Method and apparatus for frequency hopping of sounding reference signals in a partial bandwidth

Abstract

In some scenarios, SRS transmission over full SRS bandwidth can be unnecessary and / or inefficient. Thus, there is a need for methods for SRS transmission over less than full SRS bandwidth. Techniques and solutions are described herein for SRS transmission using only a portion of full SRS bandwidth or partial SRS bandwidth. The present disclosure provides for using partial SRS bandwidth by sounding mode using only partial SRS bandwidth and / or generating SRS transmission using partial SRS bandwidth by various SRS sequences configured for partial SRS bandwidth. An apparatus operates to receive an SRS configuration indicating a full SRS bandwidth, determine a frequency hopping pattern for SRS transmission based on the SRS configuration, and the frequency hopping pattern is limited to a partial SRS bandwidth that is less than the full SRS bandwidth, and transmit the SRS transmission to a base station based on the frequency hopping pattern.

Description

Technical Field

[0001]

[0002] The present disclosure generally relates to communication systems, and more particularly, to reference signals sent from user equipment to a base station within a certain bandwidth. Background Art

[0002] Wireless communication systems are widely deployed to provide a variety of telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0003] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at a city, country, region, and even global level. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of the continued mobile broadband evolution released by the 3rd Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (for example, in conjunction with the Internet of Things (IoT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC). Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There is a need for further improvements to 5G NR technology. These improvements may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies. Summary of the Invention

[0004] The following provides a brief summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects and is neither intended to identify key or critical elements of all aspects nor to delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that will be presented later.

[0005] In some example radio access technology (RAT) access networks (such as 5G New Radio (NR) access networks), a base station may use at least one sounding reference signal (SRS) to estimate at least one channel (e.g., an uplink channel) on which a transmission is received from a user equipment (UE). Additionally or alternatively, the SRS may be used for uplink frequency selective scheduling and / or uplink timing estimation. Thus, the UE transmits at least one SRS to the base station, but the UE may transmit the SRS over a wider bandwidth than the uplink channel. In this case, the UE may sound all ports of the SRS resource in each symbol of the SRS resource.

[0006] When a UE transmits an SRS, the full bandwidth may be available for SRS transmission. However, the full SRS bandwidth may be the entire bandwidth of interest, but less than the entire system bandwidth (although the bandwidth of interest may potentially be equal to the system bandwidth). In some aspects, the base station may then configure the full SRS bandwidth for the UE.

[0007] Potentially, the UE can be configured to use frequency hopping for SRS. For example, the UE may not have enough transmit power to detect over the full SRS bandwidth (e.g., when the UE is near the cell edge), and therefore, the base station can configure the UE to use frequency hopping for SRS. However, when frequency hopping is used, the UE can still transmit SRS over the full SRS bandwidth, but can do so over multiple symbols (e.g., multiple adjacent symbols).

[0008] In some scenarios, SRS transmission over the full SRS bandwidth may be unnecessary and / or inefficient (eg, in terms of power consumption). Therefore, there is a need for a method for SRS transmission over less than the full SRS bandwidth.

[0009] This disclosure describes various techniques and solutions for SRS transmission using only a portion of the full SRS bandwidth or a fraction of the SRS bandwidth. Such techniques and solutions for SRS transmission using a fraction of the SRS bandwidth can allow UE multiplexing, enabling a greater number of UEs to transmit SRS in a cell. In addition, SRS transmission using a fraction of the SRS bandwidth can reduce some of the power overhead incurred by the UE from SRS transmission.

[0010] In some aspects, the present disclosure provides for SRS transmission using a portion of the SRS bandwidth by using a sounding mode (e.g., a frequency hopping mode) that uses only a portion of the SRS bandwidth. In some other aspects, the present disclosure provides for SRS transmission using a portion of the SRS bandwidth by generating various SRS sequences configured for the portion of the SRS bandwidth.

[0011] In one aspect of the present disclosure, a method, computer-readable medium, and apparatus are provided. The apparatus may be a UE. The apparatus is configured to receive an SRS configuration indicating a full SRS bandwidth from a base station. The apparatus is further configured to determine a frequency hopping pattern for SRS transmission based on the SRS configuration, where the frequency hopping pattern may be limited to a portion of the SRS bandwidth that is less than the full SRS bandwidth. Furthermore, the apparatus is configured to send an SRS transmission to the base station based on the frequency hopping pattern.

[0012] In another aspect of the present disclosure, another method, another computer-readable medium, and another apparatus are provided. The another apparatus may be a base station. The another apparatus is configured to transmit an SRS configuration indicating a full SRS bandwidth to a UE. The another apparatus is further configured to receive an SRS transmission from the UE according to a frequency hopping pattern based on the SRS configuration, wherein the frequency hopping pattern is limited to a portion of the SRS bandwidth that is less than the full SRS bandwidth.

[0013] To accomplish the foregoing and related objectives, one or more aspects include the features hereinafter fully described and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail certain illustrative features of one or more aspects. However, these features are indicative of only some of the various ways in which the principles of the various aspects may be employed, and this description is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram illustrating an example of a wireless communication system and an access network.

[0015] Figure 2A is a diagram illustrating an example of a first frame according to various aspects of the present disclosure.

[0016] Figure 2B is a diagram illustrating an example of DL channels within a subframe according to various aspects of the present disclosure.

[0017] Figure 2C is a diagram illustrating an example of a second frame according to various aspects of the present disclosure.

[0018] Figure 2D is a diagram illustrating an example of UL channels within a subframe according to various aspects of the present disclosure.

[0019] Figure 3 is a schematic diagram illustrating an example of a base station and a user equipment (UE) in an access network.

[0020] Figure 4 is a diagram illustrating an example configuration for transmission of a sounding reference signal (SRS).

[0021] Figure 5 is a diagram illustrating an example resource mapping of SRS resources.

[0022] Figure 6 is a call flow diagram illustrating example operations for SRS transmission by a UE to a base station.

[0023] Figure 7 is a diagram illustrating an example frequency hopping pattern for SRS resources over the full bandwidth configured for SRS.

[0024] Figure 8 is a diagram illustrating an example frequency hopping pattern for SRS transmission over a fraction of the full bandwidth configured for SRS.

[0025] Figure 9 is a diagram illustrating other example frequency hopping patterns for SRS transmission over a fraction of the full bandwidth configured for SRS.

[0026] Figure 10 is a diagram illustrating another example frequency hopping pattern for SRS transmission over a fraction of the full bandwidth configured for SRS.

[0027] Figure 11 is a flow chart of a method for performing wireless communication by a UE.

[0028] Figure 12 is a flow chart of a method for performing wireless communication by a base station. DETAILED DESCRIPTION

[0029] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. For the purpose of providing a comprehensive understanding of the various concepts, the detailed description includes specific details. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0030] Several aspects of telecommunication systems will now be presented with reference to various apparatuses and methods. These apparatuses and methods will be described in the following detailed description by means of various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements") and illustrated in the accompanying drawings. These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0031] For example, an element, or any part of an element, or any combination of elements, can be implemented as a "processing system" comprising one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gating logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure. One or more processors in a processing system can execute software. Whether referred to as software, firmware, middleware, microcode, hardware description language, or other names, software should be broadly interpreted as meaning instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, processes, functions, etc.

[0032] Accordingly, in one or more example embodiments, the described functions may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored or encoded as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media. Storage media may be any available medium that can be accessed by a computer. By way of example and not limitation, such computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, a combination of the above-mentioned types of computer-readable media, or any other medium that can be used to store computer-executable code that can be accessed by a computer in the form of instructions or data structures.

[0033] Figure 1 1 is a schematic diagram illustrating an example of a wireless communication system and access network 100. The wireless communication system (also referred to as a wireless wide area network (WWAN)) includes a base station 102, a user equipment (UE) 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., a 5G core (5GC)). The base station 102 may include a macro cell (a high-power cellular base station) and / or a small cell (a low-power cellular base station). A macro cell includes a base station. Small cells include femto cells, pico cells, and micro cells.

[0034] A base station 102 configured for 4G Long Term Evolution (LTE), collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), can interface with the EPC 160 via a first backhaul link 132 (e.g., an S1 interface). A base station 102 configured for 5G New Radio (NR), collectively referred to as the Next Generation RAN (NG-RAN), can interface with the core network 190 via a second backhaul link 184. Among other functions, the base station 102 can perform one or more of the following: transmission of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), user and device tracking, RAN information management (RIM), paging, positioning, and delivery of warning messages. Base stations 102 can communicate with each other directly or indirectly (eg, through EPC 160 or core network 190) over a third backhaul link 134 (eg, an X2 interface). First backhaul link 132, second backhaul link 184, and third backhaul link 134 can be wired or wireless.

[0035] Base stations 102 can communicate wirelessly with UEs 104. Each of base stations 102 can provide communication coverage for a corresponding geographic coverage area 110. There can be overlapping geographic coverage areas 110. For example, a small cell 102′ can have a coverage area 110′ that overlaps with the coverage area 110 of one or more macro base stations 102. A network that includes both small cells and macro cells can be referred to as a heterogeneous network. A heterogeneous network can also include home evolved Node Bs (eNBs) (HeNBs), which can provide services to a restricted group called a closed subscriber group (CSG). The communication link 120 between base station 102 and UE 104 can include uplink (UL) (also known as reverse link) transmissions from UE 104 to base station 102 and / or downlink (DL) (also known as forward link) transmissions from base station 102 to UE 104. The communication link 120 can use multiple-input multiple-output (MIMO) antenna technology, which includes spatial multiplexing, beamforming, and / or transmit diversity. The communication link may be through one or more carriers. The base station 102 / UE 104 may use a spectrum of up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to Yx megahertz (MHz) (x component carriers) for transmission in each direction. The carriers may be adjacent to each other or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL ​​compared to UL). The component carrier may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell), and the secondary component carrier may be referred to as a secondary cell (SCell).

[0036] Some UEs 104 can communicate with each other using device-to-device (D2D) communication links 158. The D2D communication links 158 can use the DL / UL WWAN spectrum. The D2D communication links 158 can use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). D2D communication can be achieved through various wireless D2D communication systems, such as, for example, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

[0037] The wireless communication system may also include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 via a communication link 154 in, for example, a 5 gigahertz (GHz) unlicensed spectrum. When communicating in the unlicensed spectrum, the STA 152 / AP 150 may perform a clear channel assessment (CCA) prior to communication to determine whether the channel is available.

[0038] The small cell 102' can operate in licensed and / or unlicensed spectrum. When operating in the unlicensed spectrum, the small cell 102' can employ NR and use the same unlicensed spectrum (e.g., 5 GHz, etc.) as used by the Wi-Fi AP 150. The small cell 102' employing NR in the unlicensed spectrum can improve coverage and / or increase capacity of the access network.

[0039] The electromagnetic spectrum is often subdivided into various categories, bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating bands have been identified with the frequency range names FR1 (410 MHz - 7.125 GHz) and FR2 (24.25 GHz - 52.6 GHz). Frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, FR1 is often (interchangeably) referred to as the "sub-6 GHz" band in various documents and articles. Similar naming issues sometimes arise with respect to FR2, which is often (interchangeably) referred to as the "millimeter wave" band in documents and articles, although it is different from the extremely high frequency (EHF) band (30 GHz - 300 GHz), which is identified as the "millimeter wave" band by the International Telecommunication Union (ITU).

[0040] In view of the above, unless otherwise specified, it should be understood that the term "sub-6 GHz" and the like, if used herein, can broadly refer to frequencies that can be less than 6 GHz, can be within FR1, or can include mid-band frequencies. Furthermore, unless otherwise specified, it should be understood that the term "millimeter wave" and the like, if used herein, can broadly refer to frequencies that can include mid-band frequencies, can be within FR2, or can be within the EHF band.

[0041] Base station 102 (whether a small cell 102' or a large cell (e.g., a macro base station)) may include and / or be referred to as an eNB, gNodeB (gNB), or another type of base station. Some base stations, such as gNB 180, may operate in conventional sub-6 GHz spectrum, in millimeter wave frequencies, and / or near millimeter wave frequencies to communicate with UE 104. When gNB 180 operates in millimeter wave or near millimeter wave frequencies, gNB 180 may be referred to as a millimeter wave base station. Millimeter wave base station 180 may utilize beamforming 182 with UE 104 to compensate for path loss and short range. Base station 180 and UE 104 may each include multiple antennas (such as antenna elements, antenna panels, and / or antenna arrays) to facilitate beamforming.

[0042] Base station 180 may transmit beamformed signals in one or more transmit directions 182′ to UE 104. UE 104 may receive beamformed signals from base station 180 in one or more receive directions 182″. UE 104 may also transmit beamformed signals in one or more transmit directions to base station 180. Base station 180 may receive beamformed signals in one or more receive directions from UE 104. Base station 180 / UE 104 may perform beam training to determine optimal receive and transmit directions for each of base station 180 / UE 104. The transmit direction and receive direction for base station 180 may be the same or different. The transmit direction and receive direction for UE 104 may be the same or different.

[0043] EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, an MBMS Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. MME 162 may communicate with a Home Subscriber Server (HSS) 174. MME 162 is a control node that handles signaling between UE 104 and EPC 160. Generally, MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are transmitted through Serving Gateway 166, which itself is connected to PDN Gateway 172. PDN Gateway 172 provides IP address allocation and other functions. PDN Gateway 172 and BM-SC 170 are connected to IP Services 176. IP Services 176 may include the Internet, Intranet, IP Multimedia Subsystem (IMS), PS Streaming Services, and / or other IP services. BM-SC 170 may provide functionality for MBMS user service setup and delivery. The BM-SC 170 may serve as the entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services within a public land mobile network (PLMN), and may be used to schedule MBMS transmissions. The MBMS gateway 168 may be used to distribute MBMS services to base stations 102 belonging to a multicast broadcast single frequency network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start / stop) and for collecting eMBMS-related billing information.

[0044] The core network 190 may include an access and mobility management function (AMF) 192, other AMFs 193, a session management function (SMF) 194, and a user plane function (UPF) 195. The AMF 192 may communicate with a unified data management (UDM) 196. The AMF 192 is a control node that handles signaling between the UE 104 and the core network 190. Typically, the AMF 192 provides quality of service (QoS) flows and session management. All user Internet Protocol (IP) packets are transported through the UPF 195. The UPF 195 provides UE IP address allocation and other functions. The UPF 195 is connected to the IP services 197. The IP services 197 may include the Internet, an intranet, an IMS, packet-switched (PS) streaming services, and / or other IP services.

[0045] A base station may include and / or be referred to as a gNB, a Node B, an eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit / receive point (TRP), or some other appropriate terminology. Base station 102 provides an access point to EPC 160 or core network 190 for UE 104. Examples of UE 104 include a cellular phone, a smartphone, a Session Initiation Protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio unit, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., an MP3 player), a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor / actuator, a display, or any other similarly functional device. Some of UE 104 may be referred to as IoT devices (e.g., a parking meter, a gas pump, an oven, a vehicle, a heart monitor, etc.). UE 104 may also be referred to as a station, a mobile station, a user station, a mobile unit, a user unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile user station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handheld device, a user agent, a mobile client, a client, or some other appropriate terminology.

[0046] Although the present disclosure may focus on 5G NR, the concepts and aspects described herein may be applicable to other similar areas such as LTE, LTE-Advanced (LTE-A), Code Division Multiple Access (CDMA), Global System for Mobile Communications (GSM), or other wireless / radio access technologies.

[0047] Refer again Figure 1 In certain aspects, the base station 102 / 180 may be configured to transmit a sounding reference signal (SRS) configuration to the UE 104 that indicates a full SRS bandwidth. The full SRS bandwidth may be a bandwidth of interest over which the UE 104 communicates with the base station 102 / 180, and thus, the full SRS bandwidth may be less than the entire system bandwidth (although the full SRS bandwidth may potentially be equal to the entire system bandwidth). The base station 102 / 180 may be configured to receive SRS transmissions from the UE 104 and based on the SRS configuration according to a frequency hopping pattern that is restricted to a portion of the SRS bandwidth that is less than the full SRS bandwidth (198).

[0048] Accordingly, the UE 104 may be configured to receive an SRS configuration from the base station 102 / 180 indicating the full SRS bandwidth. The UE 104 may also be configured to determine a frequency hopping pattern for SRS transmission based on the SRS configuration, where the frequency hopping pattern is limited to a portion of the SRS bandwidth that is less than the full SRS bandwidth. Thus, the UE 104 may send an SRS transmission to the base station 102 / 180 based on the frequency hopping pattern, where the frequency hopping pattern is limited to a portion of the SRS bandwidth that is less than the full SRS bandwidth (198).

[0049] Figure 2A is a diagram 200 illustrating an example of a first subframe within a 5G NR frame structure. Figure 2B is a diagram 230 illustrating an example of DL channels within a 5G NR subframe. Figure 2C is a diagram 250 illustrating an example of a second subframe within a 5G NR frame structure. Figure 2D 280 is a diagram illustrating an example of UL channels within a 5G NR subframe. The 5G NR frame structure may be frequency division duplex (FDD) (wherein, for a particular set of subcarriers (carrier system bandwidth), a subframe within a subcarrier set is dedicated to either DL or UL), or may be time division duplex (TDD) (wherein, for a particular set of subcarriers (carrier system bandwidth), a subframe within a subcarrier set is dedicated to both DL and UL). Figure 2A 、 2C In the example provided, the 5G NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (most of which are DL), where D is DL, U is UL, and F is flexible between DL / UL, and subframe 3 is configured with slot format 34 (most of which are UL). Although subframes 3 and 4 are shown as having slot formats 34 and 28, respectively, any particular subframe can be configured with any of the various available slot formats 0-61. Slot formats 0 and 1 are all DL and all UL, respectively. Other slot formats 2-61 include a mix of DL, UL and flexible symbols. The UE is configured with the slot format (dynamically configured through DL control information (DCI) or semi-statically / statically configured through radio resource control (RRC) signaling) via the received slot format indicator (SFI). It should be noted that the following description also applies to the 5G NR frame structure as TDD.

[0050] Other wireless communication technologies may have different frame structures and / or different channels. For example, a frame of 10 milliseconds (ms) may be divided into 10 equally sized subframes (1 ms). Each subframe may include one or more time slots. A subframe may also include a mini-slot, which may include 7, 4, or 2 symbols. Each time slot may include 7 or 14 symbols, depending on the time slot configuration. For time slot configuration 0, each time slot may include 14 symbols, and for time slot configuration 1, each time slot may include 7 symbols. The symbols on the DL may be cyclic prefix (CP) orthogonal frequency division multiplexing (OFDM) (CP-OFDM) symbols. The symbols on the UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also known as single carrier frequency division multiple access (SC-FDMA) symbols) (for power-limited scenarios; limited to single stream transmission). The number of time slots within a subframe may be based on the time slot configuration and numerology. For slot configuration 0, different digital schemes μ0 to 4 allow 1, 2, 4, 8, and 16 slots per subframe, respectively. For slot configuration 1, different digital schemes 0 to 2 allow 2, 4, and 8 slots per subframe, respectively. Accordingly, for slot configuration 0 and digital scheme μ, there are 14 symbols / slot and 2 μ The subcarrier spacing and symbol length / duration are functions of the digital scheme. The subcarrier spacing can be equal to 2μ*15 kilohertz (kHz), where μ is the digital scheme 0 to 4. Thus, digital scheme μ=0 has a subcarrier spacing of 15 kHz, and digital scheme μ=4 has a subcarrier spacing of 240 kHz. Symbol length / duration is inversely related to the subcarrier spacing. Figures 2A-2D An example is provided for slot configuration 0 (with 14 symbols per slot) and digital scheme μ=2 (with 4 slots per subframe). The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs. Within a frame set, there may be one or more different bandwidth parts (BWPs) frequency-division multiplexed (see Figure 2B ). Each BWP can have a specific number scheme.

[0051] The resource grid can be used to represent the frame structure. Each time slot includes a resource block (RB) (also called a physical RB (PRB)), which includes 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0052] As in Figure 2AAs shown in , some of the REs carry reference (pilot) signals (RS) for the UE. The RS may include a demodulation RS (DM-RS) for channel estimation at the UE (indicated as R for a specific configuration). x (where 100x is the port number), but other DM-RS configurations are possible) and channel state information reference signal (CSI-RS). RS may also include beam measurement RS (BRS), beam refinement RS (BRRS), and phase tracking RS (PT-RS).

[0053] Figure 2B Examples of various DL channels within a subframe of a frame are shown. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs), each CCE including nine RE groups (REGs), and each REG including four consecutive REs in one OFDM symbol. The PDCCH within a BWP can be called a control resource set (CORESET). Additional BWPs can be located at larger and / or lower frequencies across the channel bandwidth. The primary synchronization signal (PSS) can be within symbol 2 of a specific subframe of the frame. The PSS is used by the UE 104 to determine the subframe / symbol timing and the physical layer identification. The secondary synchronization signal (SSS) can be within symbol 4 of a specific subframe of the frame. The SSS is used by the UE to determine the physical layer cell identification group number and the radio frame timing. Based on the physical layer identification and the physical layer cell identification group number, the UE can determine the physical cell identifier (PCI). Based on the PCI, the UE can determine the position of the above-mentioned DM-RS. The physical broadcast channel (PBCH) carrying the master information block (MIB) can be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block (also referred to as an SS block (SSB)). The MIB provides the number of RBs in the system bandwidth and the system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not sent via the PBCH (such as the system information block (SIB)), and paging messages.

[0054] As in Figure 2CAs illustrated, some of the REs carry DM-RS (indicated as R for one particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE can transmit DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH). The PUSCH DM-RS can be transmitted in the first one or two symbols of the PUSCH. The PUCCH DM-RS can be transmitted with different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used. The UE can transmit SRS. The SRS can be transmitted in the last symbol of a subframe. The SRS can have a comb structure, and a UE can transmit SRS on one of the combs. The SRS can be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

[0055] Figure 2D An example of various UL channels is shown within a subframe of a frame. The PUCCH can be positioned as indicated for one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and hybrid automatic repeat request (HARQ) acknowledgment (ACK) / non-acknowledgment (NACK) feedback. The PUSCH carries data, and can additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0056] Figure 33 is a block diagram of a base station 310 communicating with a UE 350 in an access network. In the DL, IP packets from the EPC 160 may be provided to the controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functions. Layer 3 includes the radio resource control (RRC) layer, and layer 2 includes the service data adaptation protocol (SDAP) layer, the packet data convergence protocol (PDCP) layer, the radio link control (RLC) layer, and the medium access control (MAC) layer. The controller / processor 375 provides: RRC layer functions associated with the following: broadcast of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functions associated with the following: header compression / decompression, security (ciphering, deciphering, integrity protection, integrity verification), and handover support functions; RLC layer functions associated with the following: transmission of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation and reassembly of RLC service data units (SDUs), resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions associated with the following: mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0057] The transmit (TX) processor 316 and receive (RX) processor 370 implement layer 1 functions associated with various signal processing functions. Layer 1, including the physical (PHY) layer, may include error detection for transport channels, forward error correction (FEC) encoding / decoding for transport channels, interleaving, rate matching, mapping onto physical channels, modulation / demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles the mapping to the signal constellation based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), and M-order quadrature amplitude modulation (M-QAM)). The coded and modulated symbols can then be divided into parallel streams. Each stream can then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., a pilot) in the time and / or frequency domain, and then combined using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time-domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation schemes, as well as for spatial processing. The channel estimates may be derived based on a reference signal and / or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0058] At the UE 350, each receiver 354RX receives a signal via its corresponding antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to a receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functions associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they can be combined into a single OFDM symbol stream by the RX processor 356. The RX processor 356 then uses a fast Fourier transform (FFT) to convert the OFDM symbol stream from the time domain to the frequency domain. The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier and the reference signal are recovered and demodulated by determining the most likely signal constellation point transmitted by the base station 310. These soft decisions can be based on the channel estimate calculated by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally sent on the physical channel by base station 310. The data and control signals are then provided to controller / processor 359, which implements layer 3 and layer 2 functionality.

[0059] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operations.

[0060] Similar to the functions described in conjunction with DL transmissions performed by the base station 310, the controller / processor 359 provides: RRC layer functions associated with: system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functions associated with: header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functions associated with: transmission of upper layer PDUs, error correction through ARQ, concatenation, segmentation and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions associated with: mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0061] Channel estimates derived by the channel estimator 358 based on a reference signal or feedback transmitted by the base station 310 may be used by the TX processor 368 to select an appropriate coding and modulation scheme, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0062] UL transmissions are processed at the base station 310 in a manner similar to that described in conjunction with the receiver functionality at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to the RX processor 370.

[0063] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the UE 350. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using an ACK and / or NACK protocol to support HARQ operations.

[0064] In some aspects, at least one of the TX processor 368, the RX processor 356, and / or the controller / processor 359 may be configured to perform operations related to Figure 1 (198) all relevant aspects.

[0065] In some other aspects, at least one of the TX processor 316, the RX processor 370, and / or the controller / processor 375 may be configured to perform operations related to Figure 1 (198) all relevant aspects.

[0066] Figure 4 FIG4 is a diagram 400 of an example configuration of SRS resources. In an access network of an example RAT, such as a 5G NR access network, a base station may use at least one SRS (which may be referred to as an SRS resource (although an SRS resource does not necessarily correspond to only one subcarrier or RE on one symbol)) to estimate at least one channel (e.g., an uplink channel) on which a transmission is received from a UE. Additionally or alternatively, the SRS may be used for uplink frequency selective scheduling and / or uplink timing estimation. Thus, the UE transmits at least one SRS to the base station (e.g., see FIG4 above). Figures 2C-2D ), although potentially over a wider bandwidth than the uplink channel. The UE may probe all ports of the SRS resource in each symbol of the SRS resource.

[0067] According to various aspects, time slot 402 can be configured to include SRS on a set of RBs that span the entire bandwidth of interest for the base station and the UE. Potentially, the entire bandwidth of interest can be the uplink bandwidth of interest. The bandwidth of interest can be less than the entire system bandwidth; however, the bandwidth of interest can potentially be equal to the entire system bandwidth. For example, the bandwidth of interest can be 36, 48, or 64 RBs (although different numbers of RBs are possible for different bandwidths of interest). In some aspects, the UE can be configured to send SRS across the entire bandwidth of interest. Therefore, in the present disclosure, the entire bandwidth of interest may also be referred to as the "full SRS bandwidth."

[0068] The base station can configure the entire bandwidth of interest and, as such, the base station can signal the full SRS bandwidth to the UE, e.g., as part of the SRS configuration. In some aspects, the base station can signal the full SRS bandwidth and / or other information associated with the SRS configuration to the UE via RRC signaling. In some other aspects, the base station can use DCI (e.g., information included in the DCI and / or DCI format) and / or MAC control elements (CEs) to signal the full SRS bandwidth and / or other SRS configuration information.

[0069] In the time domain, a slot 402 can be configured to support SRS resources spanning a certain number of symbols, which can be contiguous (e.g., 1, 2, or 4 contiguous symbols), with up to 4 ports per SRS resource. According to some aspects, SRS can only be transmitted in the last 6 symbols of a slot 402 (e.g., 5G NR Rel-15 and Rel-16 can support SRS transmission in the last 6 symbols of a slot). However, according to some other aspects, SRS can be transmitted in any symbol of a slot (e.g., 5G NR Rel-17 and beyond can potentially support SRS transmission in more or all symbols of a slot 402).

[0070] Additionally or alternatively, SRS can only be transmitted in a slot after uplink data (such as carried on PUSCH) of the slot. For example, PUSCH can be mapped to a subset of symbols 0-13 of a slot 402. Next, SRS can be mapped to a subset of the remaining symbols 8-13 of the slot 402, e.g., SRS can be mapped to 1, 2, or 4 contiguous symbols within symbols 8-13 of the slot 402.

[0071] When a UE transmits an SRS resource, the SRS resource can be included in an SRS resource set of the UE, such as SRS resource set 1 410a or SRS resource set 2 410b. An SRS resource set can be configured to include one SRS resource or a group of multiple SRS resources, where the included SRS resources are based on the use case for which the SRS is transmitted, such as antenna switching, codebook-based, non-codebook-based, beam management, etc. Further, the UE can be configured for aperiodic, semi-persistent, or periodic transmission of the SRS resource set, e.g., where aperiodic transmission of the SRS resource set is signaled to the UE from the base station via DCI.

[0072] Illustratively, for the SRS antenna switching use case, 1 or 2TX to 2 or 4RX antenna switching can be supported, which can be denoted as "1T2R," "2T4R," "1T4R," and "1T4R / 2T4R," where the UE supports both 1TX to 4RX antenna switching and 2TX to 4RX antenna switching (however, switching of an equal number of TX and RX antennas can also be supported). To support antenna switching, the SRS resource set is configured with two (for 1T2R or 2T4R) or four (for 4T4R) SRS resources transmitted in different symbols. Each SRS resource includes one (for 1T2R or 1T4R) or two (for 2T4R) antenna ports, and the SRS ports of each SRS resource are associated with different UE antenna ports.

[0073] like Figure 4 As shown in one example, SRS resource set 1 410a is based on 1T4R and therefore includes four SRS resources 1 to 4 412a-d. The four SRS resources 1 to 4 412a-d may occur in one time slot, such as within four adjacent symbols of symbols 8 to 13 of time slot 402. However, other configurations may also be supported. For example, for 1T4R, two aperiodic SRS resource sets may be configured with a total of four SRS resources transmitted in different symbols of two different time slots, rather than SRS resources 1 to 4 412a-d in one time slot.

[0074] like Figure 4 As shown in another example, SRS resource set 2 410b can be based on a use case of codebook-based transmission (e.g., for beamforming), such as when feedback of precoding information (e.g., PMI) and / or other information is configured to increase throughput at the receiver side (e.g., base station). SRS resource set 2 410b can include one SRS resource 5 412e based on codebook-based transmission. SRS resource 5 412e can be sent in a single symbol (e.g., one symbol from symbols 8 to 13 of slot 402), and therefore, SRS resource 5 412e can be wideband because SRS resource 5 412e can span the full SRS bandwidth.

[0075] Figure 5 500 is a diagram illustrating an example frequency hopping scheme for SRS transmission. As described above, an SRS resource set may span the full SRS bandwidth. For example, one SRS resource may span the full SRS bandwidth, allowing detection of the full SRS bandwidth in one symbol. However, an SRS resource set may not span the full SRS bandwidth in a symbol; rather, an SRS resource set may include one or more SRS resources spanning the full SRS bandwidth over multiple symbols.

[0076] To this end, the UE can be configured to use frequency hopping for the SRS resource set. For example, the UE may not have sufficient transmission power to detect over the full SRS bandwidth (e.g., when the UE is near the cell edge), and therefore, the base station can configure the UE to use frequency hopping for SRS transmission. However, when frequency hopping is used, the UE can still transmit SRS over the full SRS bandwidth, but can do so over multiple symbols (e.g., multiple adjacent symbols).

[0077] according to Figure 5 In the example shown in , the full SRS bandwidth (or sounding bandwidth) can be configured as 48 PRBs. The UE can sound over the full SRS bandwidth according to different SRS hopping patterns 502, 522, 542. SRS resources can be transmitted at each hop, where each hop spans a fractional amount of the full SRS bandwidth (e.g., half or a quarter of the full SRS bandwidth) over one symbol.

[0078] For example, in the first SRS hopping pattern 502, SRS resources 504 may be transmitted on two adjacent symbols 12 and 13 of at least one slot. Each of the SRS resources 504 may span 24 PRBs of a different half of the full SRS bandwidth, such that all 48 PRBs in the full SRS bandwidth are detected on two adjacent symbols.

[0079] In the example of the second SRS hopping pattern 522, SRS resources 504 may be transmitted on four adjacent symbols 10 to 13 of at least one slot. SRS resources 504 may span 12 PRBs that are different quarters of the full SRS bandwidth, such that all 48 PRBs in the full SRS bandwidth are detected on four adjacent symbols.

[0080] In the example of the third SRS hopping pattern 542, SRS resources 504 may be transmitted over four adjacent symbols 10 to 13 of at least one slot. SRS resources 504 may span all 24 PRBs of the full SRS bandwidth. However, unlike the first two SRS hopping patterns 502 and 522, SRS resources may be repeated. For example, SRS resources 504 may be repeated over symbols 10 and 11, and SRS resources 504 may be repeated over symbols 12 and 13. Such repetition may increase the effectiveness of sounding over each 24 PRB bandwidth, for example, rather than sounding each half or quarter of the 48 PRB bandwidth only once per symbol.

[0081] In some scenarios, transmission of an SRS resource set across the full SRS bandwidth may be unnecessary and / or inefficient (e.g., in terms of power overhead). For example, probing over only a portion of the full SRS bandwidth may be sufficient for certain channel estimation, uplink timing alignment, and / or uplink frequency selective scheduling of a base station. Additionally or alternatively, a UE may operate within a power constraint that prevents the UE from probing the full SRS bandwidth, such as when the UE has insufficient remaining battery charge, or when the UE is configured as a low-power device capable of achieving a relatively lower transmission power than other UEs. In other examples, a base station may provide a cell in which the number of transmitting UEs exceeds the uplink resources available for SRS transmission, without the need for some additional multiplexing mechanism. Therefore, there is a need for a method for SRS transmission over less than the full SRS bandwidth.

[0082] The present disclosure (and in particular Figure 6-12 ) describes various techniques and solutions for SRS transmission using only a portion of the full SRS bandwidth or a fraction of the SRS bandwidth. Such techniques and solutions for SRS transmission using a fraction of the SRS bandwidth can allow UE multiplexing, enabling a greater number of UEs to transmit SRS in a cell. In addition, SRS transmission using a fraction of the SRS bandwidth can reduce some power overhead, such as the power overhead incurred by the UE from SRS transmission and / or the base station from SRS reception.

[0083] exist Figure 6-12 In some embodiments, some techniques and solutions for SRS transmission using a portion of the SRS bandwidth are provided by using a sounding mode (e.g., a frequency hopping mode) that uses only a portion of the SRS bandwidth, which may be a fraction of the full SRS bandwidth. Some other solutions for SRS transmission using a portion of the SRS bandwidth are provided in Figure 6-12 The invention provides for providing a method for generating various SRS sequences configured for use with a partial SRS bandwidth that is less than the full SRS bandwidth.

[0084] Reference Figure 6 , call flow diagram 600 illustrates various operations for SRS transmission using a portion of the SRS bandwidth that is less than the full SRS bandwidth. Figure 6 In FIG, a base station 602 may be configured to provide a cell on which multiple UEs 604a-b operate. Figure 1 and 3 , the base station 602 may be implemented as the base station 102 / 180, 310, and each of the UEs ab may be implemented as the UE 104, 350.

[0085] Each of the UEs 604a-b can be configured to transmit data and / or control information to the base station 602. Transmissions in this direction can be referred to as uplink. Uplink data can be carried on an uplink data channel such as a PUSCH. The base station 602 can configure each of the UEs 604a-b with a PUSCH transmission on a respective active BWP, which can be updated by the base station 602.

[0086] To improve the accuracy and success of decoding uplink data received from the UEs 604a-b, the base station 602 can perform channel estimation, e.g., to model current channel conditions in order to reliably receive uplink data from the UEs 604a-b at high data rates. Channel estimation can be performed over an entire bandwidth of interest, which can be greater than any one active BWP (e.g., the entire bandwidth of interest for the UEs 604a-b can be an entire bandwidth spanning all BWPs that can potentially be activated by the base station 602 for the UEs 604a-b).

[0087] Each of the UEs 604a-b can be capable of sounding over a bandwidth by transmitting a set of SRS resources including one or more SRS resources. For example, each of the UEs 604a-b can sound all SRS ports in one or more symbols of the set of SRS resources. In some aspects, at least one of the UEs 604a-b can sound over an entire bandwidth of interest or a full SRS bandwidth by transmitting a set of SRS resources including one or more SRS resources that span the full SRS bandwidth in an aggregation. However, in some other aspects, at least one of the UEs 604a-b can sound over a fractional amount of the entire bandwidth of interest or a partial SRS bandwidth that is less than the full SRS bandwidth by transmitting a set of SRS resources including one or more SRS resources that span a partial SRS bandwidth rather than the full SRS bandwidth.

[0088] The base station 602 can configure the UEs 604a-b for sounding by transmitting SRS configuration information 622a-b to the UEs 604a-b. In some aspects, each of the SRS configuration information 622a-b can be configured separately for each of the UEs 604a-b. Thus, the base station 602 can transmit first SRS configuration information 622a to a first UE 604a that is different from second SRS configuration information 622b transmitted by the base station 602 to a second UE 604b.

[0089] According to various aspects, each of the SRS configuration information 622a-b can include and / or indicate any information associated with the SRS transmissions. Each of the SRS configuration information 622a-b can be transmitted in one or more messages, which can be signaled in the same or different types or formats, such as RRC signaling, DCI, and / or MAC CE. For example, the base station 602 can signal the first SRS configuration information 622a to the first UE 604a using RRC signaling, DCI, and MAC CE at respective times, such that a first portion of the first SRS configuration information 622a is signaled via RRC signaling at time t, a second portion of the first SRS configuration information 622a is signaled via DCI at time t+x, and a third portion of the first SRS configuration information 622a is signaled via MAC CE at time t+y.

[0090] The base station 602 can configure a full bandwidth of interest, also referred to as a“full SRS bandwidth,” for each of the UEs 604a-b. The base station 602 can transmit information indicating the full SRS bandwidth in a respective one of the first and second SRS configuration information 622a-b to each of the UEs 604a-b. For example, the base station 602 can indicate the full SRS bandwidth via RRC signaling; however, according to other aspects, the full SRS bandwidth can be configured via DCI or MAC CE.

[0091] In the same or different messages, the base station 602 can include a periodicity or duration for the SRS transmissions in at least one of the SRS configuration information 622a-b. The periodicity (or duration) can indicate whether the SRS transmissions are periodic or aperiodic, or potentially semi-persistent.

[0092] In some aspects, the SRS transmission periodicity can be configured as aperiodic via RRC signaling, but the base station 602 can activate the SRS transmissions from one of the UEs 604a-b via DCI. In some other aspects, the SRS transmission periodicity can be configured as periodic via RRC signaling, and such RRC signaling can also configure a number of ms of the periodicity and a subframe offset of the periodicity.

[0093] Additionally, the base station 602 can include a frequency domain location in at least one of the SRS configuration information 622a-b, which defines a starting location of the SRS transmissions in the frequency domain. For example, the frequency domain location (e.g., labeled as freqDomainPosition) can have a value of an index of a lowest RB (or PRB) that the SRS transmissions are to span.

[0094] As described above with respect to Figure 2CAs described, SRS transmission may not occur on every subcarrier of an RB (or PRB). Instead, SRS resources may be mapped to every other subcarrier of an RB in a transmission comb structure, starting from the first (e.g., lowest) subcarrier or the second (e.g., the next consecutive subcarrier after the lowest) subcarrier.

[0095] Thus, the base station 602 may include a transmission comb value (e.g., labeled transmissionComb) in at least one of the SRS configuration information 622a-b. The transmission comb value may configure one of the UEs 604a-b to transmit on every even subcarrier (e.g., transmission comb 0 starting with subcarrier index 0) or every odd subcarrier (e.g., transmission comb 1 starting with subcarrier index 1).

[0096] To maintain orthogonality, the base station 602 may include in at least one of the SRS configuration information 622a-b a value for a cyclic shift to be applied by one of the UEs 604a-b to the SRS transmission. For example, the cyclic shift value (e.g., labeled cyclicShift) may include a value between 1 and 8, inclusive (although more, fewer, or different values ​​are possible). Illustratively, when the UEs 604a-b share the same full SRS bandwidth according to the SRS configuration information 622a-b, the SRS transmissions of the UEs 604a-b may be multiplexed within the full SRS bandwidth because the corresponding different cyclic shifts will maintain orthogonality.

[0097] In accordance with some aspects, the base station 602 may include a bandwidth of an SRS resource of an SRS resource set in at least one of the SRS configuration information 622a-b. For example, the SRS resource bandwidth (e.g., labeled srs-Bandwidth) may indicate the number of RBs (or PRBs) to be spanned by each of one or more SRS resources in an SRS resource set configured for inclusion in at least one of the UEs 604a-b.

[0098] Relatedly, the base station 602 may include information configuring a hopping bandwidth for SRS transmission (e.g., labeled srs-HoppingBandwidth) in at least one of the SRS configuration information 622a-b. That is, the SRS hopping bandwidth may be a number of consecutive RBs (or PRBs) spanning the entire bandwidth of interest, starting from a frequency domain location. Therefore, in some aspects, the SRS hopping bandwidth may be equal to the full SRS bandwidth.

[0099] At least one of the SRS configuration information 622a-b may include a corresponding value for each of the SRS resource bandwidth and the SRS hopping bandwidth. The corresponding values ​​may implicitly indicate the corresponding number of RBs (or PRBs) to be spanned by each of the SRS resource bandwidth and the SRS hopping bandwidth. For example, each of the corresponding values ​​may be associated with a corresponding table (e.g., a lookup table) or similar keyed or indexed data structure that may be (pre-)configured in at least one of the UEs 604a-b.

[0100] Each of the corresponding values ​​may correspond to a row, column, or other entry of an associated table, and the number of RBs (or PRBs) configured for the SRS resource bandwidth or SRS hopping bandwidth may be explicitly or implicitly included in the row, column, or other entry corresponding to the corresponding value indicated in at least one of the SRS configuration information 622a-b.

[0101] By way of illustration, the first SRS configuration information 622a may include a value for the SRS resource bandwidth of bw3 and may also include a value for the SRS hopping bandwidth of hbw0. The first UE 604a may identify a row, column, or other entry of at least one table corresponding to bw3 and may derive from the corresponding row, column, or other entry the number of RBs (or PRBs) configured to be spanned by each SRS resource, e.g., the SRS resource bandwidth may be equal to 4. Similarly, the first UE 604a may identify a row, column, or other entry of at least one table corresponding to hbw0 and may derive from the corresponding row, column, or other entry the number of RBs (or PRBs) configured for all bandwidths of interest (e.g., the full SRS bandwidth), e.g., the SRS hopping bandwidth may be equal to 48.

[0102] According to some aspects, at least one of the UEs 604a-b may determine whether to enable or disable SRS frequency hopping based on information implicitly signaled in a corresponding one of the SRS configuration information 622a-b. Specifically, at least one of the UEs 604a-b may derive the enabled or disabled state of SRS frequency hopping from a combination of corresponding values ​​configured for the SRS resource bandwidth and the SRS hopping bandwidth.

[0103] For example, when at least one of the SRS configuration information 622a-b includes an SRS hopping bandwidth value (e.g., hbw0, hbw1, hbw2, or hbw3) configured as less than the SRS resource bandwidth value (e.g., bw0, bw1, bw2, or bw3), SRS frequency hopping may be enabled. However, when at least one of the SRS configuration information 622a-b includes an SRS hopping bandwidth value (e.g., hbw0, hbw1, hbw2, or hbw3) configured as greater than or equal to the SRS resource bandwidth value (e.g., bw0, bw1, bw2, or bw3), SRS frequency hopping may be disabled. Therefore, as shown in the foregoing description, since the SRS resource bandwidth of bw3 is greater than the SRS hopping bandwidth of hbw0, SRS frequency hopping is enabled for the first UE 604a. In practice, the first UE 604a may then frequency hop over a 48 RB bandwidth configured for an SRS hopping bandwidth (eg, full SRS bandwidth) using the 4 RBs configured for each SRS resource (eg, symbol).

[0104] In some aspects, at least one of the UEs 604a-b can be configured to perform SRS frequency hopping across the full SRS bandwidth. For example, the second UE 604b can be configured to perform SRS frequency hopping across the full SRS bandwidth. Thus, the SRS resources in the SRS resource set configured for the second UE 604b can span the full SRS bandwidth across one or more symbols.

[0105] Reference Figure 7 For example, diagram 700 illustrates a full SRS bandwidth hopping pattern 702. By way of illustration, the full SRS bandwidth can be configured to span 16x RBs (e.g., with 12 subcarriers per RB). In one example aspect, x can be equal to 4 RBs, and thus, the full SRS bandwidth can be equal to 64 RBs (e.g., 768 subcarriers with 12 subcarriers per RB). However, in some other aspects, x can be different from (e.g., greater than) 4.

[0106] The second UE 604b may be configured with SRS resources 704. The SRS bandwidth for the second UE 604b may be equal to 16 RBs, and the SRS hopping bandwidth may be equal to 64 RBs. Therefore, the second UE 604b may transmit the SRS resources 704 on a corresponding (unique) 16 RB bandwidth at a corresponding one of symbol indices 10 to 13, and thus, the second UE 604b may sound over the full 64 RB bandwidth.

[0107] In order to make the SRS resources 704 span corresponding portions of the full SRS bandwidth, an SRS frequency hopping pattern for the full SRS bandwidth may be configured. The SRS frequency hopping pattern may define a corresponding hopping bandwidth (e.g., a set of consecutive RBs) for each hop, where each hop occurs at a corresponding symbol of at least one time slot.

[0108] exist Figure 7 In the context of , for example, the full SRS bandwidth hopping pattern can define a unique 16RB bandwidth for each hop at a corresponding one of symbols 10 to 13 (e.g., assuming x=4). Thus, the second UE 604b transmits SRS on the first 16 RBs of the full SRS bandwidth at the first hop on symbol 10. At the next hop on symbol 11, the second UE 604b transmits SRS on 16 RBs starting after the first 32 RBs of the full SRS bandwidth (e.g., from subcarrier index 383 to subcarrier index 575, where for x=4 RBs, the subcarrier indices are 0, 1, 2, ..., 765, 766, 768). At the third hop on symbol 12, the second UE 604b transmits SRS on 16 RBs starting after the first 16 RBs of the full SRS bandwidth and ending with the 32nd RB. At the last hop on symbol 13, the second UE 604b transmits SRS on 16 RBs starting after the first 48 RBs of the full SRS bandwidth and ending with the last (64th) RB. Therefore, since the SRS resource 704 spans all RBs of the full SRS bandwidth over the four symbol hops occurring from symbols 10 to 13, the SRS resource 704 spans the full SRS bandwidth.

[0109] Refer again Figure 6 At least one of the UEs 604a-b may be configured to use an SRS frequency hopping pattern that uses only a portion of the full SRS bandwidth, i.e., a partial SRS bandwidth that is less than the full SRS bandwidth. In practice, at least one of the UEs 604a-b may be configured with SRS resources in an SRS resource set that spans a partial SRS bandwidth rather than the full SRS bandwidth. Sounding on a partial SRS bandwidth that is less than the full SRS bandwidth may be more efficient (e.g., in terms of power consumption and / or UE capacity) while still being sufficient for channel estimation, uplink frequency selective scheduling, uplink timing estimation, etc., by the base station 602.

[0110] However, to transmit SRS resources, UEs 604a-b may generate 624, 626 SRS sequences. In some aspects, SRS sequence generation may be based on SRS configuration information. For example, the first UE 604a may generate 624 an SRS sequence based on at least one of the full SRS bandwidth (e.g., SRS hopping bandwidth), SRS bandwidth, starting frequency position, transmission comb, and / or one or more other parameters indicated in the SRS configuration information 622a. The first UE 604a may be configured (e.g., pre-configured) with a function or other algorithm that takes one or more of the aforementioned parameters as input and returns an SRS sequence as output based on an evaluation of the function / algorithm with the input parameters.

[0111] Although the SRS sequence can be generated based on the full SRS bandwidth, one of the UEs 604a-b can be configured to truncate the SRS sequence when transmitting the SRS over a partial SRS bandwidth. For example, the first UE 604a can generate the SRS sequence based on the full SRS bandwidth configured by the base station 602, but can avoid mapping a subsequence of the SRS sequence to resources (e.g., REs) outside the partial SRS bandwidth. The subsequence can be mapped to a portion of the full SRS bandwidth outside the partial SRS bandwidth on one or more omitted symbol hops, while the truncated SRS sequence can be carried on one or more other symbol hops on the portion of the full SRS bandwidth included in the partial SRS bandwidth.

[0112] In some other aspects, SRS sequence generation can be based on a partial SRS bandwidth, which can be indicated by at least one of SRS configuration information 622a-b for at least one of the UEs 604a-b supporting SRS transmission over the partial SRS bandwidth. For example, the first UE 604a can generate 624 an SRS sequence based at least on the partial SRS bandwidth and potentially further based on at least one of the full SRS bandwidth (e.g., SRS hopping bandwidth), the SRS bandwidth, the starting frequency position, the transmission comb, and / or one or more other parameters indicated in the SRS configuration information 622a. The first UE 604a can be configured (e.g., pre-configured) with a function or other algorithm that takes at least a partial SRS bandwidth (e.g., the number and / or positions of RBs included in the partial SRS bandwidth) as input and returns an SRS sequence as output based on an evaluation of the function / algorithm with the input parameters.

[0113] Potentially, not all UEs may support SRS transmission over a partial SRS bandwidth (e.g., some legacy UEs may lack such support). Therefore, at least one cyclic shift may be used for an SRS sequence based on a partial SRS bandwidth. The at least one cyclic shift may be different from another cyclic shift used for another SRS sequence based on the full SRS bandwidth; for example, a different cyclic shift may be used for each subband. Different cyclic shifts for SRS transmission over the partial and full SRS bandwidths may reduce interference from UEs transmitting SRS over the partial SRS bandwidth to UEs transmitting SRS over the full SRS bandwidth (e.g., legacy UEs).

[0114] In other aspects, a new SRS sequence can be configured for use over a partial SRS bandwidth. When such a new SRS sequence is transmitted over the partial SRS bandwidth, the new SRS sequence can be orthogonal to another SRS sequence generated based on (and transmitted over) the full SRS bandwidth (e.g., a conventional generation of an SRS sequence). For example, a first UE 604a can generate 624 a new SRS sequence configured for use over a partial SRS bandwidth that is less than the full SRS bandwidth.

[0115] In conjunction with generating the respective SRS sequences, each of the UEs 604a-b may determine 628, 630 a respective hopping pattern for SRS transmission. At least one of the UEs 604a-b may determine an SRS hopping pattern for a partial SRS bandwidth that is less than the full SRS bandwidth. Furthermore, the respective partial SRS bandwidth hopping pattern may be periodic, aperiodic, or semi-persistent, e.g., as indicated by one of the SRS configuration information 622a-b. In some aspects, at least one of the UEs 604a-b may determine 628, 630 the respective partial SRS bandwidth hopping pattern based at least in part on the respective one of the generated SRS sequences.

[0116] In some other aspects, the base station 602 may configure a respective SRS frequency hopping pattern for at least one of the UEs 604a-b, and accordingly, at least one of the UEs 604a-b may determine 628, 630 the respective SRS frequency hopping pattern based on the configuration received from the base station 602. For example, the base station 602 may send a respective one of SRS configuration information 622a-b to each of the UEs 604a-b indicating a portion of the bandwidth (e.g., number and location of RBs) over which SRS resources are transmitted at each hop, where each hop occurs on one symbol in a set of contiguous symbols.

[0117] In various further aspects, the base station 602 can implicitly indicate a corresponding SRS frequency hopping pattern to at least one of the UEs 604a-b. Accordingly, at least one of the UEs 604a-b can determine (e.g., calculate, derive, etc.) a corresponding bandwidth position (e.g., a starting frequency position, a starting RB position, an ending frequency position, etc.) corresponding to each symbol hop for SRS resource transmission.

[0118] In another aspect, at least one of the UEs 604a-b may determine an SRS hopping pattern for the full SRS bandwidth (e.g., based on a corresponding one of the SRS configuration information 622a-b). At least one of the UEs 604a-b may then determine a partial SRS bandwidth hopping pattern by determining a portion of SRS transmission to be omitted. For example, at least one of the UEs 604a-b may determine a hopping pattern for the full SRS bandwidth, but may then determine a hopping pattern for the partial SRS bandwidth by determining to avoid SRS transmission on a portion of the full SRS bandwidth.

[0119] When determined, the SRS hopping pattern for the partial SRS bandwidth may define at least one of the following for the SRS resources in the SRS resource set: (1) a subset of the RB set for each symbol (e.g., each hop) in a symbol set (e.g., a hopping set) used for SRS transmission, and / or (2) a subset of the symbol set used for SRS transmission. In practice, at least one of the UEs 604a-b may avoid transmitting the SRS resources on one or more RBs for at least one symbol hop of the partial SRS hopping pattern and / or avoid transmitting the SRS resources at one or more symbol hops of the partial SRS hopping pattern (e.g., such that all RBs for one or more symbol hops are skipped).

[0120] Reference Figure 8 For example, diagram 800 shows example partial SRS bandwidth hopping patterns 802, 822, 842. Figure 8With the partial SRS bandwidth hopping patterns 802, 822, 842, the frequency resources (e.g., RBs) for each hop may be divided into N sub-resources (or "sub-hops"). Thus, SRS transmissions by one UE will occur on only one of the N sub-resources into which the resources for each hop are divided. For example, SRS transmissions by one UE will occur on only a subset of the set of 4x RBs for each symbol hop. Effectively, the hopping on each symbol hop may be considered an outer loop, and a partial SRS hopping pattern may be introduced into an inner loop such that one UE hops to only one of the N sub-resources into which the resources for each symbol hop are divided. Potentially, the frequency resources for each sub-hop (e.g., N sub-resources) may be greater than 4 RBs or may be greater than or equal to 4 RBs (although other numbers of frequency resources are possible).

[0121] In some aspects, the ratio of sub-hopping frequency resources to hopping frequency resources can be configured based on a threshold (e.g., a predefined threshold). For example, the ratio of sub-hopping frequency resources to hopping frequency resources can be constrained to be within the threshold. Illustratively, the threshold can be equal to 1 / 2, and the base station 602 can divide the 4x RBs of each hop into 4 sub-hops, with 1 RB per sub-hop, such that the ratio of sub-hopping frequency resources to hopping frequency resources is 1 / 4, which is within the threshold of 1 / 2.

[0122] According to some aspects illustrated by the first portion SRS bandwidth hopping pattern 802, each sub-hop of a symbol hop includes the same number of resources, e.g., each sub-hop of a symbol hop includes x RBs, and further, each hop in each hop has the same number of sub-hops, e.g., each hop has 4 sub-hops. For example, each symbol hop may include 4x RBs, where x may be equal to 4 or x may be greater than 4 (although other values ​​are possible). The 4x RBs of each symbol hop may be divided into sub-hops of (4x) / (N) RBs, e.g., if N=4, each hop may be evenly divided into x RBs.

[0123] According to some other aspects illustrated by the second portion SRS bandwidth hopping pattern 822, each sub-hop in a symbol hop includes the same number of resources, e.g., each sub-hop in a symbol hop includes x RBs, but each hop in each hop does not have the same number of sub-hops, e.g., the hops at symbols 10 and 11 have 4 sub-hops, while the hops at symbols 12 and 13 have 2 sub-hops. For example, each symbol hop may include 4x RBs, where x may be equal to 4 or x may be greater than 4 (although other values ​​are possible). The 4x RBs for the hops at symbols 10 and 11 may be divided into sub-hops of (4x) / 4 RBs or x RBs, while the 4x RBs for the hops at symbols 12 and 13 may be divided into sub-hops of (4x) / 2 RBs or 2x RBs.

[0124] According to another aspect, as illustrated by the third portion of SRS bandwidth hopping pattern 842, each of the sub-hops of some symbol hops includes a different number of resources. For example, the hops at symbols 11 and 13 each include a sub-hop with 3x RBs and a sub-hop with x RBs. Furthermore, each hop in each hop does not have the same number of sub-hops. For example, the hops at symbols 10 and 12 have 4 sub-hops, while the hops at symbols 11 and 13 have 2 sub-hops. For example, each symbol hop may include 4x RBs, where x may be equal to 4 or greater than 4 (although other values ​​are possible). The 4x RBs of the hops at symbols 10 and 12 may be divided into sub-hops of (4x) / 4 RBs or x RBs, while the 4x RBs of the hops at symbols 11 and 13 may be divided into one sub-hop of 4x RBs and another sub-hop of x RBs.

[0125] When at least one of the UEs 604a-b is configured with a partial SRS bandwidth hopping pattern that is limited to a subset of the RB set for at least one symbol hop used for SRS transmission, at least one of the UEs 604a-b may transmit the SRS on only the subset of the RB set at the at least one symbol hop. Thus, at least one of the UEs 604a-b may avoid transmitting the SRS on other RBs of the symbol hop that are not included in the RB subset.

[0126] For example, a first UE 604a may be configured with an SRS resource set including a first SRS 804a, and a second UE 604b may be configured with an SRS resource set including a second SRS 804b. Then, for one of the partial SRS bandwidth hopping patterns 802, 822, 824, the first and second UEs 604a-b may transmit the respective SRS 804a-b only on those RBs configured for one of the SRSs 804a-b per symbol hop.

[0127] Similarly, the third UE and the fourth UE may be configured to transmit a third SRS 804c and a fourth SRS 804d, respectively, according to one of the configured partial SRS bandwidth hopping patterns 802, 822, and 842. Thus, multiple UEs (e.g., up to four UEs) may be multiplexed at each symbol hop to sound on the partial SRS bandwidth.

[0128] The base station 602 may assign sub-hops of a symbol hop to the UE for such multiplexing. Furthermore, the base station 602 may configure the division of resources into sub-hops for each hop and may assign the resources of each sub-hop to one of the UEs 604a-b. The base station 602 may send such resource assignments in SRS configuration information 622a-b, for example, via RRC signaling, DCI, and / or MAC CE.

[0129] Go to Figure 9 As another example, diagram 900 shows example partial SRS bandwidth hopping patterns 902, 922, 942. Figure 9 The partial SRS bandwidth hopping patterns 902, 922, and 942 can limit the number of hops so that SRS transmission occurs only over a portion of the SRS bandwidth that is less than the full SRS bandwidth. When the number of symbol hops is limited, the UEs 604a-b can still use the configured SRS symbols and the number of hops to determine 628, 630 the SRS hopping pattern. However, the UEs 604a-b can avoid transmitting on a subset of the symbol hopping set.

[0130] In some aspects, the partial SRS bandwidth hopping pattern may include restrictions on the full SRS bandwidth hopping pattern. The base station 602 may activate corresponding restrictions for each of the UEs 604a-b that restrict the symbol hopping on which each of the UEs 604a-b may transmit the SRS 904a-b. The base station 602 may signal such restrictions in the SRS configuration information 622a-b, for example, via RRC signaling, DCI, and / or MAC CE.

[0131] For example, each of the UEs 604a-b may be configured with restrictions based on a hopping pattern that indicates the symbols that each of the UEs 604a-b will hop over and other symbols that each of the UEs 604a-b will avoid hopping over. For example, the base station 602 may send a respective bitmap indicating the respective skip pattern to each of the UEs 604a-b.

[0132] Illustratively, the base station 602 may send a first bitmap indicating [1, 1, 0, 0] to the first UE 604a, where "1" indicates an assigned hop and "0" indicates an unassigned hop. As shown in the first hopping pattern 902, the first UE 604a may then transmit an SRS 904a on the RB sets for the first and second hops at symbols 10 and 11, but may refrain from transmitting an SRS on the third and fourth hops at symbols 12 and 13.

[0133] Similarly, the base station 602 may send a second bitmap indicating [0, 0, 1, 1] to the second UE 604b. As shown in the first hopping pattern 902, the second UE 604b may then transmit an SRS 904b on the RB sets of the third and fourth hops at symbols 12 and 13, but may avoid transmitting an SRS on the first and second hops at symbols 10 and 11.

[0134] In some aspects, the restriction (e.g., skip pattern) can be periodic or cyclic. For example, the base station 602 can configure a frequency hopping pattern in which the first and second UEs 604a-b are multiplexed (e.g., as shown in patterns 902, 942), which can cycle through a frequency hopping pattern 922 in which only the first UE 604a transmits SRS 904a on all 4x RBs across all symbol hops (e.g., the second UE 604b avoids SRS transmission).

[0135] continue Figure 10 As a third example, diagram 1000 shows example partial SRS bandwidth hopping patterns 1002, 1022. Figure 10 Partial SRS bandwidth hopping pattern 1002, 1022, wherein SRS transmission is restricted to a hopping pattern of a subset of a set of RBs for at least one symbol hopping (e.g., as Figure 8 ) can be combined with a frequency hopping pattern in which the number of hops can be limited so that SRS transmission occurs only over a portion of the SRS bandwidth (e.g., as shown in FIG. Figure 9 shown here) in combination.

[0136] For example, the base station 602 can configure a skip pattern to restrict the hopping pattern to some symbol hops, and potentially, those symbol hops activated for SRS transmission can be constrained to a subset of the RB set for those symbol hops. The base station 602 can use the same signaling or different signaling to inform the UEs 604a-b of the skip pattern and the RB subset (e.g., sub-hops). Thus, each of the SRS configuration information 622a-b can include one or more messages indicating a corresponding skip pattern and a corresponding RB subset for symbol hopping for one of the UEs 604a-b. The base station 602 can send the one or more messages via RRC signaling, DCI, and / or MAC CE.

[0137] As shown in pattern 1002, the base station 602 may configure the first UE 604a to transmit SRS 1004a on the first x RBs of the 4x RBs activated for each symbol hop. Similarly, the base station 602 may configure the second UE 604b to transmit SRS 1004b on the second x RBs of the 4x RBs activated for each symbol hop. However, the base station 602 may deactivate (or skip) the hopping at symbols 11 and 13, and therefore, neither the first UE 604a nor the second UE 604b may transmit on any RBs for each hop at symbols 11 and 13.

[0138] However, in pattern 1004, the base station 602 may configure the first UE 604a to transmit SRS 1004a on the first x RBs of the 4x RBs for each hop at symbols 10 and 12. Similarly, the base station 602 may configure the second UE 604b to transmit SRS 1004b on the second x RBs of the 4x RBs for each hop at symbols 10 and 12. The base station 602 may deactivate (or skip) the hopping at symbols 11 and 13 for the second UE 604b, such that the frequency hopping pattern 630 determined by the second UE 604b causes the second UE 604b to avoid SRS transmission on each hop at symbols 11 and 13. Conversely, the base station 602 may activate full hopping at symbols 11 and 13 for the first UE 604a such that the hopping pattern determined 628 by the first UE 604a causes the first UE 604a to transmit the SRS 1004a on hops at symbols 11 and 13.

[0139] exist Figure 8-10 The above-described patterns are intended to be illustrative. Therefore, other frequency hopping patterns may be configured in accordance with the present disclosure.

[0140] Based on the frequency hopping patterns determined 628 and 630, respectively, UEs 604a-b may transmit SRSs 632 and 634, respectively. The transmitted SRSs 632 and 634 may include the sequences generated 624 and 626, respectively. However, both the first SRS 632 and the second SRS 634 may not span the full SRS bandwidth (e.g., the SRS hopping bandwidth), but may span only a subset of RBs at each symbol hop and / or may not be present in one or more symbol hops of one or more time slots.

[0141] Figure 11 1100 is a flow chart of a method of wireless communication. The method may be performed by a UE (eg, UE 104, 350, 604a, 604b). According to various aspects, one or more of the illustrated operations may be swapped, omitted, and / or performed simultaneously.

[0142] At 1102, the UE may generate a sequence for SRS transmission based on at least a portion of the full SRS bandwidth. In some aspects, the UE may generate a sequence based on the number of RBs of the full SRS bandwidth, and the UE may truncate the sequence for use in the partial SRS bandwidth. For example, the UE may assign a truncated portion of the sequence to each symbol in a subset of the symbol set based on a frequency hopping pattern, such that the SRS transmission includes each truncated portion of the sequence assigned to the subset of the symbol set. In some other aspects, the UE may generate a sequence based on the number of RBs of a partial SRS bandwidth that is less than the full SRS bandwidth, and the SRS transmission may include the sequence. For example, the UE may generate a sequence based on one or more cyclic shifts, and the number of the one or more cyclic shifts may be based on the partial SRS bandwidth. In other aspects, the UE may generate a sequence that is orthogonal to each overlapping sequence over the partial SRS bandwidth.

[0143] For example, refer to Figure 6 , the first UE 604a may generate 624 a sequence for the SRS 632 , and / or the second UE 604b may generate 626 a sequence for the SRS 634 .

[0144] At 1104, the UE may receive SRS configuration information indicating at least the full SRS bandwidth from the base station. Figure 6 , the first UE 604a may receive SRS configuration information 622a indicating at least the full SRS bandwidth from the base station 602, and / or the second UE 604b may receive SRS configuration information 622b indicating at least the full SRS bandwidth from the base station 602.

[0145] At 1106, the UE may determine a frequency hopping pattern for SRS transmission based on the SRS configuration information, and the frequency hopping pattern may be limited to a portion of the SRS bandwidth that is less than the full SRS bandwidth. For example, the SRS configuration information may further indicate a set of RBs for each symbol in a symbol set that may be used for SRS transmission, and the frequency hopping pattern may be limited to a subset of the RB set for each symbol or at least one of a subset of the symbol set. In some aspects, a ratio of the RB subset for each symbol to the RB set may be less than or equal to a threshold. In some other aspects, the corresponding RB subset for each symbol is different for at least two symbols in the symbol set. In other aspects, the SRS configuration information further indicates a subset of RBs assigned to the UE. In some further aspects, the SRS configuration indicates a subset of the symbol set assigned to (or activated for) the UE. In further aspects, the SRS configuration includes a bitmap having a first value corresponding to each symbol in the subset of the symbol set assigned to the UE and a second value corresponding to each remaining symbol in the symbol set not assigned to the UE.

[0146] For example, refer to Figure 6 , the first UE 604a may determine 628 a frequency hopping pattern for SRS transmission based on the SRS configuration information 622a, and the frequency hopping pattern may be limited to a portion of the SRS bandwidth that is less than the full SRS bandwidth, and / or the second UE 604b may determine 630 a frequency hopping pattern for SRS transmission based on the SRS configuration information 622b, and the frequency hopping pattern may be limited to a portion of the SRS bandwidth that is less than the full SRS bandwidth. Figure 8-10 , the first UE 604a and / or the second UE 604b can determine a frequency hopping pattern, which is Figure 8 One of the frequency hopping modes 802, 822, 842, Figure 9 One of the frequency hopping patterns 902, 922, 942 and / or Figure 10 One of the frequency hopping patterns 1002, 1022.

[0147] The UE may send an SRS transmission to the base station based on the frequency hopping pattern at 1108. The SRS transmission may include the generated sequence, which may be truncated or may be a new sequence based on the partial SRS bandwidth and / or orthogonal to other sequences overlapping over the partial SRS bandwidth.

[0148] For example, refer to Figure 6 , the first UE 604a may send an SRS 632 to the base station 602 based on the determined 628 frequency hopping pattern, and / or the second UE 604b may send an SRS 634 to the base station 602 based on the determined 630 frequency hopping pattern. Figure 8-10 , the first UE 604a may be based on Figure 8 The SRS 804a is sent to the base station 602 using one of the frequency hopping patterns 802, 822, and 842. Figure 9 to transmit SRS 904a to base station 602 using one of the frequency hopping patterns 902, 922, 942, and / or based on Figure 10 1004a to send the SRS 1004a to the base station 602 using one of the frequency hopping patterns 1002, 1022. Figure 8-10 , the second UE 604b may be based on Figure 8 804b to send SRS 804b to base station 602 using one of the frequency hopping patterns 802, 822, and 842. Figure 9 to transmit SRS 904b to base station 602 using one of the frequency hopping patterns 902, 922, 942, and / or based on Figure 10 The SRS 1004b is sent to the base station 602 using one of the frequency hopping patterns 1002, 1022.

[0149] Figure 12 1200 is a flow chart of a method of wireless communication. The method may be performed by a base station (e.g., base stations 102 / 180, 310, 602). According to various aspects, one or more of the illustrated operations may be swapped, omitted, and / or performed simultaneously.

[0150] At 1202, the base station may send SRS configuration information indicating at least the full SRS bandwidth to the UE. Figure 6 , the base station 602 may send SRS configuration information 622a indicating at least the full SRS bandwidth to the first UE 604a, and / or may send configuration information 622b indicating at least the full SRS bandwidth to the second UE 604b.

[0151] At 1204, the base station may receive an SRS transmission from the UE according to a frequency hopping pattern based on the SRS configuration information, and the frequency hopping pattern may be limited to a portion of the SRS bandwidth that is less than the full SRS bandwidth. For example, the SRS configuration information may further indicate a set of RBs for each symbol in a symbol set that may be used for SRS transmission, and the frequency hopping pattern may be limited to a subset of the RB set for each symbol or at least one of a subset of the symbol set. In some aspects, a ratio of the RB subset for each symbol to the RB set may be less than or equal to a threshold. In some other aspects, the corresponding RB subset for each symbol is different for at least two symbols in the symbol set. In other aspects, the SRS configuration information further indicates a subset of RBs assigned to the UE. In some further aspects, the SRS configuration indicates a subset of the symbol set assigned to (or activated for) the UE. In further aspects, the SRS configuration includes a bitmap having a first value corresponding to each symbol in the subset of the symbol set assigned to the UE and a second value corresponding to each remaining symbol in the symbol set not assigned to the UE. In some aspects, an SRS transmission may include a set of truncated portions of a sequence based on the number of RBs in the full SRS bandwidth. In some other aspects, an SRS transmission includes a sequence based on the number of RBs in a partial SRS bandwidth. In other aspects, the sequence is based on one or more cyclic shifts, and the number of one or more cyclic shifts may be based on the partial SRS bandwidth. In further aspects, the SRS transmission includes a sequence that is orthogonal to each overlapping sequence across the partial SRS bandwidth.

[0152] For example, refer to Figure 6 , the base station 602 may receive the SRS 632 from the first UE 604a according to a frequency hopping pattern based on the SRS configuration information 622a, and the frequency hopping pattern may be limited to a portion of the SRS bandwidth that is less than the full SRS bandwidth. Figure 8-10 The base station 602 can use the SRS configuration information 622a to Figure 8 802, 822, 842 to receive SRS 804a from the first UE 604a, according to the SRS configuration information 622a Figure 9 hopping patterns 902, 922, 942 to receive SRS 904a from the first UE 604a, and / or according to the SRS configuration information 622a based on Figure 10 1002, 1022 to receive SRS 1004a from the first UE 604a. Figure 6 , the base station 602 may receive the SRS 634 from the second UE 604b according to a frequency hopping pattern based on the SRS configuration information 622b, and the frequency hopping pattern may be limited to a portion of the SRS bandwidth that is less than the full SRS bandwidth. Figure 8-10 , the base station 602 can Figure 8 802, 822, 842 to receive SRS 804b from the second UE 604b, according to the SRS configuration information 622b Figure 9 hopping patterns 902, 922, 942 to receive SRS 904b from the second UE 604b, and / or according to the SRS configuration information 622b based on Figure 10 The SRS 1004b is received from the second UE 604b using one of the frequency hopping patterns 1002, 1022.

[0153] It should be understood that the specific order or hierarchy of blocks in the disclosed processes / flowcharts is illustrative of example methods. It should be understood that the specific order or hierarchy of blocks in the processes / flowcharts may be rearranged based on design preferences. In addition, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in an example order and are not meant to be limited to the specific order or hierarchy presented.

[0154] The foregoing description is provided so that any person skilled in the art can implement the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects. Therefore, the claims are not intended to be limited to the various aspects shown herein, but are given the full scope consistent with the text claims, wherein, unless explicitly stated otherwise, reference to an element in the singular form is not intended to mean "one and only one", but "one or more". Terms such as "if", "when ... " and "while ... " should be interpreted as "under the conditions of ... ", rather than implying an immediate time relationship or reaction. That is, these phrases (e.g., "when ... ") do not imply an immediate action in response to an action or during the occurrence of an action, but only imply that the action will occur if the condition is met, but do not require a specific or immediate time constraint for the action to occur. The word "exemplary" is used herein to mean "used as an example, instance or illustration". Any aspect described as "exemplary" herein is not necessarily interpreted as preferred or advantageous over other aspects. Unless otherwise expressly stated, the term "some" refers to one or more. Combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof” include any combination of A, B, and / or C and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A, B, and C, where any such combination may include one or more members or several members of A, B, or C. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later become known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Furthermore, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly recited in the claims. The words "module," "mechanism," "element," "device," and the like are not substitutes for the word "unit." Thus, any claim element should not be interpreted as a functional unit unless the element is explicitly recited using the phrase "means for..."

Claims

1. A method for wireless communication by a user equipment (UE), comprising: receiving, from a base station, sounding reference signal (SRS) configuration information indicating a full SRS bandwidth; determining a frequency hopping pattern for SRS transmission based on the SRS configuration information, the frequency hopping pattern being restricted to a portion of the SRS bandwidth that is less than the full SRS bandwidth, wherein the SRS configuration information further indicates a set of resource blocks (RBs) for each symbol in a set of symbols that may be used for the SRS transmission, and the frequency hopping pattern being restricted to at least one of a subset of the set of RBs for each symbol or a subset of the set of symbols; as well as The SRS transmission is sent to the base station based on the frequency hopping pattern.

2. The method according to claim 1, wherein A ratio of the subset of the RB set to the RB set of each symbol is less than or equal to a threshold.

3. The method according to claim 1, wherein The subset of the corresponding RB set for each symbol is different for at least two symbols in the set of symbols.

4. The method according to claim 1, wherein The SRS configuration information also indicates the subset of the RB set assigned to the UE.

5. The method according to claim 1, wherein The SRS configuration information indicates the subset of the set of symbols assigned to the UE.

6. The method according to claim 5, wherein: The SRS configuration information includes a bitmap having a first value corresponding to each symbol in the subset of the set of symbols assigned to the UE and a second value corresponding to each remaining symbol in the set of symbols not assigned to the UE.

7. The method according to claim 1, further comprising: generating a sequence based on the number of RBs of the full SRS bandwidth; as well as assigning a truncated portion of the sequence to each symbol in the subset of the set of symbols, wherein the SRS transmission comprises each truncated portion of the sequence assigned to the subset of the set of symbols.

8. The method according to claim 1, further comprising: generating a sequence based on the number of RBs of the partial SRS bandwidth, The SRS transmission includes the sequence.

9. The method according to claim 8, wherein The sequence is generated based on one or more cyclic shifts, and the number of the one or more cyclic shifts is based on the partial SRS bandwidth.

10. The method according to claim 1, wherein The SRS transmission includes a sequence that is orthogonal to each overlapping sequence over the portion of the SRS bandwidth.

11. A method for wireless communication by a base station, comprising: sending a sounding reference signal (SRS) configuration information indicating a full SRS bandwidth to a user equipment (UE); and receiving an SRS transmission from the UE according to a frequency hopping pattern based on the SRS configuration information, the frequency hopping pattern being restricted to a portion of the SRS bandwidth that is less than the full SRS bandwidth, wherein the SRS configuration information further indicates a set of resource blocks (RBs) for each symbol in a set of symbols that may be used for SRS transmission, and the frequency hopping pattern being restricted to a subset of the set of RBs for each symbol or at least one of a subset of the set of symbols.

12. The method according to claim 11, wherein A ratio of the subset of the RB set to the RB set of each symbol is less than or equal to a threshold.

13. The method according to claim 11, wherein The subset of the corresponding RB set for each symbol is different for at least two symbols in the set of symbols.

14. The method according to claim 11, wherein The SRS configuration information also indicates the subset of the RB set assigned to the UE.

15. The method according to claim 11, wherein The SRS configuration information indicates the subset of the set of symbols assigned to the UE.

16. The method according to claim 15, wherein The SRS configuration information includes a bitmap having a first value corresponding to each symbol in the subset of the set of symbols assigned to the UE and a second value corresponding to each remaining symbol in the set of symbols not assigned to the UE.

17. The method according to claim 11, wherein The SRS transmission includes a set of truncated portions of a sequence based on a number of RBs of the full SRS bandwidth.

18. The method according to claim 11, wherein The SRS transmission includes a sequence based on a number of RBs of the partial SRS bandwidth.

19. The method according to claim 18, wherein The sequence is based on one or more cyclic shifts, and the number of the one or more cyclic shifts is based on the partial SRS bandwidth.

20. The method according to claim 11, wherein The SRS transmission includes a sequence that is orthogonal to each overlapping sequence over the portion of the SRS bandwidth.

21. An apparatus for wireless communication by a user equipment (UE), comprising: Memory; as well as at least one processor coupled to the memory and configured to: receiving, from a base station, sounding reference signal (SRS) configuration information indicating a full SRS bandwidth; determining a frequency hopping pattern for SRS transmission based on the SRS configuration information, the frequency hopping pattern being restricted to a portion of the SRS bandwidth that is less than the full SRS bandwidth, wherein the SRS configuration information further indicates a set of resource blocks (RBs) for each symbol in a set of symbols that may be used for the SRS transmission, and the frequency hopping pattern being restricted to at least one of a subset of the set of RBs for each symbol or a subset of the set of symbols; as well as The SRS transmission is sent to the base station based on the frequency hopping pattern.

22. The device according to claim 21, wherein A ratio of the subset of the RB set to the RB set of each symbol is less than or equal to a threshold.

23. The device according to claim 21, wherein The subset of the corresponding RB set for each symbol is different for at least two symbols in the set of symbols.

24. The apparatus according to claim 21, wherein The SRS configuration information also indicates the subset of the RB set assigned to the UE.

25. The apparatus according to claim 21, wherein The SRS configuration information indicates the subset of the set of symbols assigned to the UE.

26. The device according to claim 25, wherein The SRS configuration information includes a bitmap having a first value corresponding to each symbol in the subset of the set of symbols assigned to the UE and a second value corresponding to each remaining symbol in the set of symbols not assigned to the UE.

27. The apparatus according to claim 21, wherein The at least one processor is further configured to: generating a sequence based on the number of RBs of the full SRS bandwidth; and assigning a truncated portion of the sequence to each symbol in the subset of the set of symbols, wherein the SRS transmission comprises each truncated portion of the sequence assigned to the subset of the set of symbols.

28. The apparatus according to claim 21, wherein The at least one processor is further configured to: generating a sequence based on the number of RBs of the partial SRS bandwidth, The SRS transmission includes the sequence.

29. The apparatus according to claim 28, wherein The sequence is generated based on one or more cyclic shifts, and the number of the one or more cyclic shifts is based on the partial SRS bandwidth.

30. The apparatus according to claim 21, wherein The SRS transmission includes a sequence that is orthogonal to each overlapping sequence over the portion of the SRS bandwidth.

31. An apparatus for wireless communication by a base station, comprising: Memory; as well as at least one processor coupled to the memory and configured to: sending a sounding reference signal (SRS) configuration information indicating a full SRS bandwidth to a user equipment (UE); and receiving an SRS transmission from the UE according to a frequency hopping pattern based on the SRS configuration information, the frequency hopping pattern being restricted to a portion of the SRS bandwidth that is less than the full SRS bandwidth, wherein the SRS configuration information further indicates a set of resource blocks (RBs) for each symbol in a set of symbols that may be used for SRS transmission, and the frequency hopping pattern being restricted to a subset of the set of RBs for each symbol or at least one of a subset of the set of symbols.

32. The apparatus according to claim 31, wherein A ratio of the subset of the RB set to the RB set of each symbol is less than or equal to a threshold.

33. The apparatus according to claim 31, wherein The subset of the corresponding RB set for each symbol is different for at least two symbols in the set of symbols.

34. The apparatus of claim 31 , wherein: The SRS configuration information also indicates the subset of the RB set assigned to the UE.

35. The apparatus of claim 31 , wherein: The SRS configuration information indicates the subset of the set of symbols assigned to the UE.

36. The apparatus of claim 35, wherein: The SRS configuration information includes a bitmap having a first value corresponding to each symbol in the subset of the set of symbols assigned to the UE and a second value corresponding to each remaining symbol in the set of symbols not assigned to the UE.

37. The apparatus of claim 31 , wherein: The at least one processor is further configured such that the SRS transmission comprises a set of truncated portions of a sequence based on a number of RBs of the full SRS bandwidth.

38. The apparatus of claim 31, wherein The SRS transmission includes a sequence based on a number of RBs of the partial SRS bandwidth.

39. The apparatus according to claim 38, wherein The sequence is based on one or more cyclic shifts, and the number of the one or more cyclic shifts is based on the partial SRS bandwidth.

40. The apparatus of claim 31 , wherein: The SRS transmission includes a sequence that is orthogonal to each overlapping sequence over the portion of the SRS bandwidth.

41. An apparatus for wireless communication by a user equipment (UE), comprising: means for receiving, from a base station, sounding reference signal (SRS) configuration information indicating a full SRS bandwidth; means for determining a frequency hopping pattern for SRS transmission based on the SRS configuration information, the frequency hopping pattern being restricted to a portion of the SRS bandwidth that is less than the full SRS bandwidth, wherein the SRS configuration information further indicates a set of resource blocks (RBs) for each symbol in a set of symbols that may be used for the SRS transmission, and the frequency hopping pattern is restricted to at least one of a subset of the set of RBs for each symbol or a subset of the set of symbols; as well as Means for sending the SRS transmission to the base station based on the frequency hopping pattern.

42. The apparatus according to claim 41, wherein A ratio of the subset of the RB set to the RB set of each symbol is less than or equal to a threshold.

43. The apparatus according to claim 41, wherein The subset of the corresponding RB set for each symbol is different for at least two symbols in the set of symbols.

44. The apparatus of claim 41, wherein The SRS configuration information also indicates the subset of the RB set assigned to the UE.

45. The apparatus of claim 41, wherein The SRS configuration information indicates the subset of the set of symbols assigned to the UE.

46. ​​The apparatus of claim 45, wherein The SRS configuration information includes a bitmap having a first value corresponding to each symbol in the subset of the set of symbols assigned to the UE and a second value corresponding to each remaining symbol in the set of symbols not assigned to the UE.

47. The apparatus of claim 41 , further comprising: means for generating a sequence based on the number of RBs of the full SRS bandwidth; as well as means for assigning a truncated portion of said sequence to each symbol of said subset of said set of symbols, wherein the SRS transmission comprises each truncated portion of the sequence assigned to the subset of the set of symbols.

48. The apparatus of claim 41 , further comprising: means for generating a sequence based on the number of RBs of the partial SRS bandwidth, The SRS transmission includes the sequence.

49. The apparatus according to claim 48, wherein The sequence is generated based on one or more cyclic shifts, and the number of the one or more cyclic shifts is based on the partial SRS bandwidth.

50. The apparatus of claim 41, wherein The SRS transmission includes a sequence that is orthogonal to each overlapping sequence over the portion of the SRS bandwidth.

51. An apparatus for wireless communication by a base station, comprising: means for sending sounding reference signal (SRS) configuration information indicating a full SRS bandwidth to a user equipment (UE); and means for receiving an SRS transmission from the UE according to a frequency hopping pattern based on the SRS configuration information, the frequency hopping pattern being restricted to a portion of the SRS bandwidth that is less than the full SRS bandwidth, wherein the SRS configuration information further indicates a set of resource blocks (RBs) for each symbol in a set of symbols that may be used for SRS transmission, and the frequency hopping pattern being restricted to at least one of a subset of the set of RBs for each symbol or a subset of the set of symbols.

52. The apparatus of claim 51, wherein A ratio of the subset of the RB set to the RB set of each symbol is less than or equal to a threshold.

53. The apparatus of claim 51, wherein The subset of the corresponding RB set for each symbol is different for at least two symbols in the set of symbols.

54. The apparatus of claim 51, wherein The SRS configuration information also indicates the subset of the RB set assigned to the UE.

55. The apparatus of claim 51 , wherein: The SRS configuration information indicates the subset of the set of symbols assigned to the UE.

56. The apparatus of claim 55, wherein: The SRS configuration information includes a bitmap having a first value corresponding to each symbol in the subset of the set of symbols assigned to the UE and a second value corresponding to each remaining symbol in the set of symbols not assigned to the UE.

57. The apparatus of claim 51, wherein The SRS transmission includes a set of truncated portions of a sequence based on a number of RBs of the full SRS bandwidth.

58. The apparatus of claim 51 , wherein: The SRS transmission includes a sequence based on a number of RBs of the partial SRS bandwidth.

59. The apparatus according to claim 58, wherein The sequence is based on one or more cyclic shifts, and the number of the one or more cyclic shifts is based on the partial SRS bandwidth.

60. The apparatus of claim 51 , wherein: The SRS transmission includes a sequence that is orthogonal to each overlapping sequence over the portion of the SRS bandwidth.

61. A computer-readable medium storing computer-executable code for wireless communication by a user equipment (UE), the code, when executed by a processor, causing the processor to: receiving, from a base station, sounding reference signal (SRS) configuration information indicating a full SRS bandwidth; A frequency hopping pattern for SRS transmission is determined based on the SRS configuration information, wherein the frequency hopping pattern is limited to a portion of the SRS bandwidth that is smaller than the full SRS bandwidth. The SRS configuration information further indicates a resource block (RB) set for each symbol in a symbol set that may be used for the SRS transmission, and the frequency hopping pattern is limited to at least one of a subset of the RB set for each symbol or a subset of the symbol set; as well as The SRS transmission is sent to the base station based on the frequency hopping pattern.

62. A computer-readable medium storing computer-executable code for wireless communication by a base station, the code, when executed by a processor, causing the processor to: sending a sounding reference signal (SRS) configuration information indicating a full SRS bandwidth to a user equipment (UE); receiving an SRS transmission from the UE according to a frequency hopping pattern based on the SRS configuration information, the frequency hopping pattern being restricted to a portion of the SRS bandwidth that is less than the full SRS bandwidth, wherein: The SRS configuration information further indicates a resource block (RB) set for each symbol in a symbol set that can be used for SRS transmission, and the frequency hopping pattern is limited to at least one of a subset of the RB set for each symbol or a subset of the symbol set.

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