PILOT PROCESSING METHOD AND RELATED DEVICE

TECHNICAL FIELD

This application relates to the field of communication technologies, and in particular, to a pilot processing method and a related device.

BACKGROUND

In a complex environment for electromagnetic wave transmission, due to a lot of scattering, reflecting, and refracting surfaces, radio signals reach at an antenna by different paths at different moments, that is, the multipath effect of transmission. When a prior symbol and a subsequent symbol of a sent signal reach at a same time by different paths, or, when a subsequent symbol reaches within a delay spread of a prior symbol, Inter Symbol Interference (ISI) is caused. Similarly, over the frequency domain, because of the Doppler effect caused by a relative speed between transmit and receive ends, each subcarrier carrying a signal has a different degree of frequency shift, leading to a loss of orthogonality of the subcarrier and overlapping, that is, Inter Carrier Interference (ICI) is caused. In the communication technologies, an Orthogonal Frequency Division Multiplex (OFDM) multi-carrier system may be used, with an additional design of Cyclic Prefix (CP), to improve the anti-ISI performance. However, a width of a subcarrier spacing in the OFDM multi-carrier system is limited. As a result, in a scenario with high-speed moving (for example, on a high-speed train), a relatively large Doppler frequency shift due to a relatively high relative speed between transmit and receive ends impairs the orthogonality of OFDM subcarriers, leading to severe ICI between the subcarriers.

In the communication technologies, the technique of Orthogonal Time Frequency Space (OTFS) may alternatively be used. The OTFS technique defines a transform from the delay-Doppler domain to the time-frequency domain. By service data and pilot mapping at both transmit and receive ends to the delay-Doppler domain, by using the pilot in the delay-Doppler domain, a delay and a Doppler characteristic of a channel are captured. In addition, by setting a guard interval, pilot pollution caused by ICI in an OFDM system is prevented, thereby bringing in more accurate channel estimation and helping improve a success rate of data decoding of a receiver.

In the OTFS technique, a pilot symbol in the delay-Doppler domain needs a guard interval around, but setting a too large guard interval causes a waste of resources, while setting a too small guard interval cannot prevent pilot pollution.

SUMMARY

Embodiments of this application provide a pilot processing method and a related device.

A first aspect provides a pilot processing method, performed by a sending device, and including:

receiving feedback information, where the feedback information is feedback information that is sent by a receiving device based on a first pilot received based on a first pilot pattern; and

determining, based on the feedback information, whether to update the first pilot pattern.

A second aspect provides a pilot processing method, performed by a sending device, and including:

receiving a measurement pilot; and

determining, based on a measurement result of the measurement pilot, whether to update a pilot pattern.

A third aspect provides a pilot processing method, performed by a receiving device, and including:

receiving, based on a first pilot pattern, a first pilot sent by a sending device; and

sending feedback information based on the first pilot, where the feedback information is used to determine whether to update the first pilot pattern.

A fourth aspect provides a pilot processing method, performed by a receiving device, and including:

sending a measurement pilot, where the measurement pilot is used to determine whether to update a pilot pattern.

A fifth aspect provides a pilot processing apparatus, including:

a first transceiving module, configured to receive feedback information, where the feedback information is feedback information that is sent by a receiving device based on a first pilot received based on a first pilot pattern; and

a first determining module, configured to determine, based on the feedback information, whether to update the first pilot pattern.

A sixth aspect provides a pilot processing apparatus, including:

a second transceiving module, configured to receive a measurement pilot; and

a second determining module, configured to determine, based on a measurement result of the measurement pilot, whether to update a pilot pattern.

A seventh aspect provides a pilot processing apparatus, including:

a third transceiving module, configured to: receive, based on a first pilot pattern, a first pilot sent by a sending device; and send feedback information based on the first pilot, where the feedback information is used to determine whether to update the first pilot pattern.

An eighth aspect provides a pilot processing apparatus, including.

a fourth transceiving module, configured to send a measurement pilot, where the measurement pilot is used to determine whether to update a pilot pattern.

A ninth aspect provides a communication device. The communication device includes a processor, a memory, and a program or an instruction that is stored in the memory and that can be run on the processor, and when the program or the instruction is executed by the processor, the steps of the method according to the first aspect are implemented, the steps of the method according to the second aspect are implemented, the steps of the method according to the third aspect are implemented, or the steps of the method according to the fourth aspect are implemented.

A tenth aspect provides a readable storage medium. The readable storage medium stores a program or an instruction, and when the program or the instruction is executed by a processor, the steps of the method according to the first aspect are implemented, or the steps of the method according to the second aspect are implemented, or the steps of the method according to the third aspect are implemented, or the steps of the method according to the fourth aspect are implemented.

An eleventh aspect of an embodiment of this application provides a chip. The chip includes a processor and a communication interface, where the communication interface is coupled to the processor, and the processor is configured to run a program or an instruction of a network device to implement the steps of the method according to the first aspect or the second aspect, the steps of the method according to the third aspect are implemented, or the steps of the method according to the fourth aspect are implemented.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a structural diagram of a network system to which an embodiment of this application can be applied;

FIG. 2 is a schematic diagram of pilot mapping in the delay-Doppler domain;

FIG. 3 is a flowchart of a pilot processing method according to an embodiment of this application;

FIG. 4 is a flowchart of another pilot processing method according to an embodiment of this application;

FIG. 5 is a flowchart of a pilot processing method according to an embodiment of this application;

FIG. 6 is a flowchart of another pilot processing method according to an embodiment of this application;

FIG. 7 is a structural diagram of a pilot processing apparatus according to an embodiment of this application;

FIG. 8 is a structural diagram of another pilot processing apparatus according to an embodiment of this application:

FIG. 9 is a structural diagram of a pilot processing apparatus according to an embodiment of this application;

FIG. 10 is a structural diagram of another pilot processing apparatus according to an embodiment of this application;

FIG. 11 is a structural diagram of a communication device according to an embodiment of this application;

FIG. 12 is a structural diagram of a network side device according to an embodiment of this application; and

FIG. 13 is a structural diagram of a terminal device according to an embodiment of this application.

DETAILED DESCRIPTION

The following describes the embodiments of this application in conjunction with the accompanying drawings in the embodiments of this application. Apparently, the described embodiments are some but not all of the embodiments of this application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of this application shall fall within the protection scope of this application.

The terms “first,” “second,” and the like in the description and the claims of this application are used to distinguish between similar objects instead of describing a specific order or sequence. It should be understood that, data used in this way is interchangeable in proper circumstances, so that the embodiments of this application can be implemented in an order other than the order illustrated or described herein. Objects classified by “first” and “second” are usually of a same type, and the number of objects is not limited. For example, there may be one or more first objects. In addition, in the specification and the claims, “and/or” represents at least one of connected objects, and a character “/” generally represents an “or” relationship between associated objects.

It should be noted that the technology described in the embodiments of this application is not limited to a Long Term Evolution (LTE)/LTE-Advanced (LTE-A) system, and may also be used in various wireless communication systems, for example, Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single-Carrier Frequency-Division Multiple Access (SC-FDMA), and another system. The terms “system” and “network” in the embodiments of this application may be used interchangeably. The described technologies can be applied to both the systems and the radio technologies mentioned above as well as to other systems and radio technologies. A New Radio (NR) system is described below as an example, and the term, NR, is used in most of the descriptions, but these technologies can also be used in an application other than an application of the NR system, for example, a 6th Generation (6G) communication system.

FIG. 1 is a block diagram of a wireless communication system to which an embodiment of this application can be applied. The wireless communication system includes user equipment 11 and a network device 12. The user equipment 11 may also be referred to as a terminal device or User Equipment (UE). The user equipment 11 may be a terminal side device, for example, a mobile phone, a tablet personal computer, a laptop computer or notebook computer, a Personal Digital Assistant (PDA), a palmtop computer, a netbook, an Ultra-Mobile Personal Computer (UMPC), a Mobile Internet Device (MID), a wearable device or Vehicle User Equipment (VUE), or Pedestrian User Equipment (PUE). The wearable device includes a band, a headset, eyeglasses, or the like. It should be noted that a specific type of the user equipment 11 is not limited in the embodiments of this application. The network device 12 may be a base station or a core network. The base station may be referred to as a NodeB, an evolved NodeB, an access point, a Base Transceiver Station (BTS), a radio base station, a radio transceiver, a Basic Service Set (BSS), an Extended Service Set (ESS), a NodeB, an evolved NodeB (eNB), a home NodeB, a home evolved NodeB, a WLAN access point, a Wi-Fi node, a Transmission Reception Point (TRP), or another appropriate term in the art. The base station is not limited to a specified technical term. It should be noted that, in the embodiments of this application, only a base station in an NR system is used as an example, but a specific type of the base station is not limited.

For ease of description, the following describes some content in the embodiments of this application:

In an Orthogonal Time Frequency Space (OTFS) system, a transmitter maps a pilot pulse to the delay-Doppler domain, and a receiver estimates a channel response h(v, τ) in the delay-Doppler domain by analyzing a delay-Doppler image of the pilot, and obtains a channel response expression in the time-frequency domain based on a relationship shown in FIG. 3, to facilitate using a conventional technique for the time-frequency domain for signal analysis and processing. The pilot mapping over a delay-Doppler plane may be performed according to a manner shown in FIG. 2.

In FIG. 2, a single-point pilot 201 at (l_p, k_p) of a sent signal includes guard symbols 202 around covering an area of (2l_v+1)(4k_v+1)−1 and a data part covering M*N−(2l_v+1)(4k_v+1). While at a receive end, two shift peaks (for example, 2021 and 2022) appear within a guard band in a delay-Doppler domain grid, meaning that a channel has two secondary paths with different Doppler delays in addition to a primary path. Amplitudes, delays, and Doppler parameters of all secondary paths are measured to obtain a delay-Doppler domain expression of the channel, that is, h(v, τ). To prevent pilot pollution from data on lattice points of received signals, which causes inaccurate channel estimation, an area of guard symbols should satisfy the following condition:

l
_r≥τ_max=MΔf, k_v≥v_maxNΔT (1)

τ_maxand v_maxare a maximum delay and a maximum Doppler frequency shift respectively, a plurality of guard symbols 202 surrounding the single-point pilot 201 to form a guard band, and the plurality of guard symbols 202 are empty resource elements.

It should be understood that an area of the guard band is determined based on τ_maxand v_max. When l_r=τ_maxMΔf, k_v=v_maxNΔT, not only a pilot signal at a receiver side is not polluted by data, but also pilot overheads are minimized. τ_maxand v_maxdepend on a channel characteristic, and a transmit end obtaining accurate τ_maxand v_maxrelies on precise measurement of channel estimation.

The pilot processing method according to the embodiments of this application is described in detail below in conjunction with the accompanying drawings in specific embodiments and application scenarios thereof.

Refer to FIG. 3. FIG. 3 is a flowchart of a pilot processing method according to an embodiment of this application. The method is performed by a sending device, as shown in FIG. 3, and includes the following steps:

Step 301: receiving feedback information, where the feedback information is feedback information that is sent by a receiving device based on a first pilot received based on a first pilot pattern.

In this embodiment of this application, the sending device may be understood as user equipment or a network device, and the receiving device may be understood as user equipment or a network device. After the receiving device receives the first pilot sent by the sending device, the first pilot may be used for channel estimation and measurement to demodulate a data packet. The first pilot pattern may be understood as a pilot pattern currently used for transceiving a pilot.

In some implementations, the pilot pattern may be indicated by using a pilot configuration message. In some embodiments, the first pilot pattern is a rectangular resource pattern formed with l*k resource elements and includes a central resource element having a pilot pulse and empty resource elements set around the resource element having the pilot pulse. The empty resource elements set around the resource element having the pilot pulse form a guard band. As shown in FIG. 2, the first pilot pattern may be a rectangular resource pattern of 5*5 that includes resource elements corresponding to 201 and 202.

It should be understood that, after receiving the first pilot, the receiving device may send feedback information to the sending device based on the first pilot, for example, may send feedback information based on a measurement result of the first pilot, or may send feedback information based on a result of demodulating a data packet by using the first pilot. This is not further limited herein.

Step 302: determining, based on the feedback information, whether to update the first pilot pattern.

In this embodiment of this application, the sending device may determine, based on the received feedback information, whether to update the first pilot pattern, and in a case in which to update is determined, a second pilot pattern may be determined based on the feedback information. After the second pilot pattern is determined, indication information may be sent to indicate an updated second pilot pattern. After the second pilot pattern is determined, a pilot signal may further be sent based on the second pilot pattern. In a case in which not to update is determined, a pilot signal is sent subsequently still based on the first pilot pattern. In this embodiment of this application, after the step of determining, based on the feedback information, whether to update the first pilot pattern, the method further includes:

determining a second pilot pattern in a case in which the first pilot pattern is determined based on the feedback information to be updated;

sending first indication information, where the first indication information is used to indicate the second pilot pattern; and

sending a second pilot based on the second pilot pattern.

A manner of indicating the second pilot pattern by using the first indication information may be set based on actual requirements. For example, the second pilot pattern may be indicated implicitly or explicitly. In some implementations, the first indication information may be sent by using a pilot configuration message. Indicating the second pilot pattern may be understood as indicating a pilot configuration corresponding to the second pilot pattern. For example, an index value of the pilot configuration corresponding to the second pilot pattern may be carried in the first indication information.

It should be understood that, after sending the second pilot pattern, the sending device may send the second pilot based on the second pilot pattern, and the receiving device may receive the second pilot based on the second pilot pattern. In this way, a pilot pattern can be configured with flexibility for the receiving device, not only ensuring accurate estimation but also reducing a waste of resources.

According to this embodiment of this application, the feedback information is received, where the feedback information is feedback information that is sent by a receiving device based on a first pilot received based on a first pilot pattern; and whether to update the first pilot pattern is determined based on the feedback information. In this way, a pilot pattern can be updated dynamically, to not only ensure accurate estimation but also reduce a waste of resources.

This embodiment of this application further provides a pilot processing method. The method is performed by a sending device, and includes: receiving feedback information, and determining the second pilot pattern based on the feedback information, where the feedback information is determined by the receiving device based on the first pilot sent by the sending device based on the first pilot pattern. In some implementations, after the second pilot pattern is determined, the first indication information may further be sent, to indicate the second pilot pattern to the receiving device. After the second pilot pattern is determined, the second pilot may further be sent based on the second pilot pattern. In some implementations, the feedback information includes at least one of the following:

a measurement result of the first pilot within a first preset time period;

second indication information, where the second indication information is used to indicate a recommended pilot pattern, and the recommended pilot pattern is determined based on the measurement result of the first pilot;

third indication information, where the third indication information is used to indicate adjustment information of a length of each side in the first pilot pattern, and the adjustment information is determined based on the measurement result of the first pilot; and

a Hybrid Automatic Repeat reQuest (HARQ) feedback for data packet decoding based on a channel estimation result of the first pilot.

In this embodiment of this application, a time length of the first preset time period is Q*T, Q is an integer greater than 1, and T is a sending periodicity of the first pilot. By feeding back the measurement result of the first pilot within the first preset time period, too frequent feedbacks can be avoided. In some implementations, the measurement result of the first pilot includes a maximum delay (τ_max) and a maximum Doppler frequency shift (v_max) of a multipath channel. In this embodiment, measurement results of a plurality of times may be included within the first preset time period. A value of a measurement result of each time is compared with another, and a largest value of the maximum delay and a largest value of the maximum Doppler frequency shift of the multipath channel in the measurement results of the plurality of times are used as the feedback information. In some embodiments, the feedback may be performed in another manner, for example, by using an average value of all measurement results or an average value of measurement results of a plurality of times that satisfy a specific condition. This is not further limited herein.

For the second indication information, the receiving device may determine, based on the measurement result of the first pilot within the first preset time period, whether to update the first pilot pattern. In a case in which to update is determined, a recommended pilot pattern that is recommended to be updated to may be determined based on the measurement result of the first pilot within the first preset time period, and the sending device may indicate the recommended pilot pattern by using the second indication information. In this case, an index value of a pilot configuration corresponding to the recommended pilot pattern may be carried in the second indication information. The sending device may determine, based on the recommended pilot pattern, whether to update the first pilot pattern. In a case in which to update is determined, the recommended pilot pattern may be used or may not be used. If the recommended pilot pattern is not used, an index value of a pilot configuration corresponding to a re-determined pilot pattern may be carried in the second indication information; or if the recommended pilot pattern is used, identity information of the recommended pilot pattern that is agreed to be used is carried in the second indication information, or the index value of the pilot configuration corresponding to the recommended pilot pattern is directly carried. This is not further limited herein. In this embodiment, because the recommended pilot pattern is directly reported, a numerical value of the measurement result does not need to be indicated, thereby reducing bit information for reporting.

The adjustment information in the third indication information may be understood as including three cases, that is, increased, decreased, and unchanged.

For example, in some embodiments, the third indication information may directly indicate a state of a side length increase, a side length decrease, or an unchanged side length. In a case in which a side length increase is indicated, the sending device may determine that each side length may increase by a preset length according to a predefined rule; or in a case in which a side length decrease is indicated, the sending device may determine that each side length may decrease by a preset length according to a predefined rule. For example, currently, the first pilot pattern is a 5*5 rectangular resource pattern, and when the third indication information indicates an increase, the second pilot pattern may be determined to be a 6*6 rectangular resource pattern; or when the third indication information indicates a decrease, the second pilot pattern may be determined to be a 4*4 rectangular resource pattern. It should be understood that per unit of a length increase or decrease may be agreed in a protocol, or may be decided by the sending device.

In some embodiments, the third indication information may include a status identifier and an adjustment amount indication. In this case, the status identifier may be used to indicate a state of a side length increase, a side length decrease, or an unchanged side length; or may be used to indicate a state of a side length increase or a side length decrease. In this embodiment, the status identifier may be used to indicate an unchanged side length, or an unchanged side length may be indicated by the adjustment amount indication indicating 0. In a case in which a side length increase or a side length decrease is indicated, a change of increase or decrease may be indicated by using the adjustment amount indication. For example, the adjustment amount indicating M represents that a side length increases or decreases by M units of length, and per unit of length may be agreed in a protocol or may be determined by the sending device. This is not further limited herein.

In some implementations, that a group of numerical values may include an increased numerical value, a decreased numerical value, and an unchanged numerical value may be defined. The third indication information may indicate one numerical value, and the sending device may determine whether to update the first pilot pattern based on the indicated numerical value, and determine an updated second pilot pattern.

It should be understood that in this embodiment of this application, different side lengths may be indicated by using different indication information. That is, the third indication information carries indication information corresponding to each side length, or an adjustment status of two side lengths may be indicated by using same indication information, that is, adjustment information of the two side lengths is the same.

The foregoing Hybrid Automatic Repeat reQuest (HARQ) feedback may include an ACKnowledgment (ACK) feedback or a Negative ACKnowledgement (NACK) feedback. For example, in a case in which demodulation fails, the receiving device sends a NACK feedback, or in a case in which demodulation is successful, the receiving device sends an ACK feedback. In some implementations, the sending device may determine, based on a quantity of NACK feedbacks and ACK feedbacks that are received within a preset time period, whether to update the first pilot pattern, and determine the updated second pilot pattern. For example, in some embodiments, if a quantity of NACK feedbacks received within the preset time period is greater than or equal to one threshold, to update the first pilot pattern may be determined, and the sending device determines the updated second pilot pattern based on a range of the quantity of the NACK feedbacks. For example, a greater range of the quantity of the NACK feedbacks means a greater side length of the second pilot pattern.

In some implementations, before the step of receiving feedback information, the method further includes:

sending or receiving a pilot configuration message, where the pilot configuration message is used to configure the first pilot pattern.

In this embodiment, in a scenario of user equipment and user equipment interaction, the sending device may configure the first pilot pattern for the receiving device. In this case, an action of the sending device may be understood as sending a pilot configuration message. In a scenario of a network device interacting with user equipment, the network device usually configures the first pilot pattern for the user equipment. Foe an uplink pilot, an action of the sending device may be understood as receiving a pilot configuration message. For a downlink pilot, an action of the sending device may be understood as sending a pilot configuration message. An example in which the sending device sends a pilot configuration message is used for description. A table of correspondence relationship between a pilot configuration and an index value may be preconfigured or agreed in a protocol, and the sending device may send an index value via the pilot configuration message. After receiving the pilot configuration message, the receiving device may determine the first pilot pattern based on the index value in the pilot configuration message. After receiving a pilot, the receiving device may perform pilot measurement and channel estimation based on the first pilot pattern.

In some implementations, before the step of sending first indication information, the method further includes:

determining a target index value corresponding to the second pilot pattern based on a correspondence relationship between a frame structure configuration and a pilot configuration, where

the first indication information carries the target index value, and the target index value is used to indicate a target pilot configuration corresponding to the second pilot pattern.

In this embodiment, by using the correspondence relationship between the frame structure configuration and the pilot configuration, the pilot configuration corresponding to the second pilot pattern is implicitly indicated by indicating the frame structure configuration.

In some implementations, the pilot configuration includes a side length of a pilot pattern; further, the pilot pattern further includes at least one of information about a power of a resource element occupied by the pilot, pilot power information, and a pilot sending periodicity.

The side length of the pilot pattern may be determined based on a resource element occupied by a pilot in the delay-Doppler domain and a resource element occupied by a guard band in the delay-Doppler domain. The information about a power of a resource element occupied by the pilot may include an offset of the power of the resource element occupied by the pilot relative to a power of a resource element occupied by data in the delay-Doppler domain, or an absolute value of the power of the resource element occupied by the pilot.

In some implementations, the frame structure configuration includes a side length of a delay-Doppler resource block. Further, the frame structure configuration further includes at least one of a subframe length and a subcarrier spacing.

The side length of the delay-Doppler resource block may be denoted as (M, N), and the side length of the pilot pattern may be denoted as (l, k). The frame structure may be understood as a resource grid of M*N in the delay-Doppler domain.

In this embodiment, based on the correspondence relationship between the frame structure configuration and the pilot configuration, the pilot configuration corresponding to the second pilot pattern may be indicated, and a pilot configuration corresponding to the first pilot pattern may further be indicated. This is not further limited herein.

It should be understood that in this embodiment, the receiving device may indicate the second pilot pattern and the frame structure configuration by using a frame indicator message, thereby reducing signaling overheads.

In some implementations, the correspondence relationship between the frame structure configuration and the pilot configuration includes any one of the following:

a one-to-one correspondence between the frame structure configuration and the pilot configuration; and

a correspondence between each frame structure configuration and at least two different pilot configurations.

In this embodiment, the correspondence relationship between the frame structure configuration and the pilot configuration may be understood as any one of the following:

a correspondence relationship between (M, N) and (l_τ, k_v);

a correspondence relationship between (M, N) and (l_τ, k_v, the pilot power information);

a correspondence relationship between (M, N) and (l_τ, k_v, the pilot sending periodicity);

a correspondence relationship between (M, N, a subframe length) and (l_τ, k_v, the pilot sending periodicity);

a correspondence relationship between (M, N, the subframe length) and (l_τ, k_v, the pilot sending periodicity, the pilot power information); and

a correspondence relationship between (M, N, the subframe length, Δf) and (l_τ, k_v, the pilot sending periodicity, the pilot power information).

In some implementations, the correspondence relationship between the frame structure configuration and the pilot configuration includes any one of the following:

a one-to-one correspondence between the frame structure configuration and the pilot configuration; and

a correspondence between each frame structure configuration and at least two different pilot configurations.

In this embodiment, the one-to-one correspondence between the frame structure configuration and the pilot configuration may be understood as that the pilot pattern is related to a size of a data packet. In some implementations, the side length of the pilot pattern (l_τ, k_v) is in direct proportion to the side length (M, N) of the delay-Doppler resource block. For example, a bigger data packet is more important, and therefore, a larger pilot pattern ensures that estimation is accurate; while a smaller data packet is less important, and even if estimation accuracy does not satisfy a decoding requirement, the problem can be solved by flexible retransmission. In this way, not only accurate estimation is ensured, but also an occupation of resources is reduced. An example in which the correspondence relationship between the frame structure configuration and the pilot configuration is (M, N) and (l_τ, k_v) is used for description. In this case, an index table of the frame structure configuration and the pilot configuration may be agreed in a protocol or preconfigured by the sending device and is as shown in Table 1:

TABLE 1

Index
Frame structure configuration
Pilot configuration

1
(M₁, N₁)
(l₁, k₁)

2
(M₂, N₂)
(l₂, k₂)

. . .
. . .
. . .

In some implementations, in a case in which each frame structure configuration corresponds to at least two different pilot configurations, the target index value includes a first index value, and the first index value is used to indicate the target pilot configuration corresponding to the second pilot pattern.

In some implementations, the target index value further includes a second index value, and the second index value is used to indicate the frame structure configuration corresponding to the target pilot configuration.

In this embodiment, because one frame structure configuration corresponds to at least two different pilot configurations, a pilot configuration corresponding to a currently configured frame structure configuration may be indicated by using the first index value. In this way, the second pilot pattern may be indicated by using different first indication information. For example, in a case in which a frame structure is relatively stable and is less likely to be changed, only a changed pilot configuration is indicated. In some implementations, the target index value only includes the first index value. In this case, the second pilot pattern is determined based on the first index value and the current frame structure configuration. In a case in which a frame structure is changed, a changed pilot configuration and a changed frame structure configuration are indicated. In some implementations, the target index value includes the first index value and the second index value. In this case, the second pilot pattern is determined based on the first index value and the second index value, and the frame structure configuration indicated by the second index value may be understood as the currently configured frame structure configuration.

An example in which the correspondence relationship between the frame structure configuration and the pilot configuration is (M, N) and (l_τ, k_v) is used for description. In this case, an index table of the frame structure configuration and the pilot configuration may be agreed in a protocol or preconfigured by the sending device and is as shown in Table 2:

TABLE 2

Index 1
Frame structure configuration
Index 2
Pilot configuration

1
(M₁, N₁)
1
(l₁, k₁)

2
(l₂, k₂)

2
(M₂, N₂)
1
(l₃, k₃)

2
(l₄, k₄)

. . .
. . .
. . .
. . .

In some implementations, the method further includes:

sending, for intervals of second preset time periods, fourth indication information, where the fourth indication information is used to indicate an adjustment of the first pilot pattern into a third pilot pattern, and a side length of the third pilot pattern is greater than or equal to a preset value.

In this embodiment, the third pilot pattern may be understood as a pilot pattern specially designed for initially obtaining channel information. At an initial obtaining stage of communication, channel information remains unknown to the receiving device. To ensure accuracy of initial channel state estimation, the sending device may send a pilot with a large enough guard interval, that is, send a pilot based on the third pilot pattern. In this embodiment, sending a pilot based on the third pilot pattern may be understood as sending an initial signal. The third pilot pattern configured for the receiving device by using the fourth indication information is sent periodically, which is equivalent to sending the initial signal periodically, to accurately measure and refresh τ_maxand v_maxof a channel. In this way, a too small guard interval of the pilot pattern is avoided, so as to prevent an inaccurate delay-Doppler response of the channel because the channel gets worse suddenly.

In some implementations, that a side length of the third pilot pattern is greater than or equal to a preset value may be understood as that both values of l and k are greater than or equal to the preset value, or a value of l is greater than or equal to a first preset value, and a value of k is greater than or equal to a second preset value. The preset value may be understood as a side length value corresponding to an optimal pilot pattern.

Further, refer to FIG. 4. An embodiment of this application further provides another pilot processing method, performed by a sending device, and including the following steps:

Step 401: receiving a measurement pilot.

In this embodiment of this application, the measurement pilot is used for pilot measurement, and the sending device may determine a suitable pilot pattern based on the measurement pilot. For example, the sending device may measure the measurement pilot to obtain a measurement result, and determine a channel status based on the measurement result, to determine a suitable pilot pattern. In some implementations, the sending device may determine, based on the measurement pilot, whether to update a previous pilot pattern.

In some implementations, the receiving device may send the measurement pilot periodically, aperiodically, or in a manner of triggering by the sending device. The measurement pilot may be a pilot sent based on a measurement pilot pattern, or may be a pilot sent based on a first pilot pattern. In other words, a pilot pattern corresponding to the measurement pilot is a measurement pilot pattern or a first pilot pattern used for channel measurement and channel estimation. The first pilot pattern is a rectangular resource pattern formed with l*k resource elements and includes a central resource element having a pilot pulse and empty resource elements set around the resource element having the pilot pulse.

Step 402: determining, based on a measurement result of the measurement pilot, whether to update a pilot pattern.

In this embodiment, the measurement result of the measurement pilot may include a maximum delay and a maximum Doppler frequency shift of a multipath channel. The sending device may determine, based on the measurement result of the measurement pilot, whether to update the pilot pattern currently configured for the receiving device, and may determine, based on the measurement result, a second pilot pattern in a case in which the pilot pattern currently configured for the receiving device is determined to be updated. In a case in which not to update is determined, a pilot signal is sent subsequently still based on the first pilot pattern. In this embodiment of this application, after the step of determining, based on a measurement result of the measurement pilot, whether to update a pilot pattern, the method further includes:

determining, based on the measurement result, a second pilot pattern in a case in which the pilot pattern is determined to be updated based on the measurement result of the measurement pilot;

sending first indication information, where the first indication information is used to indicate the second pilot pattern; and

sending a second pilot based on the second pilot pattern.

In some embodiments, based on whether the measurement result is greater than or equal to a preset value, if the measurement result is greater than or equal to the preset value, the first pilot pattern may be determined to be updated, and the second pilot pattern is determined based on the measurement result; or if the measurement result is less than the preset value, the first pilot pattern is determined not to be updated. In some implementations, if the measurement result is less than the preset value, the first pilot pattern is determined to be updated, and the second pilot pattern is determined based on the measurement result; or if the measurement result is greater than or equal to the preset value, the first pilot pattern is determined not to be updated.

In some other embodiments, in a case in which the measurement pilot is a pilot sent based on a pilot pattern for measurement, a preferred pilot pattern may first be determines, and whether to update the first pilot pattern is determined based on a difference between the preferred pilot pattern and the first pilot pattern. In a case in which the first pilot pattern is determined to be updated, the preferred pilot pattern may first be determined to be the second pilot pattern, or the second pilot pattern is determined based on the preferred pilot pattern.

After sending the second pilot pattern, the sending device may send the second pilot based on the second pilot pattern, and the receiving device may receive the second pilot based on the second pilot pattern. In this way, a pilot pattern can be configured with flexibility for the receiving device, not only ensuring accurate estimation but also reducing a waste of resources.

In this embodiment of this application, by receiving the measurement pilot, whether to update a pilot pattern is determined based on a measurement result of the measurement pilot. In this way, a pilot pattern can be updated dynamically, to not only ensure accurate estimation but also reduce a waste of resources.

In some implementations, the step of determining, based on the measurement result, a second pilot pattern in a case in which the pilot pattern is determined to be updated based on the measurement result of the measurement pilot includes: determining, based on the measurement result of the measurement pilot within a third preset time period, the second pilot pattern in a case in which the pilot pattern is determined to be updated based on the measurement result of the measurement pilot within the third preset time period.

In this embodiment of this application, in a case in which the measurement pilot is a pilot periodically sent by a receiving device, a time length of the third preset time period is Q*T, Q is an integer greater than 1, and T is a sending periodicity of the measurement pilot.

Measurement results of a plurality of times may be included within the third preset time period. A value of a measurement result of each time is compared with another, and a largest value of the maximum delay and a largest value of the maximum Doppler frequency shift of the multipath channel in the measurement results of the plurality of times are used as the feedback information. In other embodiments, the feedback may be performed in another manner, for example, by using an average value of all measurement results or an average value of measurement results of a plurality of times that satisfy a specific condition. This is not further limited herein. Because a pilot pattern of the receiving device is updated based on the measurement results of the plurality of times within the third preset time period, a frequency of updating the pilot pattern is lower, to prevent too frequent updates of the pilot pattern.

In some implementations, before the step of sending first indication information, the method further includes:

determining a target index value corresponding to the second pilot pattern based on a correspondence relationship between a frame structure configuration and a pilot configuration, where

the sent first indication information carries the target index value, and the target index value is used to indicate a target pilot configuration corresponding to the second pilot pattern.

The side length of the delay-Doppler resource block may be denoted as (M, N), and the side length of the pilot pattern may be denoted as (l, k).

In some implementations, the correspondence relationship between the frame structure configuration and the pilot configuration includes any one of the following:

a one-to-one correspondence between the frame structure configuration and the pilot configuration; and

a correspondence between each frame structure configuration and at least two different pilot configurations.

In this embodiment, the correspondence relationship between the frame structure configuration and the pilot configuration may be understood as any one of the following:

a correspondence relationship between (M, N) and (l_τ, k_v);

a correspondence relationship between (M, N) and (l_τ, k_vand the pilot power information);

a correspondence relationship between (M, N) and (l_τ, k_vand the pilot sending periodicity);

a correspondence relationship between (M, N and a subframe length) and (l_τ, k_vand the pilot sending periodicity);

a correspondence relationship between (M, N and the subframe length) and (l_τ, k_v, the pilot sending periodicity, and the pilot power information); and

a correspondence relationship between (M, N, the subframe length, and Δf) and (l_τ, k_v, the pilot sending periodicity, and the pilot power information).

In some implementations, the correspondence relationship between the frame structure configuration and the pilot configuration includes any one of the following:

a one-to-one correspondence between the frame structure configuration and the pilot configuration; and

a correspondence between each frame structure configuration and at least two different pilot configurations.

TABLE 3

Index
Frame structure configuration
Pilot configuration

1
(M₁, N₁)
(l₁, k₁)

2
(M₂, N₂)
(l₂, k₂)

. . .
. . .
. . .

TABLE 4

Index 1
Frame structure configuration
Index 2
Pilot configuration

1
(M₁, N₁)
1
(l₁, k₁)

2
(l₂, k₂)

2
(M₂, N₂)
1
(l₃, k₃)

2
(l₄, k₄)

. . .
. . .
. . .
. . .

In some implementations, in a case in which the pilot pattern corresponding to the measurement pilot is the first pilot pattern, the method further includes: sending, for intervals of second preset time periods, fourth indication information, where the fourth indication information is used to indicate an adjustment of the first pilot pattern into a third pilot pattern, and a side length of the third pilot pattern is greater than or equal to a preset value.

In this embodiment, the third pilot pattern may be understood as a pilot pattern used for initially obtaining channel information. At an initial obtaining stage of communication, channel information remains unknown to the receiving device. To ensure accuracy of initial channel state estimation, the sending device may send a pilot with a large enough guard interval, that is, send a pilot based on the third pilot pattern. In this embodiment, sending a pilot based on the third pilot pattern may be understood as sending an initial signal. The third pilot pattern configured for the receiving device by using the fourth indication information is sent periodically, which is equivalent to sending the initial signal periodically, to accurately measure and refresh τ_maxand v_maxof a channel. In this way, a too small guard interval of the pilot pattern is avoided, so as to prevent an inaccurate delay-Doppler response of the channel because the channel gets worse suddenly.

In some implementations, that a side length of the third pilot pattern is greater than or equal to a preset value may be understood as that both values of l and k are greater than or equal to the preset value, or a value of 1 is greater than or equal to a first preset value, and a value of k is greater than or equal to a second preset value. The preset value may be understood as a side length value corresponding to an optimal pilot pattern.

For better understanding of this application, different instances are given below to describe in detail an implementation process of this application.

Embodiment 1: The Receiving Device Performs Measurement

A sending device first sends a configuration of a pilot pattern to a receiving device, where the configuration of the pilot pattern should be a group of pilot configurations with an index predefined in a protocol, and the sending device indicates an index value via a pilot configuration message. After receiving the index, the receiving device can correctly learn the pilot pattern to be sent by the sending device subsequently. After receiving a pilot, the receiving device may perform measurement and channel estimation based on known information.

It is assumed that a pilot is sent with a periodicity T. To prevent too frequent feedbacks, the receiving device may define a measurement window with a length nT. All measurement results within nT are counted and denoted as (τ, v)={τ_i, v_i}, 0<i≤n. Values of measurement results of various times within one measurement window are compared, and τ_max=max_iτ, v_max=max_iv is used. The receiving device sends τ_maxand v_maxthat are obtained through measurement to the sending device in a feedback message. The sending device decides a new pilot pattern based on the feedback message.

To further reduce overheads, the receiving device may not directly indicate numerical values of τ_maxand v_max, but use only two bits to indicate an increase or a decrease respectively of a side length in each dimension of a current pilot pattern (where each bit correspondingly indicates one side length). The transmit end makes an adjustment based on a received indication and a step size specified in a protocol. Particularly, the step size may be a group of numerical values predefined in a protocol, and one value is selected when used.

In some implementations, the receiving device directly reports an index of a pilot pattern preferred by the receiving device to the sending device. The pilot pattern and the corresponding index are defined in a protocol or configured by the sending device for the receiving device.

In some implementations, the pilot configuration message may be carried in Downlink Control Information (DCI) or Sidelink Control Information (SCI) in a control channel. The message may alternatively be carried in a Radio Resource Control (RRC) message or a Medium Access Control Control Element (MAC CE) in a data channel. The feedback message may be carried in Uplink Control Information (UCI) or SCI in a control channel, or may be carried in a message in a data channel. If the indication information is two-bit, this may be indicated through pilot blind detection.

It should be understood that a pilot configuration message of the first time may be optional. In other words, the receiving device may directly measure a pilot to obtain a measurement result and further report based on the measurement result. For example, in direct measurement, a Cell Reference Signal (CRS) in 4G or a Synchronization Signal and Physical Broadcast CHannel (PBCH) Block (SSB) in 5G may be used.

Embodiment 2: The Sending Device Performs Measurement

The sending device measures a channel characteristic. A receiving device sends a measurement pilot periodically, aperiodically, or in a manner of triggering by the sending device, to send an uplink pilot. It is assumed that a measurement pilot is sent with a periodicity T. To prevent too frequent updates of a pilot pattern, the sending device may define a measurement window with a length nT. All measurement results within nT are counted and denoted as (τ, v)={τ_i, v_i}, 0<i≤n. Values of measurement results of various times within one measurement window are compared, and

$τ_{\max} = \max_{i} τ, v_{\max} = \max_{i} v$

is used. The sending device decides a new pilot pattern based on τ_maxand v_maxthat are obtained through measurement.

A pilot pattern sent by the sending device is defined in a protocol or configured by a base station, that is, the base station configures one pilot pattern and triggers the sending device for sending.

The sending device sends a configuration of pilot pattern that is determined in a previous step to the receiving device. The configuration of the pilot pattern is a group of pilot configurations with an index predefined in a protocol, and the sending device indicates an index value via a pilot configuration message. After receiving the index, the receive end can correctly learn the pilot pattern to be sent by the sending device subsequently. After receiving a pilot, the receiving device may perform channel estimation based on known information.

In some implementations, the measurement pilot sent by the receiving device is sent periodically, aperiodically, or in a manner of triggering by a base station during a continuous connection, and may be encapsulated together with data, or may be encapsulated alone by using a relatively small resource block. In this embodiment, processing of the receiving device becomes less complicated, so that power consumption of the receiving device can be reduced.

Embodiment 3: An Indirect Indication Solution, that is, a Pilot Pattern is Related to a Size of a Data Packet, is Presented

A side length (l_τ, k_v) of a pilot pattern (including a guard symbol) is in proportion to a side length (M, N) of a data mapping grid. A benefit of a proportional design is that because a bigger data packet is more important, a larger pilot pattern ensures accurate estimation. A smaller data packet is less important, and even if estimation accuracy does not satisfy a decoding requirement, the problem can be solved by flexible retransmission.

In some implementations, a group of correspondence relationships between (M, N) and (l_τ, k_v) may be defined as shown in Table 1 in the foregoing embodiment.

In some implementations, a group of correspondence relationships between (M, N) and (l_τ, k_v, the pilot power information) may be defined;

a group of correspondence relationships between (M, N) and (l_τ, k_v, the pilot sending periodicity) may be defined;

a group of correspondence relationships between (M, N, a subframe length) and (l_τ, k_v, the pilot sending periodicity) may be defined;

a group of correspondence relationships between (M, N, the subframe length) and (l_τ, k_v, the pilot sending periodicity, the pilot power information) may be defined; or

a group of correspondence relationships between (M, N, the subframe length, Δf) and (l_τ, k_v, the pilot sending periodicity, the pilot power information) may be defined.

It should be understood that in this embodiment of this application, (M,N), the subframe length, and Δf may be combined in any way, and (l_τ, k_v), the sending pilot periodicity, and the pilot power information may be combined in any way.

The subframe length may be a length of a time-domain block including X OTFSs, and X is a positive integer.

As the sending device indicates an index value in Table 1 in a frame indicator message, the receiving device can learn about a pilot pattern for channel estimation. By using this design, τ_maxand v_maxdo not need to be accurately measured, but a known ACK/NACK message may be used to determine whether need to change a paired frame structure and pilot pattern. For example, when receiving a NACK message, the transmit end considers that a signal sending rate needs to be reduced to enhance a decoding success rate, and therefore actively selects a larger (M₁, N₁) and (l_τ, k_v), to achieve a lower bit rate and higher channel estimation accuracy.

In this embodiment, measurement and feedback are not needed, so that resource overheads are reduced.

Embodiment 4: A Supplement to Embodiment 1 to Embodiment 3

An initialization initial signal is mainly used to initially obtain channel information. At an initial obtaining node in the communication, the channel information remains unknown to a receiving device. To ensure accurate estimation of an initial channel status, a sending device sends a pilot with a large enough guard interval, that is, the initial signal. τ_maxand v_maxestimated by using the pilot are used for subsequent pilot sending. The pilot is adjusted dynamically based on a pilot measurement result that is sent afterwards periodically.

In addition, the initialization initial signal in this embodiment may be sent periodically and used to measure and refresh τ_maxand v_maxof a channel accurately. In this way, a too small guard interval of the pilot pattern is avoided, so as to prevent an inaccurate delay-Doppler response of the channel because the channel gets worse suddenly.

Refer to FIG. 5. FIG. 5 is a flowchart of a pilot processing method according to an embodiment of this application. The method is performed by a receiving device, as shown in FIG. 5, and includes the following steps:

Step 501: receiving, based on a first pilot pattern, a first pilot sent by a sending device; and

Step 502: sending feedback information based on the first pilot, where the feedback information is used to determine whether to update the first pilot pattern.

In some implementations, after the step of sending feedback information based on the first pilot, the method further includes:

receiving first indication information in a case in which the sending device determines, based on the feedback information, to update the first pilot pattern, where the first indication information is used to indicate a second pilot pattern, and the second pilot pattern is determined based on the feedback information; and

receiving a second pilot based on the second pilot pattern.

In some implementations, the first pilot pattern is a rectangular resource pattern formed with l*k resource elements and includes a central resource element having a pilot pulse and empty resource elements set around the resource element having the pilot pulse.

In some implementations, the feedback information includes at least one of the following:

a measurement result of the first pilot within a first preset time period;

a HARQ feedback for data packet decoding based on a channel estimation result of the first pilot.

In some implementations, before the step of receiving a second pilot based on the second pilot pattern, the method further includes:

determining, based on a correspondence relationship between a frame structure configuration and a pilot configuration, and a target index value indicated by the first indication information, the second pilot pattern, where

the target index value is used to indicate a target pilot configuration corresponding to the second pilot pattern.

In some implementations, the correspondence relationship between the frame structure configuration and the pilot configuration includes any one of the following:

a one-to-one correspondence between the frame structure configuration and the pilot configuration; and

a correspondence between each frame structure configuration and at least two different pilot configurations.

In some implementations, the method further includes:

receiving, for intervals of second preset time periods, fourth indication information sent by the sending device, where the fourth indication information is used to indicate an adjustment of the first pilot pattern into a third pilot pattern, and a side length of the third pilot pattern is greater than or equal to a preset value.

In some implementations, a time length of the first preset time period is Q*T, Q is an integer greater than 1, and T is a sending periodicity of the first pilot.

In some implementations, the measurement result of the first pilot includes a maximum delay and a maximum Doppler frequency shift of a multipath channel.

In some implementations, the method further includes: receiving or sending a pilot configuration message, where the pilot configuration message is used to configure the first pilot pattern.

In some implementations, the pilot configuration includes a side length of a pilot pattern.

In some implementations, the pilot configuration further includes at least one of pilot power information and a pilot sending periodicity.

In some implementations, the frame structure configuration includes a side length of a delay-Doppler resource block.

In some implementations, the frame structure configuration further includes at least one of a subframe length and a subcarrier spacing.

It should be noted that this embodiment serves as an implementation of the receiving device corresponding to the embodiment shown in FIG. 3. For specific implementations of this embodiment, reference may be made to related descriptions of the embodiment shown in FIG. 3. To avoid repetition, details are not described herein again.

Refer to FIG. 6. FIG. 6 is a flowchart of another pilot processing method according to an embodiment of this application. The method is performed by a receiving device, as shown in FIG. 6, and includes the following steps:

Step 601: sending a measurement pilot, where the measurement pilot is used to determine whether to update a pilot pattern.

In some implementations, after the step of sending a measurement pilot, the method further includes: receiving first indication information in a case in which the sending device determines, based on a measurement result of the measurement pilot, to update the first pilot pattern, where the first indication information is used to indicate an updated second pilot pattern, and the second pilot pattern is determined based on the measurement result; and

receiving a second pilot based on the second pilot pattern.

In some implementations, the measurement result of the measurement pilot includes a maximum delay and a maximum Doppler frequency shift of a multipath channel.

In some implementations, before the step of receiving a second pilot based on the second pilot pattern, the method further includes:

the target index value is used to indicate a target pilot configuration corresponding to the second pilot pattern.

In some implementations, the correspondence relationship between the frame structure configuration and the pilot configuration includes any one of the following:

a one-to-one correspondence between the frame structure configuration and the pilot configuration; and

a correspondence between each frame structure configuration and at least two different pilot configurations.

In some implementations, a pilot pattern corresponding to the measurement pilot is a measurement pilot pattern or a first pilot pattern used for channel measurement and channel estimation.

In some implementations, in a case in which the pilot pattern corresponding to the measurement pilot is the first pilot pattern, the method further includes:

In some implementations, the pilot configuration includes a side length of a pilot pattern.

In some implementations, the pilot configuration further includes at least one of pilot power information and a pilot sending periodicity.

In some implementations, the frame structure configuration includes a side length of a delay-Doppler resource block.

In some implementations, the frame structure configuration further includes at least one of a subframe length and a subcarrier spacing.

It should be noted that this embodiment serves as an implementation of the receiving device corresponding to the embodiment shown in FIG. 4. For some implementations of this embodiment, reference may be made to related descriptions of the embodiment shown in FIG. 4. To avoid repetition, details are not described herein again.

It should be noted that the pilot processing method according to the embodiments of this application may be performed by a pilot processing apparatus, or a control module that is in the pilot processing apparatus and that is configured to perform the pilot processing method. In an embodiment of this application, that the pilot processing apparatus performs the pilot processing method is used as an example to describe the pilot processing apparatus according to this embodiment of this application.

Refer to FIG. 7, FIG. 7 is a structural diagram of a pilot processing apparatus according to an embodiment of this application. As shown in FIG. 7, the pilot processing apparatus 700 includes:

a first transceiving module 701, configured to receive feedback information, where the feedback information is feedback information that is sent by a receiving device based on a first pilot received based on a first pilot pattern; and

a first determining module 702, configured to determine, based on the feedback information, whether to update the first pilot pattern.

In some implementations, the first determining module 702 is further configured to determine a second pilot pattern in a case in which the first pilot pattern is determined based on the feedback information to be updated; and

the first transceiving module 701 is further configured to: send first indication information, where the first indication information is used to indicate the second pilot pattern; and send a second pilot based on the second pilot pattern.

In some implementations, the feedback information includes at least one of the following:

a measurement result of the first pilot within a first preset time period;

a HARQ feedback for data packet decoding based on a channel estimation result of the first pilot.

In some implementations, a time length of the first preset time period is Q*T, Q is an integer greater than 1, and T is a sending periodicity of the first pilot.

In some implementations, the measurement result of the first pilot includes a maximum delay and a maximum Doppler frequency shift of a multipath channel.

In some implementations, the first transceiving module 701 is further configured to send or receive a pilot configuration message, where the pilot configuration message is used to configure the first pilot pattern.

In some implementations, the first transceiving module 701 is further configured to determine a target index value corresponding to the second pilot pattern based on a correspondence relationship between a frame structure configuration and a pilot configuration, where