperiodic resource type for 1T6R, resources are transmitted in two slots, because a 1 symbol guard period is needed between two switching events, and there are six switching cases to be covered, assuming max(l offset ) = 5, which needs three slots.

[0133] According to embodiments of the present disclosure, for 1T6R, zero or one SRS resource set is configured with higher layer parameter resourceType in SRS-ResourceSet to have "periodic" or "semi-persistent", where six SRS resources are transmitted in different symbols, each SRS resource in a given set includes a single SRS port, and the SRS port of each resource is associated with a different UE antenna port.

[0134] For 1T6R, assuming max(l offset ) = 5, with zero or two SRS resource sets, each SRS resource set is configured with higher layer parameter resourceType in SRS-ResourceSet to have "aperiodic", and a total of six SRS resources are transmitted in different symbols of two different slots, and where the SRS port of each SRS resource in a given set is associated with a different UE antenna port. The two sets are each configured with three SRS resources.

[0135] For 1T8R:

[0136] • Zero or one set has periodic / semi-persistent, zero or three sets have aperiodic, since a 1 -symbol guard period is needed between every two switching events and covers all eight possible switching cases. In this scenario, assuming max(l offset ) = 5, three aperiodic SRS transmissions are needed.

[0137] • A total of eight resources should be defined, where each resource in a set includes one port. Since there are eight possible switching cases (in the case of 1 transmit antenna and 8 receive antennas), a total of eight resources are used. For the aperiodic resource type scenario, assuming max(l offset ) = 5, two sets are configured with three SRS resources, and another set is configured with two SRS resources. Since there is one port available for transmission, the number of SRS ports per resource is one.

[0138] • For the aperiodic resource type for 1T8R, resources are transmitted in three slots, since a 1 -symbol guard period is needed between two switching events, and there are eight switching cases that will be covered, assuming max(l offset ) = 5, which requires three slots.

[0139] According to embodiments of the present disclosure, for 1T8R, zero or one SRS resource set is configured with higher layer parameter resourceType in SRS-ResourceSet to have “periodic” or “semi-persistent” where eight SRS resources are transmitted in different symbols, each SRS resource in a given set includes a single SRS port, and the SRS port of each resource is associated with a different UE antenna port.

[0140] For 1T8R, assuming max(l offset ) = 5, with zero or three SRS resource sets, each SRS resource set is configured with higher layer parameter resourceType in SRS-ResourceSet to have “aperiodic” and a total of eight SRS resources are transmitted in different symbols of three different slots, and where the SRS port of each SRS resource in a given three sets is associated with a different UE antenna port. Two sets are configured with three SRS resources and another set is configured with two SRS resources.

[0141] For aperiodic SRS antenna switching, due to inter-symbol gap and set-level slot offset restrictions, the overhead of SRS aperiodic resource set configuration can be very high.

[0142] Accordingly, according to embodiments of the present disclosure, to reduce the overhead associated with SRS aperiodic resource sets, a new higher layer parameter can be introduced for resource-level slot offset of SRS resources within an aperiodic SRS resource set in case of using “antenna switching” usage. This is an additional slot offset configured separately for each resource on top of the configured set-level slot offset, and can reduce the overhead of aperiodic SRS set configuration and the latency of antenna switching procedure.

[0143] For example, an RRC configures an aperiodic SRS set and then uses DCI or MAC CE structure to activate the resources of the aperiodic SRS set, where each resource has a separate additional slot offset.

[0144] To illustrate, in the following description, the trigger slot offset indicated by DCI can be the sequence of slot offsets for the configured resources in the aperiodic SRS set.

[0145] Further, to reduce the potential high overhead of SRS resources and promote high UE power efficiency, Rel. 16 allows to configure SRS resources with a downgraded configuration using a new UE capability report. For example, a UE supporting 4T4R can also support SRS transmission of 1T1R and 2T2R in order to save uplink resources. However, in Rel. 17 to increase the number of SRS antenna ports to 8, a UE capability parameter supportedSRS-TxPortSwitch for xTyR with x = {1, 2, 4} and y = {6, 8} should be defined.

[0146] According to embodiments of the present disclosure, for xTyR scenarios with x = {1, 2, 4} and y = {6, 8}, the gNB should be able to configure a downgraded configuration of SRS for antenna switching, where the new UE capability design for SRS antenna switching is as follows:

[0147] • {t1r1, t1r2, t1r6}

[0148] • {t1r1, t1r2, t2r2, t2r6}

[0149] • {t1r1, t1r2, t2r2, t1r6, t2r6}

[0150] • {t1r1, t1r2, t1r4, t1r8}

[0151] • {t1r1, t1r2, t2r2, t2r4, t4r4, t4r8}

[0152] • {t1r1, t1r2, t2r2, t1r4, t2r4, t1r8, t2r8, t4r8}

[0153] This is combined with the existing Rel. 16 UE capabilities (i.e., {t1r1, t1r2}, {t1r1, t1r2, t1r4}, {t1r1, t1r2, t2r2, t2r4}, {t1r1, t2r2}, {t1r1, t2r2, t4r4}, {t1r1, t1r2, t2r2, t1r4, t2r4}).

[0154] Flexible antenna switching

[0155] Traditionally, a gNB can configure only one type of Tx / Rx antenna switching (e.g., 1T2R or 2T4R) at a time through RRC. If the gNB determines that the downgraded antenna switching configuration (e.g., 1T2R) suffers from large performance loss, the gNB has to reconfigure RRC to achieve the highest possible configuration (e.g., 2T4R). To avoid the potential performance loss caused by channel variation and the cost of having to perform RRC reconfiguration, the gNB rarely chooses to configure a downgraded antenna switching, and the whole intent of introducing the capability of combination falls short.

[0156] To address this issue, the gNB can follow Rel. 15 / 16 to configure multiple resource sets, and the UE selects the correct resource set through MAC CE or DCI based on the dynamic indication of a specific configuration. However, this approach can still not be efficient in terms of resource overhead.

[0157] Therefore, according to embodiments of the present disclosure, as will be described below, the alternative is to introduce a new optional RRC parameter for antenna switching usage only, which will allow RRC configuration of a downgraded SRS resource set with a specific number of antenna ports. With this new additional RRC parameter, the gNB can then use MAC CE or DCI to dynamically select / activate the downgraded configuration.

[0158] Table 4

[0159]

[0160] Note that the SRS resource is initially configured based on the maximum number of transmit ports in all possible antenna switching configurations indicated by supportedRS-TxPortSwitch. With the downgraded configuration through the optional RRC parameter downgradeSRS-TxPortSwitch, as shown in Table 4 above, the SRS resource can be reused with fewer ports. For example, for “t1r1-t1r2-t2r2-t2r4”, the maximum number of transmit ports is 2, which corresponds to the highest possible configuration “t2r4” configuration.

[0161] Furthermore, following the current specification, for each SRS resource in a given set, the SRS port(s) should be associated with different UE antenna port(s) than the SRS port(s) of the other resource(s). The number of configured SRS resources in a set should be defined based on the maximum of the number of switching events among all possible antenna switching configurations indicated by supportedRS-TxPortSwitch. For example, for "t1r1-t1r2-t2r2-t2r4", the antenna switching event maximum is 2, which corresponds to the highest possible configuration "t2r4" configuration, while for "t1r1-t1r2-t2r2-t1r4-t2r4", the antenna switching event maximum is 4, which corresponds to the degraded configuration "t1r4". The number of SRS resources in a set and the number of ports remain the same for all configurations of supportedSRS-TxPortSwitch, and the gNB can implicitly indicate / activate a specific configuration by signaling the number of switching events through a MAC CE or DCI.

[0162] For an antenna switching configuration with m switching events (i.e., m resources in a set), the UE uses a predetermined m SRS resources in a given set. For example, the first m SRS resources in a given set are used according to the SRS resource ID order. For an antenna switching configuration with m SRS ports, the UE uses a predetermined m SRS ports (e.g., the first m SRS ports) in each resource.

[0163] If SRS resources are configured to be shared between different configurations, the SRS transmit power should also be adjusted. To this end, according to embodiments of the present disclosure, as shown in Table 5 below, a new RRC parameter can be introduced conditionally for antenna switching usage, which allows for transmit power control adjustment for degraded antenna switching configurations.

[0164] Table 5

[0165]

[0166] Another approach is for the gNB to configure a periodic / semi-persistent set for the highest possible configuration and an associated aperiodic SRS resource set for the degraded configuration. That is, the periodic / semi-persistent resource with a large periodicity can be used for the highest possible configuration antenna switching and the aperiodic resource set for the degraded configuration antenna switching.

[0167] For periodic / semi-persistent SRS antenna switching, an alternative is that the gNB can configure multiple SRS resources within a set with different number of SRS ports to one periodic / semi-persistent SRS set with usage of "antenna switching". The higher layer parameter nrofSRS-Ports is configured for each SRS resource in the set based on the corresponding possible antenna switching configuration indicated by supportedRS-TxPortSwitch. For example, for "t1r4-t2r4", the configured nrofSRS-Ports for SRS resources in the set is one port corresponding to "t1r4" configuration or two ports corresponding to "t2r4" configuration. Then the gNB can indicate / activate a specific resource in the set according to channel condition, e.g., by indicating the number of transmit ports, through MAC CE or DCI. It can also let the UE determine the best antenna switching configuration among all possible configurations indicated by supportedRS-TxPortSwitch and transmit the corresponding SRS resource in the set.

[0168] Regarding aperiodic SRS antenna switching configuration, in the recent standard group meeting, there is the following agreement:

[0169] Agreement

[0170] • For aperiodic antenna switching SRS, support configuring N <= N_max resource sets, where K total resources are flexibly distributed in N resource sets based on RRC configuration.

[0171] o For 1T6R, K=6, N_max=[4], and each resource has 1 port.

[0172] o For 1T8R, K=8, N_max=[4], and each resource has 1 port.

[0173] o For 2T6R, K=3, N_max=[3], and each resource has 2 ports.

[0174] o For 2T8R, K=4, N_max=[4], and each resource has 2 ports.

[0175] o (Working Assumption) For 4T8R, K=2, N_max=[2], and each resource has 4 ports.

[0176] o FFS the number N of supported candidate values for each xTyR.

[0177] • FFS extension to increase N_max for 1T4R, 2T4R, T=R and 1T2R cases for aperiodic, periodic and semi-persistent SRS resources

[0178] • FFS number of resources and resource sets for semi-persistent and periodic antenna switching SRS

[0179] • Note: SRS can be transmitted on the last 6 OFDM symbols or any OFDM symbol within a slot limited by UE capability.

[0180] Following this agreement, in order to provide greater flexibility on SRS antenna switching configuration, a greater number of aperiodic SRS resource sets should be configured for antenna switching purposes. On the other hand, with flexible antenna switching, multiple resource sets can be configured by the gNB at the same time to correspond to all possible antenna switching configurations indicated by supportedRS-TxPortSwitch. Therefore, according to embodiments of the present disclosure, the maximum number of RRC-configurable SRS resource sets in one BWP is increased. For example, in Rel. 16, the maximum number of SRS resource sets in a BWP is 16. However, according to embodiments of the present disclosure, this number can be increased to 32 or 64 resource sets.

[0181] In addition, with the increase in the number of configured aperiodic SRS resource sets for antenna switching, the SRS resource sets configured for a particular antenna switching configuration can share the same path loss reference signal (RS). In this case, a MAC CE-based structure for simultaneously activating / deactivating the path loss RS for all configured SRS sets for a particular configuration can be an overhead-efficient method.

[0182] SRS time bundling and increased SRS repetition

[0183] With the increasing demand for SRS resources for multi-panel transmission, the possibility of SRS interference is higher, and thus the accuracy of uplink channel estimation at the gNB is reduced. SRS bundling over multiple SRS slots can improve SRS coverage with the possibility of joint estimation of the uplink channel over different transmissions. With SRS bundling, channel estimation accuracy can be enhanced over a particular portion of the BWP. In the current specification, SRS bundling over different subcarriers can be interpreted as inter-slot frequency hopping. SRS bundling over the same subcarriers can be interpreted as inter-slot repetition.

[0184] Bundled aperiodic SRS can be transmitted aperiodically between periodic / semi-persistent SRS transmissions in order to improve channel estimation accuracy.

[0185] Figure 3An example of aperiodic SRS time bundling on the same subcarriers according to an embodiment is shown.

[0186] According to embodiments of the present disclosure, to enhance SRS coverage, the aperiodic SRS bundling method described above can be employed in the present specification by allowing the associated aperiodic SRS transmissions to be bundled between periodic / semi-persistent SRS transmissions.

[0187] For aperiodic SRS bundling, all the bundled SRS transmissions can also be aperiodic resources.

[0188] According to embodiments of the present disclosure, to enhance SRS coverage, the aperiodic SRS bundling method described above can be employed in the present specification.

[0189] In the two aperiodic SRS bundling methods described above, if frequency hopping is enabled, the frequency domain parameters updated based on MAC CE can ensure that the SRS frequency allocation does not change.

[0190] For periodic or semi-persistent SRS resources with a short periodicity, the SRS time bundling method can be considered by bundling SRS symbols for each periodic instance over multiple slots of periodic / semi-persistent SRS transmissions for a specific part of the BWP.

[0191] It is also possible to bundle only some (not necessarily all) symbols for each periodic instance over multiple periods. In this scenario, the time gap between the two bundled SRS transmissions can be equal to the SRS periodicity.

[0192] Figure 4 Periodic / semi-persistent SRS time bundling on the same subcarriers according to an embodiment is shown.

[0193] According to embodiments of the present disclosure, to enhance SRS coverage, the periodic / semi-persistent SRS bundling method described above can be employed in the present specification by introducing new RRC parameters (such as a bundling indicator and / or a bundling factor) in the periodic / semi-persistent SRS resource configuration.

[0194] As described above, the frequency domain starting position equation The count n depends on the number of SRS transmissions SRS In addition, TS 38.211 Section 6.4.1.4.3 specifies that:

[0195] For the case of SRS resources configured as periodic or semi-persistent by the higher layer parameter resourceType, the SRS counter is given by:

[0196]

[0197] to satisfy slots. The periodicity T SRS and the slot offset T offset are given in clause 6.4.1.4.4.

[0198] For SRS bundling, the equation n SRS can be enhanced for SRS symbols in the slots that are bundled so as to ensure that the SRS frequency allocation does not change when frequency hopping is enabled.

[0199] According to embodiments of the disclosure, new RRC parameters bundlingSymbols and bundlingFactor in freqHopping as shown in Table 6 below, then the equation n SRS for counting the number of SRS transmissions in TS 38.211 section 6.4.1.4.3 can be enhanced as shown below.

[0200] Table 6

[0201]

[0202] In view of the above, TS 38.211 section 6.4.1.4.3 can be modified to specify that:

[0203] For the case of SRS resources configured as periodic or semi-persistent by the higher layer parameter resourceType, the SRS counter is given by:

[0204]

[0205] to satisfy slots. The periodicity T SRS and the slot offset T offset are given in clause 6.4.1.4.4.

[0206] The SRS bundling approach can also be considered in a way that each SRS transmission can be accompanied by additional SRS slot(s) with configured slot offset(s). These additional SRS slot(s) can be triggered and transmitted together with the regular SRS resource transmission to be all bundled together to improve the channel estimation accuracy. It is also possible to bundle only certain symbols in the SRS slots.

[0207] Figure 5 An example of SRS time bundling with additional accompanied SRS slot transmissions according to embodiments is shown.

[0208] According to embodiments of the present disclosure, to enhance SRS coverage, the above SRS bundling method can be employed in the specification by introducing a new RRC parameter (such as bundling) for each SRS transmission, which includes the parameters bundlingSymbols, bundlingFactor, and bundlingSlotOffsets.

[0209] In current specifications, there are consecutive orthogonal frequency-division multiplexing (OFDM) symbols in each SRS slot, while the current repetition factor is limited to R∈{1, 2, 4} symbols in TS 38.214. However, with increasing nrofSymbols (i.e., ), a larger repetition factor can also be allowed, which can improve SRS coverage.

[0210] According to embodiments of the present disclosure, to enhance SRS coverage, a larger repetitionFactor can allow an increased nrofSymbols. For example, the configurable repetitionFactor in a slot for a given SRS resource can be increased to R∈{1, 2, 4, 8, 12} symbols.

[0211] To support inter-slot SRS repetition on non-consecutive symbols in a slot (which can also be interpreted as SRS bundling), one approach is to configure multiple resources in one set. For each resource in the set, there is an associated resource configured in that given set that will be used for repetition. The associated repetition SRS resource is configured in RRC through a MAC CE (for semi-persistent SRS set) or DCI (for aperiodic SRS set) and activated together with the activation of the regular SRS resource.

[0212] The frequency allocation of the associated repetition SRS resource can change or remain the same as the regular SRS transmission. The location of the associated repetition SRS symbols can be explicitly indicated using a sequence of separate startPosition RRC parameters, or implicitly indicated through a new additional RRC parameter using SRS resource level slot / symbol offset from the reference SRS symbol. Table 7 below provides an example of RRC configuration according to embodiments of the present disclosure.

[0213] As shown in Table 7, using a list of SRS resource IDs, the associated repeated SRS resources are configured within the reference SRS resource by a new RRC parameter RepetitionSRS-ResourceIdList. The time slot offset of the associated repeated SRS resources from the reference SRS resource configuration is configured by a new RRC parameter repetitionSlotOffset. The associated repeated SRS resources are transmitted in the order of resource IDs with the time slot offset indicated in repetitionSlotOffset.

[0214] Table 7

[0215]

[0216] While the current specification indicates that the maximum number of SRS resources in the set of SRS-Config information elements shown in Table 7 does not exceed two resources for the “codebook” usage and does not exceed four resources for the “nonCodebook”, “antennaSwitching”, and “beamManagement” usages, for inter-slot SRS repetition over non-consecutive symbols, the maximum number of SRS resources in the set can be increased for repetition purposes.

[0217] As an alternative to introducing the concept of repetition, for example, as shown in Table 8 below, a time slot level offset parameter can be added within each SRS resource. In the current specification, all resources in a set are transmitted in the same time slot. Thus, by introducing a time slot level offset, multiple SRS resources can be transmitted in multiple different time slots, effectively achieving the purpose of inter-slot repetition. The UE can not be aware of the association between SRS resources for repetition purposes. Alternatively, such association can be implicitly identified by the same QCL association.

[0218] Another alternative is that multiple resources in a set can be configured and activated by gNB for repetition purpose without explicit RRC configuration association of SRS resources. The UE can implicitly determine the SRS repetition resources by SRS resource level slot / symbol offset RRC parameters, where the SRS resource level slot / symbol offset RRC parameters are optional parameters configured when the SRS resource is a repeated SRS resource. The slot / symbol offset value of zero is an indicator of the reference SRS resource and all corresponding repeated SRS resources have the same startPosition RRC parameter as the reference SRS resource. In this method, with resource level slot offset indicator, the position of the first SRS symbol remains the same across different slots, while with resource level symbol offset indicator, the position of the first SRS symbol can vary across different slots that are repeated across slots. An example is shown below where the position of the first SRS symbol does not change across different slots.

[0219] Table 8

[0220]

[0221] For SRS repetition over consecutive symbols, according to embodiments of the present disclosure, a new RRC configuration is introduced for SRS repetition, where there are two options of intra-slot repetition and inter-slot repetition. Intra-slot repetition is the same as SRS repetition in current specification. Inter-slot repetition is capable of spanning multiple consecutive slots, where there are multiple consecutive repeated SRS symbols in each slot, where the multiple consecutive repeated SRS symbols have separate repetition factors and separate starting positions of the repeated symbols. More specifically, a new RRC parameter is introduced to indicate the number of consecutive slots, and another new RRC parameter is introduced to indicate the position of the first repeated SRS symbol for each slot. As shown in Table 9, an RRC configuration is provided, where the parameter slotRepetitionFactor configures the number of consecutive slots, repetitionFactor configures a sequence of repetition factors for all slots of inter-slot repetition, and symbolOffset configures a sequence of symbol offsets of the first SRS symbol on each slot from the first SRS symbol on the first slot.

[0222] Table 9

[0223]

[0224] Optionally, the startPosition RRC parameter can be used alone to indicate the position of the first repeated SRS symbol for each consecutive slot instead of the symbol offset indication from the first SRS symbol of the first slot. Another alternative is that the repetition factor and the starting position of the SRS symbol remain constant over all consecutive slots in the inter-slot repetition. An example of RRC configuration for this method is shown in Table 10 below.

[0225] Table 10

[0226]

[0227] For the above inter-slot method, if hopping is enabled, the number R (i.e., repetition factor) in any hopping equation is the sum of all RRC-configured repetition factor values for all slots in the inter-slot repetition.

[0228] Flexible aperiodic (AP)-SRS triggering

[0229] Another point of interest for MIMO enhancements involves enhancements to aperiodic SRS triggering in order to facilitate more flexible triggering and / or DCI overhead / usage reduction. For example, in a recent standards group, the following agreement was reached:

[0230] Agreement

[0231] A given aperiodic SRS resource set is transmitted in the t+1thavailable slot from the reference slot, where t is indicated from DCI or RRC (if only one t value is configured in RRC), and the candidate values of t include at least 0. At least one of the following options is adopted for the reference slot.

[0232] • Option 1: The reference slot is the slot with the triggering DCI.

[0233] • Option 2: The reference slot is the slot indicated by the legacy triggering offset.

[0234] • FFS detailed definition of “available slot” taking into account UE processing complexity and timeline to determine available slots, potential coexistence with collision handling, etc., e.g.,

[0235] o Based on RRC configuration only, an “available slot” is a slot that has (one or more) UL or flexible symbol(s) for the (one or more) time-domain location(s) of all SRS resources in the resource set, and it satisfies the minimum timing requirement between the triggering PDCCH and all SRS resources in the resource set.

[0236] • FFS explicit indication or implicit indication of t

[0237] • Whether FFS to update the candidate trigger offset in MAC CE can be beneficial

[0238] For Option 2, the UE can receive the slot-level offset in a two-level offset configuration with more flexible triggering and less overhead and latency. In NR, the maximum trigger offset for SRS is 32 slots. Therefore, if the trigger offset for SRS transmission is indicated by DCI only, at least 5 bits are needed. Moreover, if the trigger offset is indicated separately for each SRS resource set, the overhead for trigger offset indication will be large (e.g., 5*N, where N is the number of SRS resource sets that can be triggered), which is not acceptable.

[0239] In addition, in Option 2, the trigger offset indicated by DCI is the offset in addition to the trigger offset for each SRS resource set indicated by RRC. This allows SRS transmissions corresponding to different SRS resource sets to be transmitted in different slots.

[0240] A usable slot is a slot that first meets the minimum time gap requirement according to the triggering physical downlink control channel (PDCCH) and second has enough UL symbols for all SRS resources of the AP-SRS set for triggering. A flexible slot can be considered as a usable slot. However, after the UE misses a dynamic DL scheduling, the slot should be unusable, while the UE still determines it as a usable slot.

[0241] To solve this problem, the gNB can indicate the trigger slot offset and the usable slot to the UE by using a bitmap structure. That is, the concepts of trigger offset and usable slot can be combined together, and the t+1th usable slot is indicated to the UE by DCI with a bitmap structure. This method can be implemented for both Option 1 and Option 2 in general, however, it is more compatible and feasible in the case of Option 2 due to the advantage of overhead efficiency.

[0242] An alternative method is to always consider a flexible slot as a usable slot regardless of dynamic DL scheduling. If the gNB knows that the UE counts any flexible slot as a usable slot, there is no misunderstanding between the gNB and the UE. This method can be robust; however, it can introduce some signaling inefficiency. That is, given a constant number of allocated bits for signaling, the signaling range of the trigger offset can be reduced due to the extra counting of the unusable flexible slots (i.e., the slots of dynamic DL scheduling).

[0243] With respect to aperiodic SRS triggering, for DCI format 0_1, the gNB cannot trigger SRS without data scheduling and CSI request. However, according to one embodiment of the present disclosure, Rel. 16 DCI format 0_1 can be enhanced to support aperiodic SRS triggering without data scheduling and CSI request. This enhancement can be done without changing the DCI payload size.

[0244] The usage of some bit fields of the non-scheduled DCI can be re-adjusted to allow SRS transmission. For example, the UL-SCH indicator will use the value “0” to indicate that no UL-SCH will be transmitted on the physical uplink shared channel (PUSCH).

[0245] The frequency domain resource allocation field in DCI format 0_1 allocates a set of resource blocks for PUSCH. Since there will be no scheduled data for SRS triggering, the usage of this field can be re-adjusted to indicate the aperiodic SRS trigger(s) offset(s). Similarly, the usage of the time domain resource allocation field can be re-adjusted for aperiodic SRS triggering without scheduling data. This field in DCI format 0_1 can occupy up to four bits and defines a pointer to a row within an RRC-configured lookup table, where the lookup table indicates PUSCH mapping type, slot offset, starting symbol, and number of allocated symbols. The modulation and coding scheme (MCS) field occupies five bits in DCI format 0_1 and defines a pointer to a row within a related MCS lookup table. The antenna port field is used to indicate the logical antenna port used for PUSCH transmission and it occupies five bits. The usage of all these fields can be adjusted for aperiodic SRS triggering.

[0246] Since more than one aperiodic SRS can be triggered in a single DCI with SRS request codepoint, an efficient approach is to use a bitmap structure within the fields of DCI format 0_1 with adjusted usage to indicate the SRS slot offset(s). The following describes an example of re-using DCI format 0_1 for AP-SRS triggering with the fields of adjusted usage.

[0247] In the current specification, the RRC-configured lookup table that indicates PUSCH mapping type, slot offset, starting symbol, and number of allocated symbols has a last row reserved. The time domain resource allocation field in DCI format 0_1 can be used to point to the last row (e.g., “11111”), and in combination with the value “0” of the UL-SCH indicator, this can be an implicit indication that this DCI format 0_1 is used for AP-SRS triggering, and the frequency domain resource allocation field is a bitmap for the slot offset(s) of the triggered SRS(s).

[0248] According to embodiments of the present disclosure, a new Radio Network Temporary Identifier (RNTI) can be introduced for DCI format 0_1 in order to flexibly trigger AP-SRS resource sets. The length of RNTI is 16 bits and is assigned by gNB within the Radio Access Network (RAN) and is known by both UE and gNB. RNTI is used to differentiate and identify a specific UE, a group of UEs, or all UEs. RNTI is used by UE to scramble the Cyclic Redundancy Check (CRC) bits appended to the DCI payload and provides UL / DL control information such as resource allocation, power control commands, slot format change, and system information update.

[0249] Therefore, gNB can configure a new RNTI (i.e., AP-SRS-RNTI) to UE via RRC configuration through IE PhysicalCellGroupConfig. Once the SRS request field in DCI format 0_1 is CRC scrambled with this new RNTI (i.e., AP-SRS-RNTI), the aperiodicSRS-ResourceTrigger and DCI trigger offset value can be derived.

[0250] Based on the SRS request codepoint and the configured aperiodicSRS-ResourceTrigger value or aperiodicSRS-ResourceTriggerList value, more than one aperiodic SRS can be triggered in one single DCI. Each of these triggered AP-SRS sets can have different slot offsets. In order to indicate all different slot offsets in one DCI, a specific number of bits can be allocated for the slot offset of each SRS set indicated by DCI and the corresponding slot offset bits of different SRS sets are ordered according to the SRS set ID in one DCI.

[0251] An alternative is to introduce a new RRC parameter (i.e., dci-slotOffsetID) for aperiodic SRS set in SRS-Config IE in order to arrange the transmission order of all SRS sets with the same aperiodicSRS-ResourceTrigger or aperiodicSRS-ResourceTriggerList of the same configuration value. Therefore, as shown in Table 11, the slot offset of each SRS set indicated by a specific number of bits ordered in one DCI according to the dci-slotOffsetID value configured by RRC.

[0252] Table 11

[0253]

[0254] A low overhead alternative method for indicating all different slot offsets in one DCI is to use a bitmap structure. With the bitmap method, the gNB should prioritize the triggered AP-SRS set transmission based on the SRS set ID or the same as before based on the RRC configured value such as dci-slotOffsetID. Otherwise, the order of SRS set transmission in those slot positions indicated by the bitmap also needs to be indicated in the DCI. For example, if three different aperiodic SRS sets with the same value of aperiodicSRS-ResourceTrigger are triggered together and the triggered SRS set transmission is prioritized based on the SRS set ID, the bitmap structure "0001010001" can be used to indicate the slot offset values 4, 6 and 10 corresponding to the three triggered sets in one DCI, where the slot offset 4 corresponds to the SRS set with the lowest set ID, the slot offset 6 corresponds to the SRS set with the second lowest set ID, and the slot offset 10 corresponds to the SRS set with the highest set ID.

[0255] As mentioned above, to reduce the overhead of aperiodic SRS set configuration for "antenna switching" usage, a resource level slot offset can be introduced individually for each SRS resource within an aperiodic SRS resource set in addition to the RRC configured set level slot offset. The DCI based flexible triggering of such aperiodic SRS set can be through a bitmap structure within the field of the adjusted usage of DCI format 0_1 with the introduction of a new RNTI, or through the allocation of a specific number of bits for each resource level slot offset.

[0256] For the former method, the sequence of resource level slot offsets is indicated with a bitmap structure for each triggered aperiodic SRS set, where each of those slot offsets corresponds to one of the configured resources in that triggered set. For example, for a triggered aperiodic SRS set with four configured resources, the bitmap structure "0100100101" can be used to indicate the four slot offset values 2, 5, 8 and 10.

[0257] However, for the latter method, the gNB allocates a specific number of bits for the slot offset of each configured resource in the triggered aperiodic SRS set. For the resources of an aperiodic SRS set in the SRS-Config IE, the arrangement of these resource level slot offsets in the above two methods can be performed by introducing a new RRC parameter, i.e., dci-resourceSlotOffsetID, as shown in Table 12 below. The same dci-resourceSlotOffsetID can be assigned to multiple resources to indicate that those resources are transmitted in the same slot.

[0258] Table 12

[0259]

[0260] Another method to resolve the order of slot offsets for SRS resources of a triggered AP-SRS set in DCI is to use SRS resource ID. However, this method is very practical for a specific bit allocation scheme. With this method, each SRS resource has a specific number of bits for slot offset indication in DCI ordered according to SRS resource ID.

[0261] Multiple aperiodic SRS sets can be triggered in one DCI with the same configuration value of aperiodicSRS-ResourceTrigger or aperiodicSRS-ResourceTriggerList. The same method explained above can be used to resolve the order of slot offsets in a single DCI. A new RRC parameter (i.e., dci-resourceslotOffsetID) can be introduced for all resources of all triggered aperiodic SRS sets. The same dci-resourceslotOffsetID value indicates the same slot transmission. The configured dci-resourceslotOffsetID of SRS resources can be increased consecutively across sets. For example, if the first set has three resources with dci-resourceslotOffsetID values of 0, 1, and 1 (i.e., the second and third resources are transmitted in the same slot), the dci-resourceslotOffsetID value for the second set will be greater than or equal to 1.

[0262] Optionally, the configured dci-resourceslotOffsetID of SRS resources for each set can start from zero (i.e., restart across SRS sets), and then the actual transmission order of SRS resource l in SRS set i can be calculated implicitly by the following equation (8).

[0263]

[0264] In equation (8), OffsetID m，n is the value of the configured dci-resourceslotOffsetID for SRS resource n in triggered SRS resource set m, and the triggered SRS sets are organized according to SRS set ID of SRS resource set m (i.e., numbered from zero).

[0265] For a particular bit allocation, an alternative is that the order of the slot offsets of all triggered aperiodic SRS resources in the DCI is based on the SRS resource ID and SRS set ID. That is, the order is such that the slot offsets of the resources of the lowest set ID are sorted first according to the resource IDs of the resources of the lowest set ID, then the slot offsets of the resources of the next lowest set ID, and so on. For example, when two SRS sets with IDs 2 and 8 are triggered, where SRS set #2 has three resources with IDs 1, 4, and 7, and SRS set #8 has two resources with IDs 2 and 4, the slot offsets of all five triggered aperiodic resources are ordered as: resource #1 (of set #2), resource #4 (of set #2), resource #7 (of set #2), resource #2 (of set #8), and resource #4 (of set #8).

[0266] If the resource level slot offset method is introduced only for the “antenna switching” usage, then the order of the slot offsets in one DCI for multiple triggered AP-SR sets with different usages can be determined according to the new RRC parameter dci-resourceslotOffsetID for aperiodic SRS resources with “antenna switching” usage and dci-slotOffsetID for aperiodic SRS sets with usages other than “antenna switching”. The values of the configured dci-slotOffsetID and dci-resourceslotOffsetID are configured consecutively based on the gNB priority of SRS transmission.

[0267] Group common DCI has the potential benefit of less DCI size budget compared to UE specific DCI. This applies to SRS triggering for multiple UEs.

[0268] DCI format 2_3 is a group common DCI format introduced in NR Rel-15 for SRS carrier switching. DCI format 2_3 is used to trigger aperiodic SRS resource set(s) with “antenna switching” usage for UL carriers without the need for configured PUSCH / PUCCH for a group of UEs. However, DCI format 2_3 is only used for carrier switching where the UE switches from a serving cell to another cell without the need for configured PUSCH / PUCCH or without the need to take note of another UL where SRS power control is associated with PUCCH power control.

[0269] Similar to the above method, a new RNTI (i.e., AP-SRS-RNTI) can be introduced for DCI format 2_3 in order to flexibly trigger AP-SRS resource sets without PUSCH for other purposes than carrier switching. The gNB can configure the new RNTI for a UE via RRC through the IE PhysicalCellGroupConfig.

[0270] In particular, as shown in Table 13 below, the IE AP-SRS-CommandConfig can be defined to configure the UE for extracting the command for flexible AP-SRS triggering from the group message on DCI format 2_3.

[0271] Table 13

[0272]

[0273] In Table 13, startingBitOfFormat2-3 is the index of the position of the first bit of the field for non-supplemental uplink carrier of the serving cell, and startingBitOfFormat2-3SUL-v1530 is the index of the position of the first bit of the field for supplemental UL carrier of the serving cell.

[0274] The following can be extracted from DCI format 2_3 with CRC scrambled by AP-SRS-RNTI:

[0275] - block number 1, block number 2, …, block number B

[0276] The starting position of each block is determined by the higher layer parameter AP-SRS-CommandConfig of the UE configured with the block.

[0277] For each block, the following fields are defined:

[0278] ■- SRS request - 0 bits or 2 bits. Codepoint 00 is used when no aperiodic SRS resource set is triggered, and other codepoints are used to trigger SRS resource set(s) according to the configured aperiodicSRS-ResourceTrigger value or aperiodicSRS-ResourceTriggerList value.

[0279] - AP-SRS slot offset - n bits. Each SRS set has m allocated bits to indicate its own slot offset. The bits for different SRS sets are ordered according to the SRS set ID.

[0280] Optionally, a new RRC parameter dci-slotOffsetID can be introduced for each aperiodic SRS set in the SRS-Config IE, and the bits for different SRS sets are ordered in the AP-SRS slot offset field of each block according to the configured dci-slotOffsetID values.

[0281] In NR Rel. 16, AP-SRS can also be triggered by DCI format 1_1 as well as DCI format 0_1. Similar approach as discussed above for DCI format 0_1 can be applied for DCI format 1_1 for aperiodic SRS triggering. In addition, a new RNTI can also be introduced for DCI format 1_1 to flexibly trigger AP-SRS resource set.

[0282] Figure 6 An electronic device in a network environment according to an embodiment is illustrated.

[0283] Referring to Figure 6 The electronic device 601 (e.g., a mobile terminal including a GPS function) in the network environment 600 can communicate with an electronic device 602 via a first network 698 (e.g., a short-range wireless communication network), or an electronic device 604 or a server 608 via a second network 699 (e.g., a long-range wireless communication network). The electronic device 601 can communicate with the electronic device 604 via the server 608. The electronic device 601 can include a processor 620, a memory 630, an input device 650, a sound output device 655, a display device 660, an audio module 670, a sensor module 676, an interface 677, a haptic module 679, a camera module 680, a power management module 688, a battery 689, a communication module 690, a subscriber identification module (SIM) 696, or an antenna module 697 including a GNSS antenna. In one embodiment, at least one (e.g., the display device 660 or the camera module 680) of the components can be omitted from the electronic device 601, or one or more other components can be added in the electronic device 601. In one embodiment, some of the components can be implemented as single integrated circuit (IC) or multiple ICs. The sensor module 676 (e.g., a fingerprint sensor, an iris sensor, or an illuminance sensor) can be embedded in the display device 660 (e.g., a display) in one embodiment.

[0284] The processor 620 can execute, for example, software (e.g., a program 640) to control at least one other component (e.g., a hardware or software component) of the electronic device 601 coupled with the processor 620 and can perform various data processing or computation. As at least a part of the data processing or computation, the processor 620 can load a command or data received from another component (e.g., the sensor module 676 or the communication module 690) to a volatile memory 632, process the command or the data stored in the volatile memory 632, and store resulting data in a non-volatile memory 634. The processor 620 can include a main processor 621 (e.g., a central processing unit (CPU) or an application processor) and an auxiliary processor 623 (e.g., a graphics processing unit (GPU), an image signal processor (ISP), a sensor hub processor, or a communication processor (CP)) that is operable independently from, or in conjunction with, the main processor 621. Additionally, or alternatively, the auxiliary processor 623 can be adapted to consume less power than the main processor 621, or to perform specific functions. The auxiliary processor 623 can be implemented as separate from, or as part of, the main processor 621.

[0285] The auxiliary processor 623 can replace the main processor 621 to control at least some functions or states related to at least one component of the electronic device 601 (e.g., the display device 660, the sensor module 676, or the communication module 690) while the main processor 621 is in an inactive (e.g., sleep) state, or together with the main processor 621 to control at least some functions or states related to at least one component of the electronic device 601 (e.g., the display device 660, the sensor module 676, or the communication module 690) while the main processor 621 is in an active state (e.g., executing an application). According to an embodiment, the auxiliary processor 623 (e.g., an image signal processor or a communication processor) can be implemented as a part of another component functionally related to the auxiliary processor 623 (e.g., the camera module 680 or the communication module 690).

[0286] The memory 630 can store various data used by at least one component (e.g., the processor 620 or the sensor module 676) of the electronic device 601. The various data can include, for example, software (e.g., a program 640) and input data or output data for a command related thereto. The memory 630 can include the volatile memory 632 or the non-volatile memory 634.

[0287] The program 640 can be stored in the memory 630 as software, and can include, for example, an operating system (OS) 642, middleware 644, or an application 646.

[0288] The input device 650 can receive a command or data to be used by other components (e.g., the processor 620) of the electronic device 601, from the outside (e.g., a user) of the electronic device 601. The input device 650 can include, for example, a microphone, a mouse, or a keyboard.

[0289] The sound output device 655 can output sound signals to the outside of the electronic device 601. The sound output device 655 can include, for example, a speaker or a receiver. The speaker can be used for general purposes, such as playing multimedia or recording, and the receiver can be used for receiving an incoming call. According to an embodiment, the receiver can be implemented as separate from, or as part of, the speaker.

[0290] The display device 660 can visually provide information to the outside (e.g., a user) of the electronic device 601. The display device 660 can include, for example, a display, a hologram device, or a projector and a control circuit for controlling a corresponding one of the display, the hologram device, and the projector. According to an embodiment, the display device 660 can include a touch circuitry adapted to detect a touch, or a sensor circuitry (e.g., a pressure sensor) adapted to measure the intensity of force incurred by the touch.

[0291] The audio module 670 can convert a sound into an electrical signal and vice versa. According to an embodiment, the audio module 670 can obtain the sound via the input device 650, or output the sound via the sound output device 655 or a headphone of the external electronic device 602 directly (e.g., wirelessly) or wirelessly coupled with the electronic device 601.

[0292] The sensor module 676 can detect an operational state (e.g., power or temperature) of the electronic device 601 or an environmental state (e.g., a state of a user) external to the electronic device 601, and then generate an electrical signal or data value corresponding to the detected state. The sensor module 676 can include, for example, a gesture sensor, a gyro sensor, an atmospheric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor, an infrared (IR) sensor, a biometric sensor, a temperature sensor, a humidity sensor, or an illuminance sensor.

[0293] The interface 677 can support one or more designated protocols to be used for the electronic device 601 to be coupled with the external electronic device 602 directly (e.g., wiredly) or wirelessly. According to an embodiment, the interface 677 can include, for example, a high definition multimedia interface (HDMI), a universal serial bus (USB) interface, a secure digital (SD) card interface, or an audio interface.

[0294] The connection terminal 678 can include a connector to which the electronic device 601 can be physically connected with the external electronic device 602, for example. According to an embodiment, the connection terminal 678, which can include, for example, a HDMI connector, a USB connector, a SD card connector, or an audio connector (e.g., a headphone connector), can be configured to include a plurality of connectors.

[0295] The haptic module 679 can convert electrical signal into a mechanical stimulus (e.g., vibration or movement) or electrical stimulus that can be recognized by a user via tactile sensation or kinesthetic sensation. According to an embodiment, the haptic module 679 can include, for example, a motor, a piezoelectric element, or an electrical stimuluser.

[0296] The camera module 680 can capture still images or moving images. According to an embodiment, the camera module 680 can include one or more lenses, image sensors, image signal processors, or flashes.

[0297] The power management module 688 can manage power supplied to the electronic device 601. The power management module 688 can be implemented as at least a part of, for example, a power management integrated circuit (PMIC).

[0298] The battery 689 can supply power to at least one component of the electronic device 601. According to an embodiment, the battery 689 can include, for example, a primary cell which is not rechargeable, a secondary cell which is rechargeable, or a fuel cell.

[0299] The communication module 690 can support establishing a direct (e.g., wired) communication channel or a wireless communication channel between the electronic device 601 and an external electronic device (e.g., the electronic device 602, the electronic device 604, or the server 608) and performing communication via the established communication channel. The communication module 690 can include one or more communication processors that are operable independently from the processor 620 (e.g., an application processor) and support a direct (e.g., wired) communication or a wireless communication. According to an embodiment, the communication module 690 can include a wireless communication module 692 (e.g., a cellular communication module, a short-range wireless communication module, or a global navigation satellite system (GNSS) communication module) or a wired communication module 694 (e.g., a local area network (LAN) communication module or a power line communication (PLC) module). Respective ones of these communication modules can communicate with an external electronic device, via a first network 698 (e.g., a short-range communication network such as BluetoothTM, wireless-fidelity (Wi-Fi) direct, or infrared data association (IrDA)) or a second network 699 (e.g., a long-range communication network such as a cellular network, the Internet, or a computer network (e.g., LAN or wide area network (WAN)). These various types of communication modules can be implemented as a single component (e.g., a single IC) or can be implemented as separate components (e.g., separate ICs) from each other. The wireless communication module 692 can identify and authenticate the electronic device 601 in a communication network, such as the first network 698 or the second network 699, using subscriber information (e.g., an international mobile subscriber identity (IMSI)) stored in the subscriber identification module 696.

[0300] The antenna module 697 can transmit or receive data, or power with an external electronic device (e.g., the external electronic device) through a signal or power using at least one antenna. According to an embodiment, at least one antenna can be implemented as part of the communication module 690 (e.g., the wireless communication module 692), or the communication module 690 can be implemented as part of a processor, such as the processor 620.

[0301] At least some of the above-described components can be coupled mutually and / or operatively via one or more communication buses, and communicate signals (e.g., commands or data) therebetween. The above-described components can each operate independently from the other components or together with the other components, and some of them can be implemented as single entities or multiple entities.

[0302] According to an embodiment, commands or data received from a first device 601 can be stored in the storage 630, and a command or data to be transmitted to the first device 601 can be stored in the storage 630. A component (e.g., the processor 620) can interpret the command or data stored in the storage 630, and can perform a corresponding operation.

[0303] One embodiment can be implemented as software (e.g., a program 640) including one or more instructions stored in a storage medium (e.g., an internal memory 636 or an external memory 638) that is readable by a machine (e.g., the electronic device 601). For example, a processor of the electronic device 601 can invoke at least one of the one or more instructions stored in the storage medium, and execute the at least one instruction under control of the processor, with or without using one or more other components. The machine, accordingly, can operate to perform at least one function according to the invoked at least one instruction. The one or more instructions can include a code generated by a complier or a code executable by an interpreter. The machine-readable storage medium can be provided in the form of a non-transitory storage medium. The term "non-transitory" indicates that the storage medium is tangible, but does not include a signal (e.g., an electromagnetic wave), but the term does not differentiate a location where data is semi-permanently stored from a location where data is temporarily stored.

[0304] According to an embodiment, the method of the disclosure can be included and provided in a computer program product. The computer program product can be traded as a product between a seller and a buyer. The computer program product can be distributed in the form of a machine-readable storage medium (e.g., compact disc read only memory (CD-ROM)), or be distributed online via an application store (e.g., PlayStore TM) online distribution (e.g., download or upload), or directly between two user devices (e.g., smartphones). If distributed online, at least a part of the computer program product can be temporarily generated or at least temporarily stored in a machine-readable storage medium such as a memory of a manufacturer's server, a server of an application store, or a relay server.

[0305] According to an embodiment, each of the above-described components (e.g., a module or a program) can include a single entity or multiple entities. One or more of the above-described components can be omitted, or one or more other components can be added. Alternatively or additionally, a plurality of components (e.g., modules or programs) can be integrated into a single component. In such a case, the integrated component can still perform one or more functions of each of the plurality of components in the same or similar manner as performed by the corresponding one from the plurality of components before the integration. Operations performed by the module, the program, or another component can be executed sequentially, in parallel, repeatedly, or heuristically, or one or more of the operations can be executed in a different order or omitted, or one or more other operations can be added.

[0306] As described above, embodiments of the disclosure utilize SRS bunding to improve SRS coverage in cases with the possibility of joint estimation of uplink channels on different transmissions, allow for larger configurable repetition factors and larger comb sizes, which can enhance SRS coverage, use partial sounding across frequencies, which can enhance the capability and coverage of SRS transmissions, provide additional specification for antenna switching configuration and flexible antenna switching, provide flexible and dynamic triggering of aperiodic SRS transmissions, and reduce signaling overhead for aperiodic SRS transmissions by reusing bit fields of non-scheduling DCI.

[0307] Although certain embodiments of the disclosure have been described in the detailed description of the disclosure, the disclosure can be modified in various forms without departing from the scope of the disclosure. Accordingly, the scope of the disclosure should not be determined only based on the described embodiments, but based on the following claims and their equivalents.

Claims

1. A base station device for wireless communication with a user equipment (UE), comprising: a transceiver; and a processor configured to: transmit, via the transceiver, a control message configured for the UE to the UE, and receive, via the transceiver, a sounding reference signal (SRS) from the UE based on the control message, wherein the control message indicates to the UE a triggering slot offset and available slots for the SRS transmission, and wherein the processor is further configured to configure at least one bit field of a non-scheduled downlink control information (DCI) to indicate an aperiodic SRS triggering offset, wherein the at least one bit field comprises at least one of a frequency domain resource allocation field, a time domain resource allocation field, a modulation and coding scheme field, and an antenna port field in a DCI format 0 1 or a DCI format 1 1.

2. The base station device of claim 1, wherein, the control message utilizes a bitmap structure.

3. The base station device of claim 1, wherein, the control message comprises at least one of a radio resource control (RRC) message and a DCI message.

4. The base station device of claim 1, wherein, the processor is further configured to indicate to the UE to treat all flexible slots as available slots regardless of dynamic downlink scheduling.

5. The base station device of claim 1, wherein, the processor is further configured to configure, via radio resource control (RRC), the UE with an aperiodic AP-SRS-radio network temporary identifier (RNTI).

6. The base station device of claim 1, wherein, the processor is further configured to generate the control message comprising an SRS configuration information element when at least two aperiodic SRS sets are triggered in a single DCI message, wherein the SRS configuration information element comprises a radio resource control (RRC) parameter dci-slotOffsetID.

7. The base station device of claim 6, wherein, the processor is further configured to prioritize transmission of triggered AP-SRS sets in a bitmap structure based on the dci-slotOffsetID.

8. The base station device of claim 1, wherein, the processor is further configured to: receive, via the transceiver, a UE capability message from the UE, and generate the control message based on the UE capability message.

9. The base station device of claim 1, wherein, the processor is further configured to prioritize transmission of triggered aperiodic AP-SRS sets in a bitmap structure based on an SRS set identifier.

10. The base station device of claim 1, wherein, the processor is further configured to generate the control message comprising an aperiodic AP-SRS command configuration information element, wherein the AP-SRS command configuration information element indicates to the UE to extract a command for flexible AP-SRS triggering from a group message.

11. A user equipment (UE) for wireless communication with a base station, comprising: a transceiver; and a processor configured to: receive, via the transceiver, a control message configured for the UE from the base station, and transmit, via the transceiver, a sounding reference signal (SRS) to the base station based on the control message, wherein the control message indicates to the UE a triggering slot offset and available slots for the SRS transmission, and wherein the processor is further configured to prioritize transmission of triggered aperiodic SRS sets in a bitmap structure based on an SRS set identifier. wherein at least one bit field of a non-scheduled downlink control information (DCI) of the control message indicates an aperiodic SRS trigger offset, wherein the at least one bit field comprises at least one of a frequency domain resource assignment field, a time domain resource assignment field, a modulation and coding scheme field, and an antenna port field in a DCI format 0_1 or a DCI format 1_1.

12. The UE of claim 11, wherein, The control message utilizes a bitmap structure.

13. The UE of claim 11, wherein, The control message comprises at least one of a radio resource control (RRC) message and a DCI message.

14. The UE of claim 11, wherein, The processor is further configured to configure the UE to treat all flexible slots as available slots regardless of dynamic downlink scheduling.

15. The UE of claim 11, wherein, The processor is further configured to identify an aperiodic AP-SRS-radio network temporary identifier (RNTI) via a radio resource control (RRC) configuration of the control message.

16. The UE of claim 11, wherein, The processor is further configured to identify, when at least two aperiodic SRS sets are triggered in a single DCI message, an SRS configuration information element comprising a wireless resource control (RRC) parameter dci-slotOffsetID in the control message.

17. The UE of claim 16, wherein, The processor is further configured to prioritize, based on the dci-slotOffsetID, transmission of triggered AP-SRS sets in a bitmap structure.

18. The UE of claim 11, wherein, The processor is further configured to: transmit, via the transceiver, a UE capability message to the base station, and receive the control message generated by the base station based on the UE capability message.

19. The UE of claim 11, wherein, The processor is further configured to prioritize, based on an SRS set identifier, transmission of triggered aperiodic AP-SRS sets in a bitmap structure.

20. The UE of claim 11, wherein, The processor is further configured to identify, in the control message, an aperiodic AP-SRS command configuration information element, wherein the AP-SRS command configuration information element indicates the UE to extract a command for flexible AP-SRS triggering from a group message.

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