TECHNICAL FIELD

This application relates to the field of communications technologies, and in particular, to a reference signal transmission method and apparatus.

BACKGROUND

With development of network systems, requirements on a communication rate and a capacity increase, and therefore a requirement on high-frequency resources also increases. A next-generation wireless communications network whose operating frequency band is above 6 GHz, for example, the 5th generation (5G) network, can provide an ultrahigh-speed data communication service. Within a frequency range above 6 GHz, frequency bands that can be used for the next-generation wireless communications network include frequency bands at 28 GHz, 39 GHz, 60 GHz, 73 GHz, and the like. A high-frequency communications system whose operating frequency band is above 6 GHz has significant features such as high bandwidth and a highly-integrated antenna array. Therefore, a relatively high throughput is easily implemented. However, an increase in a frequency results in an increase in phase noise (PHN) generated by random jitter of a frequency component, namely, a local oscillator. Therefore, impact of phase noise in high-frequency wireless communication cannot be ignored. As a frequency band increases, a higher phase noise level indicates greater impact on a received signal. Usually, a transmit end device may add a phase tracking reference signal (PTRS), and a receive end may estimate the phase noise based on the received PTRS.

A higher frequency band supported by a radio frequency component indicates greater impact of the phase noise. In the 5G standard, a carrier frequency band supported by a new radio (NR) network may be greater than 60 GHz, and impact of phase noise cannot be ignored in some cases. The PTRS has been allowed to be introduced in NR to measure and compensate for the phase noise.

Compared with an existing wireless communications network, the high-frequency communications system suffers more serious intermediate radio frequency distortion, especially impact caused by phase noise. In addition, impact of the Doppler effect and carrier frequency offset (CFO) on performance of the high-frequency communications system also increases as a position of a frequency band becomes higher. A common feature of the phase noise, the Doppler effect, and the CFO is that, a phase error, or referred to as phase offset, is brought to data reception of the high-frequency communications system. Consequently, the high-frequency communications system is deteriorated in performance, or even cannot operate.

In addition, in the next-generation wireless communications network, to meet an increasing communication requirement, an increasingly high requirement is imposed on higher order modulation such as 256 QAM (Quadrature Amplitude Modulation) or even 1024 QAM. In this case, in addition to a common phase error (CPE), inter-carrier interference (ICI) caused by the phase offset cannot be ignored either.

In the prior art, during PTRS configuration, impact, of inter-carrier interference caused by phase offset, on performance of a high-frequency communications system is almost not considered. Especially, when a modulation order is relatively high, the inter-carrier interference of the high-frequency communications system cannot be accurately estimated, and a bit error rate is high, resulting in relatively low spectral efficiency.

SUMMARY

This application provides a reference signal transmission method and apparatus, to reduce inter-carrier interference, thereby improving spectral efficiency.

An aspect of this application provides a reference signal transmission method, including:

generating one or more orthogonal frequency division multiplexing (OFDM) symbols, where at least one OFDM symbol includes a phase tracking reference signal (PTRS) resource block, the PTRS resource block includes at least two of three sequences: a PTRS sequence of Y elements, X elements after the PTRS sequence, and Z elements before the PTRS sequence, and the PTRS resource block occupies a plurality of consecutive resource elements (REs), where X, Y, and Z are all integers; and sending the one or more OFDM symbols.

Corresponding to the foregoing transmission solution at a transmit end, a transmission solution at a receive end is further disclosed. The transmission solution includes:

receiving one or more orthogonal frequency division multiplexing (OFDM) symbols, where at least one OFDM symbol includes a phase tracking reference signal (PTRS) resource block, the PTRS resource block includes at least two of three sequences: a PTRS sequence of Y elements, X elements after the PTRS sequence, and Z elements before the PTRS sequence, and the PTRS resource block occupies a plurality of consecutive resource elements (REs), where X, Y, and Z are all integers; and obtaining a complete PTRS sequence from the one or more OFDM symbols.

Corresponding to the foregoing method, a corresponding apparatus is further disclosed. A transmit end includes:

a processing module, configured to generate one or more orthogonal frequency division multiplexing (OFDM) symbols, where at least one OFDM symbol includes a phase tracking reference signal (PTRS) resource block, the PTRS resource block includes at least two of three sequences: a PTRS sequence of Y elements, X elements after the PTRS sequence, and Z elements before the PTRS sequence, and the PTRS resource block occupies a plurality of consecutive resource elements (REs), where X, Y, and Z are all integers; and a sending module, configured to send the one or more OFDM symbols.

A receive end includes:

a receiving module, configured to receive one or more orthogonal frequency division multiplexing (OFDM) symbols, where at least one OFDM symbol includes a phase tracking reference signal (PTRS) resource block, the PTRS resource block includes at least two of three sequences: a PTRS sequence of Y elements, X elements after the PTRS sequence, and Z elements before the PTRS sequence, and the PTRS resource block occupies a plurality of consecutive resource elements (REs), where X, Y, and Z are all integers; and a processing module, configured to obtain a complete PTRS sequence from the one or more OFDM symbols.

In the foregoing solution, each OFDM symbol may include the PTRS resource block, and there may be one or more PTRS resource blocks in one OFDM symbol. In this case, the foregoing solution may be:

generating one or more orthogonal frequency division multiplexing (OFDM) symbols, where each OFDM symbol includes at least one phase tracking reference signal (PTRS) resource block, each PTRS resource block includes at least two of three sequences: a PTRS sequence of Y elements, X elements after the PTRS sequence, and Z elements before the PTRS sequence, and the PTRS resource block occupies a plurality of consecutive resource elements (REs), where X, Y, and Z are all integers; and sending the one or more OFDM symbols.

Corresponding to the foregoing transmission solution at the transmit end, a transmission solution at the receive end is further disclosed. The transmission solution includes:

receiving one or more orthogonal frequency division multiplexing (OFDM) symbols, where each OFDM symbol includes at least one phase tracking reference signal (PTRS) resource block, each PTRS resource block includes at least two of three sequences: a PTRS sequence of Y elements, X elements after the PTRS sequence, and Z elements before the PTRS sequence, and the PTRS resource block occupies a plurality of consecutive resource elements (REs), where X, Y, and Z are all integers; and obtaining a complete PTRS sequence from the one or more OFDM symbols.

Corresponding to the foregoing method, a corresponding apparatus is further disclosed. A transmit end includes:

a processing module configured to generate one or more orthogonal frequency division multiplexing (OFDM) symbols, where each OFDM symbol includes at least one phase tracking reference signal (PTRS) resource block, each PTRS resource block includes at least two of three sequences: a PTRS sequence of Y elements, X elements after the PTRS sequence, and Z elements before the PTRS sequence, and the PTRS resource block occupies a plurality of consecutive resource elements (REs), where X, Y, and Z are all integers; and a sending module, configured to send the one or more OFDM symbols.

A receive end includes:

a receiving module, configured to receive one or more orthogonal frequency division multiplexing (OFDM) symbols, where each OFDM symbol includes at least one phase tracking reference signal (PTRS) resource block, each PTRS resource block includes at least two of three sequences: a PTRS sequence of Y elements, X elements after the PTRS sequence, and Z elements before the PTRS sequence, and the PTRS resource block occupies a plurality of consecutive resource elements (REs), where X, Y, and Z are all integers; and a processing module, configured to obtain a complete PTRS sequence from the one or more OFDM symbols.

In the foregoing solutions, if the transmit end is a network device, the receive end is a terminal device. Alternatively, if the transmit end is a terminal device, the receive end is a network device.

The foregoing apparatuses at the transmit end and the receive end may alternatively be in another form. The processing module is implemented by a processor, the receiving module is implemented by a receiver, and the sending module is implemented by a transmitter.

With reference to the foregoing method solutions and apparatus solutions, the PTRS resource block is located in one or more resource blocks (RBs).

With reference to the foregoing method solutions and apparatus solutions, the PTRS resource block includes X+Y+Z elements, and the X elements, the Y elements, and the Z elements are consecutive and arranged in a frequency division manner, where X≤Y and Z≤Y; or

the PTRS resource block includes X+Y elements or Y+Z elements, and the X elements and the Y elements, or the Y elements and the Z elements are consecutive and arranged in a frequency division manner, where X≤Y and Z≤Y; or

the PTRS resource block includes X+Z elements, and the X elements and the Z elements are consecutive and arranged in a frequency division manner, where (X+Z)≥Y, for example, (X+Z)≥(Y+2).

When the PTRS resource block includes X+Y elements or Y+Z elements, and X=Y or Y=Z, it is equivalent that the PTRS resource block includes two consecutive and same PTRS sequences.

With reference to the foregoing method solutions and apparatus solutions, when at least two OFDM symbols each include the PTRS resource block, or there are a plurality of OFDM symbols that include the PTRS resource block, the PTRS resource block may occupy a same position or different positions in the OFDM symbols, and the position herein is a frequency domain resource position in each OFDM symbol.

According to the foregoing methods and corresponding apparatuses, inter-carrier interference is reduced, thereby improving spectral efficiency.

Another aspect of this application provides a computer-readable storage medium. The computer-readable storage medium stores an instruction, and when the instruction is run on a computer, the computer is enabled to perform the methods according to the foregoing aspects.

Still another aspect of this application provides a communications chip, where the communications chip stores an instruction, and when the instruction is run on a network device or a terminal device, the network device or the terminal device is enabled to perform the methods according to the foregoing aspects.

Still another aspect of this application provides a computer program product including an instruction. When the computer program product is run on a computer, the computer is enabled to perform the methods according to the foregoing aspects.

