Patent Publication Number: US-2023163912-A1

Title: Repetition and time domain cover code based sounding reference signal resources for antenna switching

Description:
CROSS REFERENCE 
     The present Application is a 371 national stage filing of International PCT Application No. PCT/CN2020/074324 by ABDELGHAFFAR et al. entitled “REPETITION AND TIME DOMAIN COVER CODE BASED SOUNDING REFERENCE SIGNAL RESOURCES FOR ANTENNA SWITCHING,” filed Feb. 05, 2020; which is assigned to the assignee hereof, and which is expressly incorporated by reference in its entirety herein. 
    
    
     BACKGROUND 
     Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple-access communications system may include one or more base stations or one or more network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE). 
     In some cases, a UE may transmit a sounding reference signal (SRS) to a base station. The base station, upon receiving the SRS, may perform uplink or downlink channel estimation. For example, a UE having multiple antennas may support a different number of transmit antennas than receive antennas, and may transmit reference signals according to an antenna switching process to provide channel estimation for each antenna. SRS using antenna switching may enable downlink beamforming by utilizing channel reciprocity, and may also be used for uplink scheduling and beamforming. In some cases, limitations on reference signal resources may limit scheduling flexibility of reference signals or other signals. 
     SUMMARY 
     The described techniques relate to improved methods, systems, devices, and apparatuses that support repetition and time domain cover code based sounding reference signal resources for antenna switching. Generally, the described techniques provide for a user equipment (UE) using cover coding for reference signal (e.g., sounding reference signal (SRS)) resources for performing antenna switching. The UE may receive, from a base station, a configuration for a reference signal resource set for transmitting a reference signal for antenna switching. The configuration information from the base station may include an indication of a type of time division cover coding for the UE to use for repetitions of the reference signal and an indication of a type of frequency hopping. The UE may determine a reference signal resource for transmission of the reference signal based on the configuration and the type of frequency hopping receives in the configuration from the base station. The UE may then transmit a set of repetitions of the reference signal over the determined reference signal resource according to the type of time division cover coding, as part on an antenna switching process. 
     A method of wireless communications is described. The method may include receiving a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping, determining a reference signal resource for transmission of the reference signal based on the configuration and the type of frequency hopping, and transmitting a set of repetitions of the reference signal over the determined reference signal resource according to the type of time division cover coding. 
     An apparatus for wireless communications is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping, determine a reference signal resource for transmission of the reference signal based on the configuration and the type of frequency hopping, and transmit a set of repetitions of the reference signal over the determined reference signal resource according to the type of time division cover coding. 
     Another apparatus for wireless communications is described. The apparatus may include means for receiving a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping, determining a reference signal resource for transmission of the reference signal based on the configuration and the type of frequency hopping, and transmitting a set of repetitions of the reference signal over the determined reference signal resource according to the type of time division cover coding. 
     A non-transitory computer-readable medium storing code for wireless communications is described. The code may include instructions executable by a processor to receive a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping, determine a reference signal resource for transmission of the reference signal based on the configuration and the type of frequency hopping, and transmit a set of repetitions of the reference signal over the determined reference signal resource according to the type of time division cover coding. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the set of repetitions of the reference signal may include operations, features, means, or instructions for transmitting the set of repetitions of the reference signal over each of a set of subsets of the determined reference signal resource using one of a set of antennas. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the type of frequency hopping may include operations, features, means, or instructions for transmitting the set of repetitions of the reference signal over a first frequency resource within a first set of symbols of a slot. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the type of frequency hopping may include operations, features, means, or instructions for transmitting a first subset of the set of repetitions of the reference signal over a first frequency resource within a first set of symbols of a slot, and transmitting a second subset of the set of repetitions of the reference signal over a second frequency resource within a second set of symbols of the slot. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the type of frequency hopping may include operations, features, means, or instructions for transmitting a first subset of the set of repetitions of the reference signal over a first frequency resource within a first set of symbols of a first slot, and transmitting a second subset of the set of repetitions of the reference signal over a second frequency resource within a second set of symbols of a second slot. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the set of repetitions of the reference signal may include operations, features, means, or instructions for applying a first value of a cover code to a first repetition of the reference signal, the first repetition of the reference signal transmitted in a first symbol and applying a second value of the cover code to a second repetition of the reference signal, the second repetition of the reference signal transmitted in a second symbol. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first symbol and the second symbol may be in a same slot. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first symbol and the second symbol may be not contiguous symbols of the same slot. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first symbol may be in a first slot and the second symbol may be in a second slot. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the configuration for the reference signal resource set includes an indicator of a quantity of symbols of a guard period for the antenna switching. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the configuration for the reference signal resource set includes an indication of a time interlacing for the type of frequency hopping. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the reference signal may be a sounding reference signal. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the configuration for the reference signal resource set may be periodic, aperiodic, or semi-persistent. 
     A method of wireless communications is described. The method may include transmitting, to a UE, a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping and receiving a set of repetitions of the reference signal over a determined reference signal resource according to the type of time division cover coding and based on the indication of the type of frequency hopping. 
     An apparatus for wireless communications is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to transmit, to a UE, a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping and receive a set of repetitions of the reference signal over a determined reference signal resource according to the type of time division cover coding and based on the indication of the type of frequency hopping. 
     Another apparatus for wireless communications is described. The apparatus may include means for transmitting, to a UE, a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping and receiving a set of repetitions of the reference signal over a determined reference signal resource according to the type of time division cover coding and based on the indication of the type of frequency hopping. 
     A non-transitory computer-readable medium storing code for wireless communications is described. The code may include instructions executable by a processor to transmit, to a UE, a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping and receive a set of repetitions of the reference signal over a determined reference signal resource according to the type of time division cover coding and based on the indication of the type of frequency hopping. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the type of frequency hopping may include operations, features, means, or instructions for receiving the set of repetitions of the reference signal over a first frequency resource within a first set of symbols of a slot. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the type of frequency hopping may include operations, features, means, or instructions for receiving a first subset of the set of repetitions of the reference signal over a first frequency resource within a first set of symbols of a slot, and receiving a second subset of the set of repetitions of the reference signal over a second frequency resource within a second set of symbols of the slot. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the type of frequency hopping may include operations, features, means, or instructions for receiving a first subset of the set of repetitions of the reference signal over a first frequency resource within a first set of symbols of a first slot, and receiving a second subset of the set of repetitions of the reference signal over a second frequency resource within a second set of symbols of a second slot. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the set of repetitions of the reference signal may include operations, features, means, or instructions for receiving the set of repetitions of the reference signal based on an application of a first value of a cover code to a first repetition of the reference signal, the first repetition of the reference signal transmitted in a first symbol and an application of a second value of the cover code to a second repetition of the reference signal, the second repetition of the reference signal transmitted in a second symbol. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first symbol and the second symbol may be in a same slot. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first symbol and the second symbol may be not contiguous symbols of the same slot. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first symbol may be in a first slot and the second symbol may be in a second slot. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the configuration for the reference signal resource set includes an indicator of a quantity of symbols of a guard period for the antenna switching. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, to a second UE, a configuration for an uplink transmission by the second UE within the guard period for the antenna switching for the first UE. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the configuration for the reference signal resource set includes an indication of a time interlacing for the frequency hopping. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the reference signal may be a sounding reference signal. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the configuration for the reference signal resource set may be periodic, aperiodic, or semi-persistent. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates an example of a system for wireless communications that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. 
         FIG.  2    illustrates an example of a wireless communications system that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. 
         FIGS.  3 - 6    illustrate examples of slot diagrams that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. 
         FIG.  7    illustrates an example of a process flow that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. 
         FIGS.  8  and  9    show block diagrams of devices that support repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. 
         FIG.  10    shows a block diagram of a communications manager that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. 
         FIG.  11    shows a diagram of a system including a device that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. 
         FIGS.  12  and  13    show block diagrams of devices that support repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. 
         FIG.  14    shows a block diagram of a communications manager that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. 
         FIG.  15    shows a diagram of a system including a device that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. 
         FIGS.  16  through  19    show flowcharts illustrating methods that support repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     A user equipment (UE) in a wireless communications system may communicate with other wireless devices, such as a base station. The base station may configure resources for communications by the UE. In some cases, the UE may have multiple antennas, and may transmit reference signals according to an antenna switching process to provide channel estimation for each antenna. The UE may then select antennas for uplink transmissions or the base station may determine downlink transmission beams based on the channel estimation. 
     A UE may transmit a reference signal, such as a sounding reference signal (SRS) to a base station. In some cases, reference signal resources may be configured by the base station or network for a particular set of symbols, and a particular number of ports or antennas. For example, in some cases, the reference signal resources may be configured to span 1, 2, or 4 consecutive or non-consecutive symbols, with up to 4 ports per reference signal resource. Each port of a reference signal resource may be sounded in each symbol. A reference signal resource set configured by the base station may contain one or more reference signal resources for use by a UE. The UE may be configured by the base station with multiple resources, which may be grouped in a reference signal resource set depending on the use case. The use cases may include antenna switching, codebook-based communications, non-codebook-based communications, or beam management. 
     The reference signal resource configuration transmitted to the UE from the base station may include an indication of different reference signal resources sets, a guard period configuration (e.g., a number of guard symbols to use between each reference signal resource set), an indication of a type of frequency hopping, an indication of a type of cover coding. For example, the indication of the type of frequency hopping may include an indication of no frequency hopping, inter-slot frequency hopping, or intra slot frequency hopping, as well as a number of symbols to frequency hop over and other parameters. The indication of the type of cover coding may include an indication of whether to perform cover coding, intra or inter-slot application for cover coding, and on which symbols to apply cover coding. 
     The UE may then transmit reference signals in the configured resources based on the indication of the type of frequency hopping and the indication of the type of cover coding. 
     Aspects of the disclosure are initially described in the context of wireless communications systems. Aspects of the disclosure are then described in the context of slot diagrams and process flows. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to repetition and time domain cover code based sounding reference signal resources for antenna switching. 
       FIG.  1    illustrates an example of a wireless communications system  100  that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. The wireless communications system  100  may include one or more base stations  105 , one or more UEs  115 , and a core network  130 . In some examples, the wireless communications system  100  may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communications system  100  may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, communications with low-cost and low-complexity devices, or any combination thereof. 
     The base stations  105  may be dispersed throughout a geographic area to form the wireless communications system  100  and may be devices in different forms or having different capabilities. The base stations  105  and the UEs  115  may wirelessly communicate via one or more communication links  125 . Each base station  105  may provide a coverage area  110  over which the UEs  115  and the base station  105  may establish one or more communication links  125 . The coverage area  110  may be an example of a geographic area over which a base station  105  and a UE  115  may support the communication of signals according to one or more radio access technologies. 
     The UEs  115  may be dispersed throughout a coverage area  110  of the wireless communications system  100 , and each UE  115  may be stationary, or mobile, or both at different times. The UEs  115  may be devices in different forms or having different capabilities. Some example UEs  115  are illustrated in  FIG.  1   . The UEs  115  described herein may be able to communicate with various types of devices, such as other UEs  115 , the base stations  105 , or network equipment (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment), as shown in  FIG.  1   . 
     The base stations  105  may communicate with the core network  130 , or with one another, or both. For example, the base stations  105  may interface with the core network  130  through one or more backhaul links  120  (e.g., via an S1, N2, N3, or other interface). The base stations  105  may communicate with one another over the backhaul links  120  (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations  105 ), or indirectly (e.g., via core network  130 ), or both. In some examples, the backhaul links  120  may be or include one or more wireless links. 
     One or more of the base stations  105  described herein may include or may be referred to by a person having ordinary skill in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB or a giga-NodeB (either of which may be referred to as a gNB), a Home NodeB, a Home eNodeB, or other suitable terminology. 
     A UE  115  may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client, among other examples. A UE  115  may also include or may be referred to as a personal electronic device such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, a UE  115  may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communications (MTC) device, among other examples, which may be implemented in various objects such as appliances, or vehicles, meters, among other examples. 
     The UEs  115  described herein may be able to communicate with various types of devices, such as other UEs  115  that may sometimes act as relays as well as the base stations  105  and the network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown in  FIG.  1   . 
     The UEs  115  and the base stations  105  may wirelessly communicate with one another via one or more communication links  125  over one or more carriers. The term “carrier” may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication links  125 . For example, a carrier used for a communication link  125  may include a portion of a radio frequency spectrum band (e.g., a bandwidth part (BWP)) that is operated according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling that coordinates operation for the carrier, user data, or other signaling. The wireless communications system  100  may support communication with a UE  115  using carrier aggregation or multi-carrier operation. A UE  115  may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers. 
     In some examples (e.g., in a carrier aggregation configuration), a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers. A carrier may be associated with a frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN)) and may be positioned according to a channel raster for discovery by the UEs  115 . A carrier may be operated in a standalone mode where initial acquisition and connection may be conducted by the UEs  115  via the carrier, or the carrier may be operated in a non-standalone mode where a connection is anchored using a different carrier (e.g., of the same or a different radio access technology). 
     The communication links  125  shown in the wireless communications system  100  may include uplink transmissions from a UE  115  to a base station  105 , or downlink transmissions from a base station  105  to a UE  115 . Carriers may carry downlink or uplink communications (e.g., in an FDD mode) or may be configured to carry downlink and uplink communications (e.g., in a TDD mode). 
     A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communications system  100 . For example, the carrier bandwidth may be one of a number of determined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz)). Devices of the wireless communications system  100  (e.g., the base stations  105 , the UEs  115 , or both) may have hardware configurations that support communications over a particular carrier bandwidth or may be configurable to support communications over one of a set of carrier bandwidths. In some examples, the wireless communications system  100  may include base stations  105  or UEs  115  that support simultaneous communications via carriers associated with multiple carrier bandwidths. In some examples, each served UE  115  may be configured for operating over portions (e.g., a sub-band, a BWP) or all of a carrier bandwidth. 
     Signal waveforms transmitted over a carrier may be made up of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both). Thus, the more resource elements that a UE  115  receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE  115 . A wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers or beams), and the use of multiple spatial layers may further increase the data rate or data integrity for communications with a UE  115 . 
     One or more numerologies for a carrier may be supported, where a numerology may include a subcarrier spacing (Δƒ) and a cyclic prefix. A carrier may be divided into one or more BWPs having the same or different numerologies. In some examples, a UE  115  may be configured with multiple BWPs. In some examples, a single BWP for a carrier may be active at a given time and communications for the UE  115  may be restricted to one or more active BWPs. 
     The time intervals for the base stations  105  or the UEs  115  may be expressed in multiples of a basic time unit which may, for example, refer to a sampling period of T s  = ⅟(Δ/ƒ max  · N ƒ ) seconds, where Δƒ max  may represent the maximum supported subcarrier spacing, and N ƒ  may represent the maximum supported discrete Fourier transform (DFT) size. Time intervals of a communications resource may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023). 
     Each frame may include multiple consecutively numbered subframes or slots, and each subframe or slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into a number of slots. Alternatively, each frame may include a variable number of slots, and the number of slots may depend on subcarrier spacing. Each slot may include a number of symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period). In some wireless communications systems  100 , a slot may further be divided into multiple mini-slots containing one or more symbols. Excluding the cyclic prefix, each symbol period may contain one or more (e.g., N ƒ ) sampling periods. The duration of a symbol period may depend on the subcarrier spacing or frequency band of operation. 
     A subframe, a slot, a mini-slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communications system  100  and may be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communications system  100  may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs)). 
     Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using one or more of time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. A control region (e.g., a control resource set (CORESET)) for a physical control channel may be defined by a number of symbol periods and may extend across the system bandwidth or a subset of the system bandwidth of the carrier. One or more control regions (e.g., CORESETs) may be configured for a set of the UEs  115 . For example, one or more of the UEs  115  may monitor or search control regions for control information according to one or more search space sets, and each search space set may include one or multiple control channel candidates in one or more aggregation levels arranged in a cascaded manner. An aggregation level for a control channel candidate may refer to a number of control channel resources (e.g., control channel elements (CCEs)) associated with encoded information for a control information format having a given payload size. Search space sets may include common search space sets configured for sending control information to multiple UEs  115  and UE-specific search space sets for sending control information to a specific UE  115 . 
     Each base station  105  may provide communication coverage via one or more cells, for example a macro cell, a small cell, a hot spot, or other types of cells, or any combination thereof. The term “cell” may refer to a logical communication entity used for communication with a base station  105  (e.g., over a carrier) and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), or others). In some examples, a cell may also refer to a geographic coverage area  110  or a portion of a geographic coverage area  110  (e.g., a sector) over which the logical communication entity operates. Such cells may range from smaller areas (e.g., a structure, a subset of structure) to larger areas depending on various factors such as the capabilities of the base station  105 . For example, a cell may be or include a building, a subset of a building, or exterior spaces between or overlapping with geographic coverage areas  110 , among other examples. 
     A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by the UEs  115  with service subscriptions with the network provider supporting the macro cell. A small cell may be associated with a lower-powered base station  105 , as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may provide unrestricted access to the UEs  115  with service subscriptions with the network provider or may provide restricted access to the UEs  115  having an association with the small cell (e.g., the UEs  115  in a closed subscriber group (CSG), the UEs  115  associated with users in a home or office). A base station  105  may support one or multiple cells and may also support communications over the one or more cells using one or multiple component carriers. 
     In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB)) that may provide access for different types of devices. 
     In some examples, a base station  105  may be movable and therefore provide communication coverage for a moving geographic coverage area  110 . In some examples, different geographic coverage areas  110  associated with different technologies may overlap, but the different geographic coverage areas  110  may be supported by the same base station  105 . In other examples, the overlapping geographic coverage areas  110  associated with different technologies may be supported by different base stations  105 . The wireless communications system  100  may include, for example, a heterogeneous network in which different types of the base stations  105  provide coverage for various geographic coverage areas  110  using the same or different radio access technologies. 
     The wireless communications system  100  may support synchronous or asynchronous operation. For synchronous operation, the base stations  105  may have similar frame timings, and transmissions from different base stations  105  may be approximately aligned in time. For asynchronous operation, the base stations  105  may have different frame timings, and transmissions from different base stations  105  may, in some examples, not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operations. 
     Some UEs  115 , such as MTC or IoT devices, may be low cost or low complexity devices and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication). M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station  105  without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay such information to a central server or application program that makes use of the information or presents the information to humans interacting with the application program. Some UEs  115  may be designed to collect information or enable automated behavior of machines or other devices. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging. 
     Some UEs  115  may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously). In some examples, half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for the UEs  115  include entering a power saving deep sleep mode when not engaging in active communications, operating over a limited bandwidth (e.g., according to narrowband communications), or a combination of these techniques. For example, some UEs  115  may be configured for operation using a narrowband protocol type that is associated with a defined portion or range (e.g., set of subcarriers or resource blocks (RBs)) within a carrier, within a guard-band of a carrier, or outside of a carrier. 
     The wireless communications system  100  may be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof. For example, the wireless communications system  100  may be configured to support ultra-reliable low-latency communications (URLLC) or mission critical communications. The UEs  115  may be designed to support ultra-reliable, low-latency, or critical functions (e.g., mission critical functions). Ultra-reliable communications may include private communication or group communication and may be supported by one or more mission critical services such as mission critical push-to-talk (MCPTT), mission critical video (MCVideo), or mission critical data (MCData). Support for mission critical functions may include prioritization of services, and mission critical services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission critical, and ultra-reliable low-latency may be used interchangeably herein. 
     In some examples, a UE  115  may also be able to communicate directly with other UEs  115  over a device-to-device (D2D) communication link  135  (e.g., using a peer-to-peer (P2P) or D2D protocol). One or more UEs  115  utilizing D2D communications may be within the geographic coverage area  110  of a base station  105 . Other UEs  115  in such a group may be outside the geographic coverage area  110  of a base station  105  or be otherwise unable to receive transmissions from a base station  105 . In some examples, groups of the UEs  115   communicating via D2D communications may utilize a one-to-many (1:M) system in which each UE  115  transmits to every other UE  115  in the group. In some examples, a base station  105  facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between the UEs  115  without the involvement of a base station  105 . 
     In some systems, the D2D communication link  135  may be an example of a communication channel, such as a sidelink communication channel, between vehicles (e.g., UEs  115 ). In some examples, vehicles may communicate using vehicle-to-everything (V2X) communications, vehicle-to-vehicle (V2V) communications, or some combination of these. A vehicle may signal information related to traffic conditions, signal scheduling, weather, safety, emergencies, or any other information relevant to a V2X system. In some examples, vehicles in a V2X system may communicate with roadside infrastructure, such as roadside units, or with the network via one or more network nodes (e.g., base stations  105 ) using vehicle-to-network (V2N) communications, or with both. 
     The core network  130  may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network  130  may be an evolved packet core (EPC) or 5G core (5GC), which may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) and at least one user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW), a Packet Data Network (PDN) gateway (P-GW), or a user plane function (UPF)). The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for the UEs  115  served by the base stations  105  associated with the core network  130 . User IP packets may be transferred through the user plane entity, which may provide IP address allocation as well as other functions. The user plane entity may be connected to the network operators IP services  150 . The operators IP services  150  may include access to the Internet, Intranet(s), an IP Multimedia Subsystem (IMS), or a Packet-Switched Streaming Service. 
     Some of the network devices, such as a base station  105 , may include subcomponents such as an access network entity  140 , which may be an example of an access node controller (ANC). Each access network entity  140  may communicate with the UEs  115   through one or more other access network transmission entities  145 , which may be referred to as radio heads, smart radio heads, or transmission/reception points (TRPs). Each access network transmission entity  145  may include one or more antenna panels. In some configurations, various functions of each access network entity  140  or base station  105  may be distributed across various network devices (e.g., radio heads and ANCs) or consolidated into a single network device (e.g., a base station  105 ). 
     The wireless communications system  100  may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from approximately one decimeter to one meter in length. The UHF waves may be blocked or redirected by buildings and environmental features, but the waves may penetrate structures sufficiently for a macro cell to provide service to the UEs  115  located indoors. The transmission of UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz. 
     The wireless communications system  100  may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band, or in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz), also known as the millimeter band. In some examples, the wireless communications system  100  may support millimeter wave (mmW) communications between the UEs  115  and the base stations  105 , and EHF antennas of the respective devices may be smaller and more closely spaced than UHF antennas. In some examples, this may facilitate use of antenna arrays within a device. The propagation of EHF transmissions, however, may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. The techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body. 
     The wireless communications system  100  may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communications system  100  may employ License Assisted Access (LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in unlicensed radio frequency spectrum bands, devices such as the base stations  105  and the UEs  115  may employ carrier sensing for collision detection and avoidance. In some examples, operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA). Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples. 
     A base station  105  or a UE  115  may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of a base station  105  or a UE  115  may be located within one or more antenna arrays or antenna panels, which may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with a base station  105  may be located in diverse geographic locations. A base station  105  may have an antenna array with a number of rows and columns of antenna ports that the base station  105  may use to support beamforming of communications with a UE  115 . Likewise, a UE  115  may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, an antenna panel may support radio frequency beamforming for a signal transmitted via an antenna port. 
     The base stations  105  or the UEs  115  may use MIMO communications to exploit multipath signal propagation and increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such techniques may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO), where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO), where multiple spatial layers are transmitted to multiple devices. 
     Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station  105 , a UE  115 ) to shape or steer an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that some signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying amplitude offsets, phase offsets, or both to signals carried via the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation). 
     A base station  105  or a UE  115  may use beam sweeping techniques as part of beam forming operations. For example, a base station  105  may use multiple antennas or antenna arrays (e.g., antenna panels) to conduct beamforming operations for directional communications with a UE  115 . Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a base station  105  multiple times in different directions. For example, the base station  105  may transmit a signal according to different beamforming weight sets associated with different directions of transmission. Transmissions in different beam directions may be used to identify (e.g., by a transmitting device, such as a base station  105 , or by a receiving device, such as a UE  115 ) a beam direction for later transmission or reception by the base station  105 . 
     Some signals, such as data signals associated with a particular receiving device, may be transmitted by a base station  105  in a single beam direction (e.g., a direction associated with the receiving device, such as a UE  115 ). In some examples, the beam direction associated with transmissions along a single beam direction may be determined based on a signal that was transmitted in one or more beam directions. For example, a UE  115  may receive one or more of the signals transmitted by the base station  105  in different directions and may report to the base station  105  an indication of the signal that the UE  115  received with a highest signal quality or an otherwise acceptable signal quality. 
     In some examples, transmissions by a device (e.g., by a base station  105  or a UE  115 ) may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from a base station  105  to a UE  115 ). The UE  115  may report feedback that indicates precoding weights for one or more beam directions, and the feedback may correspond to a configured number of beams across a system bandwidth or one or more sub-bands. The base station  105  may transmit a reference signal (e.g., a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS)), which may be precoded or unprecoded. The UE  115  may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook). Although these techniques are described with reference to signals transmitted in one or more directions by a base station  105 , a UE  115  may employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE  115 ) or for transmitting a signal in a single direction (e.g., for transmitting data to a receiving device). 
     A receiving device (e.g., a UE  115 ) may try multiple receive configurations (e.g., directional listening) when receiving various signals from the base station  105 , such as synchronization signals, reference signals, beam selection signals, or other control signals. For example, a receiving device may try multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of an antenna array, or by processing received signals according to different receive beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, any of which may be referred to as “listening” according to different receive configurations or receive directions. In some examples, a receiving device may use a single receive configuration to receive along a single beam direction (e.g., when receiving a data signal). The single receive configuration may be aligned in a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have a highest signal strength, highest signal-to-noise ratio (SNR), or otherwise acceptable signal quality based on listening according to multiple beam directions). 
     The wireless communications system  100  may be a packet-based network that operates according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use error detection techniques, error correction techniques, or both to support retransmissions at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE  115  and a base station  105  or a core network  130  supporting radio bearers for user plane data. At the physical layer, transport channels may be mapped to physical channels. 
     The UEs  115  and the base stations  105  may support retransmissions of data to increase the likelihood that data is received successfully. Hybrid automatic repeat request (HARQ) feedback is one technique for increasing the likelihood that data is received correctly over a communication link  125 . HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., low signal-to-noise conditions). In some examples, a device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval. 
     A UE  115  may use cover coding for SRS resources for performing antenna switching. The UE  115  may receive, from a base station  105 , a configuration for a reference signal resource set for transmitting a reference signal for antenna switching. The configuration information from the base station  105  may include an indication of a type of time division cover coding for the UE  115  to use for repetitions of the reference signal and an indication of a type of frequency hopping. The UE  115  may determine a reference signal resource for transmission of the reference signal based on the configuration and the type of frequency hopping receives in the configuration from the base station  105 . The UE  115  may then transmit a set of repetitions of the reference signal over the determined reference signal resource according to the type of time division cover coding, as part on an antenna switching process. 
       FIG.  2    illustrates an example of a wireless communications system  200  that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. In some examples, wireless communications system  200  may implement aspects of wireless communication system  100 . Wireless communications system  200  may include UE  115 - a , which may be an example of a UE  115  as described with respect for  FIG.  1   . Wireless communications system  200  may also include base station  105 - a , which may be an example of a base station  105  as described with respect to  FIG.  1   . Base station  105 - a  may serve UE  115 - a  and other UEs  115  in coverage area  110 - a . Base station  105 - a  and UE  115 - a  may communicate over communication link  205 . Base station  105 - a  may schedule communications for UE  115 - a . 
     In some cases, UE  115 - a  may be configured to use (e.g., may be physically present at the UE  115 - a  or enabled) a number of transmit antennas as well as a number of receive antennas. UE  115 - a  may use up to the number of transmit antennas to transmit signals and may use up to the number of receive antennas to receive signals. In some cases, the number of transmit antennas versus the number of receive antennas may be given by xTyR, where x may be equal to the number of transmit antennas and y may be equal to the number of receive antennas. For instance, 1T4R may correspond to UE  115 - a  having 4 physical antennas, and being configured to concurrently use 1 transmit antenna and up to 4 receive antennas. 
     Performing SRS antenna switching may involve UE  115 - a  transmitting SRS to base station  105 - a  over the transmit antennas and base station  105 - a  exploiting channel reciprocity to perform downlink beamforming for a time division duplexed (TDD) channel. For instance, base station  105 - a  may receive the SRS, may perform uplink channel estimation, and may exploit channel reciprocity to determine a downlink channel estimation from the uplink channel estimation. Base station  105 - a  may use the downlink channel estimation for downlink beamforming. SRS resource sets whose resources are used for antenna switching may be said to have an antenna switching usage type. Generally, SRS antenna switching may be supported if x &lt; y for xTyR (e.g., 1T2R, 2T4R, 1T4R, 1T4R/2T4R). The number of SRS resources in an SRS resource set for antenna switching may be given by  x / y . For example an antenna switching SRS resource set for a UE configured with 1T4R may have four SRS resources. 
     Base station  105 - a  may transmit, to UE  115 - a  over communication link  205 , a reference signal resource set configuration  210 . Configuration  210  may include information for UE  115 - a  to use to transmit one or more reference signals in reference signal repetitions  215  to base station  105 - a . The reference signal resource set configuration  210  may be transmitted to UE  115 - a  by base station  105 - a , and may indicate whether reference signal transmissions by UE  115 - a  are aperiodic, semi-persistent (e.g., configured with repeating resources that are enabled and disabled via a signal such as in DCI), or periodic (e.g., repeating resources configured via RRC). In some cases, the reference signal resource set configuration  210  may be signaled in RRC signaling or downlink control information (DCI)), or a combination thereof. 
     The configuration  210  may include configuration information for UE  115 - a  to transmit a reference signal for antenna switching, including configuration information for a type of cover coding and frequency hopping for UE  115 - a  to use in the transmission of reference signal repetitions  215 . The cover coding may apply, for example, a time-domain orthogonal cover code (TD-OCC). For example, a TD-OCC of length two may take the values {+1, +1} or {+1, -1}, and additional lengths of the TD-OCC may take a similar or different structure. 
     For example, configuration  210  may include an indication of no frequency hopping, intra-slot frequency hopping, or inter-slot frequency hopping. Additionally or alternatively, configuration  210  may include an indication of no TD-OCC, intra-slot TD-OCC, or inter-slot TD-OCC. Based on the reference signal resource set configuration  210 , UE  115 - a  may transmit reference signal repetitions  215  for performing antenna switching. For example, UE  115 - a  may transmit reference signal repetitions  215  based on one or more of slot diagrams  301 ,  302 ,  401 ,  402 ,  501 ,  502 ,  601 , and  602 , or a combination of these, as described herein. UE  115 - a  may transmit reference signals according to the configured resources based on the different frequency hopping configurations, TD-OCC configurations, configured guard periods, and other parameters. 
     Thus, the efficiency of the channel resource utilization may be improved, as base station  105 - a  may configure reference signals resource sets and configurations to different UEs  115 , such that each UE  115  may perform antenna switching over non-interfering frequency, time, and code resources. 
       FIG.  3    illustrates examples of slot diagrams  301  and  302  that support repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. In some examples, slot diagrams  301  and  302  may implement aspects of wireless communication systems  100  and  200 . A UE  115  may transmit reference signals according to the time, frequency, and coding as described in slot diagrams  301  and  302 . 
     Slot diagrams  301  and  302  may illustrate examples of reference signal transmissions for antenna switching with TD-OCC application. Slot diagram  301  may illustrate and example of reference signal transmissions without frequency hopping, and slot diagram  302  may illustrate an example of reference signal transmissions with frequency hopping. A UE  115  may transmit the reference signals described herein using intra-slot repetition. A UE  115  may transmit SRS as a part of an antenna switching process. Performing SRS antenna switching may involve the UE  115  transmitting SRS to base station  105 - a  over the transmit antennas. For example, the UE  115  may transmit SRS based on the number of available antennas. Generally, SRS antenna switching may be supported if x &lt; y for xTyR (e.g., 1T2R, 2T4R, 1T4R, 1T4R/2T4R). The number of SRS resources in an SRS resource set for antenna switching may be given by  x / y . For example an antenna switching SRS resource set for a UE configured with 1T4R may have four SRS resources. 
     The example shown may be for a UE having 1T2R or 2T4R, configured to transmit two repetitions of each SRS. In the case of slot diagram  301 , SRS resources for transmission of reference signal  310  using a first antenna or subset of antennas may be repeated across a number of consecutive symbols (e.g., symbols 9 and 10) of a slot. A next set of SRS resources for transmission of reference signal  315  using a second antenna or subset of antennas may also be consecutive (e.g., symbols 12 and 13) and may be separated from the first set of reference signal resources for reference signal  310  by a guard period  320  (e.g., in symbol 11), in which the UE switches between transmit antennas or groups of transmit antennas. 
     Slot diagram  301  illustrates reference signal repetition transmissions with TD-OCC  325 - a  application on a per symbol  305  basis. The TD-OCC  325 - a  may be applied such that a first reference signal  310  may be transmitted in symbol 9 across a frequency band with the first value of a TD-OCC  325 - a . The UE  115  may transmit a repetition of reference signal  310  in symbol 10 with the second value of TD-OCC  325 - a . 
     Reference signal  315  may be configured for transmission using TD-OCC  325 - b . A UE  115  may transmit reference signal  315  in symbol 12 with the first value of TD-OCC  325 - b . The UE  115  may transmit a repetition of reference signal  315  in symbol 13 with the second value of TD-OCC  325 - b . 
     Slot diagram  302  illustrates reference signal repetition transmissions with TD-OCC  325  application on a per symbol  305  basis with frequency hopping. 
     In the case of slot diagram  302 , SRS resources for transmission of reference signal  310  may be repeated across a number of consecutive symbols (e.g., symbols 9 and 10) with a number of frequency hops. There may be N number of consecutive symbols in the reference signal resource for reference signal  310 , and there may be M number of frequency hops. In this case, each frequency hop may be over N/M number of symbols. For example, the reference signal resource for reference signal  310  may include four consecutive symbols (e.g., symbols 5, 6, 7, and 8) and two frequency hops (e.g., frequency hops HopO and Hop1). Thus, each frequency hop is over two symbols. For each frequency hop, a TD-OCC  325  may be applied to the two symbols within the slot. For example, TD-OCC  325 - c  may be applied to reference signal  310  repetitions in symbols 5 and 6 for frequency HopO, and TD-OCC  325 - d  may be applied to reference signal  310  repetitions in symbols 7 and 8 for frequency Hop1. The sequence for reference signal  310  transmitted in frequency HopO may be the same as the sequence for reference signal  310  transmitted in frequency Hop1, or the sequences for frequency HopO and frequency Hop1 may be different portions of a sequence for reference signal  310  (e.g., determined according to resource blocks or subcarriers). 
     The TD-OCC  325 - c  may be applied such that a first reference signal  310  may be transmitted by a UE  115  in symbol 5 across HopO with the first value of TD-OCC  325 - c . The UE  115  may transmit a repetition of reference signal  310  in symbol 6 in frequency HopO with the second value of TD-OCC  325 - c . Then, in frequency Hop1, UE  115  may transmit reference signal  310  repetitions with TD-OCC  325 - d . The UE  115  may transmit reference signal  310  in symbol 7 with the first value of TD-OCC  325 - d , and may transmit reference signal  310  repetition in symbol 8 with the second value of TD-OCC  325 - c . 
     A next set of SRS resources for transmission of reference signals  315  with frequency hopping may also be consecutive (e.g., symbols 10, 11, 12, and 13) and may be separated from the first set of reference signal resources for reference signal  310  by a guard period  320  (e.g., in symbol 9). The next set of reference signal resources for reference signal  315  may also include TD-OCC  325 - d . A UE  115  may transmit reference signal  315  in symbol 10 with the first value of TD-OCC  325 - e . The UE  115  may transmit a repetition of reference signal  315  in symbol 11 with a second value of TD-OCC  325 - e . 
     Then, in frequency Hop1, UE  115  may transmit reference signal  315  repetitions with TD-OCC  325 - f . The UE  115  may transmit reference signal  310  in symbol 12 with the first value of TD-OCC  325 - d , and may transmit reference signal  310  repetition in symbol 13 with the second value of TD-OCC  325 - d . 
       FIG.  4    illustrates an example of slot diagrams  401  and  402  that support repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. In some examples, slot diagrams  401  and  402  may implement aspects of wireless communication systems  100  and  200 . A UE  115  may transmit reference signals according to the time, frequency, and coding as described in slot diagrams  401  and  402 . 
     Slot diagrams  401  and  402  may illustrate examples of reference signal transmissions for antenna switching with TD-OCC application. Slot diagram  401  may illustrate and example of reference signal transmissions without frequency hopping. 
     A guard period  420  of a number of symbols  405  may be configurable by the network. The guard period  420  configuration may be indicated by a base station  105  in a configuration message to a UE  115 . The network may configure the guard period to be one or more symbols, depending on the frequency band in use. For example, the guard period  420  may be one or more symbols  405  for sub-carrier spacings of 15 kHz, 30 kHz, and 60 kHz, and the guard period  420  may be 2 or more symbols  405  for 120 kHz sub-carrier spacings. The UE may receive an indicator of a number of symbols of guard period  420 , or a configuration of resources for reference signal  410  and reference signal  415  may convey (e.g., implicitly) the number of symbols of the guard period  420 . This may allow the network to utilize the guard symbols configured for a first UE  115  for another UE  115  to perform uplink transmissions, such as reference signal transmission or uplink data channel transmission. 
     For example, a first UE  115  may be configured with reference signal resource configuration  401 , and may transmit reference signal  410  with repetitions across a first set of resources (e.g., symbols 8 and 9) with TD-OCC  425 - a  as described with reference to  FIG.  3   . The first UE  115  may then be configured with a guard period  420  of two symbols, 10 and 11. The first UE  115  may then transmit reference signal  415  with repetitions across a second set of resources (e.g., symbols 12 and 13) with TD-OCC  425 - b  as described with reference to  FIG.  3   . 
     A second UE  115  may be configured with reference signal resources according to slot diagram  402  in the same slot as slot diagram  401 . The second UE  115  may use a third set of reference signal resources for transmission of reference signal  430  with repetitions during the guard period between the first and second sets of resources (e.g., symbols 10 and 11). In some cases, the reference signal  430  may be transmitted using a TD-OCC (e.g., with TD-OCC  425 - c ). The transmission of reference signal  430  by the second UE according to slot diagram  402  may thus overlap with the guard period of slot diagram  401 , and the corresponding resource usage by the first UE. Although illustrated transmitted reference signal  430 , the second UE  115  may be configured for a different uplink transmission (e.g., PUSCH transmission) during the guard period  420  for the first UE. 
     The network may thus improve throughput and efficiency by increasing the guard period for reference signal resource sets, and by coordination guard periods  420  and reference signal transmissions between different UEs  115 . 
       FIG.  5    illustrates an example of slot diagrams  501  and  502  that support repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. In some examples, slot diagrams  501   and  502  may implement aspects of wireless communication systems  100  and  200 . A UE  115  may transmit reference signals according to the time, frequency, and coding as described in slot diagrams  501  and  502 . 
     The TD-OCC for reference signal repetitions may also be applied across non-consecutive or interlaced reference signal transmissions, with or without frequency hopping. Slot diagrams  501  and  502  may illustrate examples of reference signal transmissions for antenna switching with non-consecutive TD-OCC application. Slot diagram  501  may illustrate an example of reference signal transmissions with frequency hopping, and slot diagram  502  may illustrate an example of reference signal transmissions without frequency hopping. 
     In the case of slot diagram  501 , SRS resources for transmission of reference signal  510  may include one or more repetitions and frequency hops across a number of consecutive symbols (e.g., symbols 5, 6, 7, and 8). A next set of SRS resources for transmission of reference signal  515  may also be consecutive (e.g., symbols 10, 11, 12, and 13) and may be separated from the first set of reference signal resources for reference signal  510  by a guard period  520  (e.g., symbol 9). However, the application of TD-OCC may not be across consecutive symbols. 
     Slot diagram  501  illustrates reference signal repetition transmissions with TD-OCC  525  application on a per symbol  505  basis. The TD-OCC  525 - a  may be applied such that a first reference signal  310  may be transmitted in symbol 5 in first frequency hop0, and with the first value of TD-OCC  525 - a . The UE  115  may transmit a repetition of reference signal  510  in symbol 7 in frequency HopO with the second value of TD-OCC  525 - a . The UE  115  may also transmit, in frequency Hop1, a repetition of reference signal  510  in symbol 6 with the first value of TD-OCC  525 - b . The UE  115  may then also transmit a repetition of reference signal  510  in symbol 8 in frequency Hop1 with the second value of TD-OCC  525 - b . Thus, each full TD-ODD  525  is applied across non-consecutive symbols, but to portions of reference signal  510  transmitted in the same frequency hop. In some cases, TDD-OCC  525 - a  may be the same as TD-OCC  525 - b , and may be associated with transmission of reference signal  510  (e.g., transmission of SRS using a first antenna or subset of antennas). 
     Similarly, for the next set of reference signal resources for reference signal  515 , TD-OCC  525 - c  may be applied to reference signal repetitions in HopO in symbols 10 and 12, and TD-OCC  525 - d  may be applied to reference signal repetitions in frequency Hop1 in symbols 11 and 13. The reference signal resource set for reference signals  510  may be separated from the reference signal resource set for reference signals  515  by guard period  520 . In some cases, TD-OCC  525 - c  may be the same as TD-OCC  525 - d , and may be associated with transmission of reference signal  515  (e.g., transmission of SRS using a second antenna or subset of antennas). In some cases, TD-OCC  525 - c  and TD-OCC  525 - d  may be the same as TD-OCC  525 - a  and TD-OCC  525 - b , and may be a TD-OCC  525  allocated for the UE for reference signal transmissions. 
     Slot diagram  502  illustrates reference signal repetition transmissions with TD-OCC  525  application on a per symbol  505  basis with interlaced reference signal resources and without frequency hopping. The TD-OCC  525 - e  may be applied such that a first reference signal  510  may be transmitted in symbol 7, and with the first value of TD-OCC  525 - e . The UE  115  may transmit a repetition of reference signal  510  in symbol 11 with the second value of TD-OCC  525 - e . The UE  115  may also transmit a repetition of reference signal  515  in symbol 9 with the first value of TD-OCC  525 - f . The UE  115  may then also transmit a repetition of reference signal  515  in symbol 13 with the second value of TD-OCC  525 - e . Thus, each full TD-OCC  525  is applied across non-consecutive symbols. 
     Similarly, for the next set of reference signal resources for reference signal  515 , TD-OCC  525 - c  may be applied to reference signal repetitions in HopO in symbols 10 and 12, and TD-OCC  525 - d  may be applied to reference signal repetitions in frequency Hop1 in symbols 11 and 13. 
       FIG.  6    illustrates an example of slot diagrams  601  and  602  that support repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. In some examples, slot diagrams  601  and  602  may implement aspects of wireless communication systems  100  and  200 . A UE  115  may transmit reference signals according to the time, frequency, and coding as described in slot diagrams  601  and  602 . Slot diagrams  601  and  602  may illustrate reference signal transmission configurations with the application of inter-slot TD-OCC, with and without frequency hopping. The reference signal resources for reference signals  610  and  615  may be repeated across two or more slots  630  with the application of a TD-OCC. Reference signal  610  and  615  may be transmitted in symbols  605 . 
     In slot diagram  601 , the reference signal resource may be configured without frequency hopping. The reference signal resources for reference signal  610  may be across two slots,  630 - a  and  630 - b . The reference signal resource set of reference signal  615  may also be configured across slots  630 - a  and  630 - b . In slot  630 - a  (e.g., slot n), reference signal  610  may be transmitted in symbol 9. Reference signal  610  may be repeated in a subsequent slot  630 - b  (e.g., slot n+k, where k is greater than or equal to 1), where reference signal  610  is also in symbol 9. TD-OCC  625 - a  may be applied to reference signal  610  across slots  630 - a  and  630 - b . Reference signal  615  may be transmitted in symbol 11 in the first slot  630 - a , and also in symbol 11 in slot  630 - b . TD-OCC  625 - b  may also be applied across slots  630 - a  and  630 - b  in this case. In this example, the guard period may be in symbol 10 in both slots  630 - a  and  630 - b . A TD-OCC may be applied in additional slots or for additional repetitions. For example, a length 4 TD-OCC may be applied for four repetitions of a reference signal across four slots. Where two repetitions are transmitted in each slot, a length 4 TD-OCC may be applied across two slots (e.g., two values of the TD-OCC applied in each of two slots). In some cases, TD-OCC  625 - a  may be the same as TD-OCC  625 - b , and may be associated with transmission of reference signals by a UE  115 . 
     In slot diagram  602 , the reference signal resource may be configured to include frequency hopping with the inter-slot TD-OCC. The reference signal resource set for reference signals  610  in slot  630 - c  (e.g., slot n) may be configured in two symbols, 8 and 9. The reference signal  610  may also be in symbols 8 and 9 with frequency hopping in slot  630 - d  (e.g., slot n+k). Reference signal  610  transmitted in in frequency Hop0, for example, may have TD-OCC  625 - c  applied across slots  630 - c  and  630 - d . Similarly, reference signal  610  transmitted in frequency Hop1 may also have TD-OCC  625 - d  applied across slots  630 - c  and  630 - d . Reference signal  615  may be transmitted in symbols 11 and 12 in frequency hops HopO and Hop1, respectively, with TD-OCCs  625 - e  and  625 - f  applied across slots  630 - c  and  630 - d . The guard period  620  in this case may be shown in symbol 10 for both slots  630 - c  and  630 - d . In some cases, TD-OCC  625 - c  may be the same as TD-OCC  625 - d , and may be associated with transmission of reference signal  610  (e.g., transmission of SRS using a first antenna or subset of antennas). In some cases, TD-OCC  625 - e  may be the same as TD-OCC  625 - f , and may be associated with transmission of reference signal  615  (e.g., transmission of SRS using a second antenna or subset of antennas). In some cases, TD-OCC  625 - c  and TD-OCC  625 - d  may be the same as TD-OCC  625 - a  and TD-OCC  625 - b , and may be a TD-OCC  625  allocated for the UE for reference signal transmissions. 
       FIG.  7    illustrates an example of a process flow  700  that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. In some examples, process flow  700  may implement aspects of wireless communication systems  100  and  200 . Process flow  700  may include UE  115 - b  and base station  105 - b , which may be examples of UEs  115  and base station  105  as described with reference to  FIGS.  1  and  2   . UE  115 - b  may be served by base station  105 - b  as part of a wireless communications system as described herein. 
     At  705 , UE  115 - b  may receive, from base station  105 - b , a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding (e.g., TD-OCC) for repetitions of the reference signal and an indication of a type of frequency hopping. The reference signal may be an example of an SRS or another type of reference signal for antenna switching. The configuration for the reference signal resource set may include an indicator of a quantity of symbols of a guard period for the antenna switching. The configuration may also include an indication of a time interlacing for the type of frequency hopping. 
     At  710 , UE  115 - b  may determine a reference signal resource for transmission of the reference signal based on the configuration and the type of frequency hopping. 
     At  715 , UE  115 - b  may transmit, to base station  105 - b , a set of repetitions of the reference signal over the determined reference signal resource according to the type of time division cover coding. The UE  115 - b  may transmit the set of repetitions of the reference signal over each of a set of subsets of the determined reference signal resource using one of a set of antennas. 
     In some cases, the type of frequency hopping may be no frequency hopping. In these cases, UE  115 - b  may transmit the set of repetitions of the reference signal over a first frequency resource within a first set of symbols of a slot. 
     In some cases, the type of frequency hopping may include intra-slot frequency hopping. In these cases, UE  115 - b  may transmit a first subset of the set of repetitions of the reference signal over a first frequency resource. The UE  115 - b  may also transmit a second subset of the set of repetitions of the reference signal over a frequency resource within a second set of symbols of the slot. 
     In some cases, the type of frequency hopping may include inter-slot frequency hopping. In these cases, UE  115 - b  may transmit a first subset of the set of repetitions of the reference signal over a first frequency resource within a first set of symbols of a first slot. UE  115 - b  may also transmit a second subset of the set of repetitions of the reference signal over a second frequency resource within a second set of symbols of the second slot. 
     In any of these cases, UE  115 - b  may apply a first value of a cover code to a first repetition of the reference signal transmitted in a first symbol, and apply a second value of the cover code to a second repetition of the reference signal, the second repetition of the reference signal transmitted in a second symbol. In some cases, the first symbol and the second symbol are in the same slot. In some cases, the first symbol and the second symbol are not contiguous symbols of the same slot. In some cases, the first symbol is in a first slot and the second symbol is in a second slot. 
       FIG.  8    shows a block diagram  800  of a device  805  that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. The device  805  may be an example of aspects of a UE  115  as described herein. The device  805  may include a receiver  810 , a communications manager  815 , and a transmitter  820 . The device  805  may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). 
     The receiver  810  may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to repetition and time domain cover code based sounding reference signal resources for antenna switching, etc.). Information may be passed on to other components of the device  805 . The receiver  810  may be an example of aspects of the transceiver  1120  described with reference to  FIG.  11   . The receiver  810  may utilize a single antenna or a set of antennas. 
     The communications manager  815  may receive a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping, determine a reference signal resource for transmission of the reference signal based on the configuration and the type of frequency hopping, and transmit a set of repetitions of the reference signal over the determined reference signal resource according to the type of time division cover coding. The communications manager  815  may be an example of aspects of the communications manager  1110  described herein. 
     The communications manager  815 , or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager  815 , or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC), a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure. 
     The communications manager  815 , or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager  815 , or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager  815 , or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure. 
     The transmitter  820  may transmit signals generated by other components of the device  805 . In some examples, the transmitter  820  may be collocated with a receiver  810  in a transceiver module. For example, the transmitter  820  may be an example of aspects of the transceiver  1120  described with reference to  FIG.  11   . The transmitter  820  may utilize a single antenna or a set of antennas. 
     In some examples, the communications manager  815  described herein may be implemented as a chipset of a wireless modem, and the receiver  810  and the transmitter  820   may be implemented as sets of analog components (e.g., amplifiers, filters, phase shifters, antennas, etc.) The wireless modem may obtain and decode signals from the receiver  810  over a receive interface, and may output signals for transmission to the transmitter  820  over a transmit interface. 
     The actions performed by the communications manager  815  as described herein may be implemented to realize one or more potential advantages. one implementation may allow a UE  115  to save power and increase battery life by improving efficiency in reference signal transmissions, particularly involved with antennas switching. Another implementation may allow the UE  115  to improve reliability by aligning transmissions so to decrease interference with other UEs  115  in a wireless communications system. 
       FIG.  9    shows a block diagram  900  of a device  905  that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. The device  905  may be an example of aspects of a device  805 , or a UE  115  as described herein. The device  905  may include a receiver  910 , a communications manager  915 , and a transmitter  935 . The device  905  may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). 
     The receiver  910  may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to repetition and time domain cover code based sounding reference signal resources for antenna switching, etc.). Information may be passed on to other components of the device  905 . The receiver  910  may be an example of aspects of the transceiver  1120  described with reference to  FIG.  11   . The receiver  910  may utilize a single antenna or a set of antennas. 
     The communications manager  915  may be an example of aspects of the communications manager  815  as described herein. The communications manager  915  may include a configuration component  920 , a resource component  925 , and a reference signal component  930 . The communications manager  915  may be an example of aspects of the communications manager  1110  described herein. 
     The configuration component  920  may receive a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping. 
     The resource component  925  may determine a reference signal resource for transmission of the reference signal based on the configuration and the type of frequency hopping. 
     The reference signal component  930  may transmit a set of repetitions of the reference signal over the determined reference signal resource according to the type of time division cover coding. 
     The transmitter  935  may transmit signals generated by other components of the device  905 . In some examples, the transmitter  935  may be collocated with a receiver  910  in a transceiver module. For example, the transmitter  935  may be an example of aspects of the transceiver  1120  described with reference to  FIG.  11   . The transmitter  935  may utilize a single antenna or a set of antennas. 
     A processor of a UE  115  (e.g., controlling the receiver  910 , the transmitter  935 , or the transceiver  1120  as described with reference to  FIG.  9   ), may efficiently operate one or more components of the UE  115  to improve efficiency of the UE0.115. For example, the processor may operate the receiver  910  to receive configuration information from a base station  105 , which may be used by the processor of the UE  115  to efficiently operate reference signal antenna switching. This configuration information may further allow the UE  115  to improve reliability by enabling the network to perform channel estimation, and also decrease interference. 
       FIG.  10    shows a block diagram  1000  of a communications manager  1005  that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. The communications manager  1005  may be an example of aspects of a communications manager  815 , a communications manager  915 , or a communications manager  1110  described herein. The communications manager  1005  may include a configuration component  1010 , a resource component  1015 , a reference signal component  1020 , and a cover code component  1025 . Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses). 
     The configuration component  1010  may receive a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping. 
     In some cases, the configuration for the reference signal resource set includes an indicator of a quantity of symbols of a guard period for the antenna switching. 
     In some cases, the configuration for the reference signal resource set includes an indication of a time interlacing for the type of frequency hopping. 
     In some cases, the reference signal is a sounding reference signal. 
     In some cases, the configuration for the reference signal resource set is periodic, aperiodic, or semi-persistent. 
     The resource component  1015  may determine a reference signal resource for transmission of the reference signal based on the configuration and the type of frequency hopping. 
     The reference signal component  1020  may transmit a set of repetitions of the reference signal over the determined reference signal resource according to the type of time division cover coding. 
     In some examples, the reference signal component  1020  may transmit the set of repetitions of the reference signal over each of a set of subsets of the determined reference signal resource using one of a set of antennas. 
     In some examples, the reference signal component  1020  may transmit the set of repetitions of the reference signal over a first frequency resource within a first set of symbols of a slot. 
     In some examples, the reference signal component  1020  may transmit a first subset of the set of repetitions of the reference signal over a first frequency resource within a first set of symbols of a slot. 
     In some examples, the reference signal component  1020  may transmit a second subset of the set of repetitions of the reference signal over a second frequency resource within a second set of symbols of the slot. 
     In some examples, the reference signal component  1020  may transmit a first subset of the set of repetitions of the reference signal over a first frequency resource within a first set of symbols of a first slot. 
     In some examples, the reference signal component  1020  may transmit a second subset of the set of repetitions of the reference signal over a second frequency resource within a second set of symbols of a second slot. 
     The cover code component  1025  may apply a first value of a cover code to a first repetition of the reference signal, the first repetition of the reference signal transmitted in a first symbol and applying a second value of the cover code to a second repetition of the reference signal, the second repetition of the reference signal transmitted in a second symbol. 
     In some cases, the first symbol and the second symbol are in a same slot. 
     In some cases, the first symbol and the second symbol are not contiguous symbols of the same slot. 
     In some cases, the first symbol is in a first slot and the second symbol is in a second slot. 
       FIG.  11    shows a diagram of a system  1100  including a device  1105  that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. The device  1105  may be an example of or include the components of device  805 , device  905 , or a UE  115  as described herein. The device  1105  may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager  1110 , an I/O controller  1115 , a transceiver  1120 , an antenna  1125 , memory  1130 , and a processor  1140 . These components may be in electronic communication via one or more buses (e.g., bus  1145 ). 
     The communications manager  1110  may receive a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping, determine a reference signal resource for transmission of the reference signal based on the configuration and the type of frequency hopping, and transmit a set of repetitions of the reference signal over the determined reference signal resource according to the type of time division cover coding. 
     The I/O controller  1115  may manage input and output signals for the device  1105 . The I/O controller  1115  may also manage peripherals not integrated into the device  1105 . In some cases, the I/O controller  1115  may represent a physical connection or port to an external peripheral. In some cases, the I/O controller  1115  may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operating system. In other cases, the I/O controller  1115  may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller  1115  may be implemented as part of a processor. In some cases, a user may interact with the device  1105  via the I/O controller  1115  or via hardware components controlled by the I/O controller  1115 . 
     The transceiver  1120  may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver  1120  may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver  1120  may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas. 
     In some cases, the wireless device may include a single antenna  1125 . However, in some cases the device may have more than one antenna  1125 , which may be capable of concurrently transmitting or receiving multiple wireless transmissions. 
     The memory  1130  may include RAM and ROM. The memory  1130  may store computer-readable, computer-executable code  1135  including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory  1130  may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices. 
     The processor  1140  may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor  1140  may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into the processor  1140 . The processor  1140  may be configured to execute computer-readable instructions stored in a memory (e.g., the memory  1130 ) to cause the device  1105  to perform various functions (e.g., functions or tasks supporting repetition and time domain cover code based sounding reference signal resources for antenna switching). 
     The code  1135  may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code  1135  may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code  1135  may not be directly executable by the processor  1140  but may cause a computer (e.g., when compiled and executed) to perform functions described herein. 
       FIG.  12    shows a block diagram  1200  of a device  1205  that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. The device  1205  may be an example of aspects of a base station  105  as described herein. The device  1205  may include a receiver  1210 , a communications manager  1215 , and a transmitter  1220 . The device  1205  may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). 
     The receiver  1210  may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to repetition and time domain cover code based sounding reference signal resources for antenna switching, etc.). Information may be passed on to other components of the device  1205 . The receiver  1210  may be an example of aspects of the transceiver  1520  described with reference to  FIG.  15   . The receiver  1210  may utilize a single antenna or a set of antennas. 
     The communications manager  1215  may transmit, to a UE, a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping and receive a set of repetitions of the reference signal over a determined reference signal resource according to the type of time division cover coding and based on the indication of the type of frequency hopping. The communications manager  1215  may be an example of aspects of the communications manager  1510  described herein. 
     The communications manager  1215 , or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager  1215 , or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC), a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure. 
     The communications manager  1215 , or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager  1215 , or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager  1215 , or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure. 
     The transmitter  1220  may transmit signals generated by other components of the device  1205 . In some examples, the transmitter  1220  may be collocated with a receiver  1210  in a transceiver module. For example, the transmitter  1220  may be an example of aspects of the transceiver  1520  described with reference to  FIG.  15   . The transmitter  1220  may utilize a single antenna or a set of antennas. 
       FIG.  13    shows a block diagram  1300  of a device  1305  that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. The device  1305  may be an example of aspects of a device  1205 , or a base station  105  as described herein. The device  1305  may include a receiver  1310 , a communications manager  1315 , and a transmitter  1330 . The device  1305  may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). 
     The receiver  1310  may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to repetition and time domain cover code based sounding reference signal resources for antenna switching, etc.). Information may be passed on to other components of the device  1305 . The receiver  1310  may be an example of aspects of the transceiver  1520  described with reference to  FIG.  15   . The receiver  1310  may utilize a single antenna or a set of antennas. 
     The communications manager  1315  may be an example of aspects of the communications manager  1215  as described herein. The communications manager  1315  may include a configuration transmission component  1320  and a reference signal reception component  1325 . The communications manager  1315  may be an example of aspects of the communications manager  1510  described herein. 
     The configuration transmission component  1320  may transmit, to a UE, a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping. 
     The reference signal reception component  1325  may receive a set of repetitions of the reference signal over a determined reference signal resource according to the type of time division cover coding and based on the indication of the type of frequency hopping. 
     The transmitter  1330  may transmit signals generated by other components of the device  1305 . In some examples, the transmitter  1330  may be collocated with a receiver  1310  in a transceiver module. For example, the transmitter  1330  may be an example of aspects of the transceiver  1520  described with reference to  FIG.  15   . The transmitter  1330  may utilize a single antenna or a set of antennas. 
       FIG.  14    shows a block diagram  1400  of a communications manager  1405  that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. The communications manager  1405  may be an example of aspects of a communications manager  1215 , a communications manager  1315 , or a communications manager  1510  described herein. The communications manager  1405  may include a configuration transmission component  1410  and a reference signal reception component  1415 . Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses). 
     The configuration transmission component  1410  may transmit, to a UE, a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping. 
     In some examples, the configuration transmission component  1410  may transmit, to a second UE, a configuration for an uplink transmission by the second UE within the guard period for the antenna switching for the first UE. 
     In some cases, the configuration for the reference signal resource set includes an indicator of a quantity of symbols of a guard period for the antenna switching. 
     In some cases, the configuration for the reference signal resource set includes an indication of a time interlacing for the frequency hopping. 
     In some cases, the reference signal is a sounding reference signal. 
     In some cases, the configuration for the reference signal resource set is periodic, aperiodic, or semi-persistent. 
     The reference signal reception component  1415  may receive a set of repetitions of the reference signal over a determined reference signal resource according to the type of time division cover coding and based on the indication of the type of frequency hopping. 
     In some examples, the reference signal reception component  1415  may receive the set of repetitions of the reference signal over a first frequency resource within a first set of symbols of a slot. 
     In some examples, the reference signal reception component  1415  may receive a first subset of the set of repetitions of the reference signal over a first frequency resource within a first set of symbols of a slot. 
     In some examples, the reference signal reception component  1415  may receive a second subset of the set of repetitions of the reference signal over a second frequency resource within a second set of symbols of the slot. 
     In some examples, the reference signal reception component  1415  may receive a first subset of the set of repetitions of the reference signal over a first frequency resource within a first set of symbols of a first slot. 
     In some examples, the reference signal reception component  1415  may receive a second subset of the set of repetitions of the reference signal over a second frequency resource within a second set of symbols of a second slot. 
     In some examples, the reference signal reception component  1415  may receive the set of repetitions of the reference signal based on an application of a first value of a cover code to a first repetition of the reference signal, the first repetition of the reference signal transmitted in a first symbol and an application of a second value of the cover code to a second repetition of the reference signal, the second repetition of the reference signal transmitted in a second symbol. 
     In some cases, the first symbol and the second symbol are in a same slot. 
     In some cases, the first symbol and the second symbol are not contiguous symbols of the same slot. 
     In some cases, the first symbol is in a first slot and the second symbol is in a second slot. 
       FIG.  15    shows a diagram of a system  1500  including a device  1505  that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. The device  1505  may be an example of or include the components of device  1205 , device  1305 , or a base station  105  as described herein. The device  1505  may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager  1510 , a network communications manager  1515 , a transceiver  1520 , an antenna  1525 , memory  1530 , a processor  1540 , and an inter-station communications manager  1545 . These components may be in electronic communication via one or more buses (e.g., bus  1550 ). 
     The communications manager  1510  may transmit, to a UE, a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping and receive a set of repetitions of the reference signal over a determined reference signal resource according to the type of time division cover coding and based on the indication of the type of frequency hopping. 
     The network communications manager  1515  may manage communications with the core network (e.g., via one or more wired backhaul links). For example, the network communications manager  1515  may manage the transfer of data communications for client devices, such as one or more UEs  115 . 
     The transceiver  1520  may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver  1520  may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver  1520  may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas. 
     In some cases, the wireless device may include a single antenna  1525 . However, in some cases the device may have more than one antenna  1525 , which may be capable of concurrently transmitting or receiving multiple wireless transmissions. 
     The memory  1530  may include RAM, ROM, or a combination thereof. The memory  1530  may store computer-readable code  1535  including instructions that, when executed by a processor (e.g., the processor  1540 ) cause the device to perform various functions described herein. In some cases, the memory  1530  may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices. 
     The processor  1540  may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor  1540  may be configured to operate a memory array using a memory controller. In some cases, a memory controller may be integrated into processor  1540 . The processor  1540  may be configured to execute computer-readable instructions stored in a memory (e.g., the memory  1530 ) to cause the device  1505  to perform various functions (e.g., functions or tasks supporting repetition and time domain cover code based sounding reference signal resources for antenna switching). 
     The inter-station communications manager  1545  may manage communications with other base station  105 , and may include a controller or scheduler for controlling communications with UEs  115  in cooperation with other base stations  105 . For example, the inter-station communications manager  1545  may coordinate scheduling for transmissions to UEs  115  for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communications manager  1545  may provide an X2 interface within an LTE/LTE-A wireless communication network technology to provide communication between base stations  105 . 
     The code  1535  may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code  1535  may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code  1535  may not be directly executable by the processor  1540  but may cause a computer (e.g., when compiled and executed) to perform functions described herein. 
       FIG.  16    shows a flowchart illustrating a method  1600  that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. The operations of method  1600  may be implemented by a UE  115  or its components as described herein. For example, the operations of method  1600  may be performed by a communications manager as described with reference to  FIGS.  8  through  11   . In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware. 
     At  1605 , the UE may receive a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping. The operations of  1605  may be performed according to the methods described herein. In some examples, aspects of the operations of  1605  may be performed by a configuration component as described with reference to  FIGS.  8  through  11   . 
     At  1610 , the UE may determine a reference signal resource for transmission of the reference signal based on the configuration and the type of frequency hopping. The operations of  1610  may be performed according to the methods described herein. In some examples, aspects of the operations of  1610  may be performed by a resource component as described with reference to  FIGS.  8  through  11   . 
     At  1615 , the UE may transmit a set of repetitions of the reference signal over the determined reference signal resource according to the type of time division cover coding. The operations of  1615  may be performed according to the methods described herein. In some examples, aspects of the operations of  1615  may be performed by a reference signal component as described with reference to  FIGS.  8  through  11   . 
       FIG.  17    shows a flowchart illustrating a method  1700  that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. The operations of method  1700  may be implemented by a UE  115  or its components as described herein. For example, the operations of method  1700  may be performed by a communications manager as described with reference to  FIGS.  8  through  11   . In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware. 
     At  1705 , the UE may receive a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping. The operations of  1705  may be performed according to the methods described herein. In some examples, aspects of the operations of  1705  may be performed by a configuration component as described with reference to  FIGS.  8  through  11   . 
     At  1710 , the UE may determine a reference signal resource for transmission of the reference signal based on the configuration and the type of frequency hopping. The operations of  1710  may be performed according to the methods described herein. In some examples, aspects of the operations of  1710  may be performed by a resource component as described with reference to  FIGS.  8  through  11   . 
     At  1715 , the UE may transmit a set of repetitions of the reference signal over the determined reference signal resource according to the type of time division cover coding. The operations of  1715  may be performed according to the methods described herein. In some examples, aspects of the operations of  1715  may be performed by a reference signal component as described with reference to  FIGS.  8  through  11   . 
     At  1720 , the UE may transmit the set of repetitions of the reference signal over each of a set of subsets of the determined reference signal resource using one of a set of antennas. The operations of  1720  may be performed according to the methods described herein. In some examples, aspects of the operations of  1720  may be performed by a reference signal component as described with reference to  FIGS.  8  through  11   . 
       FIG.  18    shows a flowchart illustrating a method  1800  that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. The operations of method  1800  may be implemented by a UE  115  or its components as described herein. For example, the operations of method  1800  may be performed by a communications manager as described with reference to  FIGS.  8  through  11   . In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware. 
     At  1805 , the UE may receive a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping. The operations of  1805  may be performed according to the methods described herein. In some examples, aspects of the operations of  1805  may be performed by a configuration component as described with reference to  FIGS.  8  through  11   . 
     At  1810 , the UE may determine a reference signal resource for transmission of the reference signal based on the configuration and the type of frequency hopping. The operations of  1810  may be performed according to the methods described herein. In some examples, aspects of the operations of  1810  may be performed by a resource component as described with reference to  FIGS.  8  through  11   . 
     At  1815 , the UE may apply a first value of a cover code to a first repetition of the reference signal, the first repetition of the reference signal transmitted in a first symbol and applying a second value of the cover code to a second repetition of the reference signal, the second repetition of the reference signal transmitted in a second symbol. The operations of  1815  may be performed according to the methods described herein. In some examples, aspects of the operations of  1815  may be performed by a cover code component as described with reference to  FIGS.  8  through  11   . 
     At  1820 , the UE may transmit a set of repetitions of the reference signal over the determined reference signal resource according to the type of time division cover coding. The operations of  1820  may be performed according to the methods described herein. In some examples, aspects of the operations of  1820  may be performed by a reference signal component as described with reference to  FIGS.  8  through  11   . 
       FIG.  19    shows a flowchart illustrating a method  1900  that supports repetition and time domain cover code based sounding reference signal resources for antenna switching in accordance with aspects of the present disclosure. The operations of method  1900  may be implemented by a base station  105  or its components as described herein. For example, the operations of method  1900  may be performed by a communications manager as described with reference to  FIGS.  12  through  15   . In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware. 
     At  1905 , the base station may transmit, to a UE, a configuration for a reference signal resource set for transmitting a reference signal for antenna switching, the configuration including an indication of a type of time division cover coding for repetitions of the reference signal and an indication of a type of frequency hopping. The operations of  1905  may be performed according to the methods described herein. In some examples, aspects of the operations of  1905  may be performed by a configuration transmission component as described with reference to  FIGS.  12  through  15   . 
     At  1910 , the base station may receive a set of repetitions of the reference signal over a determined reference signal resource according to the type of time division cover coding and based on the indication of the type of frequency hopping. The operations of  1910  may be performed according to the methods described herein. In some examples, aspects of the operations of  1910  may be performed by a reference signal reception component as described with reference to  FIGS.  12  through  15   . 
     It should be noted that the methods described herein describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined. 
     Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques may be applicable to various other wireless communications systems such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, as well as other systems and radio technologies not explicitly mentioned herein. 
     Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. 
     The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration). 
     The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. 
     Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include random-access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media. 
     As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of”) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on.” 
     In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label. 
     The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration,” and not “preferred” or “advantageous over other examples.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples. 
     The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.