阅读说明：本技术 残余频偏确定方法、装置、芯片及模组设备 (Residual frequency offset determination method and device, chip and module equipment ) 是由 卢欢 徐鑫昌 于 2021-11-17 设计创作，主要内容包括：本申请公开了一种残余频偏确定方法、装置、芯片及模组设备,在单个DMRS的场景下,可以准确地确定出第N个PDSCH对应的残余频偏,从而提高解码性能。该方法可包括：根据调制方式获取第N个PDSCH对应的星座图；从第N个PDSCH对应的星座图中确定参考星座点,并根据参考星座点确定参考相位偏移；根据参考相位偏移和参考时间差,确定第N个PDSCH对应的残余频偏,参考时间差为目标DMRS对应的符号与第N个PDSCH对应的符号之间的时间差；根据第N个PDSCH对应的残余频偏,补偿第N个PDSCH对应的符号。(The application discloses a residual frequency offset determination method, a residual frequency offset determination device, a chip and module equipment, which can accurately determine the residual frequency offset corresponding to the Nth PDSCH in the scene of a single DMRS, thereby improving the decoding performance. The method can comprise the following steps: acquiring a constellation diagram corresponding to the Nth PDSCH according to the modulation mode; determining a reference constellation point from a constellation diagram corresponding to the Nth PDSCH, and determining a reference phase offset according to the reference constellation point; determining a residual frequency offset corresponding to the Nth PDSCH according to the reference phase offset and the reference time difference, wherein the reference time difference is a time difference between a symbol corresponding to the target DMRS and a symbol corresponding to the Nth PDSCH; and compensating a symbol corresponding to the Nth PDSCH according to the residual frequency offset corresponding to the Nth PDSCH.)

1. A method for determining residual frequency offset, the method comprising:

acquiring a constellation diagram corresponding to the Nth physical downlink shared channel PDSCF according to the modulation mode; n is a positive integer;

determining a reference constellation point from a constellation diagram corresponding to the Nth PDSCH, and determining a reference phase offset according to the reference constellation point;

determining a residual frequency offset corresponding to the Nth PDSCH according to the reference phase offset and the reference time difference; the reference time difference is a time difference between a symbol corresponding to a target demodulation reference signal (DMRS) and a symbol corresponding to the Nth PDSCH, and the target DMRS is the DMRS corresponding to the Nth PDSCH;

and compensating a symbol corresponding to the Nth PDSCH according to the residual frequency offset corresponding to the Nth PDSCH.

2. The method of claim 1, wherein the determining a reference constellation point from a constellation corresponding to the nth PDSCH comprises:

rotating the constellation point in the constellation diagram corresponding to the Nth PDSCH according to a preset angle, and determining the rotated constellation point which does not cross the quadrant as a reference constellation point.

3. The method of claim 1, wherein the determining a reference constellation point from a constellation corresponding to the nth PDSCH comprises:

the modulation mode is Quadrature Phase Shift Keying (QPSK), and a reference constellation point is determined from a constellation diagram corresponding to the Nth PDSCH according to a first circle; the reference constellation point is an out-of-circle constellation point of the first circle, the radius of the first circle is a first radius, and the center of the first circle is the center of a constellation diagram corresponding to the nth PDSCH;

or, the modulation mode is quadrature phase shift keying QPSK, and all constellation points in a constellation diagram corresponding to the nth PDSCH are determined as reference constellation points.

4. The method of claim 1, wherein the determining a reference constellation point from a constellation corresponding to the nth PDSCH comprises:

the modulation mode is Quadrature Amplitude Modulation (QAM), and a reference constellation point is determined from a constellation diagram corresponding to the Nth PDSCH according to a second circle; the reference constellation point is an out-of-circle constellation point of the second circle, the radius of the second circle is a second radius, and the center of the second circle is the center of a constellation diagram corresponding to the nth PDSCH.

5. The method of claim 4, wherein the second radius for a first QAM is different from the second radius for a second QAM, and wherein the second radius for the first QAM is less than the second radius for the second QAM; the first bin is less than the second bin.

6. The method of any of claims 1 to 4, wherein the determining the residual frequency offset corresponding to the Nth PDSCH according to the reference phase offset and the reference time difference comprises:

and calculating the residual frequency offset corresponding to the Nth PDSCH according to the quotient of the reference time difference removed from the reference phase offset.

7. The method according to any one of claims 1 to 4, further comprising:

and adjusting the residual frequency offset corresponding to the target DMRS to a preset value.

8. A communication device, characterized in that the communication device comprises a processing unit,

the processing unit is used for acquiring a constellation diagram corresponding to the Nth PDSCF according to a modulation mode; n is a positive integer; determining a reference constellation point from a constellation diagram corresponding to the Nth PDSCH, and determining a reference phase offset according to the reference constellation point; determining a residual frequency offset corresponding to the Nth PDSCH according to the reference phase offset and the reference time difference; the reference time difference is a time difference between a symbol corresponding to a target DMRS and a symbol corresponding to the Nth PDSCH, and the target DMRS is a DMRS corresponding to the Nth PDSCH; and compensating a symbol corresponding to the Nth PDSCH according to the residual frequency offset corresponding to the Nth PDSCH.

9. A chip, characterized in that,

the chip is used for acquiring a constellation diagram corresponding to the Nth PDSCF according to a modulation mode; n is a positive integer; determining a reference constellation point from a constellation diagram corresponding to the Nth PDSCH, and determining a reference phase offset according to the reference constellation point; determining a residual frequency offset corresponding to the Nth PDSCH according to the reference phase offset and the reference time difference; the reference time difference is a time difference between a symbol corresponding to a target DMRS and a symbol corresponding to the Nth PDSCH, and the target DMRS is a DMRS corresponding to the Nth PDSCH; and compensating a symbol corresponding to the Nth PDSCH according to the residual frequency offset corresponding to the Nth PDSCH.

10. The utility model provides a module equipment, its characterized in that, module equipment includes communication module, power module, storage module and chip module, wherein:

the power supply module is used for providing electric energy for the module equipment;

the storage module is used for storing data and instructions;

the communication module is used for carrying out internal communication of module equipment or is used for carrying out communication between the module equipment and external equipment;

the chip module is used for: acquiring a constellation diagram corresponding to the Nth PDSCF according to the modulation mode; n is a positive integer; determining a reference constellation point from a constellation diagram corresponding to the Nth PDSCH, and determining a reference phase offset according to the reference constellation point; determining a residual frequency offset corresponding to the Nth PDSCH according to the reference phase offset and the reference time difference; the reference time difference is a time difference between a symbol corresponding to a target DMRS and a symbol corresponding to the Nth PDSCH, and the target DMRS is a DMRS corresponding to the Nth PDSCH; and compensating a symbol corresponding to the Nth PDSCH according to the residual frequency offset corresponding to the Nth PDSCH.

11. A computer-readable storage medium, in which a computer program is stored which, when run on a communication apparatus, causes the communication apparatus to perform the method of any one of claims 1 to 7.

Technical Field

The present application relates to the field of communications technologies, and in particular, to a method, an apparatus, a chip, and a module device for determining a residual frequency offset.

Background

In a New Radio (NR) communication system, a physical layer signaling process may include: a Transport Block (TB) sequentially passes through Cyclic Redundancy Check (CRC), code block segmentation, channel coding, rate matching, and code block concatenation to obtain a codeword, which sequentially passes through scrambling, modulation, layer mapping, precoding, resource mapping, and Orthogonal Frequency Division Multiplexing (OFDM) signals to generate a baseband OFDM signal, which is converted into a radio frequency signal and transmitted through an antenna port. Accordingly, the signal receiving procedure of the physical layer may include: and receiving a signal, and sequentially performing time-frequency transformation, demapping, channel estimation, channel equalization, demodulation, descrambling, rate de-matching, decoding and the like on the signal to obtain a code block.

In order to obtain higher signal quality and decoding performance, the receiving end needs to eliminate the error caused by the carrier frequency offset as much as possible when receiving the signal. The estimation algorithm of the integer multiple frequency offset and the decimal frequency offset can compensate a part of carrier frequency offset, but some carrier frequency offsets are not compensated, namely residual frequency offsets. In general, the residual frequency offset is between tens and hundreds of hertz (Hz), which causes a large angular rotation of the constellation diagram during demodulation, affecting the decoding performance.

Disclosure of Invention

The application provides a residual frequency offset determination method, a residual frequency offset determination device, a chip and module equipment, which can accurately determine the residual frequency offset so as to improve the decoding performance.

In a first aspect, the present application provides a method for determining residual frequency offset, which may include: acquiring a constellation diagram corresponding to an Nth Physical Downlink Shared Channel (PDSCH) according to a modulation mode, wherein N is a positive integer; determining a reference constellation point from a constellation diagram corresponding to the Nth PDSCH, and determining a reference phase offset according to the reference constellation point; determining a residual frequency offset corresponding to the nth PDSCH according to the reference phase offset and the reference time difference, wherein the reference time difference is a time difference between a symbol corresponding to a target demodulation reference signal (DMRS) and a symbol corresponding to the nth PDSCH, and the target DMRS is the DMRS corresponding to the nth PDSCH; and compensating a symbol corresponding to the Nth PDSCH according to the residual frequency offset corresponding to the Nth PDSCH.

By the method described in the first aspect, the residual frequency offset corresponding to the nth PDSCH can be accurately determined, thereby improving the decoding performance.

In one possible implementation, determining a reference constellation point from a constellation corresponding to the nth PDSCH includes:

and rotating the constellation point in the constellation diagram corresponding to the Nth PDSCH according to a preset angle, and determining the rotated constellation point which does not cross the quadrant as a reference constellation point.

In one possible implementation, determining a reference constellation point from a constellation corresponding to the nth PDSCH includes:

the modulation mode is Quadrature Phase Shift Keying (QPSK), and a reference constellation point is determined from a constellation diagram corresponding to the nth PDSCH according to the first circle; the reference constellation point is an out-of-circle constellation point of a first circle, the radius of the first circle is a first radius, and the center of the first circle is the center of a constellation diagram corresponding to the nth PDSCH;

or, the modulation mode is quadrature phase shift keying QPSK, and all constellation points in a constellation diagram corresponding to the nth PDSCH are determined as reference constellation points.

In one possible implementation, determining a reference constellation point from a constellation corresponding to the nth PDSCH includes:

the modulation mode is Quadrature Amplitude Modulation (QAM), and a reference constellation point is determined from a constellation diagram corresponding to the nth PDSCH according to the second circle; the reference constellation point is an out-of-circle constellation point of a second circle, the radius of the second circle is a second radius, and the center of the second circle is the center of a constellation diagram corresponding to the nth PDSCH.

In a possible implementation manner, a second radius corresponding to the first binary QAM is different from a second radius corresponding to the second binary QAM, and the second radius corresponding to the first binary QAM is smaller than the second radius corresponding to the second binary QAM; the first bin is less than the second bin.

In a possible implementation manner, determining a residual frequency offset corresponding to the nth PDSCH according to the reference phase offset and the reference time difference includes:

and calculating the residual frequency offset corresponding to the Nth PDSCH according to the quotient of the reference time difference removed by the reference phase offset.

In a possible implementation manner, the method further includes: and adjusting the residual frequency offset corresponding to the target DMRS to a preset value.

In a second aspect, the present application provides a communication device, including a processing unit, configured to obtain a constellation diagram corresponding to an nth PDSCH according to a modulation scheme, where N is a positive integer; determining a reference constellation point from a constellation diagram corresponding to the Nth PDSCH, and determining a reference phase offset according to the reference constellation point; determining a residual frequency offset corresponding to the Nth PDSCH according to the reference phase offset and the reference time difference, wherein the reference time difference is a time difference between a symbol corresponding to a target DMRS and a symbol corresponding to the Nth PDSCH, and the target DMRS is a DMRS corresponding to the Nth PDSCH; and adjusting a constellation diagram corresponding to the Nth PDSCH according to the residual frequency offset corresponding to the Nth PDSCH.

In a third aspect, the present application provides a communication device comprising a processor, a memory, and a transceiver for receiving signals or transmitting signals; the memory for storing program code; the processor is configured to acquire a constellation diagram corresponding to an nth PDSCH according to a modulation mode, where N is a positive integer; determining a reference constellation point from a constellation diagram corresponding to the Nth PDSCH, and determining a reference phase offset according to the reference constellation point; determining a residual frequency offset corresponding to the Nth PDSCH according to the reference phase offset and the reference time difference, wherein the reference time difference is a time difference between a symbol corresponding to a target DMRS and a symbol corresponding to the Nth PDSCH, and the target DMRS is a DMRS corresponding to the Nth PDSCH; and compensating a symbol corresponding to the Nth PDSCH according to the residual frequency offset corresponding to the Nth PDSCH.

In a fourth aspect, the present application provides a chip, where the chip is configured to obtain a constellation diagram corresponding to an nth PDSCH according to a modulation method, where N is a positive integer; determining a reference constellation point from a constellation diagram corresponding to the Nth PDSCH, and determining a reference phase offset according to the reference constellation point; determining a residual frequency offset corresponding to the Nth PDSCH according to the reference phase offset and the reference time difference, wherein the reference time difference is a time difference between a symbol corresponding to a target DMRS and a symbol corresponding to the Nth PDSCH, and the target DMRS is a DMRS corresponding to the Nth PDSCH; and compensating a symbol corresponding to the Nth PDSCH according to the residual frequency offset corresponding to the Nth PDSCH.

In a fifth aspect, the present application provides a module device, which includes a communication module, a power module, a storage module, and a chip module, wherein: the power module is used for providing electric energy for the module equipment; the storage module is used for storing data and instructions; the communication module is used for carrying out internal communication of the module equipment or is used for carrying out communication between the module equipment and external equipment; this chip module is used for: acquiring a constellation diagram corresponding to the Nth PDSCH according to a modulation mode, wherein N is a positive integer; determining a reference constellation point from a constellation diagram corresponding to the Nth PDSCH, and determining a reference phase offset according to the reference constellation point; determining a residual frequency offset corresponding to the Nth PDSCH according to the reference phase offset and the reference time difference, wherein the reference time difference is a time difference between a symbol corresponding to a target DMRS and a symbol corresponding to the Nth PDSCH, and the target DMRS is a DMRS corresponding to the Nth PDSCH; and compensating a symbol corresponding to the Nth PDSCH according to the residual frequency offset corresponding to the Nth PDSCH.

In a sixth aspect, the present application provides a computer-readable storage medium having stored thereon computer-readable instructions that, when run on a communication device, cause the communication device to perform the method of the first aspect and any of its possible implementations.

In a seventh aspect, the present application provides a computer program or computer program product comprising code or instructions which, when run on a computer, cause the computer to perform the method as in the first aspect and any one of its possible implementations.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for a person skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic diagram of a scenario of a communication system;

fig. 2 is a flowchart of a signal reception process of a physical layer;

FIG. 3-1 is a constellation diagram for QPSK;

fig. 3-2 is a constellation diagram of 16QAM, 64QAM, and 256 QAM;

fig. 4 is a constellation diagram obtained by demodulation using QPSK;

FIG. 5 is a schematic diagram of a rotation of a constellation point;

fig. 6 is a flowchart illustrating a method for determining residual frequency offset according to an embodiment of the present application;

fig. 7 is an exemplary diagram of a relation between a target DMRS and a PDSCH in a time domain;

fig. 8-1 is a schematic diagram of determining reference constellation points for QPSK provided by an embodiment of the present application;

fig. 8-2 is a schematic diagram of determining reference constellation points for 16QAM according to an embodiment of the present disclosure;

fig. 8-3 is a schematic diagram of determining reference constellation points for 64QAM according to an embodiment of the present disclosure;

fig. 8-4 are schematic diagrams of determining reference constellation points for 256QAM according to embodiments of the present application;

fig. 9 is an adjusted constellation diagram for QPSK provided by an embodiment of the present application;

fig. 10 is a schematic structural diagram of a communication device according to an embodiment of the present application;

fig. 11 is a schematic structural diagram of another communication device provided in an embodiment of the present application;

fig. 12 is a schematic structural diagram of a module apparatus according to an embodiment of the present application.

Detailed Description

The terminology used in the following embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used in the specification of the present application and the appended claims, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the listed items.

It should be noted that the terms "first," "second," "third," and the like in the description and claims of the present application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in other sequences than described or illustrated herein. Furthermore, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or server that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The embodiment of the present application can be applied to a fifth generation (5th generation, 5G) system, which can also be referred to as an NR system; or may also be applied to a sixth generation (6th generation, 6G) system, or a seventh generation (7th generation, 7G) system, or other future communication systems; or may also be used for device to device (D2D) systems, machine to machine (M2M) systems, Long Term Evolution (LTE) systems, and so on.

For example, but not limited to, the method provided by the embodiment of the present application may be applied to a communication system as shown in fig. 1. Fig. 1 is a schematic diagram of a scenario of a communication system. The communication system may include, but is not limited to: one or more network devices (e.g., network device 101), and one or more terminal devices (e.g., terminal device 102). The number and configuration of the devices shown in fig. 1 are for example and not intended to limit the embodiments of the present application.

In the embodiment of the present application, the terminal device may include but is not limited to: user Equipment (UE), access terminal, subscriber unit, subscriber station, mobile station, remote terminal, mobile device, user terminal, user agent, or user device, etc. For another example, the terminal device may be a mobile phone, a tablet computer, a computer with a wireless transceiving function, a virtual reality terminal device, an augmented reality terminal device, a wireless terminal in industrial control, a wireless terminal in unmanned driving, a wireless terminal in telemedicine, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, a wireless terminal in an internet of vehicles, and the like.

In the embodiment of the present application, the network device may include, but is not limited to: an evolved Node B (eNB), a Radio Network Controller (RNC), a Node B (NB), a network equipment controller (BSC), a network equipment transceiver station (BTS), a home network equipment (e.g., home evolved Node B, or home Node B, HNB), a baseband unit (BBU), an Access Point (AP) in a wireless fidelity (WIFI) system, a wireless relay Node, a wireless backhaul Node, a transceiver Node (TRP), a transmission point (TP, TP), and the like; it may also be a device used in 5G, 6G or even 7G systems, such as a gNB in NR systems, or a transmission point (TRP or TP).

In the embodiment of the application, the network equipment sends the signal processed by the physical layer to the terminal equipment or other network equipment through the antenna port of the network equipment; the terminal equipment receives signals through an antenna port of the terminal equipment and performs physical layer processing on the signals. The process of the terminal device performing physical layer processing on the signal can be seen in fig. 2. Fig. 2 includes received signals, time-frequency transformation, demapping, channel estimation, channel equalization, demodulation, descrambling, de-rate matching, and decoding. Receiving a signal refers to receiving a signal transmitted by a network device through an antenna port. Time-frequency transformation refers to transforming a signal from the time domain to the frequency domain. Demapping refers to demapping of resources, which corresponds to resource mapping on the network device side. The channel estimation can be realized through the DMRS, the residual frequency offset corresponding to the DMRS can be adjusted to be 0 through the channel estimation, and the phase error of the DMRS is 0 through the channel estimation. Channel equalization, which may also be referred to as multiple-input multiple-output (MIMO) equalization, corresponds to layer mapping on the network device side. The demodulation corresponds to the modulation on the network equipment side, the network equipment adopts a certain modulation mode for modulation, and the terminal equipment adopts the same modulation mode for demodulation. Descrambling, rate de-matching and decoding respectively correspond to scrambling, rate matching and channel coding at the network equipment side.

The residual frequency offset determining method provided by the application can be applied to the demodulation process shown in fig. 2, and can accurately determine the residual frequency offset corresponding to the PDSCH, so as to perform compensation and improve the decoding performance.

First, some terms referred to in the embodiments of the present application are explained to facilitate understanding by those skilled in the art.

(1) Residual frequency offset (residual frequency offset)

OFDM is very sensitive to carrier frequency offset, and the carrier frequency offset caused by the doppler effect of the channel and the difference between the crystal oscillators at the transmitting and receiving ends destroys the orthogonality between the subcarriers, resulting in inter-carrier interference (ICI). The estimation algorithm using the integer frequency offset and the decimal frequency offset may compensate a part of the carrier frequency offset, but some carrier frequency offsets are not compensated, and the part of the frequency offsets that are not compensated may be referred to as residual frequency offset or system frequency offset error. In general, the residual frequency offset is between tens and hundreds of hertz, which causes a large angular rotation of the constellation diagram during demodulation, thereby affecting the decoding performance. By adopting the embodiment of the application, the residual frequency offset of the PDSCH can be accurately determined and compensated, so that the constellation diagram is adjusted to an expected position, and the decoding performance is improved.

(2) Modulation system

The modulation schemes referred to in the present application include QPSK, 16QAM (i.e., 16QAM), 64QAM (i.e., 64QAM), and 256QAM (i.e., 256QAM), which are used for example and do not constitute a limitation to the embodiments of the present application.

QPSK, also known as four-phase absolute phase shift modulation, uses four different phases of a carrier to represent digital bits. Specifically, the phase π/4 represents 00, the phase 3 π/4 represents 01, the phase 5 π/4 represents 11, and the phase 7 π/4 represents 10. The constellation of QPSK can be seen in fig. 3-1.

QAM represents different digital bits in terms of the amplitude and phase of the carrier. 16QAM, which represents 16 combinations by 4 bits; 64QAM, which represents 64 combinations by 6 bits; 256QAM, 16 combinations are represented by 8 bits. The constellations of 16QAM, 64QAM, and 256QAM may be as described with reference to fig. 3-2.

It can be understood that fig. 3-1 and fig. 3-2 are constellation diagrams obtained by the transmitting end using a modulation method for modulation, and due to the influence of factors such as channel interference, the constellation diagrams obtained by the receiving end using a corresponding modulation method for demodulation are not consistent with those of fig. 3-1 and fig. 3-2. Under the condition of not considering residual frequency offset, constellation points in a constellation diagram obtained by demodulation are distributed near the constellation points shown in the figure 3-1 or the figure 3-2; under the condition of considering the residual frequency offset, a constellation point in a constellation diagram obtained by demodulation may have a frequency offset of a certain angle, taking QPSK as an example, as shown in fig. 4.

(3) Cross-quadrant and non-cross-quadrant

For a constellation point, after the constellation point is rotated by a certain angle, the rotated constellation point and the constellation point before the rotation are located in the same quadrant, and the rotated constellation point can be considered not to cross the quadrant, otherwise, the rotated constellation point is considered to cross the quadrant. The cross-quadrant may also be referred to as an over-quadrant. The rotation refers to rotation at the center of the constellation diagram, i.e., the center of the coordinate point (0,0), and the rotation direction may be clockwise or counterclockwise. The constellation points rotated clockwise and/or counterclockwise are positioned in the same quadrant as the constellation points rotated by money, and can be considered to be not across the quadrant. See, for example, fig. 5. In fig. 5, after a constellation point is rotated clockwise by a certain angle, the constellation point is rotated from a position a to a position B, both the position a and the position B are located in a first quadrant, and it can be considered that the constellation point does not cross the quadrants after being rotated by the certain angle; if a is in the first quadrant and B is in the second quadrant, the constellation point can be considered to cross the quadrants after rotating by the angle.

In the embodiment of the present application, the constellation point may be rotated by a preset angle, the preset angle may be 45 ° for example, and a specific value of the preset angle may be set by a protocol convention or by a terminal device. For the constellation points which do not cross the quadrant after rotating the preset angle, the constellation points are called as reference constellation points in the application. The phase of the reference constellation point may be considered authentic and may be used to calculate the residual frequency offset.

Please refer to fig. 6, which is a flowchart illustrating a method for determining residual frequency offset according to an embodiment of the present application, where the method includes, but is not limited to, the following steps:

s101, the network equipment sends PDSCH to the terminal equipment. Accordingly, the terminal device receives the PDSCH from the network device.

The network device sends PDSCH to the terminal device, which may also be described as the network device sending data to the terminal device. When the network equipment transmits data, the DMRS is also transmitted, so that the terminal equipment can use the DMRS for channel estimation. With the number of DMRSs for data transmission being one or more, in this embodiment of the application, one DMRS is taken as an example, and the DMRS is referred to as a target DMRS, that is, a DMRS corresponding to a PDSCH.

When receiving data through the antenna port, the terminal device performs time-frequency transformation, demapping, channel estimation and channel equalization processing on the data in sequence to obtain data to be demodulated. After the channel estimation processing, the residual frequency offset corresponding to the target DMRS may be compensated, that is, the channel estimation may adjust the residual frequency offset corresponding to the target DMRS to a preset value, for example, the preset value is 0 or within a frequency offset range acceptable to the system, and the specific value may be agreed by a protocol. The residual frequency offset corresponding to the target DMRS is a preset value, which is the basis for implementing steps S102 to S105. If the residual frequency offset corresponding to the target DMRS cannot be adjusted to a preset value, the residual frequency offset corresponding to the target DMRS needs to be considered when calculating the residual frequency offset corresponding to the PDSCH, for example, when determining the reference phase offset, the residual frequency offset corresponding to the target DMRS is added or subtracted on the basis of the average value of the phases of the reference constellation points.

Optionally, the terminal device may determine, according to the high-level parameter sent by the network device, the time-frequency resource occupied by the target DMRS and the time-frequency resource occupied by the PDSCH, so as to receive the target DMRS and the PDSCH from the time-frequency resources.

For an example, the relation between the target DMRS and the PDSCH in the time domain may be as shown in fig. 7. Fig. 7 illustrates that a slot includes 14 symbols (or OFDM symbols), a target DMRS occupies the 3 rd symbol, a PDSCH occupies the 4 th to 6th symbols, and one PDSCH occupies one symbol. In the embodiment of the present application, a symbol occupied by the target DMRS is referred to as a symbol corresponding to the target DMRS, and a symbol occupied by one PDSCH is referred to as a symbol corresponding to the PDSCH. In fig. 7, the PDSCH corresponding to the 4 th symbol is referred to as the 1 st PDSCH, the PDSCH corresponding to the 5th symbol is referred to as the 2 nd PDSCH, the PDSCH corresponding to the 6th symbol is referred to as the 3 rd PDSCH, and the DMRSs corresponding to the three PDSCHs are all DMRSs corresponding to the 3 rd symbol. According to the relation between the target DMRS and the PDSCH in the time domain, the time difference between each PDSCH and the target DMRS may be determined, for example, the time difference between the 2 nd PDSCH and the target DMRS is 2 symbols.

And S102, the terminal equipment acquires a constellation diagram corresponding to the Nth PDSCH according to the modulation mode. Wherein N is a positive integer.

The terminal device demodulates the data to be demodulated according to the modulation mode, and can obtain the constellation diagram corresponding to each PDSCH. The modulation scheme may be determined according to a Modulation and Coding Scheme (MCS). The modulation mode is the same as the modulation mode adopted by the network equipment, and the network equipment can inform the terminal equipment of which modulation mode is adopted, or the protocol appoints which modulation mode is adopted by the terminal equipment and the network equipment. The nth PDSCH is any PDSCH, for example, in fig. 7, N is a positive integer greater than or equal to 1 and less than or equal to 3.

Optionally, before obtaining the constellation corresponding to each PDSCH, an estimation algorithm of integer frequency offset and decimal frequency offset may be used to estimate and compensate the frequency offset, and a residual frequency offset of several tens to several hundreds of hertz still exists after compensation.

The modulation method takes QPSK as an example, and a constellation diagram corresponding to the nth PDSCH can be seen in fig. 4, where a certain residual frequency offset exists.

And S103, the terminal equipment determines a reference constellation point from a constellation diagram corresponding to the Nth PDSCH and determines a reference phase offset according to the reference constellation point.

The reference constellation points are used for calculating reference phase offsets, the number of the reference constellation points may be multiple, and the reference phase offset is an average value of phases of the multiple reference constellation points.

In a possible implementation manner, the terminal device rotates all constellation points in a constellation diagram corresponding to the nth PDSCH according to a preset angle, compares the constellation diagram before rotation with the constellation diagram after rotation, and determines constellation points that do not cross the quadrant after rotation as reference constellation points. The calculated amount is slightly large, but the obtained reference constellation point is more accurate, so that the reference phase offset is more accurate, and the residual frequency offset compensation precision is higher.

In another possible implementation manner, the terminal device draws a circle in the constellation diagram corresponding to the nth PDSCH according to the modulation manner, the center of the circle is the center of the constellation diagram corresponding to the nth PDSCH, the constellation point outside the circle is the reference constellation point, the constellation point inside the circle crosses over the quadrant after rotating by a preset angle, and the calculation result of the phase is affected, so that the calculation result is not considered. The radius of the circle is different for different modulation modes, and the larger the order of the MCS is, the larger the radius of the circle is. The method has the advantages of small calculation amount and high calculation speed.

For QPSK, the terminal device determines a reference constellation point from a constellation diagram corresponding to the nth PDSCH according to a first circle, where the reference constellation point is an out-of-circle constellation point of the first circle, and the radius of the first circle is a first radius, and the first radius is, for example, 1. The first circle can be referred to as a circle shown by a dotted line in fig. 8-1, the constellation points outside the dotted line are reference constellation points, and the average value of the phases of the plurality of reference constellation points is the reference phase offset. Because the constellation points in the constellation diagram corresponding to the QPSK do not cross the quadrant after rotating by the preset angle, all constellation points in the constellation diagram corresponding to the nth PDSCH may be used as reference constellation points, and the average value of the phases of all constellation points is used as reference phase offset.

For QAM, the terminal device determines a reference constellation point from the constellation diagram corresponding to the nth PDSCH according to the second circle, where the reference constellation point is an out-of-circle constellation point of the second circle, and the radius of the second circle is the second radius. The second radius is related to the carry number of the QAM. The second radiuses corresponding to the QAMs in different systems are different, and the larger the system number is, the larger the second radius is. For example, in the constellation diagram corresponding to 16QAM, the second circle can be referred to as the circle shown by the dotted line in fig. 8-2, and the second radius is 1.2; in the constellation diagram corresponding to 64QAM, the second circle can refer to the circle shown by the dotted line in fig. 8-3, and the second radius is 1.4; in the constellation diagram corresponding to 256QAM, the second circle can be referred to as the circle shown by the dotted line in fig. 8-4, and the second radius is 1.5.

The constellation points on the second circle are not used as reference constellation points, and the constellation points on the circle are prevented from crossing quadrants after being rotated by a preset angle.

It should be noted that the above manner of determining the reference constellation point by drawing a circle is used for example, and does not constitute a limitation to the embodiment of the present application, and for example, the reference constellation point may also be determined by drawing a square or a rectangle.

It is understood that the values of the first radius and the second radius are normalized amplitude values.

And S104, the terminal equipment determines the residual frequency offset corresponding to the Nth PDSCH according to the reference phase offset and the reference time difference.

In a possible implementation manner, the terminal device calculates the residual frequency offset corresponding to the nth PDSCH according to the quotient of the reference time difference removed by the reference phase offset removal. For example, the residual frequency offset corresponding to the nth PDSCH can be calculated according to the reference phase offset removal quotient obtained by the reference time difference and the calculation formula.

Wherein, the calculation formula can be:af denotes a residual frequency offset corresponding to the nth PDSCH,representing a reference phase offset, at represents a reference time difference,indicating the removal of the reference phase offset to reference the time difference. The reference time difference is the time difference between the symbol corresponding to the target DMRS and the symbol corresponding to the Nth DMRS, for example, the symbol corresponding to the target DMRS and the 2 nd DMThe time difference between the symbols corresponding to the RS is 2 symbols, i.e. the reference time difference is 2 symbols. The calculation formula is used for example and does not constitute a limitation on the embodiments of the present application.

And S105, the terminal equipment compensates the symbol corresponding to the Nth PDSCH according to the residual frequency offset corresponding to the Nth PDSCH.

And under the condition of calculating the residual frequency offset corresponding to the Nth PDSCH, the terminal equipment compensates the symbol corresponding to the Nth PDSCH according to the residual frequency offset. And compensating the symbol corresponding to the nth PDSCH, namely supplementing residual frequency offset, so that the frequency offset of the symbol corresponding to the nth PDSCH is 0 or within an acceptable range. For example, the residual frequency offset corresponding to the nth PDSCH is 30Hz, and the frequency offset of the 30Hz is compensated, so that the frequency offset of the symbol corresponding to the nth PDSCH is 0. After the compensation, the constellation corresponding to the nth PDSCH is also changed correspondingly, taking QPSK as an example, the constellation after compensating the residual frequency offset can be seen in fig. 9, and compared with fig. 3-1, fig. 9 has no residual frequency offset or the residual frequency offset is within an acceptable range.

And compensating the residual frequency offset corresponding to each PDSCH according to the steps S102 to S105 so as to improve the decoding performance.

In the embodiment shown in fig. 6, the residual frequency offset is calculated by determining the reference constellation point in the constellation diagram, so that the accuracy of the residual frequency offset can be improved, and the decoding performance can be improved.

The embodiment shown in fig. 6 takes the determination of the residual frequency offset corresponding to the PDSCH as an example, and for the residual frequency offset corresponding to the PUSCH, reference may be made to the embodiment shown in fig. 6.

In the embodiment shown in fig. 6, the terminal device determines the residual frequency offset corresponding to the nth PDSCH according to the reference phase offset and the reference time difference of the reference constellation point, and in another optional embodiment, the terminal device calculates the frequency offset (i.e., the frequency offset is equal to the phase/the reference time difference) corresponding to each reference constellation point according to the phase and the reference time difference of each reference constellation point in the constellation diagram corresponding to the nth PDSCH, accumulates the frequency offsets corresponding to each reference constellation point, and calculates an average value, where the average value is the residual frequency offset corresponding to the nth PDSCH. In yet another alternative embodiment, the terminal device selects a part of reference constellation points (e.g., reference constellation points in the first quadrant and the second quadrant) from the multiple reference constellation points, uses an average value of phases of the part of reference constellation points as a reference phase offset, and determines a residual frequency offset corresponding to the nth PDSCH according to the reference phase offset and the reference time difference.

Referring to fig. 10, fig. 10 is a schematic structural diagram of a communication device according to an embodiment of the present application. The communication device 40 shown in fig. 10 may be used to perform part or all of the functions of the terminal device in fig. 6 described above. The device may be a terminal device, or a device in the terminal device, or a device capable of being used in cooperation with the terminal device. Wherein, the communication device can also be a chip system. The communication device 40 shown in fig. 10 may include a communication unit 401 and a processing unit 402. The processing unit 402 is configured to perform data processing. A communication unit 401, configured to communicate with other devices. The communication unit 401 integrates a receiving unit and a transmitting unit. The communication unit 401 may also be referred to as a transceiving unit. Alternatively, communication section 401 may be divided into a reception section and a transmission section.

The processing unit 402 is configured to obtain a constellation diagram corresponding to an nth PDSCH according to a modulation mode, where N is a positive integer; determining a reference constellation point from a constellation diagram corresponding to the Nth PDSCH, and determining a reference phase offset according to the reference constellation point; determining a residual frequency offset corresponding to the Nth PDSCH according to the reference phase offset and the reference time difference, wherein the reference time difference is a time difference between a symbol corresponding to a target DMRS and a symbol corresponding to the Nth PDSCH, and the target DMRS is a DMRS corresponding to the Nth PDSCH; and adjusting a constellation diagram corresponding to the Nth PDSCH according to the residual frequency offset corresponding to the Nth PDSCH.

In a possible implementation manner, the processing unit 402 is specifically configured to rotate a constellation point in a constellation diagram corresponding to the nth PDSCH according to a preset angle, and determine a constellation point that does not cross a quadrant after the rotation as a reference constellation point.

In a possible implementation manner, the processing unit 402 is specifically configured to determine a reference constellation point from a constellation diagram corresponding to an nth PDSCH according to a first circle, where the modulation manner is QPSK; the reference constellation point is an out-of-circle constellation point of a first circle, the radius of the first circle is a first radius, and the center of the first circle is the center of a constellation diagram corresponding to the nth PDSCH; or, the modulation mode is quadrature phase shift keying QPSK, and all constellation points in a constellation diagram corresponding to the nth PDSCH are determined as reference constellation points.

In a possible implementation manner, the processing unit 402 is specifically configured to determine a reference constellation point from a constellation diagram corresponding to the nth PDSCH according to a second circle, where the modulation manner is quadrature amplitude modulation QAM; the reference constellation point is an out-of-circle constellation point of a second circle, the radius of the second circle is a second radius, and the center of the second circle is the center of a constellation diagram corresponding to the nth PDSCH.

In a possible implementation manner, a second radius corresponding to the first binary QAM is different from a second radius corresponding to the second binary QAM, and the second radius corresponding to the first binary QAM is smaller than the second radius corresponding to the second binary QAM; the first bin is less than the second bin.

In a possible implementation manner, the processing unit 402 is specifically configured to calculate a residual frequency offset corresponding to the nth PDSCH according to the quotient of the reference time difference removed by the reference phase offset.

In a possible implementation manner, the processing unit 402 is further configured to adjust a residual frequency offset corresponding to the target DMRS to a preset value.

Fig. 11 shows a communication apparatus 50 according to an embodiment of the present application, which is used for implementing the functions of the terminal device. The apparatus may be a terminal device or an apparatus for a terminal device. The means for the terminal device may be a system of chips or a chip within the terminal device. The chip system may be composed of a chip, or may include a chip and other discrete devices.

The communication device 50 includes at least one processor 520, which is configured to implement the data processing function of the terminal device in the method provided by the embodiment of the present application. The apparatus 50 may further include a communication interface 510 for implementing transceiving operations of the terminal device in the method provided by the embodiment of the present application. In embodiments of the present application, the communication interface may be a transceiver, circuit, bus, module, or other type of communication interface for communicating with other devices over a transmission medium. For example, the communication interface 510 is used for devices in the apparatus 50 to communicate with other devices. The processor 520 utilizes the communication interface 510 to transmit and receive data and is configured to implement the method described in the method embodiment above with respect to fig. 2.

The apparatus 50 may also include at least one memory 530 for storing program instructions and/or data. The memory 530 is coupled to the processor 520. The coupling in the embodiments of the present application is an indirect coupling or a communication connection between devices, units or modules, and may be an electrical, mechanical or other form for information interaction between the devices, units or modules. The processor 520 may operate in conjunction with the memory 530. Processor 520 may execute program instructions stored in memory 530. At least one of the at least one memory may be included in the processor.

When the device 50 is powered on, the processor 520 can read the software program in the memory 530, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be sent wirelessly, the processor 520 outputs a baseband signal to the radio frequency circuit after performing baseband processing on the data to be sent, and the radio frequency circuit performs radio frequency processing on the baseband signal and sends the radio frequency signal to the outside in the form of electromagnetic waves through the antenna. When data is transmitted to the apparatus 50, the rf circuit receives an rf signal through the antenna, converts the rf signal into a baseband signal, and outputs the baseband signal to the processor 520, and the processor 520 converts the baseband signal into data and processes the data.

In another implementation, the rf circuitry and antennas may be provided independently of the processor 520 performing baseband processing, for example in a distributed scenario, the rf circuitry and antennas may be in a remote arrangement independent of the communication device.

The specific connection medium among the communication interface 510, the processor 520, and the memory 530 is not limited in the embodiments of the present application. In the embodiment of the present application, the memory 530, the processor 520, and the communication interface 510 are connected by a bus 540 in fig. 11, the bus is represented by a thick line in fig. 11, and the connection manner between other components is merely illustrative and is not limited thereto. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one thick line is shown in FIG. 11, but this is not intended to represent only one bus or type of bus.

When the apparatus 50 is specifically for a terminal device, for example, when the apparatus 50 is specifically a chip or a chip system, the output or the reception of the communication interface 510 may be a baseband signal. When the apparatus 50 is a terminal device, the communication interface 510 may output or receive a radio frequency signal. In the embodiments of the present application, the processor may be a general-purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, and may implement or execute the methods, operations, and logic blocks disclosed in the embodiments of the present application. A general purpose processor may be a microprocessor or any conventional processor or the like. The operations of the methods disclosed in connection with the embodiments of the present application may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in a processor.

As shown in fig. 12, fig. 12 is a schematic structural diagram of a module device according to an embodiment of the present application. The module device 60 can perform the steps related to the terminal device in the foregoing method embodiments, and the module device 60 includes: a communication module 601, a power module 602, a memory module 603 and a chip module 604.

The power module 602 is configured to provide power for the module device; the storage module 603 is used for storing data and instructions; the communication module 601 is used for performing module device internal communication, or for performing module device and external device communication.

The chip module 604 is configured to obtain a constellation diagram corresponding to an nth PDSCH according to a modulation method, where N is a positive integer; determining a reference constellation point from a constellation diagram corresponding to the Nth PDSCH, and determining a reference phase offset according to the reference constellation point; determining a residual frequency offset corresponding to the Nth PDSCH according to the reference phase offset and the reference time difference, wherein the reference time difference is a time difference between a symbol corresponding to a target DMRS and a symbol corresponding to the Nth PDSCH, and the target DMRS is a DMRS corresponding to the Nth PDSCH; and compensating a symbol corresponding to the Nth PDSCH according to the residual frequency offset corresponding to the Nth PDSCH.

Embodiments of the present application further provide a computer-readable storage medium, in which instructions are stored, and when the computer-readable storage medium is executed on a processor, the method flow of the above method embodiments is implemented.

Embodiments of the present application further provide a computer program product, where when the computer program product runs on a processor, the method flow of the above method embodiments is implemented.

It is noted that, for simplicity of explanation, the foregoing method embodiments are described as a series of acts or combination of acts, but those skilled in the art will appreciate that the present application is not limited by the order of acts, as some acts may, in accordance with the present application, occur in other orders and/or concurrently. Further, those skilled in the art should also appreciate that the embodiments described in the specification are preferred embodiments and that the acts and modules referred to are not necessarily required in this application.

The descriptions of the embodiments provided in the present application may be referred to each other, and the descriptions of the embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments. For convenience and brevity of description, for example, the functions and operations performed by the devices and apparatuses provided in the embodiments of the present application may refer to the related descriptions of the method embodiments of the present application, and may also be referred to, combined with or cited among the method embodiments and the device embodiments.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.