SRS carrier switching for additional SRS

Abstract

Methods, apparatus, and computer-readable media for SRS are provided. An example UE may receive a downlink transmission of an SRS configuration and a scheduled uplink transmission, the uplink transmission being scheduled on a CC, the SRS configuration including one or more additional SRS symbols relative to a first SRS symbol set associated with an aperiodic trigger type 1 or a periodic trigger type 0, the one or more additional SRS symbols being scheduled on a destination CC, at least one of the one or more additional SRS symbols at least partially overlapping with the uplink transmission. The example UE may discard or delay transmission of at least a portion of the SRS in the one or more additional SRS symbols on the destination CC or at least a portion of the uplink transmission on the source CC.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to U.S. Provisional Application No. 63 / 025,146, filed on May 14, 2020, entitled “SRS CARRIER SWITCHING FOR ADDITIONAL SRS,” and U.S. Patent Application No. 17 / 320,217, filed on May 13, 2021, entitled “SRS CARRIER SWITCHING FOR ADDITIONAL SRS,” both of which are expressly incorporated herein by reference in their entirety. background Technical Field

[0003] The present disclosure relates generally to wireless communications and, more particularly, to scheduling of sounding reference signals (SRS).

[0004] introduction

[0005] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcast. Typical wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0006] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at a city, country, region, and even global level. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of the continuous mobile broadband evolution promulgated by the Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (such as with the Internet of Things (IoT)) and other requirements. 5GNR includes services associated with enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable low latency communication (URLLC). There is a need for further improvements in 5G NR technology.

[0007] Wireless communication devices (including base stations and user equipment (UE)) may transmit various synchronization signals and reference signals. For example, the UE may transmit a sounding reference signal (SRS) to the base station on the uplink. SRS may be used to estimate the transmission quality of a transmission channel. For example, a base station may use SRS to obtain channel state information (CSI) for the UE. The base station may configure multiple resources for SRS, including one or more symbols. In some scenarios, an SRS symbol transmitted in an uplink subframe may conflict with another uplink subframe used for another transmission (such as a physical uplink shared channel (PUSCH) transmission) (e.g., due to overlap in time). Such a conflict may cause the SRS symbol in the SRS to be discarded, thereby affecting the base station's ability to obtain CSI, which in turn may potentially affect the total data rate of wireless communication. Such a conflict may also cause errors or adversely affect the other uplink transmission (such as a PUSCH transmission).

[0008] Overview

[0009] A brief summary of one or more aspects is given below to provide a basic understanding of such aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or critical elements of all aspects nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be presented later.

[0010] One innovative aspect of the subject matter described in the present disclosure can be implemented in a method for wireless communication. The method includes receiving a user equipment (UE) capability for SRS switching from a source component carrier (CC) to a destination CC for a non-periodic SRS on additional SRS symbols (such as one or more type 2 SRS symbols) relative to a first set of sounding reference signal (SRS) symbols. The method further includes transmitting a schedule that schedules the UE to avoid transmitting uplink transmissions on the source CC during a time duration that includes a retuning time for the SRS switching and a transmission time for transmitting the additional SRS symbols for the non-periodic SRS on the destination CC.

[0011] Another innovative aspect of the subject matter described in the present disclosure can be implemented in a method for wireless communication. The method includes: transmitting to a base station an indication of a UE capability for SRS switching from a source CC to a destination CC to transmit a non-periodic SRS on an additional SRS symbol relative to a first set of SRS symbols. The method further includes: receiving a schedule for communication with the base station based on the UE capability, the schedule avoiding transmitting an uplink transmission on the source CC during a time duration including a retuning time for the SRS switching and a transmission time for transmitting the additional SRS symbol for the non-periodic SRS on the destination CC.

[0012] In some implementations, the method further includes transmitting an uplink transmission on the source CC before or after transmitting the additional SRS symbols.

[0013] Another innovative aspect of the subject matter described in the present disclosure can be implemented in a method for wireless communication. The method includes: receiving an SRS configuration and a downlink transmission of a scheduled uplink transmission, the uplink transmission being scheduled on a component carrier (CC), the SRS configuration including one or more additional SRS symbols relative to a first SRS symbol set associated with an aperiodic trigger type 1 or a periodic trigger type 0, the one or more additional SRS symbols being scheduled on a destination CC, at least one of the one or more additional SRS symbols at least partially overlapping with the uplink transmission. The method further includes: discarding or delaying at least a portion of the SRS in the one or more additional SRS symbols on the destination CC or at least a portion of the uplink transmission on the source CC.

[0014] In some implementations, the method further includes using a priority rule to determine whether to drop at least a portion of the aperiodic SRS in the additional SRS symbol on the destination CC or at least a portion of the uplink transmission on the source CC.

[0015] Another innovative aspect of the subject matter described in the present disclosure can be implemented in a method for wireless communication. The method includes: receiving UE capabilities for SRS switching from a source CC to a destination CC for aperiodic SRS on additional SRS symbols relative to a first set of SRS symbols. The method further includes: transmitting a schedule that schedules the UE to avoid transmitting downlink transmissions on the source CC during a time duration that includes a retuning time for the SRS switching and a transmission time for transmitting additional SRS symbols for the aperiodic SRS on the destination CC.

[0016] Another innovative aspect of the subject matter described in the present disclosure may be implemented in a method for wireless communication. The method includes: receiving a schedule for a downlink transmission on a source CC. The method further includes: receiving a schedule for an aperiodic SRS with an SRS switch from a source CC to a destination CC on an additional SRS symbol relative to a first SRS symbol set. The method further includes: determining a time overlap between a transmission time of a downlink transmission on the source CC and a time duration of a retuning time for the SRS switch including a transmission time of an additional SRS symbol for the aperiodic SRS on the destination CC. The UE may not monitor the downlink transmission in a subframe including the time overlap.

[0017] In some implementations, the downlink transmission includes a physical downlink shared channel (PDSCH) or a physical downlink control channel (PDCCH).

[0018] Another innovative aspect of the subject matter described in the present disclosure can be implemented in a method for wireless communication. The method includes: receiving UE capabilities for SRS switching and a retuning time from a source CC to a destination CC for aperiodic SRS with carrier switching on an additional SRS relative to a first set of SRS symbols. The method further includes: scheduling communications with the UE based on the UE capabilities, the communications including the aperiodic SRS on the additional SRS symbols.

[0019] Another innovative aspect of the subject matter described in the present disclosure may be implemented in a method for wireless communication. The method includes: transmitting an indication of support for carrier switching capability for transmitting aperiodic SRS on one or more additional SRS symbols relative to a first SRS symbol set associated with aperiodic trigger type 1 or periodic trigger type 0, the one or more additional SRS symbols being associated with an SRS switch from a source CC to a destination CC and being on the destination CC. The method further includes: receiving a schedule for communication with a base station based on the carrier switching capability, the communication including the aperiodic SRS on the one or more additional SRS symbols.

[0020] In some implementations, the method further includes receiving additional UE capabilities for aperiodic SRS without carrier switching on additional SRS symbols.

[0021] To achieve the foregoing and related ends, the one or more aspects include the features fully described below and particularly pointed out in the claims. The following description and drawings set forth in detail some illustrative features of the one or more aspects. However, these features are merely indicative of several of the various ways in which the principles of the various aspects may be employed, and this description is intended to cover all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network.

[0024] Figure 2A , 2B , 2C, and 2D are diagrams illustrating examples of a first 5G / NR frame, a downlink (DL) channel within a 5G / NR subframe, a second 5G / NR frame, and a UL channel within a 5G / NR subframe, respectively.

[0025] Figure 3 is a diagram illustrating an example of a base station and a user equipment (UE) in an access network.

[0026] Figure 4 A diagram illustrating an example collision of uplink transmissions is shown.

[0027] Figure 5 A diagram illustrating an example collision of an uplink transmission with an additional sounding reference signal (SRS) relative to a first sounding reference signal (SRS) set is shown.

[0028] Figure 6 An example communication flow between a base station and a UE to support additional SRS scheduling according to some aspects of the present disclosure is shown.

[0029] Figure 7 A diagram illustrating an example schedule for avoiding collision between additional SRS and previous and next uplink transmissions in accordance with some aspects of the present disclosure is shown.

[0030] Figure 8 A diagram illustrating example rules for resolving conflicts between additional SRS symbols and the next uplink transmission in accordance with some aspects of the present disclosure is shown.

[0031] Fig. 9 A diagram illustrating example rules for resolving uplink conflicts with flexible SRS timing in accordance with some aspects of the present disclosure is shown.

[0032] Fig.10 A diagram is shown illustrating an example schedule for downlink transmissions in accordance with some aspects of the present disclosure.

[0033] Fig.11

[0013] Shown is a flow chart illustrating an example wireless communication method performed at a base station to support scheduling of additional SRS to resolve uplink conflicts in accordance with some aspects of the present disclosure.

[0034] Fig.12

[0013] Shown is a flow chart illustrating an example wireless communication method performed at a UE to support receiving scheduling of additional SRS to resolve uplink conflicts in accordance with some aspects of the present disclosure.

[0035] Fig.13 A flow chart illustrating a wireless communication method performed at a UE to support discarding of additional SRS according to some aspects of the present disclosure is shown.

[0036] Fig.14

[0013] Shown is a flow chart illustrating a wireless communication method performed at a base station to support scheduling of additional SRS to resolve downlink conflicts in accordance with some aspects of the present disclosure.

[0037] Fig.15

[0013] A flow chart illustrating a method of wireless communication performed at a UE to support receiving scheduling of additional SRS to resolve downlink conflicts in accordance with some aspects of the present disclosure is shown.

[0038] Fig.16 A flow chart illustrating a wireless communication method performed at a base station to support scheduling of additional SRSs according to some aspects of the present disclosure is shown.

[0039] Fig.17 A flow chart illustrating a method of wireless communication performed at a UE to support scheduling of additional SRSs according to some aspects of the present disclosure is shown.

[0040] Fig.18 is an illustration of an executable combination according to some aspects of the present disclosure Fig.11 , 14 16 and 17 are diagrams of examples of hardware implementations for example devices of the aspects described by the flowcharts in FIG.

[0041] Fig.19 is an illustration of an executable combination according to some aspects of the present disclosure Fig.12 , 13 , 15 and 17 are diagrams of examples of hardware implementations for example devices of the aspects described by the flowcharts.

[0042] Detailed Description

[0043] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. This detailed description includes specific details to provide a thorough understanding of the various concepts. However, it will be apparent to one of ordinary skill in the art that these concepts may be practiced without these specific details. In some instances, structures and components are shown in block diagram form in order to avoid watering down such concepts.

[0044] In various wireless communication networks, such as time division duplex (TDD) multiple input multiple output (MIMO) networks, a sounding reference signal (SRS) may be used for reciprocity-based beamforming. For example, a user equipment (UE) may transmit an SRS on an uplink, and a base station may estimate a channel and perform beamforming or precoding on a downlink based on the estimated channel. Some UEs may support more downlink CCs than uplink carriers (CCs). Some UEs may be configured with a TDD secondary cell (SCell) with downlink carrier aggregation (CA) but no uplink CA. In order to enable aperiodic SRS transmission on a TDD CC of such UEs, an additional SRS may be supported relative to a first SRS symbol set, since the first SRS symbol set may not support such aperiodic SRS transmission. The additional SRS may correspond to an SRS trigger type 2, and the first SRS symbol set may correspond to an SRS trigger type 0 and a trigger type 1.

[0045] For a SCell without a physical uplink shared channel (PUSCH) (SCell without PUSCH), the UE may be configured with one or more SRSs (hereinafter also referred to as "additional SRSs") in addition to the first SRS set. A SCell without PUSCH may refer to a cellular cell that is not configured for PUSCH transmission from the UE. The first SRS set may include a type 0 periodic SRS (in other words, an SRS with a trigger type 0) and a type 1 aperiodic SRS (in other words, an SRS with a trigger type 1) (both of which may be transmitted as the last symbol in a normal UL subframe, PUSCH), and the additional SRS may be a type 2 SRS (in other words, an SRS with a trigger type 2). The additional SRS may have different sizes, for example, between 7 and 12 symbols longer than the first SRS set. The type 1 aperiodic SRS may be an aperiodic SRS configured by radio resource control (RRC) signaling and triggered by downlink control information (DCI). The UE may also receive RRC signaling that configures a type 0 periodic SRS transmitted in a periodic manner.

[0046] The UE may support SRS carrier switching to implement periodic or non-periodic SRS transmission in a TDD SCell without PUSCH. When SRS carrier switching is enabled, the SRS carrier switching involves the UE interrupting the transmission in the first uplink CC (which may be a frequency division duplex (FDD) CC) and retuning to the TDD SCell without PUSCH on the second uplink CC. The UE may transmit SRS in the TDD SCell and then re-tune back to the first UL CC. The UE may support switching capabilities (which may include switching time) for SRS carrier switching. For example, the UE may report the ability to switch from band A (source CC) to band B (destination CC). Additionally or alternatively, the UE may report the switching time in the form of orthogonal frequency division multiplexing (OFDM) symbols. The base station may configure the serving cell so that the UE may interrupt to transmit SRS in the SCell.

[0047] For SRS carrier switching, discard rules can be defined for the UE or base station to resolve conflicts associated with carrier switching (where two or more signals or data packets overlap in time), in other words, conflicts that may occur due to the UE's SRS switching from the destination CC to the source CC (which may include additional SRS) and transmissions in the source CC. The discard rules may be applied 1) by the base station when scheduling for the UE, or 2) by the UE when transmitting SRS transmissions and uplink data transmissions. Conflicts may occur between SRS transmissions and uplink data transmissions. The base station or UE may reduce the probability of conflicts based on downlink and uplink transmission conflict rules. As used herein, the term "SRS with carrier switching" may refer to an SRS transmitted by a UE that switches carriers in order to transmit the SRS. An example uplink transmission conflict rule may define that a hybrid automatic repeat request (HARQ) transmission, a scheduling request (SR), a rank indicator (RI), a precoder type indicator (PTI), and a channel state information reference signal (CSI-RS) resource indicator (CRI) take precedence over an aperiodic SRS with carrier switching in an additional SRS, which may take precedence over an aperiodic CSI, which may take precedence over a periodic SRS in a first SRS set associated with a switch from a source CC to a destination CC, which may take precedence over other CSI, which may in turn take precedence over SRS without carrier switching. An example downlink transmission conflict rule may define that if the UE is not capable of receiving / transmitting in multiple CCs simultaneously, the UE may not monitor the physical downlink control channel (PDCCH) or the physical downlink shared channel (PDSCH) in a subframe affected by an SRS carrier switch. Additionally, the UE may not be configured with a carrier switch that may interrupt downlink reception in various subframes, which may cause a conflict between downlink reception and SRS transmission and data loss. However, it may be necessary to resolve conflicts associated with the additional SRS relative to the first SRS set because the additional SRS may include more symbols than the first SRS set and may be subject to conflict issues that are not resolved by the example conflict rules described above.

[0048] Various aspects generally relate to scheduling SRS for UEs that can perform carrier switching. Some implementations more specifically relate to scheduling additional SRS with carrier switching to avoid conflicts between the additional SRS and another uplink or downlink transmission (such as PUSCH, PDSCH, or PDCCH). The UE may transmit UE capabilities to the base station, indicating the UE's ability to perform SRS switching from a source CC to a destination CC for non-periodic SRS on additional SRS symbols. These symbols may be referred to as "additional SRS symbols" relative to a smaller first SRS symbol set, as previously discussed. The base station may schedule the UE to avoid conflicts between the additional SRS symbols and the previous uplink / downlink transmission or the next uplink / downlink transmission.

[0049] Specific implementations of the subject matter described in this disclosure may be implemented to achieve one or more of the following potential advantages. In some implementations, the described techniques may be used to resolve conflicts associated with additional SRS symbols. By scheduling the UE to avoid conflicts between additional SRS symbols and uplink transmissions, the UE may transmit additional SRS symbols and uplink transmissions so that the uplink transmission will not adversely affect the transmission of the additional SRS symbols.

[0050] Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0051] As an example, an element, or any part of an element, or any combination of elements may be implemented as a "processing system" including one or more processors. Examples of processors include: microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gating logic, discrete hardware circuits, and other suitable hardware configured to perform various functionalities described throughout this disclosure. One or more processors in a processing system may execute software. Software should be broadly interpreted as meaning instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether it is described in software, firmware, middleware, microcode, hardware description languages, or other terms.

[0052] In one or more example aspects, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, each function may be stored or encoded as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media. Storage media may be any available media that can be accessed by a computer. As an example and not limitation, such computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of various types of computer-readable media, or any other medium that can be used to store computer-accessible instructions or data structure forms of computer executable code.

[0053] Although various aspects are described in this application by explanation of some examples, it will be understood by those skilled in the art that additional implementations and use cases can be generated in many different arrangements and scenarios. The innovation described herein can be implemented across many different platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, each implementation or use can be generated via an integrated chip implementation and other devices based on non-module components (such as end-user devices, vehicles, communication equipment, computing equipment, industrial equipment, retail / shopping equipment, medical equipment, devices that enable artificial intelligence (AI), etc.). Although some examples may or may not be specifically for each use case or application, the wide applicability of the described innovation may occur. The scope of each implementation can be from chip-level or module components to non-module, non-chip-level implementations, and further to the aggregation, distributed or original equipment manufacturer (OEM) equipment or system incorporating one or more aspects of the described innovation. In some actual environments, the equipment incorporating the various aspects and features described may also include additional components and features for implementing and practicing the claimed and described aspects. For example, the transmission and reception of wireless signals necessarily include several components for analog and digital purposes (such as hardware components, including antennas, RF chains, power amplifiers, modulators, buffers, processor(s), interleavers, adders / summers, etc.). The innovations described herein are intended to be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, aggregated or disaggregated components, end-user devices, etc., of various sizes, shapes, and configurations.

[0054] Figure 11 is a diagram illustrating an example of a wireless communication system and access network 100. The wireless communication system (also referred to as a wireless wide area network (WWAN)) includes a base station 102, a UE 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., a 5G core (5GC)). The base station 102 may include a macro cell (a high-power cellular base station) or a small cell (a low-power cellular base station). A macro cell includes a base station. A small cell includes a femto cell, a pico cell, and a micro cell.

[0055] The base station 102 configured for 4G LTE (collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) can interface with the EPC 160 via a first backhaul link 132 (e.g., an S1 interface). The base station 102 configured for 5G NR (collectively referred to as the Next Generation RAN (NG-RAN)) can interface with the core network 190 via a second backhaul link 184. Among other functions, the base station 102 can also perform one or more of the following functions: delivery of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (such as handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment tracking, RAN information management (RIM), paging, positioning, and delivery of alert messages. The base stations 102 may communicate with each other over a third backhaul link 134, such as an X2 interface, directly or indirectly, such as through the EPC 160 or the core network 190. The first backhaul link 132, the second backhaul link 184, and the third backhaul link 134 may be wired or wireless.

[0056] Base stations 102 may communicate wirelessly with UEs 104. Each base station 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, a small cell 102' may have a coverage area 110' that overlaps with the coverage area 110 of one or more macro base stations 102. A network including both small cells and macro cells may be referred to as a heterogeneous network. A heterogeneous network may also include a home evolved Node B (eNB) (HeNB), which may provide services to a restricted group referred to as a closed subscriber group (CSG). A communication link 120 between a base station 102 and a UE 104 may include an uplink (UL) (also referred to as a reverse link) transmission from the UE 104 to the base station 102 or a downlink (DL) (also referred to as a forward link) transmission from the base station 102 to the UE 104. The communication link 120 may use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, or transmit diversity. These communication links may be over one or more carriers. For each carrier allocated in the carrier aggregation of up to Yx MHz (x component carriers) for transmission in each direction, the base station 102 / UE 104 may use spectrum of up to Y MHz (such as 5, 10, 15, 20, 100, 400 MHz, etc.) bandwidth. These carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (such as more or fewer carriers may be allocated to DL compared to UL). The component carrier may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell), and the secondary component carrier may be referred to as a secondary cell (SCell).

[0057] Some UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use DL / UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). The D2D communication may be through a variety of wireless D2D communication systems, such as, for example, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

[0058] The wireless communication system may further include a Wi-Fi access point (AP) 150 in communication with a Wi-Fi station (STA) 152 via a communication link 154, such as in a 5 GHz unlicensed spectrum. When communicating in an unlicensed spectrum, the STA 152 / AP 150 may perform a clear channel assessment (CCA) to determine whether the channel is available prior to communication.

[0059] The small cell 102' may operate in a licensed or unlicensed spectrum. When operating in an unlicensed spectrum, the small cell 102' may employ NR and use the same unlicensed spectrum (such as 5 GHz, etc.) used by the Wi-Fi AP 150. The small cell 102' employing NR in the unlicensed spectrum may boost the coverage of the access network or increase the capacity of the access network.

[0060] The electromagnetic spectrum is typically subdivided into various classes, bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating bands have been identified as frequency range designations FR1 (410 MHz–7.125 GHz) and FR2 (24.25 GHz–52.6 GHz). Although a portion of FR1 is greater than 6 GHz, FR1 is often (interchangeably) referred to as the “sub-6 GHz” band in various documents and articles. Similar naming issues sometimes arise with respect to FR2, which is often (interchangeably) referred to as the “millimeter wave” band in various documents and articles, although it is different from the extremely high frequency (EHF) band (30 GHz–300 GHz) identified as the “millimeter wave” band by the International Telecommunication Union (ITU).

[0061] Frequencies between FR1 and FR2 are generally referred to as mid-band frequencies. Recent 5G NR research has identified the operating bands of these mid-band frequencies as frequency range designation FR3 (7.125GHz–24.25GHz). The frequency bands falling within FR3 can inherit FR1 characteristics or FR2 characteristics, and thus the features of FR1 or FR2 can be effectively extended to mid-band frequencies. Additionally, higher frequency bands are currently being explored to extend 5GNR operations to above 52.6GHz. For example, three higher operating bands have been identified as frequency range designations FR4a or FR4-1 (52.6GHz–71GHz), FR4 (52.6GHz–114.25GHz), and FR5 (114.25GHz–300GHz). Each of these higher frequency bands falls within the EHF band.

[0062] In view of the above aspects, unless otherwise specifically stated, if used in this document, the term sub-"6GHz" and the like may broadly refer to frequencies that may be less than 6GHz, may be within FR1, or may include mid-band frequencies. In addition, unless otherwise specifically stated, if used in this document, the term "millimeter wave" and the like may broadly refer to frequencies that may include mid-band frequencies, may be within FR2, FR4, FR4-a or FR4-1 or FR5, or may be within the EHF band.

[0063] Whether a small cell 102' or a large cell (such as a macro base station), the base station 102 may include or be referred to as an eNB, a gB node (gNB), or another type of base station. Some base stations (such as gNB 180) may operate in the traditional sub-6 GHz spectrum, in millimeter wave frequencies, or near millimeter wave frequencies to communicate with UE 104. When gNB 180 operates in millimeter wave frequencies or near millimeter wave frequencies, gNB 180 may be referred to as a millimeter wave base station. Millimeter wave base station 180 may utilize beamforming 182 with UE 104 to compensate for path loss and short range. Base station 180 and UE 104 may each include multiple antennas, such as antenna elements, antenna panels, or antenna arrays to facilitate beamforming.

[0064] The base station 180 may transmit beamformed signals to the UE 104 in one or more transmit directions 182'. The UE 104 may receive beamformed signals from the base station 180 in one or more receive directions 182". The UE 104 may also transmit beamformed signals to the base station 180 in one or more transmit directions. The base station 180 may receive beamformed signals from the UE 104 in one or more receive directions. The base station 180 / UE 104 may perform beam training to determine the best receive direction and transmit direction for each of the base station 180 / UE 104. The transmit direction and receive direction of the base station 180 may be the same or may be different. The transmit direction and receive direction of the UE 104 may be the same or may be different.

[0065] The EPC 160 may include a mobility management entity (MME) 162, other MMEs 164, a serving gateway 166, a multimedia broadcast multicast service (MBMS) gateway 168, a broadcast multicast service center (BM-SC) 170, and a packet data network (PDN) gateway 172. The MME 162 may be in communication with a home subscriber server (HSS) 174. The MME 162 is a control node that handles signaling between the UE 104 and the EPC 160. In general, the MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are delivered through the serving gateway 166, which itself is connected to the PDN gateway 172. The PDN gateway 172 provides UE IP address allocation and other functions. The PDN gateway 172 and the BM-SC 170 are connected to IP services 176. The IP services 176 may include the Internet, an intranet, an IP multimedia subsystem (IMS), a PS streaming service, or other IP services. The BM-SC 170 may provide functionality for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services within a public land mobile network (PLMN), and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS traffic to base stations 102 belonging to a multicast broadcast single frequency network (MBSFN) area broadcasting a specific service, and may be responsible for session management (start / stop) and for collecting eMBMS related charging information.

[0066] The core network 190 may include an access and mobility management function (AMF) 192, other AMFs 193, a session management function (SMF) 194, and a user plane function (UPF) 195. The AMF 192 may be in communication with a unified data management (UDM) 196. The AMF 192 is a control node that handles signaling between the UE 104 and the core network 190. In general, the AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are delivered through the UPF 195. The UPF 195 provides UE IP address allocation and other functions. The UPF 195 is connected to an IP service 197. The IP service 197 may include the Internet, an intranet, an IP multimedia subsystem (IMS), a packet switching (PS) streaming (PSS) service, or other IP services.

[0067] A base station may include or be referred to as a gNB, a B node, an eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmission reception point (TRP), or some other suitable term. The base station 102 provides an access point to the EPC 160 or the core network 190 for the UE 104. Examples of UE 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (such as an MP3 player), a camera, a game console, a tablet device, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a health care device, an implant, a sensor / actuator, a display, or any other similar functional device. Some UEs 104 may be referred to as IoT devices (such as parking meters, gas pumps, ovens, vehicles, heart monitors, etc.). UE 104 may also be referred to as a station, mobile station, subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable term. In some scenarios, the term UE may also apply to one or more companion devices, such as in a device constellation arrangement. One or more of these devices may access the network collectively or individually.

[0068] Refer again Figure 1 In some aspects, the UE 104 may include a capability indication component 199 configured to indicate to the UE 102 or 180 a UE capability to transmit aperiodic SRS on additional SRS symbols relative to the first set of SRS symbols for SRS switching from a source CC to a destination CC.

[0069] In some aspects, the base station 102 or 180 may include an SRS scheduling component 198 configured to receive a UE capability from the UE 104, the UE capability being a capability for SRS switching from a source CC to a destination CC for a non-periodic SRS on an additional SRS symbol relative to the first set of SRS symbols. The SRS scheduling component 198 is further configured to transmit or cause a transmitter to transmit a schedule that schedules the UE to avoid collisions between uplink transmissions on the source CC and the additional SRS symbols for the non-periodic SRS on the destination CC.

[0070] Although the following description may focus on 5G NR, the concepts described herein may be applicable to other similar areas such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0071] Figures 2A-2D The frame structure is explained, and various aspects of the present disclosure may be applicable to other wireless communication technologies that may have different frame structures or different channels. A frame (10ms) may be divided into 10 equally sized subframes (1ms). Each subframe may include one or more time slots. A subframe may also include a mini-time slot, which may include 7, 4, or 2 symbols. Each time slot may include 14 or 12 symbols, depending on whether the cyclic prefix (CP) is a normal CP or an extended CP. For a normal CP, each time slot may include 14 symbols, and for an extended CP, each time slot may include 12 symbols. The symbols on the DL may be CP orthogonal frequency division multiplexing (OFDM) (CP-OFDM) symbols. The symbols on the UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) extended OFDM (DFT-s-OFDM) symbols (also known as single carrier frequency division multiple access (SC-FDMA) symbols) (for power-limited scenarios; limited to single stream transmission). The number of time slots within a subframe is based on the CP and parameter design. The parameter design defines the subcarrier spacing (SCS) and, in effect, the symbol length / duration, which is equal to 1 / SCS.

[0072]

[0073] For normal CP (14 symbols / slot), different parameter designs μ0 to 4 allow 1, 2, 4, 8, and 16 slots per subframe, respectively. For extended CP, parameter design 2 allows 4 slots per subframe. For normal CP and parameter design μ, there are 14 symbols / slot and 2 μ time slots / subframe. The subcarrier spacing can be equal to 2 μ *15kHz, where μ is parameter design 0 to 4. Thus, parameter design μ=0 has a subcarrier spacing of 15kHz, while parameter design μ=4 has a subcarrier spacing of 240kHz. The symbol length / duration is inversely related to the subcarrier spacing. Figures 2A-2D An example of a normal CP with 14 symbols per slot and a parameter design μ=2 and 4 slots per subframe is provided. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is about 16.67 μs. Within a frame set, there may be one or more different bandwidth parts (BWPs) that are frequency division multiplexed (see Figure 2B ). Each BWP can have a specific parameter design and CP (normal or extended).

[0074] A resource grid may be used to represent the frame structure. Each slot includes a resource block (RB) (also called a physical RB (PRB)) extending over 12 consecutive subcarriers. The resource grid is divided into a number of resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0075] like Figure 2A As illustrated in , some REs carry reference (pilot) signals (RS) for UEs. RSs may include demodulation RSs (DM-RSs) (indicated as R for one particular configuration, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RSs) for channel estimation at the UE. RSs may also include beam measurement RSs (BRSs), beam refinement RSs (BRRSs), and phase tracking RSs (PT-RSs).

[0076] Figure 2B Examples of various DL channels within a subframe of a frame are illustrated. A physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) (such as 1, 2, 4, 8, or 16 CCEs), each CCE including 6 RE groups (REGs), each REG including 12 consecutive REs in an OFDM symbol of an RB. A PDCCH within a BWP may be referred to as a control resource set (CORESET). The UE is configured to monitor PDCCH candidates in a PDCCH search space (such as a common search space, a search space that varies with the UE) during a PDCCH monitoring opportunity on a CORESET, wherein the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs may be located at higher or lower frequencies across the channel bandwidth. A primary synchronization signal (PSS) may be within symbol 2 of a particular subframe of a frame. The PSS is used by UE 104 to determine subframe / symbol timing and physical layer identity. A secondary synchronization signal (SSS) may be within symbol 4 of a particular subframe of a frame. The SSS is used by the UE to determine the physical layer cell identity group number and the radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine the physical cell identifier (PCI). Based on the PCI, the UE can determine the location of the DM-RS. The physical broadcast channel (PBCH) carrying the master information block (MIB) can be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block (also referred to as an SS block (SSB)). The MIB provides the number of RBs in the system bandwidth, and the system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH (such as system information blocks (SIBs)), and paging messages.

[0077] As in Figure 2CAs explained in , some REs carry DM-RSs for channel estimation at the base station (indicated as R for one specific configuration, but other DM-RS configurations are possible). The UE may transmit DM-RSs for the physical uplink control channel (PUCCH) and DM-RSs for the physical uplink shared channel (PUSCH). The PUSCH DM-RS may be transmitted in the first or first two symbols of the PUSCH. The PUCCH DM-RS may be transmitted in different configurations depending on whether a short PUCCH or a long PUCCH is transmitted and depending on the specific PUCCH format used. The UE may transmit a sounding reference signal (SRS). The SRS may be transmitted in the last symbol of the subframe. The SRS may have a comb structure, and the UE may transmit the SRS on one of the comb teeth. The SRS may be used by the base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

[0078] Figure 2D Examples of various UL channels within a subframe of a frame are illustrated. The PUCCH may be located at a position as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as a scheduling request, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and hybrid automatic repeat request (HARQ) acknowledgement (ACK) (HARQ-ACK) feedback (in other words, one or more HARQ ACK bits indicating one or more ACKs or negative ACKs (NACKs)). The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), or UCI.

[0079] Figure 33 is a block diagram of a base station 310 in communication with a UE 350 in an access network. In the DL, IP packets from the EPC 160 may be provided to a controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a media access control (MAC) layer. The controller / processor 375 provides RRC layer functionality associated with broadcasting of system information (such as MIB, SIB), RRC connection control (such as RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration of UE measurement reports; PDCP layer functionality associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with delivery of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0080] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, including the physical (PHY) layer, may include error detection on the transport channel, forward error correction (FEC) encoding / decoding of the transport channel, interleaving, rate matching, mapping onto the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 handles the mapping to the signal constellation based on various modulation schemes such as binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM). The decoded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (such as a pilot) in the time or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation schemes and for spatial processing. The channel estimates may be derived from a reference signal or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0081] At the UE 350, each receiver 354RX receives a signal through its corresponding antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to a receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial stream destined for the UE 350. If there are multiple spatial streams destined for the UE 350, they can be combined into a single OFDM symbol stream by the RX processor 356. The RX processor 356 then uses a fast Fourier transform (FFT) to transform the OFDM symbol stream from the time domain to the frequency domain. The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbol on each subcarrier and the reference signal are recovered and demodulated by determining the signal constellation point most likely transmitted by the base station 310. These soft decisions can be based on the channel estimate calculated by the channel estimator 358. These soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted on the physical channel by the base station 310. These data and control signals are then provided to the controller / processor 359 which implements layer 3 and layer 2 functionality.

[0082] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport channels and logical channels, packet reassembly, cipher interpretation, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using an ACK or NACK protocol to support HARQ operations.

[0083] Similar to the functionality described in conjunction with DL transmissions performed by the base station 310, the controller / processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality associated with header compression / decompression, and security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality associated with delivery of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing MAC SDUs onto TBs, demultiplexing MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0084] Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the base station 310 may be used by a TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0085] UL transmissions are processed at the base station 310 in a manner similar to that described in conjunction with the receiver functionality at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

[0086] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport channels and logical channels, packet reassembly, cipher decoding, header decompression, control signal processing to recover IP packets from the UE 350. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using an ACK or NACK protocol to support HARQ operations.

[0087] At least one of the TX processor 368, the RX processor 356, and the controller / processor 359 may be configured to perform operations related to Figure 1 The capabilities of the components 199 may be combined with various aspects of the TX processor 316, the RX processor 370, and the controller / processor 375. At least one of the TX processor 316, the RX processor 370, and the controller / processor 375 may be configured to perform the Figure 1 The SRS scheduling component 198 combines various aspects.

[0088] Figure 4 A diagram illustrating an example collision 400 of uplink transmissions is shown. In the illustrated example, PUSCH 410 at subframe N+1 collides with SRS 420 transmitted at subframe N for one symbol duration. If the PUSCH carrying data has a lower priority than SRS with carrier switching, the first symbol of the PUSCH may be punctured. The first symbol is used for retuning when the UE switches from a destination CC transmitting SRS back to a source CC transmitting PUSCH.

[0089] Figure 5 A diagram illustrating an example collision 500 of an uplink transmission with additional SRS symbols relative to a first SRS set is shown. Figure 5 As illustrated in , at subframe N-1, a first SRS set may be transmitted within a first set of symbols at 510. At subframe N, an additional SRS may be transmitted within a larger second set of symbols at 512. In the illustrated example, at 510, an additional SRS in subframe N of a destination CC (such as an SCell without PUSCH or PUCCH) conflicts with the PUSCH at subframe N-1 of the source CC and the first SRS set in the last symbol. If the retuning time is greater than one symbol, the additional SRS in subframe N may also conflict with the PUSCH at subframe N+1 of the source CC. Such a conflict may cause errors or otherwise adversely affect the transmission of the PUSCH at subframe N+1 / N-1 and / or the transmission of the additional SRS. Some implementations herein relate to scheduling of additional SRS to avoid such conflicts between additional SRS and PUSCH transmissions. A conflict refers to an overlap in time between these two transmissions.

[0090] Figure 6 A communication flow 600 between a base station 604 and a UE 602 to support additional SRS scheduling according to some aspects of the present disclosure is shown. Figure 6 , the UE may transmit UE capabilities at 606a to the base station 604. The UE capabilities may be UE capabilities for SRS switching from a source CC to a destination CC for aperiodic SRS on additional SRS symbols relative to the first SRS symbol set (in other words, aperiodic SRS triggered based on signaling from the base station). In some aspects, the UE capabilities may further indicate a retuning time from the source CC to the destination CC for aperiodic SRS on additional SRS symbols relative to the first SRS symbol set.

[0091] In some aspects, the UE capability may be a first UE capability for aperiodic SRS without carrier switching on additional SRS symbols. In some aspects, UE 602 may be a UE with license assisted access (LAA) capability, and may transmit a second UE capability for aperiodic SRS with carrier switching on additional SRS symbols at 606b. In such aspects, as part of 606b, the UE may indicate a retuning time from a source CC to a destination CC for aperiodic SRS with carrier switching on additional SRS symbols in an uplink subframe. In some aspects, the second UE capability may indicate whether the UE supports aperiodic SRS with carrier switching on additional SRS symbols for a band combination. The UE capability may depend on the carrier / band type, for example, it may not be expected that the UE is configured with aperiodic SRS with carrier switching on additional SRS symbols on an unlicensed band or on a LAA SCell. In some aspects, the second UE capability may indicate whether the UE supports aperiodic SRS with carrier switching on additional SRS symbols for a band pair of a band combination. In some aspects, the second UE capability may indicate whether the UE supports a general capability for aperiodic SRS with carrier switching on additional SRS symbols.In some aspects, the UE may indicate the second UE capability without reference to a band combination.

[0092] At 608a, the base station 604 may transmit a message including a schedule for the SRS symbols to the UE 602. In some aspects, the schedule schedules the UE 602 to avoid collisions between uplink transmissions on the source CC and the additional SRS symbols of the aperiodic SRS on the destination CC. In some aspects, the schedule may indicate (in other words, include an indication to the UE 602) that the additional SRS is to avoid collisions between the previous uplink channel (in other words, the uplink channel that occurs before the additional SRS) and the next uplink channel (in other words, the uplink channel that occurs after the additional SRS), such as the PUSCH.

[0093] In some aspects, the scheduling may account for the retuning time. If an additional SRS will be (in other words, is scheduled to be) transmitted during a time duration that includes the transmission time of another uplink or downlink transmission and the retuning time, the additional SRS may be said to "overlap," "collide," or "collide" with the other transmission. Figure 7 A diagram 700 is shown illustrating an example scheduling for avoiding collisions between an additional SRS on CC1 and the previous and next uplink transmissions on CC0. The SRS on CC1 may be referred to as an "additional" SRS because it may be scheduled on additional symbols outside of a smaller potential set of symbols that may be referred to as a first SRS symbol set or a normal SRS symbol set. Figure 7 As illustrated in , the UE may switch between CCs using a re-tuning time 702a and a re-tuning time 702b to transmit SRS on CC1. The re-tuning time 702a defines the amount of time for the UE to switch from CC0 to CC1 between a previous uplink transmission at subframe N-1 (such as PUSCH 704a) and an SRS transmission on CC1. The schedule may indicate that the UE will not transmit the one or more additional SRS symbols until the previous uplink transmission has been completed and after the re-tuning time 702a has elapsed. Similarly, the re-tuning time 702b defines the amount of time for the UE to switch back from CC1 to CC0 between an SRS transmission on CC1 and a next uplink transmission on CC0 at subframe N+1 (such as PUSCH 704b). The schedule may indicate that the UE will not transmit the next uplink transmission until the transmission of the one or more additional SRS symbols has been completed and after the re-tuning time 702b has elapsed.

[0094] In some aspects, the scheduling may avoid a conflict between the additional SRS and a previous uplink channel. In such aspects, the scheduling may indicate that the UE is not expected to be scheduled to have a conflict between the additional SRS and an uplink transmission in a previous subframe. In some aspects, the scheduling may limit the symbols of the additional SRS to in the range of. is the number of symbols used for retuning. In such aspects, it may not be expected that the UE is triggered to transmit additional SRS in subframe N on a CC without PUSCH or PUCCH that overlaps (including the retuning time) with uplink transmission in subframe N-1 on a different CC. In such aspects, considering the impact of different timing advances on different CCs in addition to the retuning time, it may not be expected that the UE is triggered to transmit additional SRS in subframe N on a CC without PUSCH or PUCCH that overlaps (including the retuning time) with uplink subframe N-1 on a different CC.

[0095] In some aspects, when a conflict occurs between the additional SRS and the next uplink transmission, the UE 602 may use a drop rule (in other words, a priority rule) at 612. As an example, Figure 8 A diagram 800 is shown illustrating example rules (such as drop rules) for resolving conflicts between additional SRS and the next uplink transmission. Figure 8 As illustrated in , SRS symbol 804a and SRS symbol 804b in the additional SRS overlap in time with the retuning time 806 for PUSCH 808. The UE 602 or the base station 604 may drop transmissions of the SRS symbol 804a and SRS symbol 804b according to an example drop rule.

[0096] Similarly, in some aspects, the schedule may instruct the UE 602 to avoid collisions between the additional SRS and the next uplink channel and may instruct the UE to use a drop rule for collisions between the additional SRS and the previous uplink transmission.

[0097] In some aspects, the schedule may instruct the UE 602 not to avoid collisions between the additional SRS and the previous or next uplink channel / signal and may instruct the UE to use a drop rule for collisions.

[0098] At 610, UE 602 may identify a collision. The UE may identify a collision based on determining that an uplink signal overlaps in time with an SRS or retuning time. UE 602 may drop or delay one or more additional SRS symbols based on scheduling and drop rules for resolving the collision.

[0099] In some aspects, the discard rule may define that hybrid automatic repeat request (HARQ) transmission, SR, RI / PTI / CRI, and physical random access channel (PRACH) take precedence over aperiodic SRS with carrier switching in the first SRS set, the aperiodic SRS takes precedence over aperiodic SRS with carrier switching in the additional SRS symbol, the aperiodic SRS takes precedence over aperiodic CSI, the aperiodic CSI takes precedence over periodic SRS with carrier switching in the first SRS set, the periodic SRS takes precedence over other CSI, the other CSI takes precedence over SRS without carrier switching. In some aspects, the discard rule may provide that if at least one symbol (including the retuning time) conflicts with a higher priority transmission, the entire additional SRS may be discarded. Alternatively, the discard rule may provide that a conflicting SRS symbol that conflicts with a higher priority transmission may be discarded.

[0100] In some aspects, UE 602 may be configured with SRS flexible timing. In some aspects, UE 602 may delay all first SRS symbol sets to the next SRS opportunity once in response to determining a conflict between an uplink transmission on a source CC and a first SRS symbol set at 610, wherein the SRS opportunity is a subframe set configured for aperiodic SRS transmission. After postponing the SRS, if there is a new conflict, the SRS may be discarded according to the discard rule. In such aspects, the UE may delay the aperiodic SRS on all additional SRS symbols to the next SRS opportunity once at 612 in response to determining a conflict between an uplink transmission on a source CC and an additional SRS symbol at 610. In some aspects, UE 602 may delay the aperiodic SRS on the additional SRS symbol subset that conflicts with the uplink transmission during a time duration including a retuning time and a transmission time for a higher priority uplink transmission, while transmitting the remaining non-overlapping SRS symbols. In some aspects, the UE 602 may discard all additional SRS symbols according to a discard rule. In some aspects, the UE 602 may discard the overlapping subset of SRS symbols and transmit the remaining non-overlapping SRS symbols.

[0101] For example, Fig. 9 A diagram 900 is shown illustrating the discarding rules for uplink collisions with flexible SRS timing. Fig. 9 As illustrated in , some of the additional SRS symbols at slots 5-13 collide with the HARQ acknowledgment transmission 904 because these additional SRS symbols overlap in time with the retuning time 902 for the HARQ acknowledgment transmission 904. As a result, the UE may start these additional SRS symbols in the next SRS opportunity.

[0102] In some aspects, at 608a, the base station may schedule the UE 602 to avoid a conflict between a downlink transmission on the source CC and an additional SRS symbol of an aperiodic SRS on the destination CC. The UE 602 may further receive, at 608b, a scheduling of an aperiodic SRS with an SRS switch from the source CC to the destination CC on an additional SRS symbol relative to the first SRS symbol set in the uplink subframe from the base station 604. The UE may then determine a conflict between a downlink transmission on the source CC and an additional SRS symbol of an aperiodic SRS on the destination CC. In some aspects, the scheduling may instruct the UE 602 to avoid a conflict between the additional SRS symbol and the previous PDSCH. In some aspects, the scheduling may instruct the UE 602 to avoid a conflict between the additional SRS symbol and the next PDCCH. In some aspects, the scheduling may instruct the UE 602 to avoid a conflict between the additional SRS symbol and the next PDCCH or the previous PDSCH. As an example, Fig.10A diagram 1000 is shown illustrating scheduling of downlink transmissions to avoid collisions with the next PDCCH 1004 and the previous PDSCH 1002. In some aspects, the scheduling may limit the symbols of the additional SRS to in the range of. is the number of symbols used for retuning. In some aspects, if a PDCCH on a different CC overlaps in time with an SRS transmission with carrier switching on additional SRS symbols (including any interruption due to uplink or downlink RF retuning time), and if the UE is not capable of receiving and transmitting on multiple CCs simultaneously, then the UE is not expected to monitor the PDCCH.

[0103] In some aspects, the schedule may indicate that the UE may not monitor the PDCCH or PDSCH in the subframes affected by the collision. In some aspects, if the additional SRS symbols may collide with the PDCCH, the schedule may indicate that the UE is not expected to be configured with a switch that will interrupt downlink reception in one or more subframes (such as subframes 0 / 5). For TDD CCs not configured for PUSCH / PUCCH transmission, if the UE is not capable of transmitting and receiving on multiple CCs simultaneously, it is not expected that the UE is configured with SRS resources such that SRS transmission on the additional SRS symbols may overlap in time with PDCCH monitoring in subframes 0 or 5 on a different cell (including any interruption caused by uplink or downlink RF re-tuning time).

[0104] In some aspects, the scheduling schedules communications with the UE 602 based on UE capabilities, including aperiodic SRS on additional SRS symbols.

[0105] Fig.11 A flow chart illustrating a wireless communication method 1100 performed at a base station to support scheduling of additional SRS to resolve uplink conflicts according to some aspects of the present disclosure is shown. The method may be performed by a base station or a component of a base station, such as base station 102, 180, 310, or 604; a processing system, which may include memory 376 and which may be the entire base station 310 or a component of the base station 310, such as TX processor 316, RX processor 370, or controller / processor 375. Fig.11 The method illustrated in may be performed by a base station in communication with a UE, such as UE 104, 350, or 602.

[0106] As illustrated in block 1102, the base station receives UE capabilities for SRS switching from a source CC to a destination CC for aperiodic SRS on additional SRS symbols relative to a first set of SRS symbols. For example, the receiving may be by Fig.18The receiving component 1830 or the UE capability component 1840 of the device 1802 in the embodiment of the present invention may be performed. The receiving at 1102 may include combining Figure 6 and Figures 7 to 10 606a. For example, the base station 604 may receive from the UE 602 a UE capability 606a for SRS switching from a source CC to a destination CC for a non-periodic SRS on an additional SRS symbol relative to a first set of SRS symbols. In some aspects, in the absence of explicit signaling, the UE capability depends on the UE type or scenario. For example, when the UE is an MTC (machine type communication) or NB-IoT (narrowband Internet of Things) type with bandwidth limitations, coverage enhancement, or low complexity, the UE cannot support additional SRS transmissions, and therefore the UE is not expected to be configured with SRS parameters for additional SRS. Another example is that when the UE is configured with multiple cellular cell groups for dual connectivity, the UE cannot support additional SRS transmissions, and therefore the UE is not expected to be configured with SRS parameters for additional SRS.

[0107] As illustrated in block 1104, the base station transmits a schedule that schedules the UE to avoid transmitting uplink transmissions on the source CC during a time duration that includes a retuning time for SRS switching and a transmission time for additional SRS symbols for transmitting aperiodic SRS on the destination CC. For example, the base station 604 may transmit a schedule that schedules the UE 602 to avoid transmitting uplink transmissions on the source CC during a time duration that includes a retuning time for SRS switching and a transmission time for additional SRS symbols for transmitting aperiodic SRS on the destination CC. In some aspects, the transmission may be performed by Fig.18 The scheduling is performed by a transmission component 1834 or a scheduling component 1844 of the device 1802 in the device 1802. In some aspects, the scheduling schedules the UE for an uplink channel that occurs before or after the additional SRS symbol on the source CC to avoid transmitting the uplink channel on the source CC when the additional SRS symbol is transmitted on the destination CC during a time duration that includes a retuning time for SRS switching. In some aspects, the scheduling indicates a restriction on limiting the transmission associated with the additional SRS symbol to a time range based on a number of retuning symbols for the retuning time for SRS switching.

[0108] In some aspects, the scheduling schedules uplink transmissions on the source CC to precede the additional SRS symbols. In some aspects, the scheduling indicates a restriction on limiting the additional SRS symbols to starting after the uplink transmissions on the source CC and the retuning time. In some aspects, the scheduling schedules uplink transmissions on the source CC to follow the additional SRS symbols. In some aspects, the scheduling indicates a restriction on limiting the uplink transmissions on the source CC to avoid time overlap between the additional SRS symbols and the retuning time and at least a portion of the uplink transmissions before or after the additional SRS symbols. The transmission at 1104 may include combining Figure 6 and Figures 7 to 10 The aspects described in 608a.

[0109] Fig.12 A flow chart illustrating a wireless communication method 1200 performed at a UE to support the scheduling of receiving additional SRS to resolve uplink conflicts according to some aspects of the present disclosure is shown. The method may be performed by: a UE or a component of a UE (such as UE 104, 350, or 602); a processing system, which may include a memory 360 and which may be the entire UE 350 or a component of the UE 350 (such as a TX processor 368, an RX processor 356, or a controller / processor 359). Fig.12 The method illustrated in may be performed by a UE in communication with a base station, such as base station 102, 180, 310, or 604.

[0110] As illustrated in block 1202, the UE transmits to the base station an indication of the UE's ability to transmit aperiodic SRS on additional SRS symbols relative to the first set of SRS symbols for SRS switching from a source CC to a destination CC. The transmission at 1202 may include combining Figure 6 and Figures 7 to 10 For example, UE 602 may transmit to base station 604 an indication of UE capability 606a for transmitting aperiodic SRS on additional SRS symbols relative to the first SRS symbol set for SRS switching from a source CC to a destination CC. In some aspects, the transmission may be by Fig.19 The UE capability component 1940 in the device 1902 is executed.

[0111] As illustrated in block 1204, the UE receives a schedule for communication with the base station based on the UE capabilities that avoids transmitting uplink transmissions on the source CC during a time duration that includes a retuning time for SRS switching and a transmission time for additional SRS symbols for transmitting aperiodic SRS on the destination CC. For example, the UE 602 may receive a schedule 608a / 608b for communication with the base station 604 based on the UE capabilities 606a / 606b that avoids transmitting uplink transmissions on the source CC during a time duration that includes a retuning time for SRS switching and a transmission time for additional SRS symbols for transmitting aperiodic SRS on the destination CC. The schedule may be Fig.19 The scheduling component 1942 or the receiving component 1930 of the device 1902 in the device 1902 is received. In some aspects, the scheduling schedules the UE to be used for an uplink channel that appears before or after the additional SRS codeword on the source CC to avoid transmitting the uplink channel on the source CC when the additional SRS codeword is transmitted on the destination CC during the time duration including the retuning time for SRS switching. In some aspects, the scheduling indicates a restriction on limiting the transmission associated with the additional SRS codeword to a time range based on the number of retuning codewords for the retuning time for SRS switching. In some aspects, the scheduling schedules the uplink transmission on the source CC to be before the additional SRS codeword. In some aspects, the scheduling indicates a restriction on limiting the additional SRS codeword to uplink transmission on the source CC and starting after the retuning time. In some aspects, the scheduling schedules the uplink transmission on the source CC to be after the additional SRS codeword. In some aspects, the scheduling indicates a restriction on limiting uplink transmissions on the source CC to avoid time overlap between the additional SRS symbol and the retuning time and at least a portion of the uplink transmissions before or after the additional SRS symbol. The receiving at 1204 may include combining Figure 6 and Figures 7 to 10 The aspects described in 608a.

[0112] Fig.13 A flowchart 1300 is shown illustrating a wireless communication method for supporting the dropping of additional SRS performed at a UE according to some aspects of the present disclosure. The method may be performed by: a UE or a component of a UE (such as UE 104, 350, or 602); a processing system, which may include a memory 360 and which may be the entire UE 350 or a component of the UE 350 (such as a TX processor 368, a RX processor 356, or a controller / processor 359). Fig.13 The method illustrated in may be performed by a UE in communication with a base station, such as base station 102, 180, 310, or 604.

[0113] As illustrated in block 1302, the UE receives an SRS configuration and a downlink transmission (such as a PDCCH) scheduling an uplink transmission, the uplink transmission being scheduled on a CC, the SRS configuration including one or more additional SRS symbols relative to a first SRS symbol set associated with an aperiodic trigger type 1 or a periodic trigger type 0, the one or more additional SRS symbols being scheduled on a destination CC, at least one of the one or more additional SRS symbols at least partially overlapping with the uplink transmission. The receiving at 1302 may include combining Figure 6 and Figures 7 to 10 For example, UE 602 may receive a downlink transmission of an SRS configuration and a scheduled uplink transmission on a source component carrier (CC) from base station 604. In some aspects, the reception may be performed by Fig.19 1902 of the device 1902. In some aspects, a license assisted access (LAA) UE, a bandwidth limited / coverage enhanced (BL / CE) UE, or a UE configured with multiple cell groups may not be configured with the one or more additional SRS symbols. In some aspects, the one or more additional SRS symbols may be type 2 SRS symbols, and the first set of SRS symbols may be type 1 SRS symbols. In some aspects, the UE may not be a LAA UE, a BL / CE UE, or a UE configured with multiple cell groups may not be configured with the one or more additional SRS symbols.

[0114] As illustrated in block 1304, the UE may drop or delay transmission of at least a portion of the SRS in the one or more additional SRS symbols on the destination CC or at least a portion of the uplink transmission on the source CC. For example, the UE 602 may drop or delay at least a portion of the SRS in the one or more additional SRS symbols on the destination CC or at least a portion of the uplink transmission on the source CC. In some aspects, the dropping or delaying may be caused by Fig.19 1902 in the device 1902. In some aspects, the UE may drop transmission of the SRS in the one or more additional SRS symbols based on the one or more additional SRS symbols on a first cell in a first subframe overlapping with a second subframe on a second serving cell, the first serving cell and the second serving cell being within the same set of serving cells. For example, the UE may not be triggered to transmit a type 2 SRS on serving cell d in a subframe N overlapping with an uplink subframe N-1 on a serving cell in the set S(d) (including any interruption due to uplink or downlink RF retuning time).

[0115] In some aspects, the UE may further use priority rules (such as in conjunction with Figure 6In some aspects, the UE discards the aperiodic SRS in the additional SRS symbol on the destination CC or at least a portion of the uplink transmission on the source CC according to the discarding rules described. In some aspects, the UE discards the aperiodic SRS in the additional SRS symbol on the destination CC if the uplink transmission includes at least one of the following: HARQ feedback, SR, RI, PTI, CSI-RS CRI, or RACH. In some aspects, the UE discards the uplink transmission if the uplink transmission includes at least one of the following: aperiodic channel state information (A-CSI), channel state information other than HARQ feedback, SR, RI, PTI or CRI, another SRS not on a CC with PUSCH or PUCCH, or a periodic SRS on a CC without PUSCH or PUCCH. In some aspects, the UE discards the aperiodic SRS in the additional SRS symbol on the destination CC if the uplink transmission includes at least one of the following: an aperiodic SRS not in the additional SRS symbol on another CC without PUSCH or PUCCH. In some aspects, the UE discards the uplink transmission if the uplink transmission includes at least one of the following: an aperiodic SRS that is not in an additional SRS symbol on a CC without PUSCH or PUCCH. In some aspects, the UE may further discard the aperiodic SRS on each additional SRS symbol in response to determining a time overlap between a higher priority uplink transmission on the source CC and the additional SRS symbol. In some aspects, the UE may further discard the aperiodic SRS on the additional SRS symbol that overlaps with a higher priority uplink transmission (including a retuning time for SRS switching from the source CC to the destination CC). In some aspects, if SRS flexible timing is configured for the UE, the UE delays the aperiodic SRS on each additional SRS symbol in response to determining a time overlap between an uplink transmission on the source CC and the additional SRS symbol. In some aspects, if SRS flexible timing is configured for a UE, the UE may delay aperiodic SRS on additional SRS symbols that overlap with a higher priority uplink transmission (including a retuning time for SRS switching from a source CC to a destination CC). In some aspects, if the UE discards aperiodic SRS on each additional SRS symbol in response to determining a time overlap between an uplink transmission on a source CC and an additional SRS symbol. In some aspects, if the UE discards aperiodic SRS on additional SRS symbols that overlap with a higher priority uplink transmission (including a retuning time for SRS switching from a source CC to a destination CC). In some aspects, if SRS flexible timing is configured for a first set of SRS symbols and not configured for the one or more additional SRS symbols, the UE discards transmission of SRS on the one or more additional SRS symbols.In some aspects, if SRS flexible timing is configured for the UE and uplink transmission on the source CC has a higher priority than the one or more additional SRS symbols, the UE drops transmission of SRS on the one or more additional SRS symbols.The dropping or delaying at 1304 may include combining. Figure 6 and Figures 7 to 10 The aspects described in 608a and 612.

[0116] Fig.14 A flow chart illustrating a wireless communication method 1400 performed at a base station to support scheduling of additional SRS to resolve downlink conflicts according to some aspects of the present disclosure is shown. The method may be performed by a base station or a component of a base station, such as base station 102, 180, 310, or 604; a processing system, which may include memory 376 and which may be the entire base station 310 or a component of the base station 310, such as TX processor 316, RX processor 370, or controller / processor 375. Fig.14 The method illustrated in may be performed by a base station in communication with a UE, such as UE 104, 350, or 602.

[0117] As illustrated in block 1402, the base station receives UE capabilities for SRS switching from a source CC to a destination CC for aperiodic SRS on additional SRS symbols relative to a first set of SRS symbols. For example, the receiving may be by Fig.18 The receiving component 1830 or UE capability component 1840 of the device 1802 in the embodiment of the present invention may be performed. In some aspects, the UE is not capable of receiving / transmitting in multiple CCs at the same time. The receiving at 1402 may include combining Figure 6 The aspects described in 606a.

[0118] As illustrated in block 1404, the base station transmits a schedule that schedules the UE to avoid transmitting downlink transmissions on the source CC during a time duration that includes a retuning time for SRS switching and a transmission time of additional SRS symbols for aperiodic SRS on the destination CC (including the retuning time for SRS switching). For example, the transmission may be by Fig.18The scheduling is performed by the transmission component 1834 or the scheduling component 1844 of the device 1802 in. In some aspects, the downlink transmission includes a PDSCH or a PDCCH. In some aspects, the scheduling schedules an uplink channel on the source CC for the UE to appear before or after the additional SRS codeword, and avoids the transmission of the uplink channel on the source CC when the additional SRS codeword is transmitted on the destination CC during a time duration including a retuning time for SRS switching. In some aspects, the scheduling includes a restriction on limiting the transmission associated with the additional SRS codeword to a time range based on the number of retuning codewords for the retuning time for SRS switching. In some aspects, the scheduling indicates an indication of limiting the additional SRS codeword including the retuning time for SRS switching to potentially interrupting the reception or monitoring of the downlink transmission in the defined resources. The transmission at 1404 may include a combination Figure 6 The aspects described in 608a.

[0119] Fig.15 A flow chart 1500 is shown illustrating a wireless communication method 1500 performed at a UE to support receiving scheduling of additional SRS to resolve downlink conflicts according to some aspects of the present disclosure. The method may be performed by a UE or a component of a UE (such as UE 104, 350, or 602); a processing system, which may include a memory 360 and which may be the entire UE 350 or a component of the UE 350 (such as a TX processor 368, a RX processor 356, or a controller / processor 359). Fig.15 The method illustrated in may be performed by a UE in communication with a base station, such as base station 102, 180, 310, or 604.

[0120] As illustrated in block 1502, the UE receives a schedule for a downlink transmission on a source CC. In some aspects, the downlink transmission includes a PDSCH or a PDCCH. In some aspects, the UE is not capable of receiving / transmitting in multiple CCs simultaneously. The reception at 1502 may include combining Figure 6 The scheduling can be performed by Fig.19 The scheduling component 1942 or the receiving component 1930 of the device 1902 is received.

[0121] As illustrated in block 1504, the UE receives a schedule for aperiodic SRS with SRS switching from a source CC to a destination CC on an additional SRS symbol for the first set of SRS symbols. The receiving at 1504 may include combining Figure 6 The scheduling can be performed by Fig.19 The scheduling component 1942 or the receiving component 1930 of the device 1902 is received.

[0122] As illustrated in block 1506, the UE determines a time overlap between a transmission time of a downlink transmission on the source CC and a time duration of a transmission time of an additional SRS symbol including an aperiodic SRS on the destination CC and a retuning time for SRS switching. The UE may not monitor downlink transmissions in a subframe including the time overlap. The determination at 1506 may include combining Figure 6 For example, the overlap may be caused by Fig.19 The overlapping component 1944 of the device 1902 in is determined.

[0123] Fig.16 A flow chart illustrating a wireless communication method 1600 performed at a base station to support scheduling of additional SRSs according to some aspects of the present disclosure is shown. The method may be performed by a base station or a component of a base station, such as base station 102, 180, 310, or 604; a processing system, which may include memory 376 and which may be the entire base station 310 or a component of the base station 310, such as TX processor 316, RX processor 370, or controller / processor 375. Fig.16 The method illustrated in may be performed by a base station in communication with a UE, such as UE 104, 350, or 602.

[0124] As illustrated in block 1602, the base station receives UE capabilities for SRS switching and a retuning time from a source CC to a destination CC for aperiodic SRS with carrier switching on additional SRS symbols relative to a first set of SRS symbols. For example, the receiving may be performed by Fig.18 The base station may further receive additional UE capabilities for aperiodic SRS without carrier switching on additional SRS symbols. In some aspects, the UE may be a LAA UE. In some aspects, the UE capabilities indicate whether the UE supports aperiodic SRS with carrier switching on additional SRS symbols for a frequency band combination. In some aspects, the UE capabilities indicate whether the UE supports aperiodic SRS with carrier switching on additional SRS symbols for a frequency band pair of a frequency band combination. In some aspects, the UE capabilities indicate whether the UE supports general capabilities for aperiodic SRS with carrier switching on additional SRS symbols. In some aspects, the UE capabilities indicate whether the UE supports aperiodic SRS with carrier switching on additional SRS symbols without reference to a frequency band combination or a frequency band pair. The reception at 1602 may include combining Figure 6 All aspects described.

[0125] As illustrated in block 1604, the base station transmits a schedule that schedules communications with the UE based on UE capabilities, including aperiodic SRS on additional SRS symbols. For example, the transmission may be by Fig.18 1802 of the device 1802. In some aspects, if the carrier used for dual connectivity is configured with aperiodic SRS with carrier switching on additional SRS symbols, the base station disables SRS carrier switching. In some aspects, the base station determines that a low complexity (BL) / coverage enhanced (CE) UE with reduced bandwidth does not support aperiodic SRS with carrier switching on additional SRS symbols. In some aspects, the base station determines that the BL / CE UE supports aperiodic SRS without carrier switching on additional SRS symbols but does not support aperiodic SRS with carrier switching on additional SRS symbols. In some aspects, the base station determines that a BL / CE UE in CE mode B (CEMode B) does not support aperiodic SRS on additional SRS symbols. In some aspects, a dual connectivity UE may not support additional SRS with carrier switching, and SRS carrier switching on such UEs may be disabled. Alternatively, the transmission of the additional SRS may be disabled during carrier switching. The transmission at 1604 includes combining Figure 6 All aspects described.

[0126] Fig.17 A flow chart illustrating a wireless communication method 1700 for supporting scheduling of additional SRSs performed at a UE according to some aspects of the present disclosure is shown. The method may be performed by: a UE or a component of a UE (such as UE 104, 350, or 602); a processing system, which may include a memory 360 and which may be the entire UE 350 or a component of the UE 350 (such as a TX processor 368, an RX processor 356, or a controller / processor 359). Fig.17 The method illustrated in may be performed by a UE in communication with a base station, such as base station 102, 180, 310, or 604.

[0127] As illustrated in block 1702, the UE may transmit an indication of support for a carrier switching capability for transmitting aperiodic SRS on one or more additional SRS symbols relative to a first SRS symbol set associated with aperiodic trigger type 1 or periodic trigger type 0, the one or more additional SRS symbols being associated with an SRS switch from a source component carrier CC to a destination CC and being on the destination CC. For example, UE 602 may transmit an indication of support for a carrier switching capability (UE capability 606a / 606b) for transmitting aperiodic SRS on one or more additional SRS symbols relative to a first SRS symbol set associated with aperiodic trigger type 1 or periodic trigger type 0, the one or more additional SRS symbols being associated with an SRS switch from a source component carrier CC to a destination CC and being on the destination CC. The UE may be a LAA UE. The transmission at 1702 may include in conjunction with Figure 6In some aspects, the transmission may be performed by Fig.19 The UE capability component 1940 in the device 1902 is executed.

[0128] In some aspects, the indication indicates whether the UE supports aperiodic SRS with carrier switching on additional SRS symbols for a band combination. In some aspects, the indication indicates whether the UE supports aperiodic SRS with carrier switching on additional SRS symbols for a band pair of the band combination. In some aspects, the indication indicates whether the UE supports a general capability for aperiodic SRS with carrier switching on additional SRS symbols. In some aspects, the indication is indicated without a reference band combination. In some aspects, the indication indicates that the UE does not support aperiodic SRS with carrier switching on one or more additional SRS symbols in a license-assisted access carrier.

[0129] As illustrated in block 1704, the UE receives a schedule for communications with the base station based on the carrier switching capability, including the aperiodic SRS on the one or more additional SRS symbols. The receiving at 1704 may include combining Figure 6 The scheduling can be performed by Fig.19 The scheduling component 1942 or the receiving component 1930 of the device 1902 is received.

[0130] Fig.18 1800 is an example of a hardware implementation of an illustrated device 1802. The device 1802 is a BS and includes a baseband unit 1804. The baseband unit 1804 can communicate with the UE 104 via a cellular RF transceiver. The baseband unit 1804 may include a computer-readable medium / memory. The baseband unit 1804 is responsible for general processing, including the execution of software stored on the computer-readable medium / memory. The software, when executed by the baseband unit 1804, causes the baseband unit 1804 to perform the various functions described above. The computer-readable medium / memory may also be used to store data manipulated by the baseband unit 1804 when executing the software. The baseband unit 1804 further includes a receiving component 1830, a communication manager 1832, and a transmission component 1834. The communication manager 1832 includes the one or more illustrated components. The components within the communication manager 1832 may be stored in a computer-readable medium / memory or configured as hardware within the baseband unit 1804. The baseband unit 1804 may be a component of the BS 310 and may include the memory 376 or at least one of the following: the TX processor 316 , the RX processor 370 , and the controller / processor 375 .

[0131] The communication manager 1832 includes a UE capability component 1840 and a scheduling component 1844, which can be configured to perform a combined Fig.11 , 14 Or any aspects described in any of 16.

[0132] The apparatus may include executing Fig.11 , 14 or 16. Thus, Fig.11 , 14 Each block in the aforementioned flow chart of 16 may be performed by a component and the device may include one or more of those components. These components may be one or more hardware components specifically configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0133] In one configuration, the device 1802 (and specifically the baseband unit 1804) includes a Fig.11 , Fig.14 or Fig.16 The aforementioned means may be one or more of the aforementioned components in the device 1802 configured to perform the functions recited by the aforementioned means. As described above, the device 1802 may include the TX processor 316, the RX processor 370, and the controller / processor 375. Thus, in one configuration, the aforementioned means may be the TX processor 316, the RX processor 370, and the controller / processor 375 configured to perform the functions recited by the aforementioned means.

[0134] Fig.191900 is an example of a hardware implementation of an illustrated device 1902. The device 1902 is a UE and includes a cellular baseband processor 1904 (also referred to as a modem) coupled to a cellular RF transceiver 1922 and one or more subscriber identity modules (SIM) cards 1920, an application processor 1906 coupled to a secure digital (SD) card 1906 and a screen 1910, a Bluetooth module 1912, a wireless local area network (WLAN) module 1914, a global positioning system (GPS) module 1916, and a power supply 1918. The cellular baseband processor 1904 communicates with the UE 104 or BS 102 / 180 through the cellular RF transceiver 1922. The cellular baseband processor 1904 may include a computer-readable medium / memory. The cellular baseband processor 1904 is responsible for general processing, including the execution of software stored on a computer-readable medium / memory. The software, when executed by the cellular baseband processor 1904, causes the cellular baseband processor 1904 to perform the various functions described above. The computer-readable medium / memory may also be used to store data manipulated by the cellular baseband processor 1904 when executing software. The cellular baseband processor 1904 further includes a receiving component 1930, a communication manager 1932, and a transmission component 1934. The communication manager 1932 includes the one or more illustrated components. The components within the communication manager 1932 may be stored in a computer-readable medium / memory or configured as hardware within the cellular baseband processor 1904. The cellular baseband processor 1904 may be a component of the UE 350 and may include the memory 360 or at least one of the following: the TX processor 368, the RX processor 356, and the controller / processor 359. In one configuration, the device 1902 may be a modem chip and include only the baseband processor 1904, and in another configuration, the device 1902 may be an entire UE (such as a Figure 3 350) and includes additional modules of device 1902.

[0135] The communication manager 1932 includes a Fig.12 , Fig.13 , Fig.15 or Fig.17 A UE capabilities component 1940, a scheduling component 1942, an overlapping component 1944, and a determining component 1946 of the described aspects.

[0136] The device may include executing Fig.12 , Fig.13 , Fig.15 or Fig.17 The additional components of each box of the algorithm in the preceding flowchart. Thus, Fig.12 , Fig.13 , Fig.15 or Fig.17Each block in the aforementioned flow chart may be performed by a component and the device may include one or more of those components. These components may be one or more hardware components specifically configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0137] In one configuration, the device 1902 (and specifically the cellular base station processor 1904) includes a processor for performing a combined Fig.12 , Fig.13 , Fig.15 or Fig.17 The aforementioned means may be one or more of the aforementioned components in the device 1902 configured to perform the functions recited by the aforementioned means. As described above, the device 1902 may include a TX processor 368, an RX processor 356, and a controller / processor 359. Thus, in one configuration, the aforementioned means may be a TX processor 368, an RX processor 356, and a controller / processor 359 configured to perform the functions recited by the aforementioned means.

[0138] The specific order or hierarchy of the various boxes in the disclosed process / flowcharts is an illustration of an example approach. Based on design preferences, the specific order or hierarchy of the various boxes in these process / flowcharts can be rearranged. In addition, some boxes can be combined or omitted. The attached method claims present the elements of the various boxes in an exemplary order and are not meant to be limited to the specific order or hierarchy presented.

[0139] The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be easily understood by those skilled in the art, and the universal principles defined in this article can be applied to other aspects. The claims are not intended to be limited to the aspects shown in this article, but should be granted the full scope consistent with the claims in language, and the citation of the singular form of the elements is not intended to represent "there is and only one", but "one or more". Unless otherwise stated, the term "some / certain" refers to one or more. Combinations such as "at least one of A, B or C", "one or more of A, B or C", "at least one of A, B and C", "one or more of A, B and C", and "A, B, C or any combination thereof" include any combination of A, B or C, and may include multiple A, multiple B or multiple C. Specifically, combinations such as "at least one of A, B, or C", "one or more of A, B, or C", "at least one of A, B and C", "one or more of A, B, and C", and "A, B, C, or any combination thereof" may be only A, only B, only C, A and B, A and C, B and C, or A and B and C, wherein any such combination may include one or more members of A, B, or C. The term "or" may mean "or". For example, "A, B, or C" may include any combination of A, B, or C as described above. All structural and functional equivalents of the elements of the various aspects described throughout the present disclosure that are currently or hereafter known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly stated in the claims. The terms "module", "mechanism", "element", "device", etc. may not be a substitute for the term "device". Thus, no claim element should be construed as means-plus-function unless the element is explicitly recited using the phrase "means for."

[0140] The following examples are merely illustrative and may be combined with other aspects or teachings described herein without limitation.

[0141] Aspect 1 is a method for wireless communication at a base station, comprising: receiving UE capability for SRS switching from a source CC to a destination CC for a non-periodic SRS on an additional SRS symbol relative to a first SRS symbol set in an uplink subframe; and transmitting a schedule that schedules the UE to avoid transmitting uplink transmissions on the source CC during a time duration that includes a retuning time for the SRS switching and a transmission time for transmitting the additional SRS symbol for the non-periodic SRS on the destination CC.

[0142] Aspect 2 is the method of aspect 1, wherein the scheduling schedules the UE for an uplink channel that appears before or after the additional SRS codeword on the source CC to avoid transmitting the uplink channel on the source CC when the additional SRS codeword is transmitted on the destination CC during a time duration including a retuning time for SRS switching.

[0143] Aspect 3 is the method of any one of aspects 1-2, wherein the scheduling indication limits transmission associated with the additional SRS symbol to a time range based on a number of retuning symbols for the SRS switching.

[0144] Aspect 4 is the method of any one of aspects 1-3, wherein the scheduling schedules uplink transmission on the source CC to precede the additional SRS symbol.

[0145] Aspect 5 is the method of any one of aspects 1-4, wherein the scheduling indication is about limiting the additional SRS symbols to start after the uplink transmission on the source CC and the retuning time.

[0146] Aspect 6 is the method of any one of aspects 1-5, wherein the scheduling schedules uplink transmission on the source CC to follow the additional SRS symbol.

[0147] Aspect 7 is the method of any one of aspects 1-6, wherein the scheduling indication is a restriction on limiting uplink transmission on the source CC to avoid time overlap between the additional SRS codeword and the retuning time and at least a portion of the uplink transmission before or after the additional SRS codeword.

[0148] Aspect 8 is a method for performing wireless communications at a UE, comprising: transmitting to a base station an indication of the UE capability of transmitting a non-periodic SRS on an additional SRS symbol relative to a first SRS symbol set in an uplink subframe for SRS switching from a source CC to a destination CC; and receiving a schedule for communication with the base station based on the UE capability, the schedule avoiding transmitting uplink transmissions on the source CC during a time duration including a retuning time for the SRS switching and a transmission time for transmitting an additional SRS symbol for transmitting the non-periodic SRS on the destination CC.

[0149] Aspect 9 is the method of aspect 8, wherein the scheduling schedules the UE for an uplink channel that appears before or after the additional SRS codeword on the source CC to avoid transmitting the uplink channel on the source CC when the additional SRS codeword is transmitted on the destination CC during a time duration including a retuning time for SRS switching.

[0150] Aspect 10 is the method of any of aspects 8-9, wherein the schedule indicates a restriction on limiting transmission associated with the additional SRS symbol to within a time range based on a number of retuning symbols for a retuning time for SRS switching.

[0151] Aspect 11 is the method of any one of aspects 8-10, wherein the scheduling schedules uplink transmission on the source CC to precede the additional SRS symbols.

[0152] Aspect 12 is the method of any one of aspects 8-11, wherein the scheduling indication is about limiting the additional SRS symbols to start after the uplink transmission on the source CC and the retuning time.

[0153] Aspect 13 is the method of any one of aspects 8-12, wherein the scheduling schedules uplink transmission on the source CC to follow the additional SRS symbol.

[0154] Aspect 14 is the method of any one of aspects 8-13, wherein the scheduling indication is a restriction on limiting uplink transmission on the source CC to avoid time overlap between the additional SRS codeword and the retuning time and at least a portion of the uplink transmission before or after the additional SRS codeword.

[0155] Aspect 15 is a method for performing wireless communications at a base station, comprising: receiving a UE capability for SRS switching from a source CC to a destination CC for a non-periodic SRS on an additional SRS symbol relative to a first SRS symbol set in an uplink subframe; and transmitting a schedule that schedules the UE to avoid transmitting downlink transmissions on the source CC during a time duration that includes a retuning time for the SRS switching and a transmission time for transmitting additional SRS symbols for the non-periodic SRS on the destination CC (including the retuning time for the SRS switching).

[0156] Aspect 16 is the method of aspect 15, wherein the downlink transmission includes PDSCH or PDCCH.

[0157] Aspect 17 is a method of any one of Aspects 15-16, wherein the scheduling is for the UE to schedule an uplink channel that appears before or after the additional SRS codeword on the source CC, and avoid transmitting the uplink channel on the source CC when the additional SRS codeword is transmitted on the destination CC during a time duration including a retuning time for SRS switching.

[0158] Aspect 18 is the method of any of aspects 15-17, wherein the scheduling includes a restriction on limiting transmission associated with the additional SRS symbol to within a time range based on a number of retuning symbols for a retuning time for SRS switching.

[0159] Aspect 19 is the method of any one of aspects 15-18, wherein the scheduling indication limits the additional SRS symbols including the re-tuning time for SRS switching to potentially interrupting the reception or monitoring of downlink transmissions in the predefined resources.

[0160] Aspect 20 is the method of any one of aspects 15-19, wherein the UE is unable to receive / transmit in multiple CCs simultaneously.

[0161] Aspect 21 is a method for performing wireless communications at a base station, comprising: receiving UE capabilities for SRS switching and a retuning time from a source CC to a destination CC for a non-periodic SRS with carrier switching on an additional SRS symbol relative to a first SRS symbol set; and scheduling communications with the UE based on the UE capabilities, the communications including the non-periodic SRS on the additional SRS symbol.

[0162] Aspect 22 is the method of aspect 21, further comprising: receiving additional UE capabilities for aperiodic SRS without carrier switching on additional SRS symbols.

[0163] Aspect 23 is the method of any one of Aspects 21-22, wherein the UE comprises a LAA UE.

[0164] Aspect 24 is the method of any one of aspects 21-23, wherein the UE capability indicates whether the UE supports aperiodic SRS with carrier switching on additional SRS symbols for the frequency band combination.

[0165] Aspect 25 is the method of any one of aspects 21-24, wherein the UE capability indicates whether the UE supports aperiodic SRS with carrier switching on an additional SRS symbol for a band pair of the band combination.

[0166] Aspect 26 is the method of any one of aspects 21-25, wherein the UE capability indicates whether the UE supports a general capability for aperiodic SRS with carrier switching on additional SRS symbols.

[0167] Aspect 27 is the method of any one of aspects 21-26, wherein the UE capability indicates whether the UE supports aperiodic SRS with carrier switching on additional SRS symbols without reference to a band combination or a band pair.

[0168] Aspect 28 is the method of any one of aspects 21-27, further comprising: disabling SRS carrier switching if the carrier used for dual connectivity is configured with aperiodic SRS with carrier switching on additional SRS symbols.

[0169] Aspect 29 is the method of any one of aspects 21-28, wherein the base station determines that the BL / CE UE does not support aperiodic SRS with carrier switching on the additional SRS symbol.

[0170] Aspect 30 is the method of any one of aspects 21-29, wherein the base station determines that the BL / CE UE supports aperiodic SRS without carrier switching on the additional SRS symbols but does not support aperiodic SRS with carrier switching on the additional SRS symbols.

[0171] Aspect 31 is the method of any one of aspects 21-30, wherein the base station determines that the BL / CE UE in CE mode B does not support aperiodic SRS on the additional SRS symbol.

[0172] Aspect 32 is a method for performing wireless communications at a UE, comprising: receiving a downlink transmission of an SRS configuration and a scheduled uplink transmission, the uplink transmission being scheduled on a CC, the SRS configuration comprising one or more additional SRS symbols relative to a first SRS symbol set associated with a non-periodic trigger type 1 or a periodic trigger type 0, the one or more additional SRS symbols being scheduled on a destination CC, at least one of the one or more additional SRS symbols at least partially overlapping with the uplink transmission; and discarding or delaying transmission of at least a portion of the SRS in the one or more additional SRS symbols on the destination CC or at least a portion of the uplink transmission on the source CC.

[0173] Aspect 33 is a method of aspect 32, wherein the UE discards transmission of the SRS in the one or more additional SRS symbols based on the one or more additional SRS symbols on a first service cell in a first subframe overlapping with a second subframe on a second service cell, and the first service cell and the second service cell are within the same service cell set.

[0174] Aspect 34 is the method of any of aspects 32-33, further comprising: using a priority rule to determine whether to discard at least a portion of the SRS in the one or more additional SRS symbols on the destination CC or at least a portion of the uplink transmission on the source CC.

[0175] Aspect 35 is a method of any one of Aspects 32-34, wherein the UE drops transmission of the SRS in the one or more additional SRS symbols on the destination CC based on the uplink transmission including at least one of: HARQ feedback, SR, RI, PTI, CSI-RS CRI, or RACH.

[0176] Aspect 36 is a method of any one of Aspects 32-35, wherein the UE discards the uplink transmission based on the uplink transmission including at least one of the following: A-CSI, channel state information other than HARQ feedback, SR, RI, PTI, or CRI, another SRS not on a CC with PUSCH or PUCCH, or periodic SRS on a CC without PUSCH or PUCCH.

[0177] Aspect 37 is a method of any one of Aspects 32-36, wherein the UE discards transmission of the SRS in the one or more additional SRS symbols on the destination CC based on the uplink transmission including: a non-periodic SRS that is not in the one or more additional SRS symbols on another CC without PUSCH or PUCCH.

[0178] Aspect 38 is the method of any one of aspects 32-37, wherein the UE drops the uplink transmission based on the uplink transmission including: a non-periodic SRS that is not in the one or more additional SRS symbols on a CC without PUSCH or PUCCH.

[0179] Aspect 39 is the method of any one of aspects 32-38, further comprising: discarding the transmission of the SRS on the one or more additional SRS symbols, wherein the uplink transmission on the source CC has a higher priority than the one or more additional SRS symbols.

[0180] Aspect 40 is the method of any one of aspects 32-39, further comprising: dropping transmission of the SRS on the one or more additional SRS symbols, wherein uplink transmission on the source CC has a higher priority than the one or more additional SRS symbols.

[0181] Aspect 41 is the method of any one of aspects 32-40, wherein if SRS flexible timing is configured for the first set of SRS symbols and is not configured for the one or more additional SRS symbols, the UE drops transmission of the SRS on the one or more additional SRS symbols.

[0182] Aspect 42 is the method of any one of aspects 32-41, wherein if SRS flexible timing is configured for the UE and uplink transmission on the source CC has a higher priority than the one or more additional SRS symbols, the UE drops transmission of the SRS on the one or more additional SRS symbols.

[0183] Aspect 43 is the method of any one of aspects 32-42, wherein the UE drops transmission of the SRS on the one or more additional SRS symbols based on uplink transmission on the source CC having a higher priority than the one or more additional SRS symbols.

[0184] Aspect 44 is a method for wireless communication at a UE, comprising: transmitting an indication of support for a carrier switching capability for transmitting a non-periodic SRS on one or more additional SRS symbols relative to a first SRS symbol set associated with a non-periodic trigger type 1 or a periodic trigger type 0, the one or more additional SRS symbols being associated with an SRS switch from a source CC to a destination CC and being on the destination CC; and receiving a schedule for communication with a base station based on the carrier switching capability, the communication including the non-periodic SRS on the one or more additional SRS symbols.

[0185] Aspect 45 is the method of aspect 44, wherein the indication indicates whether the UE supports a general capability of aperiodic SRS with carrier switching on the one or more additional SRS symbols, the general capability not referencing a frequency band combination.

[0186] Aspect 46 is the method of any one of aspects 44-45, wherein the indication indicates that the UE does not support aperiodic SRS with carrier switching on the one or more additional SRS symbols in the license-assisted access carrier.

[0187] Aspect 47 is a device at a base station, comprising: at least one processor; and at least one memory communicatively coupled to the at least one processor and storing processor-readable code, which, when executed by the at least one processor, is configured to cause the base station to perform any one of the methods of Aspects 1-7.

[0188] Aspect 48 is the apparatus of Aspect 47, further comprising a transceiver.

[0189] Aspect 49 is a device at a UE, comprising: at least one processor; and at least one memory communicatively coupled to the at least one processor and storing processor-readable code, which, when executed by the at least one processor, is configured to cause the UE to perform any method of Aspects 8-14.

[0190] Aspect 50 is the apparatus of Aspect 49, further comprising a transceiver.

[0191] Aspect 51 is a device at a base station, comprising: at least one processor; and at least one memory communicatively coupled to the at least one processor and storing processor-readable code, which, when executed by the at least one processor, is configured to cause the base station to perform a method of any one of Aspects 15-20.

[0192] Aspect 52 is the apparatus of Aspect 51, further comprising a transceiver.

[0193] Aspect 53 is a device at a base station, comprising: at least one processor; and at least one memory communicatively coupled to the at least one processor and storing processor-readable code, which, when executed by the at least one processor, is configured to cause the base station to perform a method of any one of Aspects 21-31.

[0194] Aspect 54 is the apparatus of Aspect 51, further comprising a transceiver.

[0195] Aspect 55 is a device at a UE, comprising: at least one processor; and at least one memory communicatively coupled to the at least one processor and storing processor-readable code, which, when executed by the at least one processor, is configured to cause the UE to perform a method of any one of Aspects 32-43.

[0196] Aspect 56 is the apparatus of Aspect 55, further comprising a transceiver.

[0197] Aspect 57 is a device at a UE, comprising: at least one processor; and at least one memory communicatively coupled to the at least one processor and storing processor-readable code, which, when executed by the at least one processor, is configured to cause the UE to perform a method of any one of Aspects 44-46.

[0198] Aspect 58 is the apparatus of Aspect 57, further comprising a transceiver.

[0199] Aspect 59 is an apparatus at a base station, comprising means for performing the method of any one of aspects 1-7.

[0200] Aspect 60 is the apparatus of aspect 59, further comprising a transceiver.

[0201] Aspect 61 is an apparatus at a UE, comprising means for performing the method of any one of aspects 8-14.

[0202] Aspect 62 is the apparatus of Aspect 61, further comprising a transceiver.

[0203] Aspect 63 is an apparatus at a base station, comprising means for performing the method of any one of aspects 15-20.

[0204] Aspect 64 is the apparatus of Aspect 63, further comprising a transceiver.

[0205] Aspect 65 is an apparatus at a base station, comprising means for performing the method of any one of aspects 21-31.

[0206] Aspect 66 is the apparatus of Aspect 65, further comprising a transceiver.

[0207] Aspect 67 is an apparatus at a UE, comprising means for performing the method of any one of aspects 32-43.

[0208] Aspect 68 is the apparatus of Aspect 67, further comprising a transceiver.

[0209] Aspect 69 is an apparatus at a UE, comprising means for performing the method of any one of aspects 44-46.

[0210] Aspect 70 is the apparatus of aspect 69, further comprising a transceiver.

[0211] Aspect 71 is a computer readable medium storing computer executable code, wherein the code, when executed by a processor, causes the processor to perform the method of any one of aspects 1-7.

[0212] Aspect 72 is a computer readable medium storing computer executable code, wherein the code, when executed by a processor, causes the processor to perform the method of any one of aspects 8-14.

[0213] Aspect 73 is a computer readable medium storing computer executable code, wherein the code, when executed by a processor, causes the processor to perform the method of any one of aspects 15-20.

[0214] Aspect 74 is a computer readable medium storing computer executable code, wherein the code, when executed by a processor, causes the processor to perform the method of any one of aspects 21-31.

[0215] Aspect 75 is a computer readable medium storing computer executable code, wherein the code, when executed by a processor, causes the processor to perform the method of any one of aspects 32-43.

[0216] Aspect 76 is a computer readable medium storing computer executable code, wherein the code, when executed by a processor, causes the processor to perform the method of any one of aspects 44-46.

Claims

1. A method of wireless communication at a user equipment (UE), include: receiving a sounding reference signal (SRS) configuration and a downlink transmission scheduling an uplink transmission, the uplink transmission being scheduled on a source component carrier (CC), the SRS configuration comprising one or more additional SRS symbols relative to a first set of SRS symbols associated with an aperiodic trigger type 1 or a periodic trigger type 0, the one or more additional SRS symbols being scheduled on a destination CC, at least one of the one or more additional SRS symbols at least partially overlapping with the uplink transmission, the one or more additional SRS symbols being scheduled on a first serving cell in a first subframe overlapping with a second subframe on a second serving cell, the first subframe being subframe N and the second subframe being subframe N+1, the first serving cell and the second serving cell being within the same serving cell set; as well as Transmission of at least a portion of the SRS in the one or more additional SRS symbols on the destination CC or at least a portion of the uplink transmission on the source CC is dropped based on a priority rule, wherein the priority rule is determined based on a type of the uplink transmission.

2. The method according to claim 1, in, The UE drops transmission of the SRS in the one or more additional SRS symbols on the destination CC based on the uplink transmission comprising at least one of: Hybrid Automatic Repeat Request (HARQ) feedback, Scheduling Request (SR), Rank Indicator (RI), Precoder Type Indicator (PTI), Channel State Information Reference Signal (CSI-RS) Resource Indicator (CRI), or Random Access Channel (RACH).

3. The method according to claim 1, in, The UE discards the uplink transmission based on the uplink transmission comprising at least one of: Aperiodic channel state information (A-CSI), Channel state information other than hybrid automatic repeat request (HARQ) feedback, SR, RI, PTI or CRI, another SRS that is not on a CC including the Physical Uplink Shared Channel (PUSCH) or the Physical Uplink Control Channel (PUCCH), or A periodic SRS on a CC without the PUSCH or the PUCCH.

4. The method according to claim 1, in, The UE discards transmission of the SRS in the one or more additional SRS symbols on the destination CC based on the uplink transmission including: a non-periodic SRS that is not in the one or more additional SRS symbols on another CC without a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH).

5. The method according to claim 1, in, The UE drops the uplink transmission based on the uplink transmission comprising: an aperiodic SRS that is not in the one or more additional SRS symbols on a CC without a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH).

6. The method of claim 1, wherein the uplink transmission on the source CC has a higher priority than the one or more additional SRS symbols.

7. The method according to claim 1, in, The UE drops transmission of the SRS in the one or more additional SRS symbols based on SRS flexible timing being configured for the first set of SRS symbols and not configured for the one or more additional SRS symbols.

8. The method according to claim 1, in, If SRS flexible timing is configured for the UE and the uplink transmission on the source CC has a higher priority than the one or more additional SRS symbols, the UE drops transmission of the SRS in the one or more additional SRS symbols.

9. The method according to claim 1, in, The UE drops transmission of the SRS in the one or more additional SRS symbols based on the uplink transmission on the source CC having a higher priority than the one or more additional SRS symbols.

10. An apparatus for wireless communication at a user equipment (UE), include: A device for wireless communication at a base station, comprising: at least one processor; and at least one memory communicatively coupled to the at least one processor and storing processor-readable code, the processor-readable code being configured, when executed by the at least one processor, to cause the UE to: receiving a sounding reference signal (SRS) configuration and a downlink transmission scheduling an uplink transmission, the uplink transmission being scheduled on a component carrier (CC), the SRS configuration comprising one or more additional SRS symbols relative to a first set of SRS symbols associated with an aperiodic trigger type 1 or a periodic trigger type 0, the one or more additional SRS symbols being scheduled on a destination CC, at least one of the one or more additional SRS symbols at least partially overlapping with the uplink transmission, the one or more additional SRS symbols being scheduled on a first serving cell in a first subframe overlapping with a second subframe on a second serving cell, the first subframe being subframe N and the second subframe being subframe N+1, the first serving cell and the second serving cell being within the same serving cell set; and Transmission of at least a portion of the SRS in the one or more additional SRS symbols on the destination CC or at least a portion of the uplink transmission on the source CC is discarded based on a priority rule, wherein the priority rule is determined based on a type of the uplink transmission.

11. The device according to claim 10, in, The at least one processor is configured to drop transmission of the SRS in the one or more additional SRS symbols on the destination CC based on the uplink transmission comprising at least one of: Hybrid Automatic Repeat Request (HARQ) feedback, Scheduling Request (SR), Rank Indicator (RI), Precoder Type Indicator (PTI), Channel State Information Reference Signal (CSI-RS) Resource Indicator (CRI), or Random Access Channel (RACH).

12. The device according to claim 10, in, The at least one processor is configured to drop transmission of the uplink transmission based on the uplink transmission comprising at least one of: Aperiodic channel state information (A-CSI), Channel state information other than hybrid automatic repeat request (HARQ) feedback, SR, RI, PTI or CRI, another SRS that is not on a CC including the Physical Uplink Shared Channel (PUSCH) or the Physical Uplink Control Channel (PUCCH), or A periodic SRS on a CC without the PUSCH or the PUCCH.

13. The device according to claim 10, in, The at least one processor is configured to discard transmission of the SRS in the one or more additional SRS symbols on the destination CC based on the uplink transmission including: a non-periodic SRS that is not in the one or more additional SRS symbols on another CC without a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH).

14. The device according to claim 10, in, The at least one processor is configured to drop transmission of the uplink transmission based on the uplink transmission comprising: an aperiodic SRS that is not in the one or more additional SRS symbols on a CC without a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH).

15. The device according to claim 10, in, The at least one processor is configured to drop transmission of the SRS in the one or more additional SRS symbols, wherein the uplink transmission on the source CC has a higher priority than the one or more additional SRS symbols.

16. The device according to claim 10, in, The UE that is not a license assisted access (LAA) UE, a bandwidth limited / coverage enhanced (BL / CE) UE, or a UE configured with multiple cell groups will not be configured with the one or more additional SRS symbols.

17. The device according to claim 10, in, The at least one processor is configured to delay transmission of the SRS on the one or more additional SRS symbols based on SRS flexible timing being configured for the UE and the uplink transmission on the source CC having a higher priority than the one or more additional SRS symbols.

18. The device according to claim 10, in, The UE does not include a assisted access (LAA) UE, a bandwidth limited / coverage enhanced (BL / CE) UE, or a UE configured with multiple cell groups.

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