Patent Description:
In comparison with Long Term Evolution (LTE), a higher carrier frequency (a high frequency for short) is used in a <NUM> communications system. A current standard stipulates that a high frequency is usually above <NUM>, and a currently most researched band is <NUM>, <NUM>, <NUM>, or the like, to implement wireless communication with higher bandwidth and a higher transmission rate. However, in comparison with conventional low-frequency communication, a high frequency system has more serious intermediate radio frequency distortion, especially impact of phase noise. In addition, impact of a Doppler shift and a carrier frequency offset (CFO) increases with a frequency.

In an example of multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM), both phase noise and a carrier frequency offset of a receive end and those of a transmit end are considered, and a reception expression of an nth receive antenna on a kth subcarrier after the receive end performs fast Fourier transform (FFT) is: <MAT> where <MAT> namely: <MAT><MAT> represents a channel from an mth transmit antenna to the nth receive antenna on the kth subcarrier, <MAT> represents data sent by using the mth transmit antenna on the kth subcarrier, <MAT> represents noise of the nth receive antenna on the kth subcarrier, <MAT> represents a phase deviation caused by the phase noise and the CFO of the receive end for the nth receive antenna on the kth subcarrier, and <MAT> represents a phase deviation caused by the phase noise and the CFO of the transmit end for an mth transmit antenna on the kth subcarrier. It can be learned from the expression that impact of phase noise on OFDM performance is mainly reflected in two aspects: a common phase error (CPE) and inter-carrier interference (ICI), and impact of CFO on OFDM performance is mainly reflected in ICI. In an actual system, the impact of the ICI on the performance is less than the impact of the CPE on the performance. Therefore, the CPE is preferentially compensated for in a phase noise compensation scheme.

<FIG> shows a constellation point at which a 64QAM modulation signal is not affected by phase noise. <FIG> shows a constellation point at which a <NUM> quadrature amplitude modulation (QAM) signal on a <NUM> band is affected by phase noise. <FIG> shows a constellation point at which a <NUM> QAM modulation signal on a <NUM> band is affected by phase noise. As shown in <FIG>, phase noise is used as an example, and a phase noise level deteriorates with a band at a level of <NUM>×log(f1/f2). A <NUM> band and a <NUM> band are used as an example, and a phase noise level of the <NUM> band is higher than that of the <NUM> band by <NUM> dB. A higher phase noise level causes greater impact of a common phase error (CPE), and the CPE causes a bigger phase error.

A CPE imposes same impact on different subcarriers of a same OFDM symbol, and phase errors on the different subcarriers are different because of white Gaussian noise. Therefore, in frequency domain, a specific quantity of phase compensation reference signals (PCRS) (which may also be referred to as phase tracking reference signals (PTRS), where the PCRS is not uniformly named currently in the industry, but is uniformly referred to as the PTRS subsequently for convenience in the present invention) needs to be used to estimate the CPE and calculate an average, to reduce impact of the white Gaussian noise as much as possible. R1-<NUM> discloses UL-PTRS design, proposal <NUM> defines power boosting of PT-RS according to PT-RS port to DMRS port group mapping. R1-<NUM> discloses PT-RS sharing among UEs and layers, Proposal <NUM> defines For UE specific data, PT-RS should be UE-specific and not be shared among UEs.

Currently, how to determine transmit power of a PTRS is a technical problem that needs to be urgently resolved.

Embodiments of this application provide a transmit power determining method, so as to flexibly adapt to different quantities of demodulation reference signal (DMRS) ports, different quantities of PTRS ports, and different port multiplexing manner configurations, thereby ensuring efficient energy use, and improving PTRS measurement accuracy.

In the embodiments of this application, a transmit end device first obtains the relative power ratio of the PTRS to the data channel or to the DMRS by searching a table or through calculation, determines the transmit power of the PTRS based on the transmit power of the data channel or the transmit power of the DMRS, and sends the PTRS by using the transmit power, so that different quantities of DMRS ports, different quantities of PTRS ports, and different port multiplexing manner configurations can be flexibly adapted, thereby ensuring efficient energy use.

To describe the technical solutions in the embodiments of the present invention more clearly, the following briefly describes the accompanying drawings required for describing the embodiments or the prior art. Apparently, the accompanying drawings in the following description show merely some embodiments, and a person of ordinary skill in the art may derive other drawings from these accompanying drawings without creative efforts.

The following further describes in detail this application with reference to accompanying drawings. The examples <NUM> and <NUM> described below are not presented as embodiments of the invention, but as examples useful for understanding the invention.

The embodiments of this application can be applied to various mobile communications systems, such as a Global System for Mobile Communications (GSM), a Code Division Multiple Access (CDMA) system, a Wideband Code Division Multiple Access (WCDMA) system, a general packet radio service (GPRS), a Long Term Evolution (LTE) system, a Long Term Evolution Advanced (LTE-A) system, a Universal Mobile Telecommunications System (UMTS), an evolved Long Term Evolution (eLTE) system, a <NUM> system (for example, a new radio (NR) system), and other mobile communications systems.

Some terms in this application are described below to facilitate understanding of a person skilled in the art.

<FIG> is a schematic structural diagram of an application scenario according to an embodiment of this application. A networking architecture shown in <FIG> mainly includes a base station <NUM> and a terminal <NUM>. The base station <NUM> may communicate with the terminal <NUM> by using a millimeter-wave band with a low frequency (mainly below <NUM>) or a relatively high frequency (above <NUM>). For example, the millimeter-wave band may be <NUM>, <NUM>, or an enhanced band (Enhanced band) of a data plane with a relatively small coverage area, for example, a band above <NUM>. The terminal <NUM> covered by the base station <NUM> may communicate with the base station <NUM> by using a millimeter-wave band with a low frequency or a relatively high frequency. <FIG> is merely an example of a simplified schematic diagram, and a network may further include another device that is not shown in <FIG>.

A communication method and a communications device provided in the embodiments of this application can be applied to a terminal, and the terminal includes a hardware layer, an operating system layer running above the hardware layer, and an application layer running above the operating system layer. The hardware layer includes hardware such as a central processing unit (CPU), a memory management unit (MMU), and a memory (also referred to as a main memory). An operating system may be any one or more of computer operating systems that implement service processing by using a process (Process), for example, a Linux operating system, a UNIX operating system, an Android operating system, an iOS operating system, or a Windows operating system. The application layer includes applications such as a browser, a contact list, word processing software, and instant messaging software.

In addition, aspects or features of this application may be implemented as a method, an apparatus, or a product that uses standard programming and/or engineering technologies. The term "product" used in this application covers a computer program that can be accessed from any computer readable component, carrier or medium. For example, a computer readable medium may include but is not limited to a magnetic storage component (for example, a hard disk, a floppy disk, or a magnetic tape), an optical disc (for example, a compact disc (CD) or a digital versatile disc (DVD)), a smart card, and a flash memory component (for example, an erasable programmable read-only memory (EPROM), a card, a stick, or a key drive). In addition, various storage media described in this specification may indicate one or more devices and/or other machine readable media for storing information. The term "machine readable media" may include but is not limited to various media that can store, contain, and/or carry an instruction and/or data.

To better understand this application, the following describes this application with reference to the accompanying drawings.

<FIG> is a diagram of a resource grid in an LTE system. As shown in the diagram, a channel is sent in a unit of a radio frame in the LTE system. One radio frame includes <NUM> subframes, a length of each subframe is <NUM> millisecond (ms), each subframe includes two timeslots (slot), and each slot is <NUM>. A quantity of symbols included in each slot is associated with a length of a CP (cyclic prefix) in a subframe. If the CP is a normal CP, each slot includes seven symbols, and each subframe includes <NUM> symbols. If the CP is an extended CP, each slot includes six symbols, and each subframe includes <NUM> symbols. A downlink symbol is referred to as an orthogonal frequency division multiplexing (OFDM) symbol. In the LTE system, a resource element (RE) is a minimum unit in time-frequency domain, and is uniquely identified by an index pair (k, l), where k is a subcarrier index, and <NUM> is a symbol index.

Compared with an existing wireless communications network, a next-generation wireless communications network that works in a range of above <NUM> suffers more serious intermediate radio frequency distortion, especially impact of phase noise. A higher phase noise level causes greater CPE impact. Therefore, a PTRS is introduced for phase noise estimation.

However, the PTRS occupies some REs, and the occupied RE is originally used to send a data channel (during uplink transmission, the data channel includes a physical uplink shared channel (PUSCH), and during downlink transmission, the data channel includes a physical downlink shared channel (PDSCH)) or another reference signal. A most common case is that the occupied RE is originally used to send the data channel. In this case, total power of the PTRS needs to be equal to total power of the data channel that is originally to be sent in the occupied RE ("power" in this embodiment of this application is equivalent to "transmit power"). Total available power of a transmit end is preconfigured. Therefore, if transmit power of the PTRS is greater than transmit power of the data channel that is originally to be sent in the occupied RE, the total available power is exceeded. If the transmit power of the PTRS is less than the transmit power of the data channel that is originally to be sent in the occupied RE, a power waste is caused. Certainly, it is feasible that the transmit power of the PTRS is only slightly less than the transmit power of the data channel that is originally to be sent in the occupied RE (a difference does not exceed a preset threshold).

In an example of uplink transmission, if the transmit power of the PTRS is equal to the transmit power of the data channel that is originally to be sent in the occupied RE, a formula (<NUM>) may be obtained: <MAT>.

Nlayers is a quantity of transport layers, NRE/layers is a quantity of REs at each transport layer that cannot be used because of the PTRS (in a unit of one resource block (RB) and one OFDM symbol), PPUSCH is power of a PUSCH at the transport layer (in a unit of one RE), NPTRS ports is a quantity of PTRS ports, NRE/PTRS ports is a quantity of REs occupied by each PTRS port (in a unit of one RB and one OFDM symbol, where it is assumed that the quantity of REs is <NUM> herein), and PPTRS is the power of the PTRS (in a unit of one RE).

A formula (<NUM>) may be further obtained according to the formula (<NUM>): <MAT>.

Because NRE/layers = NPTRS ports × NRE/PTRS ports, a formula (<NUM>) may be further obtained: <MAT>.

Because the quantity of transport layers is equal to a quantity of DMRS ports, a formula (<NUM>) may be further obtained: <MAT>.

A terminal device may obtain a relative power ratio of the PTRS to the PUSCH through calculation according to the formula (<NUM>) or (<NUM>), finally obtain the power of the PTRS based on the power of the PUSCH, and send the PTRS by using the power of the PTRS.

It can be learned, through calculation according to the formula (<NUM>) or (<NUM>), that when the quantity of transport layers is <NUM> to <NUM>, the quantity of DMRS ports is <NUM> to <NUM>, and the quantity of PTRS ports is equal to or less than the quantity of DMRS ports, the relative power ratio of the PTRS to the PUSCH is shown in Table (<NUM>):.

When the quantity of transport layers is <NUM> to <NUM>, the quantity of DMRS ports is <NUM> to <NUM>, and the quantity of PTRS ports is equal to or less than the quantity of DMRS ports, Table (<NUM>) may be further extended, and the relative power ratio of the PTRS to the PUSCH is shown in Table (<NUM>):.

To facilitate industrial practice, rounding down may be performed on the relative power ratio of the PTRS to the PUSCH in Table (<NUM>) and Table (<NUM>). For example, when the quantity of transport layers is <NUM> and the quantity of DMRS ports is <NUM>, rounding down may be performed on the relative power ratio <NUM> of the PTRS to the PUSCH to obtain a value <NUM>. Alternatively, only a one-digit decimal may be retained for the relative power ratio of the PTRS to the PUSCH in Table (<NUM>) and Table (<NUM>). For example, when the quantity of transport layers is <NUM> and the quantity of DMRS ports is <NUM>, one-digit decimal may be retained for the relative power ratio <NUM> of the PTRS to the PUSCH to obtain a value <NUM>. Whether rounding off is performed when rounding down is performed or a one-digit decimal is retained is not limited in this embodiment of this application.

The terminal device may further search a table (for example, Table (<NUM>) or Table (<NUM>)) to obtain the relative power ratio of the PTRS to the PUSCH, finally obtain the power of the PTRS based on the power of the PUSCH, and send the PTRS by using the power of the PTRS.

In addition, in the example of uplink transmission, when transmit power of a DMRS is equal to the transmit power of the data channel that is originally to be sent in the occupied RE, a formula (<NUM>) may be obtained: <MAT>.

Nlayers is a quantity of transport layers, NDMRS ports is a quantity of DMRS ports, N'RE/layers is a quantity of REs at each transport layer (in a unit of one RB and one OFDM symbol, where the quantity of REs is usually <NUM>), NRE/DMRS ports is a quantity of REs occupied by each DMRS port (in a unit of one RB and one OFDM symbol), PDMRS is a power spectrum density (PSD) of the DMRS (in a unit of one RE), and PPUSCH is power of a PUSCH at the transport layer (in a unit of one RE).

Because the quantity of transport layers is equal to the quantity of DMRS ports, a formula (<NUM>) may be obtained: <MAT>.

Because DDMRS is a frequency domain density of the DMRS, and is equal to <MAT>, a formula (<NUM>) may be obtained: <MAT>.

A formula (<NUM>) may be further obtained according to the formula (<NUM>) and the formula (<NUM>): <MAT>.

Because the quantity of transport layers is equal to the quantity of DMRS ports, a formula (<NUM>) may be further obtained: <MAT>.

The terminal device may obtain a relative power ratio of the PTRS to the DMRS through calculation according to the formula (<NUM>) or (<NUM>), finally obtain the power of the PTRS based on the power of the DMRS, and send the PTRS by using the power of the PTRS.

It can be learned, through calculation according to the formula (<NUM>) or (<NUM>), that when the quantity of transport layers is <NUM> to <NUM>, the quantity of DMRS ports is <NUM> to <NUM>, and the quantity of PTRS ports is equal to or less than the quantity of DMRS ports, the relative power ratio of the PTRS to the DMRS is shown in Table (<NUM>):.

When the quantity of transport layers is <NUM> to <NUM>, the quantity of DMRS ports is <NUM> to <NUM>, and the quantity of PTRS ports is equal to or less than the quantity of DMRS ports, Table (<NUM>) may be further extended, and the relative power ratio of the PTRS to the DMRS is shown in Table (<NUM>):.

The frequency domain density of the DMRS may be another value such as <NUM>/<NUM> or <NUM>/<NUM>. Assuming that the frequency domain density of the DMRS may be <NUM>/<NUM>, <NUM>/<NUM>, <NUM>/<NUM>, or <NUM>/<NUM> for each quantity of transport layers or each quantity of DMRS ports, Table (<NUM>) below may be obtained:.

Table (<NUM>) provides many possibilities to configure the relative power ratio of the PTRS to the DMRS for any split use. This is not limited in this embodiment of this application.

In Table (<NUM>) to Table (<NUM>), because the quantity of transport layers is equal to the quantity of DMRS ports, only one of the first two columns may be retained. In addition, to facilitate industrial practice, rounding down may be performed on the relative power ratio of the PTRS to the DMRS in Table (<NUM>) to Table (<NUM>). For example, when the quantity of transport layers is <NUM> and the quantity of DMRS ports is <NUM>, rounding down may be performed on the relative power ratio <NUM> of the PTRS to the DMRS to obtain a value <NUM>. Alternatively, only a one-digit decimal may be retained for the relative power ratio of the PTRS to the DMRS in Table (<NUM>) to Table (<NUM>). For example, when the quantity of transport layers is <NUM> and the quantity of DMRS ports is <NUM>, a one-digit decimal may be retained for the relative power ratio <NUM> of the PTRS to the DMRS to obtain a value <NUM>. Whether rounding off is performed when rounding down is performed or a one-digit decimal is retained is not limited in this embodiment of this application.

The terminal device may search a table (for example, Table (<NUM>), Table (<NUM>), or Table (<NUM>)) to obtain the relative power ratio of the PTRS to the DMRS, finally obtain the power of the PTRS based on the power of the DMRS, and send the PTRS by using the power of the PTRS.

In a formula derivation process in this embodiment of this application, it is assumed that the quantity NRE/PTRS ports of REs occupied by each PTRS port (in a unit of one RB and one OFDM symbol) is <NUM>. However, in implementation, the quantity of REs occupied by each PTRS port may alternatively be greater than <NUM> within one RB and one OFDM symbol, namely, NRE/PTRS ports><NUM>. In this case, a frequency domain density of the PTRS needs to be added to the formula (<NUM>), the formula (<NUM>), the formula (<NUM>), and the formula (<NUM>) as another variable, as shown in a formula (<NUM>): <MAT>.

DPTRS is the frequency domain density of the PTRS.

Correspondingly, the relative power ratio in Table (<NUM>) to Table (<NUM>) varies with the frequency domain density of the PTRS, but may be obtained through calculation according to the formula (<NUM>).

In this embodiment of this application, after obtaining the relative power ratio of the PTRS to the PUSCH through calculation according to the formal (<NUM>) or (<NUM>) or by searching Table (<NUM>) or Table (<NUM>), the terminal device may finally obtain the power of the PTRS based on the power of the PUSCH and another parameter OFFSETPTRS-PUSCH, and send the PTRS by using the power of the PTRS. OFFSETPTRS-PUSCH represents a reference offset between the power of the PTRS and the power of the PUSCH, and may be configured by a base station. Likewise, after obtaining the relative power ratio of the PTRS to the DMRS through calculation according to the formal (<NUM>) or (<NUM>) or by searching Table (<NUM>), Table (<NUM>), or Table (<NUM>), the terminal device may finally obtain the power of the PTRS based on the power of the PUSCH and another parameter OFFSETPTRS-DMRS, and send the PTRS by using the power of the PTRS. OFFSETPTRS-DMRS represents a reference offset between the power of the PTRS and the power of the DMRS, may be configured by the base station, and may be obtained by accumulating OFFSETPTRS-PUSCH and a reference offset OFFSETDMRS-PUSCH between the power of the DMRS and the power of the PUSCH.

In this embodiment of this application, the relative power ratio of the PTRS to the PUSCH and the relative power ratio of the PTRS to the DMRS may be preset or configured by the base station. After directly obtaining the relative power ratio of the PTRS to the PUSCH and the relative power ratio of the PTRS to the DMRS, the terminal device obtains the power of the PTRS by using the method described in this embodiment of this application.

In this embodiment of this application, the base station may further configure maximum power PMAX of the PTRS. When the power of the PTRS that is obtained by the terminal device through calculation according to any formula in this embodiment of this application is greater than PMAX, the terminal device sends the PTRS by using PMAX.

Next, in this embodiment of this application, the formula (<NUM>), the formula (<NUM>), the formula (<NUM>), and the formula (<NUM>), and Table (<NUM>) to Table (<NUM>) are verified by using an example. In the following example, DMRS ports are grouped based on different crystal oscillators, DMRS ports of a same local oscillator are grouped into one group, and phase noise of all ports in this group may be measured by using a PTRS on one port.

<FIG> is a schematic diagram of a pilot pattern according to an embodiment of this application (uplink transmission, one transport layer, one DMRS port, and one PTRS port). It can be learned from <FIG> that in such a time-frequency resource mapping manner of the PTRS, the power of the PTRS and the power of the PUSCH are consistent, and the relative power ratio of the PTRS to the PUSCH is <NUM> dB.

<FIG> and <FIG> are schematic diagrams of pilot patterns according to an embodiment of this application (uplink transmission, two transport layers, two DMRS ports, and one PTRS port, where the two DMRS ports are grouped into one group). It can be learned from <FIG> and <FIG> that <FIG> is a schematic diagram of a pilot pattern of a transport layer <NUM>, and <FIG> is a schematic diagram of a pilot pattern of a transport layer <NUM>. Because two-layer transmission is performed, power of a PUSCH at each layer is only half of total power, and the PTRS is sent by only one port by using the total power. Therefore, the relative power ratio of the PTRS to the PUSCH is <NUM> dB.

<FIG> and <FIG> are schematic diagrams of pilot patterns according to an embodiment of this application (uplink transmission, two transport layers, two DMRS ports, and two PTRS ports, where the two DMRS ports are grouped into two groups). It can be learned from <FIG> and <FIG> that <FIG> is a schematic diagram of a pilot pattern of a transport layer <NUM>, and <FIG> is a schematic diagram of a pilot pattern of a transport layer <NUM>. Because of orthogonal hypothesis between the PTRS and data, an RE for sending the PTRS at the transport layer <NUM> cannot be mapped to data at the transport layer <NUM>. Therefore, power of unavailable REs may be used to increase the transmit power of the PTRS. That is, to keep total power consistent, power of a PTRS sent at each layer should be twice power of a data channel.

It can be learned that all the formulas and tables in this embodiment of this application are verified in <FIG>, and this is also true for other examples of the quantity of transport layers, the quantity of DMRS ports, and the quantity of PTRS ports. No enumeration is provided herein. "Other" in <FIG> means that whether the RE is mapped to a data channel, another reference signal, or other signals is not limited. "Unavailable" means that the RE is unavailable or cannot be used for data mapping because of orthogonal multiplexing of a PTRS and a data channel.

<FIG> is a schematic flowchart of a transmit power determining method according to an embodiment of this application.

A terminal device determines a relative power ratio of a PTRS to a PUSCH.

The terminal device may determine the relative power ratio of the PTRS to the PUSCH according to a formula provided in this embodiment of this application or by searching a table provided in this embodiment of this application, or the terminal device may further determine a relative power ratio of the PTRS to a DMRS.

The terminal device determines transmit power of the PTRS.

The terminal device determines the transmit power of PTRS based on the relative power ratio of the PTRS to the PUSCH and transmit power of the PUSCH, or determines the transmit power of the PTRS based on the relative power ratio of the PTRS to the DMRS and transmit power of the DMRS.

The terminal device sends the PTRS by using the determined transmit power.

Uplink transmission is used as an example for description in this embodiment of this application. For downlink transmission, because a new radio (NR) uses an uplink-downlink symmetrical pilot pattern of the DMRS and an uplink-downlink symmetrical pilot pattern of the PTRS, all formulas and tables in this embodiment of this application are also applicable to downlink PTRS power determining, providing that the related "PUSCH" changes to a "PDSCH".

In this embodiment of this application, after a base station device obtains a pilot pattern, when a pilot pattern of a to-be-sent PTRS conflicts with a pilot pattern of another to-be-sent reference signal (that is, a reference signal other than the PTRS), in other words, when the pilot pattern indicates that the to-be-sent PTRS and the another to-be-sent reference signal need to occupy a same RE or several same REs (a conflicting RE), optionally, the PTRS is not allowed to occupy an RE of the another reference signal, that is, a priority of sending the another reference signal is higher than a priority of sending the PTRS. In this case, the base station device maps the another to-be-sent reference signal to the conflicting RE, and sends only the another reference signal on the conflicting RE. The transmit power of the PTRS may be determined by using the method described in the foregoing embodiment.

Alternatively, the to-be-sent PTRS is allowed to occupy an RE of the another to-be-sent reference signal. In this case, the base station device maps the to-be-sent PTRS to the conflicting RE, and sends only the PTRS on the conflicting RE. In addition, power of an RE originally used to send the another reference signal (excluding the conflicting RE mapped to the to-be-sent PTRS) may be used to increase the power of the PTRS.

Generally, in this embodiment of this application, power of an RE that is not mapped to data (in this embodiment of this application, the following expressions have a same meaning: an RE that cannot be used for data mapping, an RE that is not used for data mapping, an RE that is not mapped to data, and a muted RE) is used to increase the power of the PTRS. A relative power ratio of the PTRS after the increment to data (which may also be referred to as "a difference between the power of the PTRS and power of the data) is equal to a logarithm of a quantity of transport layers (the quantity of transport layers is greater than or equal to <NUM> during multi-layer transmission), namely, 10log<NUM>(Nlayers). When a quantity of PTRS ports is equal to a quantity of DMRS ports, to ensure orthogonal multiplexing of PTRSs and data at different transport layers of the terminal device, some REs at a specific transport layer are not mapped to data, and power of these REs that are not mapped to the data is used to increase power of a PTRS at the transport layer. In this case, a relative power ratio of a PTRS to data at each transport layer is equal to the logarithm of the quantity of transport layers. When the quantity of PTRS ports is less than the quantity of DMRS ports, power may be "borrowed" across layers. That is, power of an RE at a specific transport layer that is not mapped to data is used to increase power of a PTRS at another transport layer, and a relative power ratio of transmit power of the PTRS to data at the transport layer of the PTRS is equal to the logarithm of the quantity of transport layers.

In this embodiment of this application, a transmit end device first obtains the relative power ratio of the PTRS to the data channel or to the DMRS by searching a table or through calculation, determines the transmit power of the PTRS based on the transmit power of the data channel or the transmit power of the DMRS, and sends the PTRS by using the transmit power, so that different quantities of DMRS ports, different quantities of PTRS ports, and different port multiplexing manner configurations can be flexibly adapted, thereby ensuring efficient energy use.

<FIG> is a schematic structural diagram of hardware of a communications device <NUM> according to an embodiment of this application. As shown in <FIG>, the communications device <NUM> includes a memory <NUM>, a processor <NUM>, and a transmitter <NUM>.

The memory <NUM> is configured to store program code including a computer operation instruction.

The processor <NUM> is configured to run the computer operation instruction to perform the following operations:.

The transmitter <NUM> is configured to send the PTRS to another communications device by using the transmit power of the PTRS.

Optionally, the processor <NUM> is further configured to run the computer operation instruction to perform the following operations:.

Different from Embodiment <NUM> in which the transmit end first obtains the relative power ratio of the PTRS to the data channel or to the DMRS, and then determines the transmit power of the PTRS based on the transmit power of the data channel or the transmit power of the DMRS, in this example of this application, the transmit power of the PTRS is directly obtained through calculation.

In an LTE system, uplink transmit power needs to meet a requirement of a signal to interference plus noise ratio (SINR) required when a bit error rate of data transmission on a PUSCH reaches <NUM>% based on different modulation and coding schemes (MCS). A base station device determines transmit power of the PUSCH based on this requirement.

In an example of uplink transmission, a formula for calculating transmit power of a data channel may be: <MAT>.

In the formula (<NUM>), i represents a subframe number (or a timeslot number or a symbol number), c represents a cell number (or a beam number or a beam group number), and j represents a preset value, and may be preset or configured by the base station device;.

In this example of this application, considering that the PTRS is used for phase tracking to assist data demodulation, when the transmit power of the PTRS is directly obtained through calculation, a transmit power determining method may be obtained based on some parameters in the formula (<NUM>). The method includes the following steps:
A terminal device obtains a preset adjustment parameter and transmission bandwidth of a PTRS.

The terminal device determines transmit power of the PTRS, where the transmit power of the PTRS is determined by using at least a preset function, an adjustment parameter, and the transmission bandwidth of the PTRS.

The terminal device sends the PTRS to a base station device by using the transmit power of the PTRS.

In this example of this application, considering that the PTRS is used for phase tracking to assist data demodulation, when the transmit power of the PTRS is directly obtained through calculation, the transmit power of the PTRS may be determined based on some parameters in the formula (<NUM>) according to the following formula: <MAT>.

In the formula (<NUM>), parameters PCMAX,c(i), PO_PUSCH,c(j), αc(j), PLc, and fc(i) are all reused from the formula (<NUM>). In addition, PPTRS,c(i) represents the transmit power of the PTRS that includes transmit power used by the terminal device to send the PTRS to the cell c in the subframe i and whose value is in a unit of dBm, MPTRS,c represents the transmission bandwidth of the PTRS, PPTRS_OFFSET,c(m) represents the present adjustment parameter, and m is equal to <NUM> or <NUM>.

In this example of this application, the base station device may configure or preset a parameter by using RRC signaling or DCI.

In this example of this application, the transmit power of the PTRS is directly obtained through calculation, so that the terminal device can conveniently determine the transmit power of the PTRS.

This example of this application provides another method for directly obtaining transmit power of a PTRS through calculation. The method includes the following steps:
A terminal device obtains reference power of a PTRS.

The terminal device determines transmit power of the PTRS, where the transmit power of the PTRS is determined by using at least a preset function and the reference power of the PTRS.

The terminal device may determine the transmit power of the PTRS according to the following formula: <MAT>.

In the formula (<NUM>), meanings of parameters PPTRS,c(i), PCMAX,c(i), αc(j), and PLc are the same as those of the parameters in the formula (<NUM>). In addition, PO_PTRS,c(j) represents the reference power of the PTRS, and PO_PTRS,c(j) = PO_NOMINAL_PTRS + PO_UE_PTRS, where PO_NOMINAL_PTRS represents a common value configured by the base station device for all terminal devices in a cell c, and PO_UE_PTRS represents a specific value configured by the base station device for each terminal device in the cell c.

Further, a parameter g(i) may be further added to the formula (<NUM>), so that each terminal device can adjust the transmit power of the PTRS based on a condition of the terminal device, as shown in the following formula: <MAT> where
g(i) represents an adjustment parameter specific to the terminal device.

Further, parameters h(nRS), ΔPTRS(F), and ΔTxD(NPTRS-port) may be further added to the formula (<NUM>) to obtain the following formula: <MAT>.

In the formula (<NUM>), nRS represents a priority parameter of the PTRS, and h(nRS) represents a power offset obtained by the terminal device by using nRS;.

The transmit power determining method provided in example <NUM> and example <NUM> may be performed by the communications device shown in <FIG>. For example, the memory <NUM> is configured to store program code including a computer operation instruction. The processor <NUM> is configured to: obtain a required parameter, and obtain transmit power of a PTRS by using the parameter and the formulas (<NUM>) to (<NUM>). The transmitter <NUM> is configured to send the PTRS to another communications device by using the transmit power of the PTRS.

An embodiment of this application further provides a computer readable storage medium, configured to store a computer software instruction that needs to be executed by the foregoing processor. The computer software instruction includes a program that needs to be executed by the foregoing processor.

Moreover, the present invention may use a form of a computer program product that is implemented on one or more computer-usable storage media (including but not limited to a disk memory, an optical memory, and the like) that include computer-usable program code.

This application is described with reference to the flowcharts and/or block diagrams of the method, the device (system), and the computer program product according to this application. It should be understood that computer program instructions may be used to implement each process and/or each block in the flowcharts and/or the block diagrams and a combination of a process and/or a block in the flowcharts and/or the block diagrams. These computer program instructions may be provided for a general-purpose computer, a dedicated computer, an embedded processor, or a processor of any other programmable data processing device to generate a machine, so that the instructions executed by a computer or a processor of any other programmable data processing device generate an apparatus for implementing a specific function in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.

Claim 1:
A method of wireless communication comprising:
determining (<NUM>) a power ratio between a phase tracking reference signal, PTRS, and a data channel according to a mapping relationship between a quantity of transport layers and the power ratio;
wherein the power ratio is used for determining (<NUM>) a transmit power, the transmit power is used for sending (<NUM>) the PTRS during downlink transmission, the quantity of transport layers is greater than or equal to <NUM>, and the mapping relationship comprises:
the power ratio of the PTRS to the data channel is <NUM> dB when the quantity of transport layers is <NUM>;
the power ratio of the PTRS to the data channel is <NUM> dB when the quantity of transport layers is <NUM>;
the power ratio of the PTRS to the data channel is <NUM> dB when the quantity of transport layers is <NUM>;
the power ratio of the PTRS to the data channel is <NUM> dB when the quantity of transport layers is <NUM>; and
the power ratio of the PTRS to the data channel is <NUM> dB when the quantity of transport layers is <NUM>,
wherein a quantity of one or more PTRS ports for the PTRS is less than the quantity of transport layers.