Frequency tracking loop using frequency error wraparound detection and correction to introduce range extension

Abstract

Various aspects presented herein relate to methods and apparatus for wireless communications, including an apparatus, such as a UE. The apparatus may measure a frequency error from a first pair of pilot symbols and a second pair of pilot symbols received via a channel associated with communications between the UE and a base station, the frequency errors measured from the first pair of pilot symbols and the second pair of pilot symbols corresponding to a first frequency error measurement and a second frequency error measurement. The apparatus may detect a first frequency wraparound in the first frequency error measurement and a second frequency wraparound in the second frequency error measurement. The apparatus may adjust the first frequency error measurement based on the first frequency wraparound or adjust the second frequency error measurement based on the second frequency wraparound if the first frequency wraparound or the second frequency wraparound is a non-zero value.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. patent application serial number 17 / 457,894, entitled “FREQUENCY TRACKING LOOP PULL-IN RANGE EXTENSION USING FREQUENCY ERRORWRAPAROUND DETECTION AND CORRECTION,” filed on December 6, 2021, which is expressly incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates generally to communication systems and, more particularly, to frequency error detection in wireless communications. Background Art

[0004] Wireless communication systems are widely deployed to provide a variety of telecommunication services, such as telephony, video, data, messaging, and broadcast. Typical wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0005] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at city, country, region, and even global levels. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of the continuous mobile broadband evolution promulgated by the Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the Internet of Things (IoT)) and other requirements. 5GNR includes services associated with enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable low latency communication (URLLC). Certain aspects of 5G NR may be based on 4G Long Term Evolution (LTE) standards. It is necessary to further improve 5G NR technology. In addition, these improvements may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies. Summary of the invention

[0006] The following presents a simplified overview of one or more aspects in order to provide a basic understanding of these aspects. This summary is not an extensive overview of all contemplated aspects, and is neither intended to identify key or important elements of all aspects, nor to describe the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to a more detailed description presented later.

[0007] In one aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a user equipment (UE). The apparatus may receive at least one of a pilot or data from a base station via a channel, wherein the channel includes a first pair of pilot symbols and a second pair of pilot symbols, wherein a first frequency error measurement is based on the first pair of pilot symbols received via the channel, and a second frequency error measurement is based on the second pair of pilot symbols received via the channel. The apparatus may also measure a frequency error from a first pair of pilot symbols and a second pair of pilot symbols received via a channel associated with communication between the UE and the base station, the frequency error measured from the first pair of pilot symbols corresponding to the first frequency error measurement, and the frequency error measured from the second pair of pilot symbols corresponding to the second frequency error measurement. Additionally, the apparatus may combine the first frequency error measurement and the second frequency error measurement, wherein the first frequency error measurement or the second frequency error measurement is adjusted based on the combination. The device may also calculate a difference between the first frequency error measurement and the second frequency error measurement, wherein the first frequency wraparound or the second frequency wraparound is detected based on the difference between the first frequency error measurement and the second frequency error measurement. In addition, the device may detect a first frequency wraparound in the first frequency error measurement and a second frequency wraparound in the second frequency error measurement. The device may also adjust the first frequency error measurement based on the first frequency wraparound or adjust the second frequency error measurement based on the second frequency wraparound when the detected first frequency wraparound is a non-zero value or the detected second frequency wraparound is a non-zero value. In addition, the device may update a frequency tracking loop (FTL) state of the frequency error between the UE and the base station based on the adjusted first frequency error measurement or the adjusted second frequency error measurement. The device may also compensate for the first frequency wraparound or the second frequency wraparound based on the adjusted first frequency error measurement or the adjusted second frequency error measurement.

[0008] To achieve the foregoing and related ends, one or more aspects include the features fully described below and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail some exemplary features of one or more aspects. However, these features are merely indicative of some of the various ways in which the principles of the various aspects may be employed, and this specification is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network.

[0010] Figure 2A is a diagram illustrating an example of a first frame according to various aspects of the present disclosure.

[0011] Figure 2B is a diagram illustrating an example of DL channels within a subframe according to various aspects of the present disclosure.

[0012] Figure 2C is a diagram illustrating an example of a second frame according to various aspects of the present disclosure.

[0013] Figure 2D is a diagram illustrating an example of UL channels within a subframe according to various aspects of the present disclosure.

[0014] Figure 3 is a diagram illustrating an example of a base station and a user equipment (UE) in an access network.

[0015] Figure 4 is a diagram illustrating example pilot symbols for wireless communications.

[0016] Figure 5 is a diagram illustrating an example flow chart for wireless communications.

[0017] Figure 6 is a graph illustrating an example frequency error measurement.

[0018] Figure 7 is a diagram illustrating an example flow chart for wireless communications.

[0019] Figure 8 is a graph illustrating an example frequency error measurement.

[0020] Fig.9A and Fig. 9B is a graph illustrating example levels of frequency error measurement.

[0021] Fig.10 is a diagram illustrating example communications between a UE and a base station.

[0022] Fig.11 is a flow chart of a method of wireless communication.

[0023] Fig.12 is a flow chart of a method of wireless communication.

[0024] Fig.13 is a diagram illustrating an example of a hardware implementation for an example apparatus. DETAILED DESCRIPTION

[0025] 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 configuration with which the concepts described herein can be practiced. In order to provide a thorough understanding of the various concepts, the detailed description includes specific details. However, it is apparent to those skilled in the art that these concepts can be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring these concepts.

[0026] Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0027] As an example, an element, or any part of an element, or any combination of elements can be implemented as a "processing system", which includes one or more processors. The example of a processor includes a microprocessor, a microcontroller, a graphics processing unit (GPU), a central processing unit (CPU), an application processor, a digital signal processor (DSP), a reduced instruction set computing (RISC) processor, a system on a chip (SoC), a baseband processor, a field programmable gate array (FPGA), a programmable logic device (PLD), a state machine, a gate logic, a discrete hardware circuit and other suitable hardware configured to perform various functionalities described throughout the present disclosure. One or more processors in a processing system can execute software. Whether it is referred to as software, firmware, middleware, microcode, hardware description language or other names, software should be widely 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.

[0028] Therefore, in one or more example embodiments, the described functions can be implemented with hardware, software or any combination thereof. If implemented with software, the function can be stored or encoded on a computer-readable medium as one or more instructions or codes. Computer-readable media include computer storage media. Storage media can be any available medium that can be accessed by a computer. As an example and not limitation, such computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage devices, magnetic disk storage devices, other magnetic storage devices, combinations of these types of computer-readable media, or any other medium that can be used to store instructions or data structure forms that can be accessed by a computer.

[0029] Although aspects and implementations are described in this application by way of illustration of some examples, it will be understood by those skilled in the art that additional implementations and use cases may be generated in many other arrangements and scenarios. The innovations described herein may be implemented across many different platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, specific implementations and / or uses may be generated via integrated chip implementations and other devices based on non-module components (e.g., end-user devices, vehicles, communication equipment, computing equipment, industrial equipment, retail / purchase equipment, medical equipment, artificial intelligence (AI) enabled devices, etc.). Although some examples may or may not specifically point to use cases or applications, the applicability of various types of described innovations may occur. Specific implementations may range from chip-level or modular components to non-modular, non-chip-level specific implementations, and further to the scope of aggregated, distributed or original equipment manufacturer (OEM) devices or systems that merge one or more aspects of the described innovations. In some actual settings, the device combined with the various aspects and features described may also include additional components and features for implementing and practicing the claimed and described aspects. For example, the transmission and reception of wireless signals necessarily include multiple components for analog and digital purposes (e.g., hardware components including antennas, RF chains, power amplifiers, modulators, buffers, processors, interleavers, adders / summers, etc.). The innovations described herein are intended to be practiced in a variety of devices of different sizes, shapes, and configurations, chip-level components, systems, distributed arrangements, aggregated or disaggregated components, end-user devices, etc.

[0030] Figure 11 is a diagram illustrating an example of a wireless communication system and access network. The wireless communication system (also referred to as a wireless wide area network (WWAN)) includes a base station 102, a UE 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., a 5G core (5GC)). The base station 102 may include a macro cell (a high-power cellular base station) and / or a small cell (a low-power cellular base station). A macro cell includes a base station. A small cell includes a femto cell, a pico cell, and a micro cell.

[0031] The base station 102 configured for 4G LTE (collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) can interface with the EPC 160 via a first backhaul link 132 (e.g., an S1 interface). The base station 102 configured for 5G NR (collectively referred to as the Next Generation RAN (NG-RAN)) can interface with the core network 190 via a second backhaul link 184. Among other functions, the base station 102 can perform one or more of the following functions: 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), subscriber and equipment tracking, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 may communicate with each other directly or indirectly (eg, via the EPC 160 or the core network 190) via the third backhaul link 134 (eg, an X2 interface). The first backhaul link 132, the second backhaul link 184, and the third backhaul link 134 may be wired or wireless.

[0032] Base station 102 can communicate wirelessly with UE 104. Each of base stations 102 can provide communication coverage for a corresponding geographic coverage area 110. There may 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 including both small cells and macro cells can be referred to as a heterogeneous network. A heterogeneous network can also include a home evolved Node B (eNB) (HeNB), 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 an uplink (UL) (also called a reverse link) transmission from UE 104 to base station 102 and / or a downlink (DL) (also called a forward link) transmission from base station 102 to UE 104. The communication link 120 can use multiple input multiple output (MIMO) antenna technology, including spatial multiplexing, beamforming and / or transmission diversity. The communication link can be through one or more carriers. For each carrier allocated in the carrier aggregation for a total of up to Yx MHz (x component carriers) for transmission in each direction, the base station 102 / UE 104 can use a spectrum of up to Y MHz (e.g., 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz, 400 MHz, etc.) bandwidth. The carriers may 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).

[0033] Some UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use DL / UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). The D2D communication may be through a variety of wireless D2D communication systems, such as, for example, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

[0034] 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, e.g., in a 5 GHz unlicensed spectrum, etc. When communicating in an unlicensed spectrum, the STA 152 / AP 150 may perform a clear channel assessment (CCA) prior to communication to determine whether a channel is available.

[0035] The small cell 102' can operate in licensed and / or unlicensed spectrum. When operating in the unlicensed spectrum, the small cell 102' can adopt NR and use the same unlicensed spectrum (e.g., 5 GHz, etc.) used by the Wi-Fi AP 150. The small cell 102' adopting NR in the unlicensed spectrum can improve the coverage of the access network and / or increase the capacity of the access network.

[0036] The electromagnetic spectrum is typically 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). Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to (interchangeably) as the "sub-6 GHz" band in various documents and articles. A similar naming issue sometimes occurs 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) identified as the "millimeter wave" band by the International Telecommunication Union (ITU).

[0037] Frequencies between FR1 and FR2 are generally referred to as mid-band frequencies. Recent 5G NR research has identified the operating bands for these mid-band frequencies as the frequency range name FR3 (7.125GHz–24.25GHz). The bands falling within FR3 can inherit FR1 characteristics and / or FR2 characteristics, so the features of FR1 and / or FR2 can be effectively extended to mid-band frequencies. In addition, higher frequency bands are currently being explored to extend 5G NR operations to more than 52.6GHz. For example, three higher operating bands have been identified as the frequency range names FR4a or FR4-1 (52.6GHz-71GHz), FR4 (52.6GHz-114.25GHz) and FR5 (114.25GHz-300GHz). Each of these higher frequency bands falls within the EHF band.

[0038] In view of the above aspects, unless otherwise specifically stated, it should be understood that if the term "below 6 GHz" or the like is used in this document, it can be broadly referred to as a frequency that can be less than 6 GHz, can be within FR1, or can include mid-band frequencies. In addition, unless otherwise specifically stated, it should be understood that if the term "millimeter wave" or the like is used in this document, it can be broadly referred to as a frequency that can include mid-band frequencies, can be within FR2, FR4, FR4-a or FR4-1 and / or FR5, or can be within the EHF band.

[0039] The 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, a gNodeB (gNB), or another type of base station. Some base stations, such as gNB 180, may operate in the traditional sub-6 GHz spectrum, in millimeter wave frequencies, and / or near millimeter wave frequencies to communicate with the UE 104. When the gNB 180 operates in millimeter wave or near millimeter wave frequencies, the gNB 180 may be referred to as a millimeter wave base station. The millimeter wave base station 180 may utilize beamforming 182 with the UE 104 to compensate for path loss and short range. The base station 180 and the UE 104 may each include multiple antennas, such as antenna elements, antenna panels, and / or antenna arrays, to facilitate beamforming.

[0040] The base station 180 may transmit beamformed signals in one or more transmission directions 182' to the UE 104. The UE 104 may receive the beamformed signals from the base station 180 in one or more reception directions 182". The UE 104 may also transmit beamformed signals to the base station 180 in one or more transmission directions. The base station 180 may receive the beamformed signals from the UE 104 in one or more reception directions. The base station 180 / UE 104 may perform beam training to determine the best reception direction and transmission direction for each of the base station 180 / UE 104. The transmission direction and reception direction of the base station 180 may be the same or different. The transmission direction and reception direction of the UE 104 may be the same or different.

[0041] The EPC 160 may include a mobility management entity (MME) 162, other MMEs 164, a serving gateway 166, a multimedia broadcast multicast service (MBMS) gateway 168, a broadcast multicast service center (BM-SC) 170, and a packet data network (PDN) gateway 172. The MME 162 may communicate with a home subscriber server (HSS) 174. The MME 162 is a control node that handles signaling between the UE 104 and the EPC 160. Typically, the MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are transmitted through the serving gateway 166, which itself is connected to the PDN gateway 172. The PDN gateway 172 provides UE IP address allocation and other functions. The PDN gateway 172 and the BM-SC 170 are connected to IP services 176. The IP services 176 may include the Internet, an intranet, an IP multimedia subsystem (IMS), a PS streaming service, and / or other IP services. The BM-SC 170 may provide functions for MBMS user service provision and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services in a public land mobile network (PLMN), and may be used to schedule MBMS transmissions. The MBMS gateway 168 may be used to distribute MBMS traffic to base stations 102 belonging to a multicast broadcast single frequency network (MBSFN) area that broadcasts a specific service, and may be responsible for session management (start / stop) and for collecting eMBMS-related billing information.

[0042] 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. In general, the AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are transmitted through the UPF 195. The UPF 195 provides UE IP address allocation and other functions. The UPF 195 is connected to an IP service 197. The IP service 197 may include the Internet, an intranet, an IP multimedia subsystem (IMS), a packet switching (PS) stream (PSS) service, and / or other IP services.

[0043] 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 transmission reception point (TRP), or some other suitable term. 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 smart phone, a Session Initiation Protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (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, a toaster, a vehicle, a heart monitor, etc.). UE 104 may also be referred to as a station, mobile station, subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable term. In some scenarios, the term UE may also be applied to one or more supporting devices, such as in a device constellation arrangement. One or more of these devices may access a network together and / or individually.

[0044] Reference again Figure 1In certain aspects, the UE 104 may include a receiving component 198 configured to receive at least one of a pilot or data from a base station via a channel, wherein the channel includes a first pair of pilot symbols and a second pair of pilot symbols, wherein a first frequency error measurement is based on the first pair of pilot symbols received via the channel, and a second frequency error measurement is based on the second pair of pilot symbols received via the channel. The receiving component 198 may also be configured to measure frequency error from the first pair of pilot symbols and the second pair of pilot symbols received via a channel associated with communication between the UE and the base station, the frequency error measured from the first pair of pilot symbols corresponding to the first frequency error measurement, and the frequency error measured from the second pair of pilot symbols corresponding to the second frequency error measurement. The receiving component 198 may also be configured to combine the first frequency error measurement and the second frequency error measurement, wherein the first frequency error measurement or the second frequency error measurement is adjusted based on the combination. The receiving component 198 may also be configured to calculate a difference between the first frequency error measurement and the second frequency error measurement, wherein the first frequency wraparound or the second frequency wraparound is detected based on the difference between the first frequency error measurement and the second frequency error measurement. The receiving component 198 may also be configured to detect a first frequency wraparound in the first frequency error measurement and a second frequency wraparound in the second frequency error measurement. The receiving component 198 may also be configured to adjust the first frequency error measurement based on the first frequency wraparound or adjust the second frequency error measurement based on the second frequency wraparound if the detected first frequency wraparound is a non-zero value or the detected second frequency wraparound is a non-zero value. The receiving component 198 may also be configured to update a frequency tracking loop (FTL) state of the frequency error between the UE and the base station based on the adjusted first frequency error measurement or the adjusted second frequency error measurement. The receiving component 198 may also be configured to compensate for the first frequency wraparound or the second frequency wraparound based on the adjusted first frequency error measurement or the adjusted second frequency error measurement.

[0045] Although the following description may focus on 5G NR, the concepts described herein may be applicable to other similar areas such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0046] Figure 2A FIG200 is a diagram 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 250 is a diagram illustrating an example of a second subframe within a 5G NR frame structure. Figure 2DFIG280 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), subframes within that subcarrier set are dedicated to either DL or UL), or may be time division duplex (TDD) (wherein for a particular set of subcarriers (carrier system bandwidth), subframes within that subcarrier set are dedicated to both DL and UL). Figure 2A , Figure 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 1 (all of which are UL). Although subframes 3 and 4 are shown as having slot formats 1 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 DL and UL, respectively. Other slot formats 2-61 include a mix of DL, UL and flexible symbols. The slot format is configured for the UE by a received slot format indicator (SFI) (dynamically configured by DL control information (DCI) or semi-statically / statically configured by radio resource control (RRC) signaling). Note that the following description also applies to the 5G NR frame structure as TDD.

[0047] FIG. 2A to FIG. 2D The frame structure is illustrated, and various aspects of the present disclosure may be applicable to other wireless communication technologies that may have different frame structures and / or different channels. A frame (10ms) may be divided into 10 subframes (1ms) of equal size. Each subframe may include one or more time slots. A subframe may also include a microslot, which may include 7, 4, or 2 symbols. Each time slot may include 14 or 12 symbols, depending on whether the cyclic prefix (CP) is normal or extended. For a normal CP, each time slot may include 14 symbols, and for an extended CP, each time slot may include 12 symbols. The symbol on the DL may be a CP orthogonal frequency division multiplexing (OFDM) (CP-OFDM) symbol. The symbol on the UL may be a CP-OFDM symbol (for high throughput scenarios) or a discrete Fourier transform (DFT) extended OFDM (DFT-s-OFDM) symbol (also known as a single carrier frequency division multiple access (SC-FDMA) symbol) (for power-limited scenarios; limited to single-stream transmission). The number of slots within a subframe is based on the CP and the parameter set. The parameter set defines the subcarrier spacing (SCS) and effectively defines the symbol length / duration, which is equal to 1 / SCS.

[0048]

[0049] For normal CP (14 symbols / slot), different parameter sets μ0 to 4 allow 1, 2, 4, 8, and 16 slots per subframe, respectively. For extended CP, parameter set 2 allows 4 slots per subframe. Accordingly, for normal CP and parameter set μ, there are 14 symbols / slot and 2 μ timeslots / subframe. The subcarrier spacing can be equal to 2 μ *15kHz, where μ is parameter set 0 to 4. Therefore, the subcarrier spacing for parameter set μ=0 is 15kHz, and the subcarrier spacing for parameter set μ=4 is 240kHz. The symbol length / duration is inversely related to the subcarrier spacing. FIG. 2A to FIG. 2D An example of a parameter set μ=2 with a normal CP of 14 symbols per slot and 4 slots per subframe is provided. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is about 16.67 μs. Within a frame set, there may be one or more different bandwidth parts (BWPs) that are frequency-division multiplexed (see Figure 2B ). Each BWP can have a specific parameter set and CP (normal or extended).

[0050] A resource grid may be used to represent a frame structure. Each slot includes a resource block (RB) (also referred to as a physical RB (PRB)) extending over 12 consecutive subcarriers. The resource grid is divided into a plurality of resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0051] like Figure 2A As shown in , some of the REs carry reference (pilot) signals (RS) for the UE. The RS may include a demodulation RS (DM-RS) (indicated as R for a particular configuration, but other DM-RS configurations are possible) and a channel state information reference signal (CSI-RS) for channel estimation at the UE. The RS may also include a beam measurement RS (BRS), a beam refinement RS (BRRS), and a phase tracking RS (PT-RS).

[0052] Figure 2BExamples of various DL channels within a subframe of a frame are illustrated. A physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) (e.g., 1, 2, 4, 8, or 16 CCEs), each CCE including six RE groups (REGs), each REG including 12 consecutive REs in an OFDM symbol of an RB. A PDCCH within a BWP may be referred to as a control resource set (CORESET). The UE is configured to monitor PDCCH candidates in a PDCCH search space (e.g., a common search space, a UE-specific search space) during a PDCCH monitoring opportunity on a CORESET, wherein the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs may be located at higher and / or lower frequencies on the channel bandwidth. A primary synchronization signal (PSS) may be within symbol 2 of a particular subframe of a frame. The PSS is used by UE 104 to determine subframe / symbol timing and physical layer identification. A secondary synchronization signal (SSS) may be within symbol 4 of a particular subframe of a frame. The SSS is used by the UE to determine the physical layer cell identity group number and the radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine the physical cell identifier (PCI). Based on the PCI, the UE can determine the location of the DM-RS. The physical broadcast channel (PBCH) carrying the master information block (MIB) can be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block (also referred to as an SS block (SSB)). The MIB provides the number of RBs in the system bandwidth and the system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted via the PBCH (such as a system information block (SIB)), and paging messages.

[0053] like Figure 2C As illustrated, some of the REs carry DM-RS (indicated as R for a particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE may transmit the DM-RS of the physical uplink control channel (PUCCH) and the DM-RS of the physical uplink shared channel (PUSCH). The PUSCH DM-RS may be transmitted in the first or first two symbols of the PUSCH. Depending on whether a short PUCCH or a long PUCCH is transmitted and depending on the specific PUCCH format used, the PUCCH DM-RS may be transmitted in different configurations. The UE may transmit a sounding reference signal (SRS). The SRS may be transmitted in the last symbol of a subframe. The SRS may have a comb structure, and the UE may transmit the SRS on one of the comb structures in the comb structure. The SRS may be used by the base station for channel quality estimation to achieve frequency-dependent scheduling of the UL.

[0054] Figure 2DExamples of various UL channels within a subframe of a frame are illustrated. The PUCCH may be located at a position as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicators (CQI), precoding matrix indicators (PMI), rank indicators (RI), and hybrid automatic repeat request (HARQ) acknowledgement (ACK) (HARQ-ACK) feedback (i.e., one or more HARQ ACK bits indicating one or more ACKs and / or negative ACKs (NACKs)). The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0055] Figure 3 3 is a block diagram of a base station 310 in an access network communicating with a UE 350. 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 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller / processor 375 provides RRC layer functionality associated with broadcasting 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 functionality associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with transmission of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0056] The transmission (TX) processor 316 and the reception (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1 (which includes the physical (PHY) layer) may include error detection on the transmission channel, forward error correction (FEC) decoding / decoding of the transmission channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 processes the mapping to the signal constellation based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-order phase shift keying (M-PSK), M-order quadrature amplitude modulation (M-QAM)). The decoded and modulated symbols can then be divided into parallel streams. Subsequently, each stream can be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., a pilot) in the time domain and / or frequency domain, and then combined using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially pre-decoded to generate 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. Channel estimates may be derived based on reference signals 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 a radio frequency (RF) carrier with a corresponding spatial stream for transmission.

[0057] At the UE 350, each receiver 354RX receives a signal through its corresponding antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to a receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial stream destined for the UE 350. If multiple spatial streams are destined for the UE 350, they can be merged into a single OFDM symbol stream by the RX processor 356. The RX processor 356 then converts the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbol on each subcarrier and the reference signal are recovered and demodulated by determining the signal constellation point most likely to be 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 transmitted on the physical channel by the base station 310. The data and control signals are then provided to the controller / processor 359, which implements layer 3 and layer 2 functionality.

[0058] 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, cipher interpretation, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using an ACK and / or NACK protocol to support HARQ operations.

[0059] Similar to the functionality described in conjunction with DL transmissions performed by the base station 310, the controller / processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality associated with header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality associated with 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 functionality 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.

[0060] The TX processor 368 may use channel estimates derived by the channel estimator 358 from a reference signal or feedback transmitted by the base station 310 to select appropriate coding and modulation schemes and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0061] UL transmissions are processed at the base station 310 in a manner similar to that described in conjunction with the receiver functionality at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

[0062] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport channels and logical channels, packet reassembly, cipher interpretation, header decompression, control signal processing to recover IP packets from the UE 350. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operations.

[0063] At least one of the TX processor 368, the RX processor 356, and the controller / processor 359 may be configured to combine Figure 1 The 198 came to execute all aspects.

[0064] Some aspects of wireless communications (e.g., LTE or 5G NR) may utilize orthogonal frequency division multiplexing (OFDM) as a digital multi-carrier modulation scheme. OFDM systems may also utilize channel estimation. For example, channel estimation may be used to increase the capacity of an OFDM access (OFDMA) system, such as by improving system performance in terms of bit error rate. To facilitate estimation of channel characteristics, wireless communications may utilize cell-specific reference signals (e.g., pilot symbols) in both time and frequency. In some instances, pilot symbols may be used to provide an estimate of a channel at a given position within a subframe.

[0065] In some aspects, the location within the pilot symbol allocation subframe can be based on the cell identification number and / or the transmission antenna. Since the pilot symbol is uniquely located within the subframe, this can help ensure that the pilot symbols do not interfere with each other. Therefore, the pilot symbol can be used to provide a reliable estimate of the gain associated with each resource element within the grid transmitted by the propagation channel.

[0066] Figure 4 4 is a diagram illustrating example pilot symbols within a subframe. Figure 4 As shown, diagram 400 includes pilot symbols 410 (e.g., 8 pilot positions in 4 different OFDM symbols within a subframe). Diagram 400 depicts that the subframe extends across both time and frequency. In addition, pilot symbols 410 are uniquely positioned within the subframe to ensure that pilot symbols do not interfere with each other. For example, each of pilot symbols 410 is spaced across the subframe to avoid interfering with other pilot symbols.

[0067] Some aspects of wireless communication may measure a frequency error between a UE and a base station during transmission. The frequency error may correspond to the difference between the actual frequency of transmission / reception (eg, at a base station) and the assigned frequency at the receiver.

[0068] Additionally, in some aspects of wireless communication, pilot symbols may be utilized in order to measure frequency error of certain transmissions. For example, a pilot or data may be transmitted via a certain channel, and the pilot symbols may be used to measure the frequency error. That is, the frequency error may be measured from pilot symbols (e.g., two pilot symbols) received via the channel. The frequency error may also be associated with the spacing between pilots in a subframe.

[0069] As indicated herein, the frequency error may be estimated based on an algorithm (e.g., a frequency tracking loop (FTL) algorithm). Additionally, the maximum pull-in range of the FTL algorithm may be limited by the time separation (Tp) between pilot symbols. This time separation between pilot symbols may be used to estimate the frequency error. In some instances, any residual frequency error outside a certain range (e.g., Wrapping (e.g., frequency wrapping) can cause the frequency error to change in sign, which can cause frequency compensation to be applied in the wrong direction. This can then result in an increase in the total frequency offset, rather than a decrease in the total frequency offset. Furthermore, this can ultimately result in a total frequency offset equal to Or multiples of the time separation in the steady state, including a residual frequency error due to wraparound (e.g., a residual frequency error of 0). Therefore, wraparound may prevent correct frequency tracking. In addition, such high frequency offsets in the steady state can lead to a persistent and significant loss of orthogonality of OFDM, and therefore a loss of signal-to-noise ratio (SNR). This can lead to severe decoding errors and a loss of throughput.

[0070] Figure 5 5 is a diagram illustrating an example flow chart for frequency error estimation. Figure 5 As shown, diagram 500 includes steps 510-530 for frequency error estimation. More specifically, diagram 500 depicts frequency error estimation using frequency tracking loop (FTL) states. At step 510, the frequency error (f ij ). Next, at step 520, the frequency tracking loop (FTL) state may be updated. At step 530, the frequency error may be applied.

[0071] Figure 6 6 is a graph 600 illustrating an example frequency error measurement. Figure 6 As shown, graph 600 includes an x-axis of true frequency error (in Hz) and a y-axis of measured phase error (in radians). More specifically, graph 600 depicts frequency error measurements 610 using pilot symbols (e.g., two pilot symbols {4, 7}) with a time interval (T) in seconds. Figure 6As shown, there is a phase difference between the channels of the two pilot symbols. For example, the phase difference from the two pilot symbols {4,7} can be equal to: Φ = 2*π*fe*T, where Φ is the phase difference, fe is the frequency error, and T is the time interval between the pilot symbols. Figure 6 In , phase wrap occurs at + / -π times 2π, which corresponds to a frequency error wrap at + / -(1 / 2T) times (1 / T). This phase wrap and frequency error wrap can lead to frequency error compensation in the incorrect direction and severe loss of SNR.

[0072] As indicated herein, some types of wireless communications may utilize inefficient frequency error measurements that result in frequency wraparound. For example, frequency wraparound may prevent proper frequency tracking. Furthermore, frequency wraparound may result in a significant loss of orthogonality of OFDM, and therefore a loss of SNR. This may result in severe decoding errors and a loss of throughput. Therefore, it may be beneficial to utilize frequency error measurements that allow for proper frequency tracking. For example, it may be beneficial to utilize frequency error measurements that maintain the orthogonality of OFDM and do not result in a loss of SNR. Additionally, it may be beneficial to utilize frequency error measurements that result in accurate decoding and maintain throughput.

[0073] Aspects of the present disclosure may utilize efficient and accurate frequency error measurements. For example, aspects of the present disclosure may adjust the frequency error measurements based on the detected frequency wraparound. Aspects of the present disclosure may also utilize frequency error measurements that allow proper frequency tracking. Additionally, in some instances, aspects of the present disclosure may utilize frequency error measurements that maintain the orthogonality of OFDM and do not result in SNR loss. More specifically, aspects of the present disclosure may utilize frequency error measurements that result in accurate decoding and provide the ability to maintain throughput.

[0074] In some examples, aspects of the present disclosure may utilize frequency wraparound (e.g., FTL wraparound) detection and correction. Aspects of the present disclosure may utilize frequency errors measured from different pilot symbol pairs (e.g., two different pilot symbol pairs) with different time separations in order to detect FTL wraparound. For two pilot symbol pairs, aspects of the present disclosure may use symbols S with time separation T1. i1 , S j1 To represent a pair of symbols, and use the symbol S with a time separation T2 i2 , S j2 To represent another pair of symbols. The actual residual frequency error can be expressed by f e Indicates. From this pair S i1 S j1 The estimated frequency error can be f1, and from this pair S i2 S j2The estimated frequency error can be f2. Due to possible wraparound, f1 and f2 may not be equal to (or similar to) f e . Additionally, the amounts of wraparound corresponding to time separations T1 and T2 can be expressed as F1 and F2, where: F1 = 1 / T1, and F2 = 1 / T2. Thus, ignoring the effects of noise, for i = 1, 2: f i = f e mod F i , such that f1 = M*F1 + f e , and f2 = N*F2 + f e . This can result in: f2 - f1 = N*F2 - M*F1 = d(M,N). In the above equation, M and N respectively represent the number of wraparounds in the frequency error estimates f1 and f2. The difference term d(M,N) can take discrete values and can become independent of f e . These values can be referred to as difference levels.

[0075] Aspects of the present disclosure can also counter noise in frequency error measurements. In the presence of noise, the above equation may result in noise measurement d(M,N) + noise. However, as long as the difference levels have sufficient separation (for different (M,N) pairs), aspects of the present disclosure can detect the difference level d(M,N) with high reliability and thus detect (M,N) even in the presence of noise. As described herein, aspects of the present disclosure can reliably detect up to several wraparounds in f1 and f2.

[0076] Additionally, aspects of the present disclosure can allow for the reconstruction of the unwrapped frequency error. For example, once (M,N) is known, aspects of the present disclosure can use the above equations for f1 or f2 to calculate the unwrapped frequency error f e . However, aspects of the present disclosure can choose between the equations discussed below. The frequency error can be obtained by dividing the estimate of the cumulative phase difference between two pilot symbols by 2π*T p . Additionally, the variance of the estimated cumulative phase can correspond to a function of the SNR and can thus remain independent of T p (ignoring the effects of channel variations due to Doppler spread). Thus, as the pilot interval T p increases, the variance of the calculated frequency can decrease. Thus, aspects of the present disclosure can choose one equation (e.g., f1 = M*F1 + f e ) in the case of F1 < F2 (equivalent to T2 < T1) or can choose another equation (e.g., f2 = N*F2 + f e ) in the case of F1 ≥ F2.

[0077] Aspects of the present disclosure may also utilize a process to determine and expand the scope of introduction. For example, the various aspects presented herein may be designed to determine a process for determining a set A, which is a feasible set of pairs (M, N) such that the difference between any two different levels d(M=i, N=j) and d(M=l, N=k) is greater than a threshold τ. τ may be a design parameter and may help prevent noise. In addition, τ may be tuned based on SNR or determined based on the lowest supported SNR. Set A may have (M=i, N=j) and (M=l, N=k), which are different pairs, and i=l or j=k. For any N=k winding in f2, the actual potential frequency error may be in the following range: Similarly, The actual frequency error range corresponding to the M=1 wrapping in f1 can be defined. In addition, it can be assumed that F2>F1 without loss of generality.

[0078] Aspects of the present disclosure may determine the elements in the set A. Considering k≥0 and l≥0, and starting from k=0, the aspects presented herein may perform the following steps 1-3 until a stopping criterion is reached. In step 1, for a current value N=k, the aspects presented herein may determine all possible values ​​M=l≥0 such that (i.e., the empty set). In step 2, aspects presented herein may pick each value l obtained from step 1 in ascending order and add two pairs (M=l, N=k) and (M=-l, N=-k) to set A until a stopping criterion is met. The stopping criterion may be defined as: for any (M=i, N=j) that has been added to A, |d(M=i, N=j)-d(M=l, N=k)|≤τ. In step 3, if the stopping criterion is not met, N=k+1 may be incremented.

[0079] In addition, in some examples, aspects of the present disclosure may implement introduction ranges and effective time separations. The introduction range may be determined based on the maximum allowed values ​​of M and N. For example, consider M ≥ 0 and N max =max(N), consider N≥0, let M max = max(M), so that (M,N)∈A. Similarly, let N be -N max Change to N max The fundamental frequency can be crossed: And make M from -M max Change to M max You can cross this range: (-M max *F1- Therefore, the achieved introduction range can be the intersection of these two ranges, given by: (-F max ,F max),in

[0080] Aspects of the present disclosure may also achieve effective time separation. For example, given the implemented introduction range (-F max ,F max ), the various aspects presented herein can separate the effective time by T eff Defined to provide effective time separation similar to the introduced range: Furthermore, using the same actual time separations T1 and T2, the aspects presented herein can achieve an extended introduction range T corresponding to the effective time separation. eff , provided by:

[0081] In some instances, aspects of the present disclosure may generalize the aforementioned techniques when f1 and f2 are measured from different subframes and have different rotator values, i.e., when current frequency compensation is applied. i1 , S j1 The rotator value when measuring f1 can be F rot1 , and when from S i2 , S j2 The rotator value when measuring f2 can be F rot2 The basic total frequency error when measuring f1 and f2 can be assumed to remain the same. In addition, with the rotator value F ro The fundamental residual frequency can be And has F rot2 The fundamental residual frequency can be This can result in: and So the difference between f1 and f2 can be: Since the basic total frequency error can be assumed to be the same, this leads to the following formula: Using the above equation, d(M,N) can be redefined as: f2-f1-(F rot1 -F rot2 ) = N*F2 - M*F1 = d(M,N). Therefore, the same techniques discussed above can be used for wraparound detection and correction.

[0082] Figure 7 7 is a diagram illustrating an example flow chart for frequency error estimation. Figure 7 As shown, diagram 700 includes steps 710-760 for frequency error estimation. More specifically, diagram 700 depicts frequency error estimation using wraparound detection and correction. At step 710, S i1 and S j1 To estimate the frequency error (f1). In addition, at step 720, S i2and S j2 To estimate the frequency error (f2). At step 730, aspects presented herein can perform wraparound detection and correction. Additionally, at step 740, aspects presented herein can determine values ​​of A and d(M,N), which can be determined offline and stored. At step 750, the frequency tracking loop (FTL) state can be updated. Furthermore, at step 760, the frequency error can be applied. Figure 7 Depicted is an example of a frequency error estimate that can utilize multiple frequency error measurements to detect and correct frequency wraparound.

[0083] Figure 8 8 is a graph 800 illustrating an example frequency error measurement. Figure 8 As shown, graph 800 includes an x-axis of true frequency error (in Hz) from the correlation calculated between pilots and a y-axis of measured phase error (in radians). More specifically, graph 800 depicts frequency error measurements 810 using a first pair of pilot symbols (e.g., pilot symbol pair {4,7}) with time interval T1 and frequency error measurements 820 using a second pair of pilot symbols (e.g., pilot symbol pair {0,4}) with time interval T2. Figure 8 As depicted in FIG. 8 , frequency error measurement 810 and frequency error measurement 820 may use a first pair of pilot symbols and a second pair of pilot symbols, respectively, to detect the amount of wrapping. The first pair of pilot symbols and the second pair of pilot symbols may have different pilot intervals T1 and T2, respectively. Figure 8 In the example, phase wrapping occurs at + / -π times 2π, which corresponds to the phase wrapping at + / -(1 / 2T i ) multiplied by (1 / T i ) frequency error wraps around. Figure 8 As shown, for the first pair of pilot symbols and the second pair of pilot symbols, the wrapping point and the wrapping amount are different. Figure 8 , both the measured frequency error measurement 810 and the frequency error measurement 820 may be parallel at some points. The difference between the frequency error measurement 810 and the frequency error measurement 820 is a function of the amount of wraparound of each curve, rather than the true frequency error, so the difference between the two curves can be quantified. Therefore, the difference can be used to detect and correct for wraparound.

[0084] Fig.9A is a graph 900 illustrating different levels of frequency error measurements possible in LTE. Fig.9A d(M,N) corresponding to different levels of set A are shown. Fig.9A The separation between any two levels in can be 1000 Hz, which provides high wraparound detection reliability in the presence of noise. Fig.9AIn the example of , to measure the residual frequency error, the example wireless device may use CRS symbols 0,4 or CRS symbols 4,7. Similarly, if T1 is the time separation between symbols 0 and 4, and T2 is the time separation between symbols 4 and 7, this may result in F1 = 3503.6 Hz, with an introduction range of (-1752, 1752) Hz, and may result in F2 = 4660.2 Hz, with an introduction range of (-2330, 2330) Hz. Based on this, for Fig.9A , set A can be:

[0085] A={(0,0),(1,0),(-1,0),(1,1),(-1,-1),(2,1),(-2,-1)}.

[0086] like Fig.9A As depicted in , aspects presented herein can detect up to a certain number of wraps (e.g., 2, 1 wraps) of frequency measurements from pilot symbol pairs in LTE (e.g., pilot symbol pairs {0,4}, {4,7}). In addition, the difference level (d(M,N)) can be quantized to levels that are greater than 1000 Hz apart. Therefore, the difference can be resilient to noise. The aspects presented herein can also result in a lead-in range improvement, where the default lead-in range is: + / -2330 Hz, and the improved lead-in range according to the present disclosure is: + / -6990 Hz (i.e., 3x improvement). In addition, the effective symbol interval can be 6990=1 / (2*T eff ), where T eff =71.53μsec or 1 OFDM symbol. Fig. 9B As depicted in graph 950 in , a sinusoidally varying frequency offset with an amplitude of 10,000 Hz and a time period of 1 second can be applied under different wireless channel fading models at 3 dBBSNR. Various aspects presented herein can apply FTL wrap detection and correction logic to reconstruct the actual unwrapped frequency error in the range [-6.9 kHz, 6.9 kHz]. The implemented introduction range (in Hz) can be: (-6990.3, 6990.3), which can provide an introduction range improvement because otherwise the closest pilot spacing that can be achieved in LTE is from CRS 4 and 7, where the introduction range is limited to + / -2330 Hz.

[0087] Aspects of the present disclosure may include several benefits or advantages. For example, aspects of the present disclosure may result in an extended FTL introduction range. Aspects of the present disclosure may also allow for lower noise variance in frequency error measurements compared to reduced pilot spacing. For example, the measured frequency error may be Φ / 2*π*T, where T is the spacing between pilots. Since the noise in Φ may be divided by T, the frequency estimate error variance may be: α(1 / T2 ). Aspects of the present disclosure may perform wraparound detection based on frequency measurements from different pilot symbol pairs, and apply wraparound correction to the frequency measurements from the symbol pairs with the largest time interval, thereby reducing noise variance. In addition, aspects of the present disclosure may effectively reduce pilot density, thereby achieving increased capacity. Aspects presented herein may be able to converge FTL even with higher frequency errors.

[0088] Additionally, the various aspects presented herein may also reduce the complexity and processing power of the UE during certain reception modes, such as an extended discontinuous reception (eDRX) mode. The various aspects presented herein may be used to correct large potential frequency errors during wakeup after long sleep in an eDRX scenario in a subframe, thereby reducing warm-up time, which may result in power savings.

[0089] In some aspects, the target maximum frequency offset detection and correction supported by the UE can be determined by + / -F max Then the effective pilot interval can be: By utilizing various aspects presented herein, there may be two different pilot pairs with spacings T1, T2 such that frequency measurements from each of these pairs may be used to obtain an effective pilot spacing Teff = Tp. In some instances, Teff may be smaller than T1 and T2, with a factor of In some aspects, wherein F max may become a bottleneck in selecting the pilot spacing Tp, the aspects presented herein can achieve the same F with a significantly larger average pilot spacing provided by T1 and T2 max .

[0090] Fig.10 1000 is a diagram illustrating example communications between a UE 1002 and a base station 1004.

[0091] At 1010, UE 1002 may receive at least one of a pilot or data (e.g., pilot / data 1014) from a base station (e.g., base station 1004) via a channel, wherein the channel includes a first pair of pilot symbols and a second pair of pilot symbols, wherein a first frequency error measurement is based on the first pair of pilot symbols received via the channel, and a second frequency error measurement is based on the second pair of pilot symbols received via the channel. Likewise, at 1012, base station 1004 may transmit at least one of a pilot or data (e.g., pilot / data 1014) via a channel, wherein the channel includes the first pair of pilot symbols and the second pair of pilot symbols.

[0092] At 1020, the UE 1002 may measure a frequency error from a first pair of pilot symbols and a second pair of pilot symbols received via a channel associated with communications between the UE and a base station, the frequency error measured from the first pair of pilot symbols corresponding to a first frequency error measurement, and the frequency error measured from the second pair of pilot symbols corresponding to a second frequency error measurement. The first frequency error measurement and the second frequency error measurement may be associated with a frequency tracking loop (FTL) algorithm.

[0093] At 1030, UE 1002 may combine the first frequency error measurement and the second frequency error measurement, wherein the first frequency error measurement or the second frequency error measurement is adjusted based on the combination.

[0094] At 1040, UE 1002 may calculate a difference between the first frequency error measurement and the second frequency error measurement, wherein the first frequency wraparound or the second frequency wraparound is detected based on the difference between the first frequency error measurement and the second frequency error measurement. In some aspects, the difference between the first frequency error measurement and the second frequency error measurement may be calculated as: f2-f1=N*F2-M*F1, wherein f1 is the first frequency error measurement, f2 is the second frequency error measurement, M is the number of first frequency wraparounds in the first frequency error measurement, N is the number of second frequency wraparounds in the second frequency error measurement, F1=1 / T1, F2=1 / T2, T1 is the first time interval between the first pair of pilot symbols, and T2 is the second time interval between the second pair of pilot symbols. In addition, the difference between the first frequency error measurement and the second frequency error measurement may be calculated as: f2-f1=N*F2-M*F1+(F comp1 –F comp2 ), where f1 is the first frequency error measurement, f2 is the second frequency error measurement, M is the number of first frequency wraparounds in the first frequency error measurement, N is the number of second frequency wraparounds in the second frequency error measurement, F1=1 / T1, F2=1 / T2, T1 is the first time interval between the first pair of pilot symbols, T2 is the second time interval between the second pair of pilot symbols, F comp1 is a first frequency compensation value based on at least one previous frequency error measurement at the time of the first frequency error measurement, and F comp2 is a second frequency compensation value based on one or more previous frequency error measurements at the time of the second frequency error measurement.

[0095] At 1050, the UE 1002 may detect a first frequency wrap in the first frequency error measurement and a second frequency wrap in the second frequency error measurement. The first frequency wrap may be proportional to a first in-phase wrap based on a correlation between a first pair of pilot symbols, and the second frequency wrap may be proportional to a second in-phase wrap based on a correlation between a second pair of pilot symbols, wherein the first in-phase wrap is a first constant value and the second in-phase wrap is a second constant value. Additionally, a first time interval (T1) between the first pair of pilot symbols may be different from a second time interval (T2) between the second pair of pilot symbols, wherein an amount of the first frequency wrap may be equal to (1 / T1), and an amount of the second frequency wrap may be equal to (1 / T2).

[0096] At 1060, the UE 1002 may adjust the first frequency error measurement based on the first frequency wrap or adjust the second frequency error measurement based on the second frequency wrap if the detected first frequency wrap is a non-zero value or the detected second frequency wrap is a non-zero value. In some aspects, adjusting the first frequency error measurement or the second frequency error measurement may include: correcting the first frequency error measurement or the second frequency error measurement. In addition, adjusting the first frequency error measurement or the second frequency error measurement may include: adding or subtracting a first multiple (1 / T1) from the first frequency error measurement (f1), or adding or subtracting a second multiple (1 / T2) from the second frequency error measurement (f2), where T1 is a first time interval between a first pair of pilot symbols, and T2 is a second time interval between a second pair of pilot symbols. In addition, adding or subtracting the first multiple (1 / T1) from the first frequency error measurement (f1) may unwrap the first frequency wrap, and adding or subtracting the second multiple (1 / T2) from the second frequency error measurement (f2) may unwrap the second frequency wrap.

[0097] At 1070, UE 1002 may update a frequency tracking loop (FTL) state of the frequency error between the UE and the base station based on the adjusted first frequency error measurement or the adjusted second frequency error measurement.

[0098] At 1080, the UE 1002 may compensate for the first frequency wraparound or the second frequency wraparound based on the adjusted first frequency error measurement or the adjusted second frequency error measurement.

[0099] Fig.11 1100 is a flow chart of a method of wireless communication. The method may be performed by a UE or a component of a UE (eg, UE 104, 350, 1002; device 1302). The methods described herein may provide several benefits, such as improved communication signaling, resource utilization, and / or power conservation.

[0100] At 1104, the UE may measure a frequency error from a first pair of pilot symbols and a second pair of pilot symbols received via a channel associated with communications between the UE and the base station, the frequency error measured from the first pair of pilot symbols corresponding to a first frequency error measurement, and the frequency error measured from the second pair of pilot symbols corresponding to a second frequency error measurement, as combined with Figures 4 to 10 For example, UE 1002 may measure a frequency error from a first pair of pilot symbols and a second pair of pilot symbols received via a channel associated with communications between the UE and a base station, the frequency error measured from the first pair of pilot symbols corresponding to a first frequency error measurement, and the frequency error measured from the second pair of pilot symbols corresponding to a second frequency error measurement, as described in conjunction with Fig.10 In addition, 1104 can be composed of Fig.13 The first frequency error measurement and the second frequency error measurement may be associated with a frequency tracking loop (FTL) algorithm.

[0101] At 1110, the UE may detect a first frequency wraparound in the first frequency error measurement and a second frequency wraparound in the second frequency error measurement, such as in combination with Figures 4 to 10 For example, UE 1002 may detect a first frequency wraparound in the first frequency error measurement and a second frequency wraparound in the second frequency error measurement, such as in combination with Fig.10 In addition, 1110 may be composed of Fig.13 The determining component 1340 in is executed. The first frequency wrap can be proportional to the first in-phase wrap based on the correlation between the first pair of pilot symbols, and the second frequency wrap can be proportional to the second in-phase wrap based on the correlation between the second pair of pilot symbols, wherein the first in-phase wrap is a first constant value and the second in-phase wrap is a second constant value. In addition, the first time interval (T1) between the first pair of pilot symbols can be different from the second time interval (T2) between the second pair of pilot symbols, wherein the amount of the first frequency wrap can be equal to (1 / T1), and the amount of the second frequency wrap can be equal to (1 / T2).

[0102] At 1112, the UE may adjust the first frequency error measurement based on the first frequency wrap or adjust the second frequency error measurement based on the second frequency wrap if the detected first frequency wrap is a non-zero value or the detected second frequency wrap is a non-zero value, such as in combination with Figures 4 to 10 For example, UE 1002 may adjust the first frequency error measurement based on the first frequency wrap or adjust the second frequency error measurement based on the second frequency wrap if the detected first frequency wrap is a non-zero value or the detected second frequency wrap is a non-zero value, such as in combination with Fig.10 In addition, 1112 can be composed of Fig.13 , wherein the first frequency error measurement (f1) is performed by the determination component 1340 in . In some aspects, adjusting the first frequency error measurement or the second frequency error measurement may include: correcting the first frequency error measurement or the second frequency error measurement. In addition, adjusting the first frequency error measurement or the second frequency error measurement may include: adding or subtracting a first multiple (1 / T1) from the first frequency error measurement (f1), or adding or subtracting a second multiple (1 / T2) from the second frequency error measurement (f2), wherein T1 is a first time interval between a first pair of pilot symbols, and T2 is a second time interval between a second pair of pilot symbols. In addition, adding or subtracting the first multiple (1 / T1) from the first frequency error measurement (f1) may unwind the first frequency wraparound, and adding or subtracting the second multiple (1 / T2) from the second frequency error measurement (f2) may unwind the second frequency wraparound.

[0103] Fig.12 1200 is a flow chart of a method of wireless communication. The method may be performed by a UE or a component of a UE (eg, UE 104, 350, 1002; device 1302). The methods described herein may provide several benefits, such as improved communication signaling, resource utilization, and / or power conservation.

[0104] At 1202, the UE may receive at least one of a pilot or data from a base station via a channel, wherein the channel includes a first pair of pilot symbols and a second pair of pilot symbols, wherein a first frequency error measurement is based on the first pair of pilot symbols received via the channel, and a second frequency error measurement is based on the second pair of pilot symbols received via the channel, as in combination with Figures 4 to 10 For example, UE 1002 may receive at least one of a pilot or data from a base station via a channel, wherein the channel includes a first pair of pilot symbols and a second pair of pilot symbols, wherein a first frequency error measurement is based on the first pair of pilot symbols received via the channel, and a second frequency error measurement is based on the second pair of pilot symbols received via the channel, as described in conjunction with Fig.10 In addition, 1202 can be composed of Fig.13 The determination component 1340 in is executed.

[0105] At 1204, the UE may measure a frequency error from a first pair of pilot symbols and a second pair of pilot symbols received via a channel associated with communications between the UE and the base station, the frequency error measured from the first pair of pilot symbols corresponding to a first frequency error measurement, and the frequency error measured from the second pair of pilot symbols corresponding to a second frequency error measurement, as combined with Figures 4 to 10For example, UE 1002 may measure a frequency error from a first pair of pilot symbols and a second pair of pilot symbols received via a channel associated with communications between the UE and a base station, the frequency error measured from the first pair of pilot symbols corresponding to a first frequency error measurement, and the frequency error measured from the second pair of pilot symbols corresponding to a second frequency error measurement, as described in conjunction with Fig.10 In addition, 1204 can be composed of Fig.13 The first frequency error measurement and the second frequency error measurement may be associated with a frequency tracking loop (FTL) algorithm.

[0106] At 1206, the UE may combine the first frequency error measurement and the second frequency error measurement, wherein the first frequency error measurement or the second frequency error measurement is adjusted based on the combination, such as in combination with Figures 4 to 10 For example, UE 1002 may combine the first frequency error measurement and the second frequency error measurement, wherein the first frequency error measurement or the second frequency error measurement is adjusted based on the combination, such as in combination with Fig.10 In addition, 1206 can be composed of Fig.13 The determination component 1340 in is executed.

[0107] At 1208, the UE may calculate a difference between the first frequency error measurement and the second frequency error measurement, wherein the first frequency wraparound or the second frequency wraparound is detected based on the difference between the first frequency error measurement and the second frequency error measurement, such as in combination with Figures 4 to 10 For example, UE 1002 may calculate a difference between the first frequency error measurement and the second frequency error measurement, wherein the first frequency wraparound or the second frequency wraparound is detected based on the difference between the first frequency error measurement and the second frequency error measurement, such as in combination with Fig.10 In addition, 1208 may be provided by Fig.13 , performed by the determination component 1340 in. In some aspects, the difference between the first frequency error measurement and the second frequency error measurement can be calculated as: f2-f1=N*F2-M*F1, where f1 is the first frequency error measurement, f2 is the second frequency error measurement, M is the number of first frequency wraparounds in the first frequency error measurement, N is the number of second frequency wraparounds in the second frequency error measurement, F1=1 / T1, F2=1 / T2, T1 is the first time interval between the first pair of pilot symbols, and T2 is the second time interval between the second pair of pilot symbols. In addition, the difference between the first frequency error measurement and the second frequency error measurement can be calculated as: f2-f1=N*F2-M*F1+(Fcomp1 –F comp2 ), where f1 is the first frequency error measurement, f2 is the second frequency error measurement, M is the number of first frequency wraparounds in the first frequency error measurement, N is the number of second frequency wraparounds in the second frequency error measurement, F1=1 / T1, F2=1 / T2, T1 is the first time interval between the first pair of pilot symbols, T2 is the second time interval between the second pair of pilot symbols, F comp1 is a first frequency compensation value based on at least one previous frequency error measurement at the time of the first frequency error measurement, and F comp2 is a second frequency compensation value based on one or more previous frequency error measurements at the time of the second frequency error measurement.

[0108] At 1210, the UE may detect a first frequency wraparound in the first frequency error measurement and a second frequency wraparound in the second frequency error measurement, such as in combination with Figures 4 to 10 For example, UE 1002 may detect a first frequency wraparound in the first frequency error measurement and a second frequency wraparound in the second frequency error measurement, such as in combination with Fig.10 In addition, 1210 can be composed of Fig.13 The determining component 1340 in is executed. The first frequency wrap can be proportional to the first in-phase wrap based on the correlation between the first pair of pilot symbols, and the second frequency wrap can be proportional to the second in-phase wrap based on the correlation between the second pair of pilot symbols, wherein the first in-phase wrap is a first constant value and the second in-phase wrap is a second constant value. In addition, the first time interval (T1) between the first pair of pilot symbols can be different from the second time interval (T2) between the second pair of pilot symbols, wherein the amount of the first frequency wrap can be equal to (1 / T1), and the amount of the second frequency wrap can be equal to (1 / T2).

[0109] At 1212, the UE may adjust the first frequency error measurement based on the first frequency wrap or adjust the second frequency error measurement based on the second frequency wrap if the detected first frequency wrap is a non-zero value or the detected second frequency wrap is a non-zero value, such as in combination with Figures 4 to 10 For example, UE 1002 may adjust the first frequency error measurement based on the first frequency wrap or adjust the second frequency error measurement based on the second frequency wrap if the detected first frequency wrap is a non-zero value or the detected second frequency wrap is a non-zero value, such as in combination with Fig.10 In addition, 1212 can be composed of Fig.13, wherein the first frequency error measurement (f1) is performed by the determination component 1340 in . In some aspects, adjusting the first frequency error measurement or the second frequency error measurement may include: correcting the first frequency error measurement or the second frequency error measurement. In addition, adjusting the first frequency error measurement or the second frequency error measurement may include: adding or subtracting a first multiple (1 / T1) from the first frequency error measurement (f1), or adding or subtracting a second multiple (1 / T2) from the second frequency error measurement (f2), wherein T1 is a first time interval between a first pair of pilot symbols, and T2 is a second time interval between a second pair of pilot symbols. In addition, adding or subtracting the first multiple (1 / T1) from the first frequency error measurement (f1) may unwind the first frequency wraparound, and adding or subtracting the second multiple (1 / T2) from the second frequency error measurement (f2) may unwind the second frequency wraparound.

[0110] At 1214, the UE may update a frequency tracking loop (FTL) state of the frequency error between the UE and the base station based on the adjusted first frequency error measurement or the adjusted second frequency error measurement, such as in conjunction with Figures 4 to 10 For example, UE 1002 may update a frequency tracking loop (FTL) state of the frequency error between the UE and the base station based on the adjusted first frequency error measurement or the adjusted second frequency error measurement, as described in conjunction with Fig.10 In addition, 1214 can be composed of Fig.13 The determination component 1340 in is executed.

[0111] At 1216, the UE may compensate for the first frequency wraparound or the second frequency wraparound based on the adjusted first frequency error measurement or the adjusted second frequency error measurement, such as in combination with Figures 4 to 10 For example, UE 1002 may compensate for the first frequency wraparound or the second frequency wraparound based on the adjusted first frequency error measurement or the adjusted second frequency error measurement, as described in conjunction with Fig.10 In addition, 1216 can be made of Fig.13 The determination component 1340 in is executed.

[0112] Fig.131300 is an example of a hardware implementation of an example device 1302. The device 1302 may be a UE, a component of a UE, or may implement UE functionality. In some aspects, the device 1302 may include a cellular baseband processor 1304 (also referred to as a modem) coupled to a cellular RF transceiver 1322. In some aspects, the device 1302 may also include one or more subscriber identity module (SIM) cards 1320, an application processor 1306 coupled to a secure digital (SD) card 1308 and a screen 1310, a Bluetooth module 1312, a wireless local area network (WLAN) module 1314, a global positioning system (GPS) module 1316, or a power supply 1318. The cellular baseband processor 1304 communicates with the UE 104 and / or the BS 102 / 180 via the cellular RF transceiver 1322. The cellular baseband processor 1304 may include a computer-readable medium / memory. The computer-readable medium / memory may be non-transitory. The cellular baseband processor 1304 is responsible for general processing, including executing software stored on a computer-readable medium / memory. The software, when executed by the cellular baseband processor 1304, enables the cellular baseband processor 1304 to perform the various functions described above. The computer-readable medium / memory can also be used to store data manipulated by the cellular baseband processor 1304 when executing the software. The cellular baseband processor 1304 also includes a receiving component 1330, a communication manager 1332, and a transmission component 1334. The communication manager 1332 includes one or more of the illustrated components. The components within the communication manager 1332 can be stored in a computer-readable medium / memory and / or configured as hardware within the cellular baseband processor 1304. The cellular baseband processor 1304 can be a component of the UE 350 and can include at least one of a memory 360 and / or a TX processor 368, an RX processor 356, and a controller / processor 359. In one configuration, the device 1302 may be a modem chip and include only the baseband processor 1304, and in another configuration, the device 1302 may be the entire UE (e.g., see Figure 3 350), and includes additional modules of device 1302.

[0113] The communication manager 1332 includes a determining component 1340 configured to receive at least one of a pilot or data from a base station via a channel, wherein the channel includes a first pair of pilot symbols and a second pair of pilot symbols, wherein a first frequency error measurement is based on the first pair of pilot symbols received via the channel, and a second frequency error measurement is based on the second pair of pilot symbols received via the channel, e.g., as described above in connection with step 1202. The determining component 1340 may also be configured to measure frequency error from the first pair of pilot symbols and the second pair of pilot symbols received via a channel associated with communications between the UE and the base station, the frequency error measured from the first pair of pilot symbols corresponding to the first frequency error measurement, and the frequency error measured from the second pair of pilot symbols corresponding to the second frequency error measurement, e.g., as described above in connection with step 1204. The determining component 1340 may also be configured to combine the first frequency error measurement and the second frequency error measurement, wherein the first frequency error measurement or the second frequency error measurement is adjusted based on the combination, e.g., as described above in connection with step 1206. The determining component 1340 may also be configured to calculate a difference between the first frequency error measurement and the second frequency error measurement, wherein the first frequency wraparound or the second frequency wraparound is detected based on the difference between the first frequency error measurement and the second frequency error measurement, e.g., as described above in connection with step 1208. The determining component 1340 may also be configured to detect a first frequency wraparound in the first frequency error measurement and a second frequency wraparound in the second frequency error measurement, e.g., as described above in connection with step 1210. The determining component 1340 may also be configured to adjust the first frequency error measurement based on the first frequency wraparound or adjust the second frequency error measurement based on the second frequency wraparound if the detected first frequency wraparound is a non-zero value or the detected second frequency wraparound is a non-zero value, e.g., as described above in connection with step 1212. The determining component 1340 may also be configured to update a frequency tracking loop (FTL) state of the frequency error between the UE and the base station based on the adjusted first frequency error measurement or the adjusted second frequency error measurement, e.g., as described above in conjunction with step 1214. The determining component 1340 may also be configured to compensate for the first frequency wraparound or the second frequency wraparound based on the adjusted first frequency error measurement or the adjusted second frequency error measurement, e.g., as described above in conjunction with step 1216.

[0114] The apparatus may include executing Figures 10 to 12 Each box in the flowchart of the algorithm is an additional component. Therefore, Figures 10 to 12Each block in the flowchart of can be performed by a component, and the device may include one or more of these components. These components can be one or more hardware components, which are specifically configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium so as to be implemented by a processor, or some combination thereof.

[0115] As shown, the apparatus 1302 may include a variety of components configured for various functions. In one configuration, the apparatus 1302 (and in particular, the cellular baseband processor 1304) includes means for receiving at least one of a pilot or data from a base station via a channel, wherein the channel includes a first pair of pilot symbols and a second pair of pilot symbols, wherein a first frequency error measurement is based on the first pair of pilot symbols received via the channel, and a second frequency error measurement is based on the second pair of pilot symbols received via the channel; means for measuring frequency error from the first pair of pilot symbols and the second pair of pilot symbols received via a channel associated with communication between a UE and a base station, the frequency error measured from the first pair of pilot symbols corresponding to the first frequency error measurement, and the frequency error measured from the second pair of pilot symbols corresponding to the second frequency error measurement; means for combining the first frequency error measurement and the second frequency error measurement, wherein the first frequency error measurement or the second frequency error measurement is adjusted based on the combination; means for calculating the first frequency error measurement; and means for calculating the second frequency error measurement. A means for detecting a difference between a first frequency error measurement and a second frequency error measurement, wherein the first frequency wraparound or the second frequency wraparound is detected based on the difference between the first frequency error measurement and the second frequency error measurement; a means for detecting a first frequency wraparound in the first frequency error measurement and a second frequency wraparound in the second frequency error measurement; a means for adjusting the first frequency error measurement based on the first frequency wraparound or adjusting the second frequency error measurement based on the second frequency wraparound if the detected first frequency wraparound is a non-zero value or the detected second frequency wraparound is a non-zero value; a means for updating a frequency tracking loop (FTL) state of the frequency error between the UE and the base station based on the adjusted first frequency error measurement or the adjusted second frequency error measurement; a means for compensating for the first frequency wraparound or the second frequency wraparound based on the adjusted first frequency error measurement or the adjusted second frequency error measurement. Means may be one or more of the components of the device 1302 configured to perform the functions recorded by means. As described above, the device 1302 may include a TX processor 368, an RX processor 356, and a controller / processor 359. Thus, in one configuration, the means may be the TX processor 368, the RX processor 356, and the controller / processor 359 configured to perform the functions recited by the means.

[0116] It should be understood that the specific order or hierarchy of the blocks in the disclosed process / flowchart is only an illustration of the exemplary method. It should be understood that the specific order or hierarchy of the blocks in the process / flowchart can be rearranged based on design preferences. Further, some blocks can be combined or omitted. The attached method claims provide the elements of various blocks in a sample order, but are not meant to be limited to the specific order or hierarchy provided.

[0117] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be 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 aspects shown herein, but to conform to the full scope consistent with the language claims, wherein the elements mentioned in the singular are not intended to represent "one and only one", unless specifically so stated, but "one or more". Terms such as "if", "when ......" and "while ......" should be interpreted as "under the condition of ......", rather than meaning an immediate time relationship or reaction. That is, these phrases, such as "when ......", do not mean instantaneous action in response to the occurrence of an action or during the occurrence of an action, but simply imply that if the conditions are met, then the action will occur, but no specific or immediate time limit is required for the occurrence of the action. 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 being preferred or having advantages over other aspects. Unless otherwise specified, 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 multiple A, multiple B, or multiple C. Specifically, combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof" may be only A, only B, only C, A and B, A and C, B and C, or A and B and C, wherein any such combination may include one or more members of A, B, or C. All structural and functional equivalents to the elements of the various aspects described throughout the present 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 covered by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is expressly recited in the claims. The words “module,” “mechanism,” “element,” “device,” etc. cannot replace the word “means.” Therefore, no claim element will be construed as a functional means unless the element is explicitly recited using the phrase “means for . . . .”

[0118] The following aspects are merely illustrative and may be combined with other aspects or teachings described herein without limitation.

[0119] Aspect 1 is a device for performing wireless communications at a UE, the device comprising: at least one processor, the at least one processor coupled to the memory and configured to: measure frequency error from a first pair of pilot code elements and a second pair of pilot code elements received via a channel associated with communication between the UE and a base station, the frequency error measured from the first pair of pilot code elements corresponding to a first frequency error measurement, and the frequency error measured from the second pair of pilot code elements corresponding to a second frequency error measurement; detect a first frequency wrap in the first frequency error measurement and a second frequency wrap in the second frequency error measurement; and in a case where the detected first frequency wrap is a non-zero value or the detected second frequency wrap is a non-zero value, adjust the first frequency error measurement based on the first frequency wrap or adjust the second frequency error measurement based on the second frequency wrap.

[0120] Aspect 2 is an apparatus according to aspect 1, wherein the at least one processor is further configured to: combine the first frequency error measurement and the second frequency error measurement, wherein the first frequency error measurement or the second frequency error measurement is adjusted based on the combination.

[0121] Aspect 3 is an apparatus according to any one of Aspects 1 and 2, wherein the at least one processor is further configured to: calculate a difference between the first frequency error measurement and the second frequency error measurement, wherein the first frequency wraparound or the second frequency wraparound is detected based on the difference between the first frequency error measurement and the second frequency error measurement.

[0122] Aspect 4 is an apparatus according to any one of Aspects 1 to 3, wherein the difference between the first frequency error measurement and the second frequency error measurement is calculated as: f2–f1=N*F2–M*F1, wherein f1 is the first frequency error measurement, f2 is the second frequency error measurement, M is the number of first frequency wraps in the first frequency error measurement, N is the number of second frequency wraps in the second frequency error measurement, F1=1 / T1, F2=1 / T2, T1 is the first time interval between the first pair of pilot code elements, and T2 is the second time interval between the second pair of pilot code elements.

[0123] Aspect 5 is an apparatus according to any one of aspects 1 to 4, wherein the difference between the first frequency error measurement and the second frequency error measurement is calculated as: f2-f1=N*F2-M*F1+(F comp1 –F comp2), where f1 is the first frequency error measurement, f2 is the second frequency error measurement, M is the number of first frequency wraparounds in the first frequency error measurement, N is the number of second frequency wraparounds in the second frequency error measurement, F1=1 / T1, F2=1 / T2, T1 is the first time interval between the first pair of pilot symbols, T2 is the second time interval between the second pair of pilot symbols, F comp1 is a first frequency compensation value based on at least one previous frequency error measurement at the time of the first frequency error measurement, and F comp2 is a second frequency compensation value based on one or more previous frequency error measurements at the time of the second frequency error measurement.

[0124] Aspect 6 is an apparatus according to any one of Aspects 1 to 5, wherein in order to adjust the first frequency error measurement or the second frequency error measurement, the at least one processor is configured to: correct the first frequency error measurement or the second frequency error measurement.

[0125] Aspect 7 is an apparatus according to any one of Aspects 1 to 6, wherein the first frequency wrap is proportional to a first in-phase wrap based on the correlation between the first pair of pilot code symbols, and the second frequency wrap is proportional to a second in-phase wrap based on the correlation between the second pair of pilot code symbols, wherein the first in-phase wrap is a first constant value and the second in-phase wrap is a second constant value.

[0126] Aspect 8 is an apparatus according to any one of Aspects 1 to 7, wherein in order to adjust the first frequency error measurement or the second frequency error measurement, the at least one processor is configured to: add or subtract a first multiple (1 / T1) to the first frequency error measurement (f1), or add or subtract a second multiple (1 / T2) to the second frequency error measurement (f2), wherein T1 is the first time interval between the first pair of pilot code elements, and T2 is the second time interval between the second pair of pilot code elements.

[0127] Aspect 9 is an apparatus according to any one of Aspects 1 to 8, wherein the first frequency wrap is unwrapped by adding or subtracting the first multiple (1 / T1) from the first frequency error measurement (f1), and wherein the second frequency wrap is unwrapped by adding or subtracting the second multiple (1 / T2) from the second frequency error measurement (f2).

[0128] Aspect 10 is an apparatus according to any one of Aspects 1 to 9, wherein the at least one processor is further configured to: update a frequency tracking loop (FTL) state of the frequency error between the UE and the base station based on the adjusted first frequency error measurement or the adjusted second frequency error measurement.

[0129] Aspect 11 is an apparatus according to any one of Aspects 1 to 10, wherein the at least one processor is further configured to: compensate for the first frequency wraparound or the second frequency wraparound based on the adjusted first frequency error measurement or the adjusted second frequency error measurement.

[0130] Aspect 12 is an apparatus according to any one of aspects 1 to 11, wherein the first frequency error measurement and the second frequency error measurement are associated with a frequency tracking loop (FTL) algorithm.

[0131] Aspect 13 is an apparatus according to any one of Aspects 1 to 12, wherein the first time interval (T1) between the first pair of pilot code elements is different from the second time interval (T2) between the second pair of pilot code elements, wherein the amount of the first frequency wrap is equal to (1 / T1), and the amount of the second frequency wrap is equal to (1 / T2).

[0132] Aspect 14 is an apparatus according to any one of Aspects 1 to 13, wherein the at least one processor is further configured to: receive at least one of a pilot or data from the base station via the channel, wherein the channel includes the first pair of pilot code symbols and the second pair of pilot code symbols, wherein the first frequency error measurement is based on the first pair of pilot code symbols received via the channel, and the second frequency error measurement is based on the second pair of pilot code symbols received via the channel.

[0133] Aspect 15 is an apparatus according to any one of aspects 1 to 14, the apparatus further comprising: a transceiver or an antenna coupled to the at least one processor.

[0134] Aspect 16 is a method for implementing wireless communication of any one of aspects 1 to 15.

[0135] Aspect 17 is an apparatus for wireless communication, the apparatus comprising means for implementing any one of aspects 1 to 15.

[0136] Aspect 18 is a computer-readable medium storing computer-executable code, wherein the code, when executed by a processor, causes the processor to implement any one of aspects 1 to 15.

Claims

1. An apparatus for wireless communication at a user equipment (UE), the apparatus comprising: Memory; and at least one processor coupled to the memory and configured to: measuring frequency error from a first pair of pilot symbols and a second pair of pilot symbols received via a channel associated with communications between the UE and a base station, the frequency error measured from the first pair of pilot symbols corresponding to a first frequency error measurement, and the frequency error measured from the second pair of pilot symbols corresponding to a second frequency error measurement; detecting a first frequency wraparound in the first frequency error measurement and a second frequency wraparound in the second frequency error measurement; as well as In a case where the detected first frequency wrap is a non-zero value or the detected second frequency wrap is a non-zero value, the first frequency error measure is adjusted based on the first frequency wrap or the second frequency error measure is adjusted based on the second frequency wrap.

2. The apparatus of claim 1 , wherein the at least one processor is further configured to: The first frequency error measure and the second frequency error measure are combined, wherein the first frequency error measure or the second frequency error measure is adjusted based on the combination.

3. The apparatus of claim 1 , wherein the at least one processor is further configured to: A difference between the first frequency error measurement and the second frequency error measurement is calculated, wherein the first frequency wraparound or the second frequency wraparound is detected based on the difference between the first frequency error measurement and the second frequency error measurement.

4. The apparatus of claim 3, wherein the difference between the first frequency error measurement and the second frequency error measurement is calculated as: f2-f1=N*F2-M*F1, wherein f1 is the first frequency error measurement, f2 is the second frequency error measurement, M is the number of first frequency wraparounds in the first frequency error measurement, N is the number of second frequency wraparounds in the second frequency error measurement, F1=1 / T1, F 2＝ 1 / T2, T1 is a first time interval between the first pair of pilot symbols, and T2 is a second time interval between the second pair of pilot symbols.

5. The apparatus of claim 3, wherein the difference between the first frequency error measurement and the second frequency error measurement is calculated as: f2-f1=N*F2-M*F1+(F comp1 -F comp2 ), where f1 is the first frequency error measurement, f2 is the second frequency error measurement, M is the number of first frequency wraparounds in the first frequency error measurement, N is the number of second frequency wraparounds in the second frequency error measurement, F1=1 / T1, F2=1 / T2, T1 is the first time interval between the first pair of pilot symbols, T2 is the second time interval between the second pair of pilot symbols, F comp1 is a first frequency compensation value based on at least one previous frequency error measurement at the time of the first frequency error measurement, and F comp2 is a second frequency compensation value based on one or more previous frequency error measurements at the time of the second frequency error measurement.

6. The apparatus of claim 1, wherein to adjust the first frequency error measure or the second frequency error measure, the at least one processor is configured to: correct the first frequency error measure or the second frequency error measure.

7. The apparatus of claim 1 , wherein the first frequency wrap is proportional to a first in-phase wrap based on a correlation between the first pair of pilot symbols, and the second frequency wrap is proportional to a second in-phase wrap based on a correlation between the second pair of pilot symbols, wherein the first in-phase wrap is a first constant value, and the second in-phase wrap is a second constant value.

8. The apparatus of claim 1 , wherein, in order to adjust the first frequency error measure or the second frequency error measure, the at least one processor is configured to: add or subtract a first multiple (1 / T1) from the first frequency error measure (f1), or add or subtract a second multiple (1 / T2) from the second frequency error measure (f2), wherein T1 is a first time interval between the first pair of pilot symbols, and T2 is a second time interval between the second pair of pilot symbols.

9. The apparatus of claim 8, wherein the first frequency wrap is unwrapped by adding or subtracting the first multiple (1 / T1) from the first frequency error measurement (f1), and wherein the second frequency wrap is unwrapped by adding or subtracting the second multiple (1 / T2) from the second frequency error measurement (f2).

10. The apparatus of claim 1, wherein the at least one processor is further configured to: A frequency tracking loop (FTL) state of the frequency error between the UE and the base station is updated based on the adjusted first frequency error measurement or the adjusted second frequency error measurement.

11. The apparatus of claim 1 , wherein the at least one processor is further configured to: The first frequency wraparound or the second frequency wraparound is compensated based on the adjusted first frequency error measure or the adjusted second frequency error measure.

12. The apparatus of claim 1, wherein the first frequency error measurement and the second frequency error measurement are associated with a frequency tracking loop (FTL) algorithm.

13. The apparatus of claim 1, wherein a first time interval (T1) between the first pair of pilot symbols is different from a second time interval (T2) between the second pair of pilot symbols, wherein an amount of the first frequency wraparound is equal to (1 / T1), and an amount of the second frequency wraparound is equal to (1 / T2).

14. The apparatus of claim 1, further comprising a transceiver or an antenna coupled to the at least one processor, wherein the at least one processor is further configured to: At least one of a pilot or data is received from the base station via the channel, wherein the channel includes the first pair of pilot symbols and the second pair of pilot symbols, wherein the first frequency error measurement is based on the first pair of pilot symbols received via the channel, and the second frequency error measurement is based on the second pair of pilot symbols received via the channel.

15. A method of wireless communication at a user equipment (UE), the method comprising: measuring frequency error from a first pair of pilot symbols and a second pair of pilot symbols received via a channel associated with communications between the UE and a base station, the frequency error measured from the first pair of pilot symbols corresponding to a first frequency error measurement, and the frequency error measured from the second pair of pilot symbols corresponding to a second frequency error measurement; detecting a first frequency wraparound in the first frequency error measurement and a second frequency wraparound in the second frequency error measurement; as well as In a case where the detected first frequency wrap is a non-zero value or the detected second frequency wrap is a non-zero value, the first frequency error measure is adjusted based on the first frequency wrap or the second frequency error measure is adjusted based on the second frequency wrap.

16. The method according to claim 15, further comprising: The first frequency error measure and the second frequency error measure are combined, wherein the first frequency error measure or the second frequency error measure is adjusted based on the combination.

17. The method according to claim 15, further comprising: A difference between the first frequency error measurement and the second frequency error measurement is calculated, wherein the first frequency wraparound or the second frequency wraparound is detected based on the difference between the first frequency error measurement and the second frequency error measurement.

18. The method of claim 17, wherein the difference between the first frequency error measurement and the second frequency error measurement is calculated as: f2-f1=N*F2-M*F1, wherein f1 is the first frequency error measurement, f2 is the second frequency error measurement, M is the number of first frequency wraparounds in the first frequency error measurement, N is the number of second frequency wraparounds in the second frequency error measurement, F1=1 / T1, F 2＝ 1 / T2, T1 is a first time interval between the first pair of pilot symbols, and T2 is a second time interval between the second pair of pilot symbols.

19. The method of claim 17, wherein the difference between the first frequency error measurement and the second frequency error measurement is calculated as: f2-f1=N*F2-M*F1+(F comp1 -F comp2 ), where f1 is the first frequency error measurement, f2 is the second frequency error measurement, M is the number of first frequency wraparounds in the first frequency error measurement, N is the number of second frequency wraparounds in the second frequency error measurement, F1=1 / T1, F2=1 / T2, T1 is the first time interval between the first pair of pilot symbols, T2 is the second time interval between the second pair of pilot symbols, F comp1 is a first frequency compensation value based on at least one previous frequency error measurement at the time of the first frequency error measurement, and F comp2 is a second frequency compensation value based on one or more previous frequency error measurements at the time of the second frequency error measurement.

20. The method of claim 15, wherein adjusting the first frequency error measure or the second frequency error measure comprises: The first frequency error measurement or the second frequency error measurement is corrected.

21. The method of claim 15, wherein the first frequency wrap is proportional to a first in-phase wrap based on a correlation between the first pair of pilot symbols, and the second frequency wrap is proportional to a second in-phase wrap based on a correlation between the second pair of pilot symbols, wherein the first in-phase wrap is a first constant value, and the second in-phase wrap is a second constant value.

22. The method of claim 15, wherein adjusting the first frequency error measure or the second frequency error measure comprises: A first multiple (1 / T1) is added to or subtracted from the first frequency error measurement (f1), or a second multiple (1 / T2) is added to or subtracted from the second frequency error measurement (f2), where T1 is a first time interval between the first pair of pilot symbols, and T2 is a second time interval between the second pair of pilot symbols.

23. The method of claim 22, wherein the first frequency wrap is unwrapped by adding or subtracting the first multiple (1 / T1) from the first frequency error measurement (f1), and wherein the second frequency wrap is unwrapped by adding or subtracting the second multiple (1 / T2) from the second frequency error measurement (f2).

24. The method according to claim 15, further comprising: A frequency tracking loop (FTL) state of the frequency error between the UE and the base station is updated based on the adjusted first frequency error measurement or the adjusted second frequency error measurement.

25. The method according to claim 15, further comprising: The first frequency wraparound or the second frequency wraparound is compensated based on the adjusted first frequency error measure or the adjusted second frequency error measure.

26. The method of claim 15, wherein the first frequency error measurement and the second frequency error measurement are associated with a frequency tracking loop (FTL) algorithm.

27. The method of claim 15, wherein a first time interval (T1) between the first pair of pilot symbols is different from a second time interval (T2) between the second pair of pilot symbols, wherein an amount of the first frequency wraparound is equal to (1 / T1), and an amount of the second frequency wraparound is equal to (1 / T2).

28. The method of claim 15, further comprising: At least one of a pilot or data is received from the base station via the channel, wherein the channel includes the first pair of pilot symbols and the second pair of pilot symbols, wherein the first frequency error measurement is based on the first pair of pilot symbols received via the channel, and the second frequency error measurement is based on the second pair of pilot symbols received via the channel.

29. An apparatus for wireless communication at a user equipment (UE), the apparatus comprising: means for measuring frequency error from a first pair of pilot symbols and a second pair of pilot symbols received via a channel associated with communications between the UE and a base station, the frequency error measured from the first pair of pilot symbols corresponding to a first frequency error measurement and the frequency error measured from the second pair of pilot symbols corresponding to a second frequency error measurement; means for detecting a first frequency wraparound in the first frequency error measurement and a second frequency wraparound in the second frequency error measurement; and Means for adjusting the first frequency error measure based on the first frequency wrap or adjusting the second frequency error measure based on the second frequency wrap if the detected first frequency wrap is a non-zero value or the detected second frequency wrap is a non-zero value.

30. A computer readable medium storing computer executable code at a user equipment (UE) which, when executed by a processor, causes the processor to: measuring frequency error from a first pair of pilot symbols and a second pair of pilot symbols received via a channel associated with communications between the UE and a base station, the frequency error measured from the first pair of pilot symbols corresponding to a first frequency error measurement, and the frequency error measured from the second pair of pilot symbols corresponding to a second frequency error measurement; detecting a first frequency wraparound in the first frequency error measurement and a second frequency wraparound in the second frequency error measurement; as well as In a case where the detected first frequency wrap is a non-zero value or the detected second frequency wrap is a non-zero value, the first frequency error measure is adjusted based on the first frequency wrap or the second frequency error measure is adjusted based on the second frequency wrap.

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