CN115176446B - Apparatus and method for cyclic prefix based time and/or frequency correction - Google Patents

Abstract

Embodiments of apparatus and methods for cyclic prefix (CP)-based time and frequency correction are disclosed. In one example, symbols including CP and payload are received. Detect CP and perform autocorrelation of CP and payload. At least one of the time or frequency of the received symbols is adjusted based on the results of the autocorrelation.

Description

Apparatus and method for cyclic prefix-based time and/or frequency correction

Cross-references to related applications

This application claims the benefit of priority from U.S. Provisional Patent Application No. 62/971,608, entitled "POWER SAVING METHOD FOR CP-OFDMBASED SIGNAL WITH DISCONTINUOUS RECEPTION", filed on February 7, 2020, which U.S. Provisional Application is incorporated by reference in its entirety incorporated herein.

Technical field

Embodiments of the present disclosure relate to apparatuses and methods for wireless communications.

Background technique

Wireless communication systems are widely deployed to provide various telecommunications services such as telephony, video, data, messaging and broadcasting. Orthogonal frequency division multiplexing (OFDM) is one of the most widely used and adopted digital multi-carrier modulation methods and has been widely used in cellular communications such as 4th generation (4G) Long Term Evolution (LTE) and 5th generation (5G) New Radio (NR). For example, one version of OFDM used in 4G LTE is cyclic prefix OFDM (CP-OFDM). CP-OFDM has a waveform format designed to overcome inter-symbol interference caused by delays and reflections. (inter-symbol interference, ISI).

Discontinuous reception (DRX) mode is a method used in mobile communications to save the battery of mobile devices. The periodic repetition of "sleep mode and wake mode" can greatly reduce the power consumption of the user equipment (UE) used to receive data from the network.

Contents of the invention

Disclosed herein are embodiments of apparatus and methods for wireless communications using cyclic prefix (CP)-based time and frequency correction.

In one example, an apparatus is disclosed that includes at least one processor and a memory storing instructions. When executed by at least one processor, the instructions cause the device to receive symbols including a CP and a payload. When executed by the at least one processor, the instructions also cause the device to detect the CP and perform autocorrelation of the CP and the payload. When executed by the at least one processor, the instructions further cause the apparatus to adjust at least one of the timing or frequency of the received symbols based on the results of the autocorrelation.

In another example, a baseband chip is disclosed that includes an interface and time and frequency correction circuitry operatively coupled to the interface. The interface is configured to receive OFDM symbols including CP and payload. The time and frequency correction circuitry is configured to detect the CP and perform autocorrelation of the CP and the payload. The time and frequency correction circuitry is further configured to adjust at least one of time or frequency of the received symbols based on the results of the autocorrelation.

In yet another example, an apparatus for wireless communications is disclosed, including a data processing module and a time and frequency correction module. The data processing module is configured to receive OFDM symbols including CP and payload. The time and frequency correction module is configured to detect CP and perform autocorrelation of CP and payload. The time and frequency correction module is further configured to adjust at least one of time or frequency of the received symbols based on the results of the autocorrelation. The data processing module is further configured to process OFDM symbols based on adjusted time or frequency.

In yet another example, a method for time and/or frequency correction is disclosed. Receive symbols including CP and payload. Detect CP, and perform autocorrelation of CP and payload. At least one of the time or frequency of the received symbols is adjusted based on the results of the autocorrelation.

In yet another example, a non-transitory computer-readable medium encoded with instructions that perform a process when executed by at least one processor of a terminal device is disclosed. The process includes receiving symbols including CP and payload. The process also includes detecting the CP and performing autocorrelation between the CP and the payload. The process also includes adjusting at least one of time or frequency of the received symbols based on the results of the autocorrelation.

In yet another example, a device for time and/or frequency correction is disclosed, which device includes a receiving module, a detection module, an autocorrelation module, and a time or frequency correction module. The receiving module is configured to receive OFDM symbols including cyclic prefix (CP) and payload. The detection module is configured to detect the CP. The autocorrelation module is configured to perform autocorrelation of the CP and payload. The time or frequency correction module is configured to adjust at least one of time or frequency of the received symbols based on the results of the autocorrelation.

Description of drawings

The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the disclosure and, together with the description, further serve to explain the principles of the disclosure and enable any person skilled in the relevant art to make and use the disclosure.

Figure 1 illustrates an example wireless network in accordance with some embodiments of the present disclosure.

2 illustrates a detailed block diagram of an exemplary wireless communications system using CP-based time and frequency correction in accordance with some embodiments of the present disclosure.

Part A of FIG. 3 shows a schematic diagram of an exemplary CP addition process applied to an OFDM symbol stream in the wireless communication system in FIG. 2 according to some embodiments of the present disclosure.

Part B of FIG. 3 shows the autocorrelation results of CP and payload in the time domain in the wireless communication system in FIG. 2 according to some embodiments of the present disclosure.

4 illustrates a timing diagram of exemplary time and frequency correction performed when a receiving device wakes up in the wireless communication system of FIG. 2, in accordance with some embodiments of the present disclosure.

5A and 5B respectively illustrate an exemplary implementation of the wireless communication system in FIG. 2 in software and hardware, including a host chip, a radio frequency (RF) chip and a baseband chip, according to some embodiments of the present disclosure. Block diagram of the device.

Figure 6 illustrates a flowchart of an exemplary method for CP-based time and frequency correction in accordance with some embodiments of the present disclosure.

7 illustrates a flowchart of an exemplary method for autocorrelation of the CP-based time and frequency correction method of FIG. 6 in accordance with some embodiments of the present disclosure.

8 illustrates a flowchart of another exemplary method for CP-based time and frequency correction in accordance with some embodiments of the present disclosure.

Figure 9 illustrates a block diagram of an exemplary receiving device in accordance with some embodiments of the present disclosure.

Embodiments of the present disclosure will be described with reference to the accompanying drawings.

Detailed ways

Although specific configurations and arrangements are discussed, it is understood that this is for illustrative purposes only. Those skilled in the relevant art will recognize that other configurations and arrangements may be used without departing from the spirit and scope of the present disclosure. It will be apparent to those skilled in the relevant art that the present disclosure may also be used in a variety of other applications.

It should be noted that references in the specification to "one embodiment," "an embodiment," "exemplary embodiments," "some embodiments," "certain embodiments," etc., indicate that the described embodiments may include specific features, structures, or characteristics, but each embodiment may not necessarily include specific features, structures, or characteristics. Furthermore, such phrases are not necessarily referring to the same embodiment. Furthermore, when a particular feature, structure or characteristic is described in connection with an embodiment, such feature, structure or characteristic may be implemented in conjunction with other embodiments, whether explicitly described or not, within the knowledge of one skilled in the relevant art.

Often, terms can be understood, at least in part, from context of use. For example, the term "one or more" as used herein may be used to describe any feature, structure or characteristic in the singular, or may be used to describe a combination of features, structures or characteristics in the plural, depending at least in part on context. Similarly, terms such as "a," "an," or "the" may be understood to convey a singular usage or convey a plural usage, again depending at least in part on the context. Additionally, it will be understood that the term "based on" is not necessarily intended to convey an exclusive set of factors, but may instead allow for the presence of additional factors that may not necessarily be explicitly described, again at least in part by context.

Various aspects of a wireless communication system will now be described with reference to various apparatuses and methods. These apparatus and methods are described in the detailed description below and illustrated in the accompanying drawings by various blocks, modules, units, components, circuits, steps, operations, processes, algorithms, etc. (collectively, "elements"). These elements may be implemented using electronic hardware, firmware, computer software, or any combination thereof. Whether such elements are implemented as hardware, firmware, or software depends on the specific application and the design constraints imposed on the overall system.

The technology described in this article can be used in various wireless communication networks, such as 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 other networks, including but not limited to 4G LTE and 5G NR cellular networks. The terms "network" and "system" are often used interchangeably. The techniques described in this article can be used on the wireless networks mentioned above as well as other wireless networks.

Discontinuous reception (DRX) is a method used in mobile communications to save the battery of mobile devices. The periodic repetition of "sleep mode and wake mode" can greatly reduce the power consumption of the user equipment (UE) used to receive data from the network. To reduce the power consumed by the UE, the UE stops listening on the channel, stays in sleep mode (ie, idle mode) for a period of time and wakes up at intervals. During sleep (eg, periods in sleep mode), the master clock used to ensure synchronization of the UE (eg, the high-resolution clock source and the portion of the processor associated with the clock) is turned off. Therefore, time and/or frequency drift may occur due to sleep.

In order to perform time and frequency correction (i.e., synchronization) after waking up from sleep mode, in traditional discontinuous reception (DRX) technology, additional wake-up time is required to receive one or more reference signals based on which time and Frequency correction.

For example, in 4G and LTE scenarios, when the UE wakes up from sleep mode, before the activation period (onDuration) or paging occasion (PO) of the modulation symbol corresponding to the original data is received (for example, when the UE is in Before the PO of radio resource control (RRC) idle mode, or before the activation period of the UE in RRC connected mode), the UE starts the RF module. In some embodiments, time and frequency corrections are performed based on one or more cell specific reference signals (CRS), and the additional wake-up duration is for one or more LTE/CRSs to receive the CRS. 4G subframe. Using the CRS-based algorithm, the UE may perform channel estimation based on the CRS, and may perform time and frequency correction based on the channel estimation.

In some other embodiments, if the time and/or frequency drift is higher than the drift that the CRS can track, a cell search based on a primary synchronization signal (PSS) or a secondary synchronization signal (SSS) may be performed. Therefore, additional wake-up may be required (e.g., before the time slot of the PO or activation period) to receive PSS/SSS.

For another example, in a 5G scenario, time and frequency correction may be performed based on a synchronization signal block (SSB). SSB has a duration of 4 symbols and may not be aligned with PO or activation periods. Therefore, the UE may need to perform additional wake-ups to receive the SSB to correct time and frequency errors based on the SSB. All of the above additional wake-up time results in additional UE power being consumed to perform time and frequency corrections.

In accordance with various embodiments of the present disclosure, systems and methods for time and frequency correction based on CP of received symbols are provided. The CP of a symbol may be an exact copy of the last part of the symbol (eg, a predetermined length such as 16 samples, 128 samples, etc.) that is copied to the front of the signal. CP is designed to overcome inter-symbol interference (ISI) caused by delays and reflections (e.g., multipath interference). Time and frequency correction may be performed based on detecting the CP of the symbol and performing autocorrelation of the CP of the symbol and the payload. Therefore, no additional wake-up is required for time and frequency correction, and the UE's power consumption can be reduced as desired.

Adjust the timing or frequency of symbols based on one or more peaks in autocorrelation. Because the CP is a copy of the last part of the symbol (e.g., the last part of the payload), ideally the highest peak of the autocorrelation between the CP and the payload in the time domain provides information related to the timing error (e.g., Indicates the end position of the symbol with drift), and the phase of the peak in the frequency domain provides information related to the frequency error. Based on the detected symbol's end position, time and frequency corrections can be performed on the symbol. In some embodiments, time and frequency drift of the symbols may be corrected according to the communication protocol used to transmit the symbols. For example, the time and frequency drift of the symbols may be corrected based on the time and frequency of the symbols indicated by the results of the autocorrelation, according to a predetermined (eg, predetermined based on the communication protocol) sampling frequency used to demodulate the symbols. .

In some embodiments, more than one peak above a threshold may be detected in the correlation due to interference (eg, inter-symbol interference (ISI) and multipath interference) (eg, the threshold is set to ensure that the peak is not caused by a valid symbol caused by some random similarities within the loads). For example, due to multipath issues, one or more delayed copies of a symbol may be received, and the peak may show up where the delayed copies end. In some embodiments, because the delayed copy is received after a certain delay due to the long transmission path, the earliest peak above the threshold may be selected to locate the end of the symbol. In some other embodiments, because the delayed copies are reflected by surrounding objects, the peak indicating the end of the delayed copy may be weaker (e.g., have a smaller value in the autocorrelation result) than the peak indicating the end of the received symbol. amplitude). Therefore, the strongest peak (e.g., the highest peak in the autocorrelation result) can be selected to locate the end of the symbol.

In some embodiments, the length of the CP (eg, bits or time span) may not be sufficient to mask the impact caused by ISI. For example, the time span of more than one peak above the threshold is longer than the time span of the CP (e.g., the time span between the first and last peak of the more than one peak is longer than the time span of the CP). In some embodiments, a received symbol may be converted into multiple copies based on the number of peaks above a threshold that are separated from each other by at least the time span of the CP. Time and frequency corrections can be performed on each copy of the symbol separately (e.g., correlation of the CP and payload of each copy is performed), and each copy can be processed based on the adjusted time or frequency of that copy (e.g., from Convert time domain to frequency domain, demodulate each copy, etc.). The output of the demodulation process may be selected from the processed replicas based on a metric for each processed replica (eg, the quality of the replica, such as signal-to-noise ratio (SNR)).

In some embodiments, when no valid CP is detected, or no peak above a threshold is detected (e.g. due to poor quality of received symbols), processing can be performed without performing time and frequency corrections symbols (e.g., using default timing), or processing the symbols using an alternative method for performing time and frequency correction (e.g., using one of the reference signal-based time and frequency correction methods in traditional DRX technology).

In some embodiments, the conditions of the received symbols may also be used to determine activities for subsequent wake-ups (e.g., time and frequency correction methods to be performed) and/or starting time points for subsequent wake-ups (e.g., if additional wake-ups are required to receive one or more reference signals).

FIG. 1 illustrates an exemplary wireless network 100 in which certain aspects of the present disclosure may be implemented, in accordance with some embodiments of the present disclosure. As shown in Figure 1, wireless network 100 may include a network of nodes, such as UEs 102, access nodes 104, and core network elements 106. The user device 102 may be any terminal device, such as a mobile phone, a desktop computer, a laptop, a tablet, a vehicle computer, a game console, a printer, a pointing device, a wearable electronic device, a smart sensor, or capable of receiving, processing, and Any other device that transmits information, such as any member of a vehicle-to-everything (V2X) network, a cluster network, a smart mesh node, or an Internet of Things (IoT) node. It should be understood that the user equipment 102 is shown as a mobile phone by way of illustration only and not by way of limitation.

Access node 104 may be a device that communicates with UE 102, such as a wireless access point, a base station (BS), a Node B, an enhanced Node B (eNodeB or eNB), a next generation Node B (gNodeB or gNB), a cluster master node wait. Access node 104 may have a wired connection to UE 102, a wireless connection to UE 102, or any combination thereof. Access node 104 may be connected to UE 102 through multiple connections, and UE 102 may be connected to other access nodes in addition to access node 104. Access node 104 may also be connected to other UEs. It should be understood that the access node 104 is shown as a radio tower by way of illustration and not limitation.

Core network elements 106 may serve access nodes 104 and user equipment 102 to provide core network services. Examples of core network elements 106 may include a home subscriber server (HSS), a mobility management entity (MME), a serving gateway (SGW), or a packet data network gateway. PGW). These are examples of core network elements of the Evolved Packet Core (EPC) system, the core network of the LTE system. Other core network elements may be used in LTE and other communications systems. In some embodiments, the core network element 106 includes an access and mobility management function (AMF) device, a session management function (SMF) device or a user plane function of the core network of the NR system. user plane function (UPF) device. It should be understood that core network element 106 is shown as a set of rack-mounted servers by way of illustration and not limitation.

Core network element 106 may interface with a larger network, such as the Internet 108 or another Internet Protocol (IP) network, to transport packet data over any distance. In this manner, data from user device 102 may be communicated to other user devices connected to other access points, including computer 110 connected to Internet 108 using, for example, a wired or wireless connection, or wirelessly through router 114 Internet 108 Tablet 112. Thus, computer 110 and tablet 112 provide additional examples of possible user devices, and router 114 provides another example of possible access nodes.

A general example of a rack-mounted server is provided by the illustrated core network element 106. However, there may be multiple elements present in the core network, including a database server such as database 116, and security and authentication servers such as authentication server 118. For example, database 116 may manage data related to user subscriptions to network services. A home location register (HLR) is an example of a standardized database of subscriber information for a cellular network. Similarly, authentication server 118 may handle authentication of users, sessions, etc. In an NR system, an authentication server function (AUSF) device may be a specific entity that performs user device authentication. In some embodiments, a single server rack may handle multiple such functions such that the connections between core network element 106, authentication server 118, and database 116 may be local connections within a single rack.

As described in detail below, in some embodiments, wireless communications may be established between any suitable nodes in wireless network 100, for example, wireless communications are established between UE 102 and access node 104, and between UE 102 and Wireless communications are established between core network elements 106 for sending and receiving data (eg, one or more OFDM symbols). The transmitting node may generate one or more OFDM symbols (e.g., perform mapping, serial to parallel, inverse fast Fourier transform (IFFT), CP addition, parallel to serial, etc.) and transmit the symbols to the receiving device (e.g., UE). When the receiving device wakes up from the sleep mode and receives the symbol, the receiver may detect the CP, perform autocorrelation of the CP of the symbol and the payload, and adjust at least one of time or frequency of the symbol based on a result of the automatic correction.

Each node of the wireless network 100 adapted for DRX in Figure 1 may be considered a receiving device. Further details regarding possible implementations of the receiving device are provided by way of example in the description of the receiving device 900 in FIG. 9 . The receiving device 900 may be configured as the user equipment 102, the access node 104 or the core network element 106 in Figure 1 . Similarly, the receiving device 900 may also be configured as the computer 110, the router 114, the tablet 112, the database 116 or the authentication server 118 in FIG. 1 . As shown in Figure 9, receiving device 900 may include a processor 902, a memory 904, and a transceiver 906. These components are shown connected to each other via a bus, but other connection types are also allowed. When the receiving device 900 is the user device 102, additional components may also be included, such as a user interface (UI), sensors, etc. Similarly, when the receiving device 900 is configured as a core network element 106, the receiving device 900 may be implemented as a blade in a server system. Other implementations are possible.

Transceiver 906 may include any suitable device for sending and/or receiving data. Receiving device 900 may include one or more transceivers, although only one transceiver 906 is shown for simplicity of illustration. Antenna 908 is shown as a possible communication mechanism for receiving device 900 . If the antenna is MIMO, multiple antennas and/or antenna arrays may be utilized. Additionally, examples of receiving device 900 may communicate using wired technologies instead of (or in addition to) wireless technologies. For example, access node 104 may communicate with user equipment 102 wirelessly, and may communicate with core network element 106 through a wired connection (eg, through optical or coaxial cables). Other communications hardware may also be included, such as a network interface card (NIC).

As shown in Figure 9, receiving device 900 may include a processor 902. Although only one processor is shown, it is understood that multiple processors may be included. The processor 902 may include a microprocessor, a microcontroller, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) ), programmable logic devices (PLDs), state machines, gating logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure. Processor 902 may be a hardware device having one or more processing cores. Processor 902 can run software. Software shall be construed broadly to mean instructions, set of instructions, code, code segment, program code, program, subroutine, software module, application, software application, software package, routine, subroutine, object, executable file, A thread of execution, a process, a function, etc., whether the software is called software, firmware, middleware, microcode, a hardware description language, or something else. Software may include computer instructions written in interpreted language, compiled language, or machine code. Other techniques for indicating hardware are also allowed under the broad category of software.

As shown in Figure 9, receiving device 900 may also include memory 904. Although only one memory is shown, it is understood that multiple memories may be included. Memory 904 may broadly include both memory and storage devices. For example, memory 904 may include random access memory (RAM), read only memory (ROM), static RAM (SRAM), dynamic RAM (DRAM), ferroelectric RAM (FRAM), electrically erasable programmable ROM (EEPROM) , CD-ROM or other optical disk storage, hard disk drive (HDD) such as magnetic disk storage or other magnetic storage device, flash drive, solid state drive (SSD) or may be used to carry or store instructions in the form of instructions that can be accessed and executed by processor 902 Any other medium where program code is expected. Broadly speaking, memory 904 may be implemented by any computer-readable medium (eg, non-transitory computer-readable media).

The processor 902, memory 904, and transceiver 906 may be implemented in various forms in the receiving device 900 for performing wireless communications using CP-based time and frequency correction functions. In some embodiments, the processor 902, memory 904, and transceiver 906 of the receiving device 900 are implemented (eg, integrated) on one or more system-on-chips (SoCs). In one example, the processor 902 and the memory 904 may be integrated on an application processor (AP) SoC (sometimes referred to as a "host" and herein, referred to as a "host chip") that handles processing in an operating system environment. Apply processing, including generating raw data to be sent. In another example, the processor 902 and the memory 904 may be integrated on a baseband processor (BP) SoC (sometimes referred to as a modem, referred to herein as a "baseband chip"), which will, for example, be derived from a host chip. Raw data is converted into signals that can be used to modulate the carrier frequency for transmission, and vice versa, and the BP SoC can run a real-time operating system (RTOS). In yet another example, the processor 902 and the transceiver 906 (and in some cases, the memory 904) may be integrated on an RF SoC (sometimes referred to as a transceiver, and herein referred to as an "RF chip"). Antenna 908 is used to transmit and receive RF signals. It should be understood that in some examples, some or all of the host chip, baseband chip, and RF chip may be integrated into a single SoC. For example, the baseband chip and the RF chip can be integrated into a single SoC that manages all radio functions for cellular communications.

Various aspects of the present disclosure related to time and frequency correction may be implemented as software and/or firmware elements executed by a general-purpose processor (eg, a baseband processor) in a baseband chip. It will be appreciated that in some examples, one or more of the software and/or firmware elements may be replaced by dedicated hardware components in the baseband chip, such dedicated hardware components including integrated circuits (ICs), such as application specific integrated circuits (ASICs). Implementations of the present disclosure may be located at layer 1 (eg, physical (PHY) layer) by mapping to a wireless communication (eg, 4G, LTE, 5G, etc.) layer architecture.

2 illustrates a detailed block diagram of an exemplary wireless communications system 200 using CP-based time and frequency correction in accordance with some embodiments of the present disclosure. Wireless communication system 200 may be used between suitable nodes in wireless network 100. As shown in FIG. 2 , the wireless communication system 200 may include a sending device 201 and a receiving device 202 . For example, the sending device 201 may be an example of a user equipment 102, an access node 104, or a core network element 106, and the receiving device 202 may be an example of a user equipment 102 or a core network element 106 of the wireless network 100 in FIG. 1 . The wireless communication system 200 can be used to save power consumption of the receiving device 202 and improve the accuracy of wireless communication by providing better synchronization performance. Both the sending device 201 and the receiving device 202 may include a processor, memory, and transceiver, which may be examples of the processor 902, memory 904, and transceiver 906 respectively described in detail above with respect to FIG. 9 .

As shown in Figure 2, the sending device 201 can process raw data (e.g., process input data through various functional stages such as data modulation, mapping, IFFT, CP addition, etc.), and can send processed data (e.g., OFDM symbols). The receiving device 202 may receive symbols, perform time and frequency correction, and detect original data (eg, decoded bits) through a reverse process (eg, demodulation, demapping, CP removal, FFT, etc.).

As shown in Figure 2, the sending device 201 may include a data mapping module 210, an OFDM modulation module 220 and a CP adding module 230 for processing original data to be transmitted.

For example, data mapping module 210 may apply a mapper (eg, quadrature phase shift keying (QPSK)) to group the information bits of the original data into symbols. In OFDM modulation module 220, IFFT (eg, when the number of subcarriers is 2 ⁿ ) or inverse discrete Fourier transform (IDFT) may be applied to the symbols to keep the subcarriers still orthogonal. CP adding module 230 may add a CP to a symbol by taking a last portion of a predetermined length (eg, number of bits) and copying the last portion to the front of the symbol. For example, part A of FIG. 3 shows a schematic diagram of an exemplary CP addition process applied to symbol stream 302 of OFDM symbols 304 in accordance with some embodiments of the present disclosure.

As shown in part A of FIG. 3 , each OFDM symbol 304 may include a payload 306 carrying data and a CP 308 located at the beginning of the OFDM symbol 304 . In some embodiments, the last portion of payload 306 is inserted at the beginning of payload 306 of OFDM symbol 304 as CP 308. In some embodiments, CP 308 may be used as a guard interval to prevent ISI between consecutive OFDM symbols 304.

Referring back to FIG. 2 , OFDM symbols may be transmitted to receiving device 202 over a channel (eg, one or more communication links between transmitting device 201 and receiving device 202 ). When the receiving device 202 wakes up from sleep mode, upon receiving an OFDM symbol, the CP-based time and frequency correction module 240 may perform the CP (eg, CP 308 ) and payload (eg, OFDM symbol 304 ) of the OFDM symbol (eg, OFDM symbol 304 ). For example, autocorrelation of payload 306) to perform time and frequency corrections.

For example, FIG. 4 illustrates a timing diagram of exemplary time and frequency corrections performed when receiving device 202 wakes up, in accordance with some embodiments of the present disclosure. As shown in Figures 4a) to 4c), in conventional DRX technology that performs traditional time and frequency correction schemes, during the DRX cycle (e.g., the time span from the beginning of the PO or activation period to the beginning of the next PO or activation period ) requires an additional wake-up period (e.g., wake-up in addition to the PO or activation period) for receipt of one or more reference signals (e.g., CRS, PSS/SSS, SSB, etc.) used to perform time and frequency corrections . Therefore, the UE (eg, receiving device 202) requires additional power consumption to adjust the time or frequency accordingly.

As shown in Figure 4d), for the same DRX cycle, no additional wake-up period is required to perform CP-based time and frequency correction since the CP is aligned with the payload of the OFDM symbol. Therefore, this can greatly reduce the power consumption of the receiving device 202. Furthermore, compared to other autocorrelation based time and frequency detection (where the entire OFDM symbol is used for correlation), using CP (e.g. with much fewer bits than the entire OFDM symbol) is used to perform efficient detection with OFDM symbols. Correction of the load (which will be described in detail together with the description of part B of Figure 3 below) can further save significant computational resources used to perform time and frequency corrections.

Referring back to FIG. 2 , the CP-based time and frequency correction module 240 may include a CP detection unit 242 , an autocorrelation unit 244 , and a time and frequency correction unit 246 . In some embodiments, CP detection unit 242 may detect a CP (eg, CP 308 in part A of Figure 3) when an OFDM symbol (eg, OFDM symbol 304) is received. When starting to receive the payload of the OFDM symbol (eg, OFDM symbol 304), autocorrelation unit 224 may begin performing autocorrelation of the CP (eg, CP 308) and the payload (eg, payload 306). For example, part B of Figure 3 shows autocorrelation results in the time domain for CP 308 and payload 306 in accordance with some embodiments of the present disclosure. In part B of Figure 3, the “T” axis represents time and the “Amplitude” axis represents the amplitude of the autocorrelation results. T ₀ represents the end time point of OFDM symbol 304. As shown in Part B of Figure 3, as the correlation window moves from the beginning of the payload 306 to the end of the payload 306, peaks above a threshold (e.g., the threshold is set to avoid being caused by some random noise within multiple portions of the OFDM symbol) The peak due to similarity) may indicate the location of the end of OFDM symbol 304 since CP 308 is an exact copy of the last portion of payload 306 . In some embodiments, multiple peaks in the autocorrelation results may be above a threshold. For example, delayed copies of symbols may be received due to interference such as ISI and multipath interference. Since the delayed copy of the symbol has weaker energy (e.g., the delayed copy of the symbol is reflected and therefore loses some of its energy), the peak with the highest amplitude (e.g., corresponding to the strongest received symbol) may be used to indicate the end of the OFDM symbol 304 Location.

Referring back to FIG. 2, based on the position of the end of the OFDM symbol, time and frequency correction unit 246 may adjust the time or frequency of the OFDM symbol to accordingly correct for time and/or frequency drift caused by being in sleep mode.

In some embodiments, OFDM symbols with adjusted time or frequency may be sent to data processing module 250 for extraction of raw data. For example, data processing module 250 may convert the adjusted OFDM symbols from the time domain to the frequency domain using a fast Fourier transform (FFT), and may use a physical downlink control channel (PDCCH) receiver such as a physical downlink control channel (PDCCH) receiver based on the adjusted time or frequency. and/or a channel such as a Physical Downlink Shared Channel (PDSCH) receiver to demodulate and demap the symbols. Raw data (eg, data input of sending device 201 ) may be the output of data processing module 250 .

In some embodiments, more than one peak above the threshold may be detected in the autocorrelation results due to interference (eg, ISI and multipath interference). For example, due to multipath issues, one or more delayed copies of a symbol may be received, and one or more peaks may show up at the end of the delayed copies.

In some embodiments, if the time span between peaks is not longer than the time span of the CP, time and frequency correction unit 246 may adjust the time or frequency of the received OFDM symbols based on the earliest or strongest peak above the threshold. For example, because delayed copies are received after a certain delay due to longer transmission distances, the earliest peak above a threshold can be selected to locate the end of the symbol. For another example, because the delayed copies are reflected by surrounding objects, the peak corresponding to the delayed copy may be weaker (eg, have a smaller amplitude in the autocorrelation result) than the peak indicating the end of the received symbol. Therefore, the strongest peak (e.g., the highest peak in the autocorrelation result) can be selected to locate the end of the symbol.

In some embodiments, the time span of more than one peak above the threshold is longer than the time span of the CP. In some embodiments, a received symbol may be converted into multiple copies based on the number of peaks above a threshold that are separated from each other by at least the time span of the CP. Time and frequency correction can be performed on each replica separately (e.g., correlating the CP with each replica), and each replica can be processed based on the adjusted time or frequency of that replica separately (e.g., converting from the time domain to the frequency domain , demodulating each copy, etc.). The output of the demodulation process may be selected from the processed replicas based on a metric for each processed replica (eg, quality of the replica, such as signal-to-noise ratio (SNR)).

In some embodiments, if no valid CP is detected, the OFDM symbols may be processed without performing time and frequency correction (e.g., processed using default timing), or using an already determined time and frequency correction method. Adjust the time or frequency (e.g., using one of the reference signal-based time and frequency correction methods in traditional DRX technology) to process the symbols. Therefore, in this scenario, the CP-based time and frequency correction performed in the CP-based time and frequency correction module 240 (eg, the processing performed in the autocorrelation unit 244, and the time and frequency correction unit 246 ). For one example, OFDM symbols may be sent to data processing module 250 for further processing, but without updating the time and frequency drift. In other embodiments, the receiving device 202 may start the FFT function unit and the associated PDCCH receiver in the data processing module 250, attempt to decode the PDCCH, and obtain the PDCCH demodulation reference signal (DMRS) or CRS to perform time and frequency correction.

In some embodiments, based on the received symbols, the time and frequency correction for the current wake-up may be used to determine the activity of the subsequent wake-up (eg, the time and frequency correction module to be used) and/or the starting time point of the subsequent wake-up. Quality Standard. For example, the receiving device 202 may further include an optional time and frequency correction module 260 in which an optional time and frequency correction method (eg, a method based on one or more reference signals) is performed. ). The time and frequency correction module selection process may be controlled by a processor (eg, processor 902) in conjunction with time and frequency correction module selection control signals provided by time and frequency correction scheme selection module 270 in accordance with one or more schemes disclosed above. For one example, if no above-threshold CP correlation peaks are detected in the current wakeup (eg, due to lower quality of the received symbols), then in subsequent wakeups, the alternative time and frequency correction module 260 may be selected to perform Time and frequency correction, and may also indicate early wake-up (e.g., with additional wake-up for reception of one or more reference signals).

It is contemplated that possible time and frequency correction modules and time and frequency correction module selection methods for time and frequency correction are not limited to those disclosed herein. Any other suitable alternative time and frequency correction modules and time and frequency correction module selection methods may be applied by the receiving device 202 for time and frequency correction. However, based on the selected time and frequency correction module, the adjusted OFDM symbols may be sent to the data processing module 250 for further processing based on the adjusted time or frequency.

It is contemplated that the wireless communication system 200 with the CP-based time and frequency correction described above may be implemented in software or hardware. For example, FIG. 5A and FIG. 5B respectively illustrate an exemplary device 500 including a host chip, an RF chip and a baseband chip that implements the wireless communication system 200 in FIG. 2 in software and hardware according to some embodiments of the present disclosure. Block diagram of a wireless communication system 200 with CP-based time and frequency correction. The apparatus 500 may be an example of any node (eg, user equipment 102 or core network element 106) of the wireless network 100 in FIG. 1 that is suitable for DRX. As shown in FIG. 5 , the device 500 may include an RF chip 502 , a baseband chip 504 (baseband chip 504A in FIG. 5A or baseband chip 504B in FIG. 5B ), a host chip 506 and an antenna 510 . In some embodiments, baseband chip 504 is implemented by processor 902 and memory 904, and RF chip 502 is implemented by processor 902, memory 904, and transceiver 906, as described above with respect to FIG. 9. In addition to on-chip memory 512 on each chip 502, 504, or 506 (also referred to as "internal memory", e.g., referred to as a register, buffer, or cache), the device 500 may further include system memory 508 (also referred to as Main memory), system memory 508 may be shared by each chip 502, 504, or 506 via the main bus. Although the baseband chip 504 is shown as an independent SoC in FIGS. 5A and 5B , it should be understood that in one example, the baseband chip 504 and the RF chip 502 may be integrated into one SoC; in another example, the baseband chip 504 and the host The chip 506 may be integrated into one SoC; in yet another example, the baseband chip 504, the RF chip 502, and the host chip 506 may be integrated into one SoC, as described above.

In the uplink, host chip 506 may generate raw data and send the raw data to baseband chip 504 for encoding, modulation, mapping, and CP addition. Baseband chip 504 may access raw data from host chip 506 directly using interface 514 or through system memory 508 and then perform the functions of modules 210, 220, and 230, as described in detail above with respect to FIG. 2. The baseband chip 504 may then transmit the modulated signals (eg, OFDM symbols) to the RF chip 502 through the interface 514 . The transmitter (Tx) 516 of the RF chip 502 can convert the modulated signal in digital form from the baseband chip 504 into an analog signal, ie, an RF signal, and transmit the RF signal into the channel through the antenna 510.

In the downlink, antenna 510 may receive RF signals (eg, OFDM symbols) over the channel and transmit the RF signals to receiver (Rx) 518 of RF chip 502 . RF chip 502 can perform any suitable front-end RF functions (such as filtering, frequency downconversion, or sample rate conversion) and convert the RF signal into a low-frequency digital signal (baseband signal) that can be processed by baseband chip 504 . In the downlink, the interface 514 of the baseband chip 504 may receive baseband signals, such as OFDM symbols. Baseband chip 504 may then perform the functions of modules 240, 250, 260, and 270 as described in detail above with respect to FIG. 2, Part A of FIG. 3, and Part B of FIG. 3. The raw data may be extracted from the baseband signal by baseband chip 504 and transferred to host chip 506 through interface 514 or stored in system memory 508 .

In some embodiments, the time and frequency correction scheme disclosed herein (eg, through CP-based time and frequency correction module 240, instead of time and frequency correction module 260, or wireless communication system 200) can be implemented by baseband chip 504A in FIG. 5A with Software implementation, baseband chip 504A has baseband processor 520 that executes stored instructions, as shown in Figure 5A. Baseband processor 520 may be a general-purpose processor not dedicated to time and frequency correction, such as a central processing unit or DSP. That is, the baseband processor 520 is also responsible for any other functions of the baseband chip 504A, and when performing time and frequency correction, the baseband processor 520 may be interrupted due to other processes of higher priority. Each element in the apparatus 500 may be implemented as a software module executed by the baseband processor 520 to perform the corresponding function described in detail above.

In some other embodiments, the time and frequency correction scheme disclosed herein (eg, through CP-based time and frequency correction module 240, alternative time and frequency correction module 260, or wireless communication system 200) may be implemented by baseband chip 504B in FIG. 5B Implemented in hardware, the baseband chip 504B has a dedicated time and frequency correction circuit 522, as shown in Figure 5B. Time and frequency correction circuitry 522 may include one or more ICs, such as an ASIC, dedicated to implementing the time and frequency correction detection schemes disclosed herein. Each element in the wireless communication system 200 may be implemented as a circuit that performs the corresponding function described in detail above. One or more microcontrollers (not shown) in baseband chip 504B may be used to program and/or control the operation of time and frequency correction circuit 522 . It should be understood that in some examples, the time and frequency correction detection schemes disclosed herein may be implemented in a hybrid manner, for example, in both hardware and software. For example, some elements in wireless communication system 200 may be implemented as software modules executed by baseband processor 520, and some elements in wireless communication system 200 may be implemented as circuits.

6 and 7 illustrate flowcharts of an exemplary method 600 for wireless communications using CP-based time and frequency correction, and FIG. 8 illustrates a method 600 for using CP-based time and frequency correction in accordance with some embodiments of the present disclosure. A flow diagram of another exemplary method 800 for wireless communication and frequency correction. Examples of devices that may perform the operations of methods 600 and 800 include, for example, the devices depicted in FIGS. 2, 5A, and 5B or any other devices disclosed herein. It should be understood that the operations illustrated in methods 600 and 800 are not exhaustive and that other operations may be performed before, after, or between any illustrated operations. Additionally, some operations may be performed concurrently or in a different order than that shown in FIGS. 6, 7, and 8. FIGS. 6 and 7 will be described together, and FIG. 8 will be described in conjunction with FIGS. 6 and 7 .

Referring to FIG. 6 , method 600 begins at operation 602 , in which a UE (eg, receiving device 202 ) wakes up from sleep mode and receives, by the UE, a payload (eg, payload 306 ) and a CP (eg, CP 308) OFDM symbol (e.g., OFDM symbol 304). In some embodiments, transceiver 906 in Figure 9 may be configured to receive OFDM symbols.

Method 600 proceeds to operations at 604, where it is determined whether a CP is detected. If CP is detected, method 600 proceeds to operations at 608, 610, and 612 where autocorrelation of the CP of the OFDM symbol and the payload is performed, based on one or more of the autocorrelation peaks to perform time and frequency corrections, and to process data based on time and frequency corrections. As shown in FIG. 2 , the CP-based time and frequency correction module 240 of the receiving device 202 may perform autocorrelation and time and frequency correction. The data processing module 250 of the receiving device 202 may perform data processing. The details of operations 608, 610, and 612 may be described in greater detail in Figure 7.

For example, as shown in Figure 7, after performing autocorrelation of the CP and the payload in operation 608, it is determined in operation 702 whether more than one peak above a predetermined threshold is detected. As shown in Figure 2, the CP-based time and frequency correction module 240 of the receiving device 202 may perform this determination.

In some embodiments, if only one peak above the threshold is detected, method 600 proceeds to operation 610a where time and frequency corrections are performed based on the peak of the autocorrelation. Method 600 then proceeds to operation 612a where data (eg, received OFDM symbols) are processed based on time and frequency corrections. As shown in FIG. 2, the data processing module 250 of the receiving device 202 may perform data processing.

Referring back to operation 702 , if more than one peak above the threshold is detected, method 600 proceeds to operation 704 , in which it is determined whether the time span between the more than one peak above the threshold is greater than The time span for CP is long. If the time span between more than one peak above the threshold is not longer than the time span for the CP, method 600 proceeds to operation at 610b where the autocorrelation is determined based on the earliest peak or the strongest peak. Perform time and frequency corrections. Method 600 proceeds to operation 612a where the data is processed based on time and frequency corrections (eg, adjusted time or frequency).

Referring back to operation 704 , if the time span between more than one peak above the threshold is longer than the time span for the CP, method 600 proceeds to operation 706 in which the peak value above the threshold is determined based on the time span between the peaks above the threshold. The number of received OFDM symbols converted into replicas, these peaks are separated from each other by at least the time span of the CP. For example, if m peaks are detected to be above a threshold and separated from each other by at least the time span of the CP, the received OFDM symbol may be converted into m copies accordingly.

Method 600 then proceeds to operation at 610c, where time and frequency corrections are performed on each replica separately. For example, autocorrelation unit 244 may associate a CP with each replica separately, and time and frequency correlation unit 246 may adjust the time or frequency of each replica based on each correlation result, respectively.

Method 600 then proceeds to operations at 612c, where each replica is processed based on a time and frequency correction of the replica used to demodulate the OFDM symbol, and may be based on a measure of the demodulated original data (eg, signal-to-noise ratio (SNR)) to select at least one demodulated raw data as the output of the data processing module 250 in the receiving device 202 . For example, data processing module 250 may demodulate each copy separately and select the one with the best quality (eg, best SNR) as output.

Referring back to operation 604 in Figure 6, if no valid CP is detected, then in operation 606, the data may be processed using default timing (eg, without correcting for time and/or frequency drift based on CP) .

In operation 614, activities for subsequent wake-ups are determined. For example, the time and frequency correction method for subsequent wake-ups may be determined based on the time and frequency correction results of the current wake-up. For example, if no valid CP is detected, the SNR of the received data is less than a threshold, or the time or frequency drift is greater than the detection range of the CP-based time and frequency correction scheme disclosed herein, alternative time and frequency corrections may be selected for subsequent wake-ups. schemes (e.g. time and frequency correction schemes based on reference signals). In some embodiments, the time point for subsequent wake-ups may also be determined based on selection of a time and frequency correction scheme for subsequent wake-ups (eg, if additional wake-up periods are required to receive the reference signal). As shown in Figure 2, modules 240, 260, and 270 of receiving device 202, operating in conjunction, may be configured to determine activities for subsequent wake-ups.

In operation 616, after processing the received data, the UE may enter sleep mode again to reduce power consumption.

8 illustrates a flow diagram of an exemplary method 800 for wireless communications using additional steps in addition to method 600, in accordance with some embodiments of the present disclosure.

Referring to Figure 8, method 800 begins at operation 802, in which a UE (eg, receiving device 202) wakes up from sleep mode and the UE receives OFDM symbols.

Method 800 proceeds to operation 804 where it is determined whether CP-based time and frequency correction is enabled. For example, the UE may determine whether to enable CP-based time and frequency correction based on instructions from a previous wakeup (eg, instructions generated in operation 614 of method 600). For example, if one or more of the following was detected in the last wakeup: 1) no valid CP was detected, 2) no peak above the threshold was detected, 3) the SNR of the demodulated symbol (e.g., data processing module 250 output) is too low, 4) the time or frequency drift is greater than the detection range of the CP-based time and frequency correction scheme, the UE may indicate not to enable CP-based time and frequency correction for the current wakeup. If CP-based time and frequency correction is not enabled, method 800 proceeds to operations at 806 where an alternative time and frequency correction (eg, based on a reference signal such as PSS, SSS, CRS, or SSB method) to perform time and frequency corrections. As shown in FIG. 2, the alternative time and frequency correction module 260 may perform time and frequency correction based on at least one of the reference signals described above.

If CP-based time and frequency correction is enabled, method 800 proceeds to operation 604 where CP-based time and frequency correction is performed similar to the operations described in FIGS. 6 and 7 . For the sake of clarity and simplicity, the same operations will not be described.

In method 800, when CP-based time and frequency correction is performed, operations are different from those performed in method 600. In operation 606', when no valid CP is detected in the current wakeup in operation 604, the data may be processed based on the time and frequency adjusted according to the alternative time and frequency correction generated in operation 806, and Instead of using the default time to process the data. As shown in Figure 2, data processing module 250 may demodulate data based on the adjusted time.

In various aspects of the disclosure, the functionality described herein may be implemented in hardware, software, firmware, or any combination thereof. If the functionality is implemented in software, the functionality may be stored on, or encoded on, a non-transitory computer-readable medium as instructions or code. Computer-readable media includes computer storage media. The storage medium can be any available medium that can be accessed by a receiving device (eg, receiving device 900 in Figure 9). By way of example and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, HDD, such as magnetic disk storage or other magnetic storage devices, flash drives, SSDs, or may be used in Any other medium that carries or stores the desired program code in the form of instructions or data structures that can be accessed by a processing system (such as a mobile device or computer). As used herein, disks and disks include CDs, laser disks, optical disks, DVDs, and floppy disks, where disks typically reproduce data magnetically, while disks reproduce data optically using lasers. Combinations of the above should also be included within the scope of computer-readable media.

According to one aspect of the present disclosure, an apparatus is disclosed that includes at least one processor and a memory storing instructions. When executed by at least one processor, the instructions cause the device to receive symbols including a CP and a payload. When executed by the at least one processor, the instructions also cause the device to detect the CP and perform autocorrelation of the CP and the payload. When executed by the at least one processor, the instructions further cause the apparatus to adjust at least one of the timing or frequency of the received symbols based on the results of the autocorrelation.

In some embodiments, execution of the instructions also causes the apparatus to convert the adjusted symbols from the time domain to the frequency domain.

In some embodiments, execution of the instructions further causes the apparatus to demodulate the converted symbols based on at least one of adjusted time or frequency.

In some embodiments, to detect one or more peaks of autocorrelation above a threshold, execution of the instructions further causes the apparatus to detect one or more peaks of autocorrelation above the threshold.

In some embodiments, execution of the instructions further causes the apparatus to adjust at least one of the timing or frequency of the received symbols based on the one or more peaks.

In some embodiments, execution of the instructions further causes the device to detect a plurality of peaks above a threshold in order to adjust at least one of the timing or frequency of the received symbols.

In some embodiments, execution of the instructions further causes the apparatus to determine whether the time span of the plurality of peaks is longer than the time span of the CP.

In some embodiments, to adjust at least one of the time or frequency of the received symbols, execution of the instructions further causes the device to respond to a plurality of peaks whose time span is no longer than the time span of the CP, based on the earliest of the plurality of peaks. At least one of the peaks or strongest peaks to adjust at least one of the time or frequency of the received symbols.

In some embodiments, in order to adjust at least one of the time or frequency of the received symbols, execution of the instructions further causes the apparatus to respond to a plurality of peaks with a time span longer than a CP time span, then select at least one of the plurality of peaks. At least some peaks separated by the time span of the CP.

In some embodiments, execution of the instructions further causes the apparatus to convert the received symbol into a plurality of copies based on the selected peak in order to adjust at least one of the time or frequency of the received symbol.

In some embodiments, execution of the instructions further causes the apparatus to: separately adjust at least one of time or frequency of each of the plurality of copies of the symbol; convert each copy of the symbol from the time domain to the frequency domain; based on the corresponding Demodulating each converted copy of the symbol at at least one of adjusted time or frequency; and selecting at least one of the demodulated copies of the symbol based on a measure of the demodulated copy of the symbol.

In some embodiments, execution of the instructions further causes the apparatus to determine whether a quality criterion is met based on the received symbol and to adjust at least one of the time or frequency of another symbol received in the next wake based on the determination.

In some embodiments, wherein the quality criterion includes the SNR of the received symbols being above a threshold.

In some embodiments, wherein the quality criterion includes at least one peak of the autocorrelation being above a threshold.

In some embodiments, execution of the instructions further causes the apparatus, in response to meeting the quality criteria, to adjust another symbol based on a result of automatic correction of another CP and another payload of the other symbol received in the next wake-up. At least one of time or frequency.

In some embodiments, execution of the instructions further causes the apparatus to adjust at least one of time or frequency of another symbol based on a reference signal received in a next wake-up in response to not meeting the quality criterion.

In some embodiments, the reference signal includes at least one of PSS, SSS, CRS or SSB.

In some embodiments, execution of the instructions further causes the device to determine a time point for initiating an immediately subsequent wake-up based on the received symbol.

In some embodiments, the received symbols are OFDM symbols.

In some embodiments, before a symbol is received, at least one of time or frequency has a drift caused by the device being in sleep mode.

In some embodiments, at least one of the time or frequency of the received symbols is adjusted based on the end of the received symbols, the end of the received symbols being indicated by the results of the automatic correction.

In some embodiments, at least one of the time or frequency of the received symbols is adjusted based on the time and frequency of the symbols indicated by the results of the autocorrelation according to the sampling frequency used to demodulate the received signal.

According to another aspect of the present disclosure, a baseband chip is disclosed. The baseband chip includes an interface and a time and frequency correction circuit operatively coupled to the interface. The interface is configured to receive OFDM symbols including CP and payload. The time and frequency correction circuitry is configured to detect the CP and perform autocorrelation of the CP and the payload. The time and frequency correction circuitry is further configured to adjust at least one of time or frequency of the received symbols based on the results of the autocorrelation.

In some embodiments, the baseband chip further includes a data processing circuit configured to: convert the adjusted symbols from the time domain to the frequency domain; and perform a processing on the converted symbols based on at least one of the adjusted time or frequency. demodulation.

In some embodiments, the time and frequency correction circuit is an application specific integrated circuit ASIC.

According to yet another aspect of the present disclosure, a method for time and/or frequency correction is disclosed. Receive symbols including CP and payload. Detect CP, and perform autocorrelation of CP and payload. At least one of the time or frequency of the received symbols is adjusted based on the results of the autocorrelation.

In some embodiments, to adjust at least one of time or frequency of the received symbols, one or more peaks of autocorrelation above a threshold are detected, and the received symbols are adjusted based on the one or more peaks. At least one of time or frequency.

In some embodiments, the adjusted symbols are converted from the time domain to the frequency domain.

In some embodiments, the converted symbols are demodulated based on at least one of adjusted time or frequency.

In some embodiments, multiple peaks are detected above a threshold, and it is determined whether the time span of the multiple peaks is longer than the time span of the CP.

In some embodiments, in response to the time span of the plurality of peaks being no longer than the time span of the CP, the time or frequency of the received symbol is adjusted based on at least one of the earliest peak or the strongest peak among the plurality of peaks. at least one of.

In some embodiments, in response to the time span of the plurality of peaks being longer than the time span of the CP, then selecting at least some peaks from the plurality of peaks that are separated by at least the time span of the CP, and based on the selected peaks, The received symbols are converted into multiple copies.

In some embodiments, at least one of time or frequency of each copy of the symbol is adjusted separately, and each copy of the symbol is converted from the time domain to the frequency domain based on the corresponding adjusted at least one of time or frequency.

In some embodiments, each converted copy of the symbol is demodulated based on at least one of adjusted time or frequency, and at least one demodulated copy of the symbol is selected based on a measure of the demodulated copy of the symbol .

In some embodiments, a determination is made based on the received symbols whether a quality criterion is met, and at least one of the time or frequency of another symbol received in the next wakeup is adjusted based on the determination.

In some embodiments, the quality criterion includes the SNR of the received symbols being above a threshold.

In some embodiments, the quality criterion includes at least one peak of the autocorrelation being above a threshold.

In some embodiments, in response to meeting the quality criteria, adjusting the time or frequency of the other symbol based on the results of automatic correction of another CP and another payload of the other symbol received in the next wake-up. at least one.

In some embodiments, in response to not meeting the quality criteria, at least one of the time or frequency of the other symbol is adjusted based on the reference signal received in the next wakeup.

In some embodiments, the reference signal includes at least one of PSS, SSS, CRS or SSB.

In some embodiments, a time point for initiating an immediately subsequent wake-up is determined based on the received symbols.

In some embodiments, the received symbols are OFDM symbols.

In some embodiments, before a symbol is received, at least one of time or frequency has a drift caused by the baseband chip being in sleep mode.

In some embodiments, at least one of the time or frequency of the received symbols is adjusted based on the end of the received symbols, the end of the received symbols being indicated by the results of the automatic correction.

In some embodiments, at least one of the time or frequency of the received symbols is adjusted based on the time and frequency of the symbols indicated by the results of the autocorrelation according to the sampling frequency used to demodulate the received signal.

According to another aspect of the present disclosure, a non-transitory computer-readable medium is disclosed. The non-transitory computer-readable medium is encoded with instructions that, when executed by at least one processor of a terminal device, perform a process. The process includes receiving symbols including CP and payload. The process also includes detecting the CP and performing autocorrelation between the CP and the payload. The process also includes adjusting at least one of time or frequency of the received symbols based on the results of the autocorrelation.

According to another aspect of the present disclosure, a device for time and/or frequency correction is disclosed, which device includes a receiving module, a detection module, an autocorrelation module, and a time or frequency correction module. The receiving module is configured to receive OFDM symbols including cyclic prefix (CP) and payload. The detection module is configured to detect the CP. The autocorrelation module is configured to perform autocorrelation of the CP and payload. The time or frequency correction module is configured to adjust at least one of time or frequency of the received symbols based on the results of the autocorrelation.

Accordingly, the foregoing description of specific embodiments will disclose the general nature of the disclosure, which may be readily modified by others without undue experimentation by applying knowledge within the skill of the art, without departing from the general spirit of the disclosure. and/or adaptation for various applications (e.g., specific embodiments). Accordingly, such adaptations and modifications are intended to fall within the meaning and scope of equivalents of the disclosed embodiments based on the teachings and guidance presented herein. It is to be understood that the terms or terminology used herein are for the purpose of description and not for limitation, so that the terms or terminology used in the specification will be interpreted by one skilled in the art in accordance with the teachings and guidance.

Embodiments of the present disclosure have been described above with the aid of functional building blocks illustrating the implementation of specified functions and their relationships. For ease of description, the boundaries of these functional building blocks are arbitrarily defined in this article. Alternative boundaries can be defined as long as the specified functions and their relationships are appropriately implemented.

As the inventors contemplate, the Summary and Abstract sections may set forth one or more, but not all, exemplary embodiments of the disclosure, and therefore the Summary and Abstract sections are not intended to limit the disclosure in any way. Attached Claims.

Various functional blocks, modules and steps are disclosed above. The specific arrangements provided are illustrative and not restrictive. Therefore, functional blocks, modules and steps may be reordered or combined differently than the examples provided above. Similarly, certain embodiments include only a subset of functional blocks, modules, and steps, and any such subset is permitted.

The breadth and scope of the present disclosure should not be limited by any above-described exemplary embodiments, but should be defined only in accordance with the following appended claims and their equivalents.

Claims (31)

1. An apparatus for wireless communication, comprising:

at least one processor; and

a memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least:

receiving a symbol including a cyclic prefix CP and a payload; wherein, before receiving the symbol,

at least one of time or frequency has drift caused by the device being in sleep mode;

detecting the CP;

performing an autocorrelation of the CP and the payload; and

adjusting at least one of time or frequency of the received symbol based on the result of the autocorrelation;

To detect one or more peaks of the autocorrelation that are above a threshold, execution of the instructions causes the apparatus to:

detecting that a plurality of peaks is above a threshold;

wherein execution of the instructions causes the apparatus to:

determining whether a time span of the plurality of peaks is longer than a time span of the CP;

wherein, to adjust at least one of a time or a frequency of the received symbol based on one or more peaks of the autocorrelation, execution of the instructions causes the apparatus to:

at least one of a time or a frequency of the received symbol is adjusted based on the plurality of peaks according to the determination.

2. The apparatus of claim 1, wherein execution of the instructions further causes the apparatus to:

converting the symbol from the time domain to the frequency domain; and

the converted symbols are demodulated based on at least one of the adjusted time or frequency.

3. The apparatus of claim 1, wherein to adjust at least one of a time or a frequency of the received symbol based on the plurality of peaks in accordance with the determination, execution of the instructions causes the apparatus to:

in response to the time span of the plurality of peaks not being longer than the time span of the CP, at least one of the time or frequency of the received symbol is adjusted based on at least one of the earliest peak or strongest peak of the plurality of peaks.

4. The apparatus of claim 2, wherein to adjust at least one of a time or a frequency of the received symbol based on the plurality of peaks in accordance with the determination, execution of the instructions further causes the apparatus to:

selecting at least some peaks from the plurality of peaks that are separated by at least the time span of the CP in response to the plurality of peaks having a longer time span than the time span of the CP;

converting the received symbol into a plurality of copies based on the selected peak value; and

at least one of a time or a frequency of each of the plurality of copies of the symbol is adjusted separately.

5. The apparatus of claim 4, wherein execution of the instructions causes the apparatus to:

converting each copy of the symbol from the time domain to the frequency domain;

demodulating each converted copy of the symbol based on at least one of a respective adjusted time or frequency; and

at least one of the demodulated copies of the symbol is selected based on a metric of the demodulated copies of the symbol.

6. The apparatus of any of claims 1-5, wherein execution of the instructions causes the apparatus to:

Determining whether a quality criterion is met based on the received symbols; and

at least one of a time or a frequency of another symbol received in a next wakeup is adjusted based on the determination.

7. The apparatus of claim 6, wherein the quality criteria comprises at least one of: the signal-to-noise ratio SNR of the received symbol is above a threshold or at least one peak of the autocorrelation is above a threshold.

8. The apparatus of claim 7, wherein to adjust at least one of a time or a frequency of another symbol received in a next wake-up, execution of the instructions causes the apparatus to:

in response to the quality criterion being met, at least one of a time or frequency of another symbol received in the next wakeup is adjusted based on a result of automatic correction of the other CP and the other payload of the other symbol.

9. The apparatus of claim 7, wherein to adjust at least one of a time or a frequency of another symbol received in the next wakeup, execution of the instructions causes the apparatus to:

in response to not meeting the quality criterion, at least one of a time or frequency of the other symbol is adjusted based on a reference signal received in the next wakeup.

10. The apparatus of claim 9, wherein the reference signal comprises at least one of a primary synchronization signal PSS, a secondary synchronization signal SSS, a common reference signal CRS, or a synchronization signal block SSB.

11. The apparatus of any one of claims 1-5, wherein execution of the instructions further causes the apparatus to:

a point in time for starting an immediately subsequent wakeup is determined based on the received symbols.

12. The apparatus of claim 11, wherein to determine a point in time for starting an immediately subsequent wakeup, execution of the instructions further causes the apparatus to:

determining whether a quality criterion is met;

in the event that it is determined that the quality criterion is met, waking up at a point in time at which reception of the symbol begins; and

in case it is determined that the quality criterion is not met, waking up at a point in time before the point in time at which reception of the symbol starts for receiving a reference signal for time and frequency correction.

13. The apparatus of claim 12, wherein to determine a point in time for starting an immediately subsequent wakeup, execution of the instructions causes the apparatus to:

at least one of the time or frequency of the received symbols is adjusted based on the time and frequency of the symbols indicated by the result of the autocorrelation in accordance with a sampling frequency used to demodulate the received signal.

14. A baseband chip, comprising:

an interface configured to receive an orthogonal frequency division multiplexing, OFDM, symbol; and

time and frequency correction circuitry operably coupled to the interface and configured to:

receiving the OFDM symbol including a cyclic prefix CP and a payload; wherein at least one of time or frequency has a drift caused by the baseband chip being in sleep mode prior to receiving the symbol;

detecting the CP;

performing an autocorrelation of the CP and the payload; and

adjusting at least one of time or frequency of the received symbol based on the result of the autocorrelation;

detecting that a plurality of peaks is above a threshold;

determining whether a time span of the plurality of peaks is longer than a time span of the CP;

at least one of a time or a frequency of the received symbol is adjusted based on the plurality of peaks according to the determination.

15. The baseband chip of claim 14, further comprising data processing circuitry configured to:

converting the symbol from the time domain to the frequency domain; and

the converted symbols are demodulated based on at least one of the adjusted time or frequency.

16. The baseband chip according to claim 14 or 15, wherein the time and frequency correction circuit is an application specific integrated circuit ASIC.

17. A method for time and/or frequency correction, comprising:

receiving a symbol including a cyclic prefix CP and a payload; wherein at least one of time or frequency has a drift caused by the baseband chip being in sleep mode prior to receiving the symbol;

detecting the CP;

performing an autocorrelation of the CP and the payload; and

adjusting at least one of time or frequency of the received symbol based on the result of the autocorrelation;

it is detected that a plurality of peaks are above a threshold,

wherein the method further comprises:

determining whether a time span of the plurality of peaks is longer than a time span of the CP;

wherein adjusting at least one of a time or a frequency of the received symbol based on one or more peaks of the autocorrelation comprises:

at least one of a time or a frequency of the received symbol is adjusted based on the plurality of peaks according to the determination.

18. The method of claim 17, further comprising:

converting the adjusted symbol from the time domain to the frequency domain; and

The converted symbols are demodulated based on at least one of the adjusted time or frequency.

19. The method of claim 17, wherein adjusting at least one of a time or a frequency of the received symbol based on the plurality of peaks in accordance with the determination comprises:

in response to the time span of the plurality of peaks not being longer than the time span of the CP, at least one of the time or frequency of the received symbol is adjusted based on at least one of the earliest peak or strongest peak of the plurality of peaks.

20. The method of claim 18, wherein adjusting at least one of a time or a frequency of the received symbol based on the plurality of peaks in accordance with the determination comprises:

selecting at least two peaks from the plurality of peaks separated by at least the time span of the CP in response to the time span of the plurality of peaks being longer than the time span of the CP;

converting the received symbol into a plurality of copies based on the selected peak value; and

at least one of a time or a frequency of each of the plurality of copies of the symbol is adjusted separately.

21. The method of claim 20, the method comprising:

Converting each adjusted copy of the symbol from the time domain to the frequency domain;

demodulating each converted copy of the symbol based on at least one of a respective adjusted time or frequency; and

at least one of the demodulated copies of the symbol is selected based on a metric of the demodulated copies of the symbol.

22. The method of any of claims 17 to 21, further comprising:

determining whether a quality criterion is met based on the received symbols; and

at least one of a time or a frequency of another symbol received in a next wakeup is adjusted based on the determination.

23. The method of claim 22, wherein the quality criteria comprises: the signal-to-noise ratio SNR of the received symbol is above a threshold or at least one peak of the autocorrelation is above a threshold.

24. The method of claim 23, wherein adjusting at least one of a time or a frequency of another symbol received in a next wakeup further comprises:

in response to the quality criterion being met, at least one of a time or frequency of another symbol received in the next wakeup is adjusted based on a result of automatic correction of the other CP and the other payload of the other symbol.

25. The method of claim 23, wherein adjusting at least one of a time or a frequency of another symbol received in the next wakeup further comprises:

in response to not meeting the quality criterion, at least one of a time or frequency of the other symbol is adjusted based on a reference signal received in the next wakeup.

26. The method of claim 25, wherein the reference signal comprises at least one of a primary synchronization signal PSS, a secondary synchronization signal SSS, a common reference signal CRS, or a synchronization signal block SSB.

27. The method of any of claims 17 to 21, further comprising:

a point in time for starting an immediately subsequent wakeup is determined based on the quality of the received symbol.

28. The method of claim 27, wherein determining a point in time for starting an immediately subsequent wakeup further comprises:

determining whether a quality criterion is met;

waking up a baseband chip at a point in time when reception of the symbol is started, in a case where it is determined that the quality criterion is satisfied; and

in case it is determined that the quality criterion is not met, waking up at a point in time before the point in time at which reception of the symbol starts for receiving a reference signal for time and frequency correction.

29. The method of claim 28, wherein adjusting at least one of a time or a frequency of the received symbol comprises:

at least one of the time or frequency of the received symbols is adjusted based on the time and frequency of the symbols indicated by the result of the autocorrelation in accordance with a sampling frequency used to demodulate the received signal.

30. A non-transitory computer-readable medium encoded with instructions that, when executed by at least one processor of an apparatus, perform a process comprising:

receiving a symbol including a cyclic prefix CP and a payload; wherein at least one of time or frequency has a drift caused by the apparatus being in sleep mode prior to receiving the symbol;

detecting the CP;

performing an autocorrelation of the CP and the payload; and

adjusting at least one of time or frequency of the received symbol based on the result of the autocorrelation;

detecting that a plurality of peaks is above a threshold;

determining whether a time span of the plurality of peaks is longer than a time span of the CP;

at least one of a time or a frequency of the received symbol is adjusted based on the plurality of peaks according to the determination.

31. An apparatus for time and/or frequency correction, comprising:

a receiving module configured to receive an OFDM symbol including a cyclic prefix CP and a payload; wherein at least one of time or frequency has a drift caused by the baseband chip being in sleep mode prior to receiving the symbol;

a detection module configured to detect the CP;

an autocorrelation module configured to perform an autocorrelation of the CP and the payload; and

a time or frequency correction module configured to adjust at least one of a time or frequency of the received symbol based on a result of the autocorrelation;

a detection module further configured to detect that the plurality of peaks is above a threshold;

determining whether a time span of the plurality of peaks is longer than a time span of the CP; at least one of a time or a frequency of the received symbol is adjusted based on the plurality of peaks according to the determination.