Cyclic prefix setting method and apparatus, communication apparatus, and storage medium

Abstract

The present disclosure relates to a cyclic prefix setting method and apparatus, a communication apparatus, and a storage medium. In at least one embodiment of the present disclosure, an explicit cyclic prefix and / or an implicit cyclic prefix of a first orthogonal frequency division multiplexing symbol are determined such that the explicit cyclic prefix is a cyclic prefix having a fixed length, and the implicit cyclic prefix is a cyclic prefix having an adjustable length. Furthermore, the explicit cyclic prefix is set in the first orthogonal frequency division multiplexing symbol, and the implicit cyclic prefix is set in a second orthogonal frequency division multiplexing symbol, thereby achieving compatibility with the frame structure of an NR system. Hence, if the cyclic-prefix length requirement changes, the length of the implicit cyclic prefix can be adjusted directly, without having to change the cyclic-prefix length by reconfiguring the subcarrier spacing. In this way, the cyclic-prefix length requirement is met and spectrum usage efficiency is improved; moreover, since the subcarrier spacing remains unchanged, the transmission time of each orthogonal frequency division multiplexing symbol also remains unchanged, thereby avoiding an increase in service transmission latency.

Description

Method and apparatus for setting cyclic prefix, communication apparatus and storage medium

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present disclosure claims priority to the Chinese patent application No. 202411363423.X entitled "Method and apparatus for setting cyclic prefix, communication apparatus and storage medium" filed with the China Patent Office on September 27, 2024, the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] Embodiments of the present disclosure relate to the field of communication technology, in particular to a method and apparatus for setting cyclic prefix, a communication apparatus and a storage medium. BACKGROUND

[0004] Currently, the new radio (NR) system of the fifth generation mobile communication technology (5G) transmits signals using the orthogonal frequency division multiplexing (OFDM) modulation method.

[0005] In order to overcome the OFDM symbol interference problem caused by multipath, a cyclic prefix (CP) is introduced in the guard interval of the OFDM symbol to ensure that the number of cycles of the time delay multipath signal waveform of the OFDM symbol within the fast Fourier transform (FFT) period is also an integer, so that the signal with a time delay less than the guard interval will not produce symbol interference in the demodulation process.

[0006] However, the setting of the CP is determined by a fixed frame structure, and a CP with a fixed length is used in the frame structure. Since the length of the CP is related to the multipath delay difference, that is, the larger the multipath delay difference, the longer the CP required, and the smaller the multipath delay difference, the smaller the CP required, therefore, using a CP with a fixed length cannot meet the length requirements of different terminals with different CPs, and cannot improve the spectral efficiency. If the length of the CP is to be changed, only the subcarrier spacing (SCS) in the frame structure can be reconfigured, which has at least two defects as follows:

[0007] 1: The change of the SCS can only be configured in a semi-static manner, and cannot meet the length requirements of different terminals with different CPs.

[0008] 2: change of SCS, which will affect user experience, for example, by increasing CP by reducing SCS, since SCS determines the period of OFDM symbol (SCS is inversely proportional to the period of OFDM symbol), thus reducing SCS will cause the period of OFDM symbol to increase, that is, the transmission time of each OFDM symbol becomes longer, thus causing the service transmission delay to increase. SUMMARY

[0009] At least one embodiment of the present disclosure provides a cyclic prefix setting method, device, communication device and storage medium, without changing the length of the cyclic prefix by reconfiguring the subcarrier spacing.

[0010] In a first aspect, the present disclosure provides a cyclic prefix setting method, which comprises:

[0011] determining the explicit cyclic prefix and / or the implicit cyclic prefix of the first OFDM symbol; wherein the explicit cyclic prefix is a cyclic prefix with fixed length, and the implicit cyclic prefix is a cyclic prefix with adjustable length;

[0012] setting the explicit cyclic prefix in the first OFDM symbol, and / or setting the implicit cyclic prefix in the second OFDM symbol; wherein the second OFDM symbol is the adjacent symbol of the first OFDM symbol.

[0013] In some embodiments, the position of the explicit cyclic prefix is before the first OFDM symbol, and the position of the implicit cyclic prefix is the end of the second OFDM symbol; wherein the second OFDM symbol is the previous symbol of the first OFDM symbol; (Note: the generation of the cyclic prefix (including the explicit cyclic prefix and the implicit cyclic prefix) here is the cyclic prefix of the first OFDM symbol);

[0014] Alternatively, the position of the explicit cyclic prefix is after the first OFDM symbol, and the position of the implicit cyclic prefix is the starting position of the second OFDM symbol; wherein the second OFDM symbol is the next symbol of the first OFDM symbol. (Note: the generation of the cyclic prefix (including the explicit cyclic prefix and the implicit cyclic prefix) here is the cyclic prefix of the first OFDM symbol, which can also be called cyclic suffix);

[0015] Alternatively, the position of the explicit cyclic prefix is before the first OFDM symbol, and the position of the implicit cyclic prefix is the starting position of the second OFDM symbol; wherein the second OFDM symbol is the previous symbol of the first OFDM symbol; (Note: the generation of the cyclic prefix (including the explicit cyclic prefix and the implicit cyclic prefix) here is the cyclic prefix of the first OFDM symbol);

[0016] Alternatively, the position of the explicit cyclic prefix is after the first OFDM symbol, and the position of the implicit cyclic prefix is at the end of the second OFDM symbol; wherein the second OFDM symbol is the next symbol of the first OFDM symbol. (Note: the cyclic prefix (including the explicit cyclic prefix and the implicit cyclic prefix) generated here is the cyclic prefix of the first OFDM symbol, which can also be called the cyclic suffix).

[0017] In a second aspect, the embodiments of the present disclosure further provide a cyclic prefix setting device, which comprises:

[0018] A determination unit is configured to determine an explicit cyclic prefix and / or an implicit cyclic prefix of the first OFDM symbol; wherein the explicit cyclic prefix is a cyclic prefix with a fixed length, and the implicit cyclic prefix is a cyclic prefix with an adjustable length.

[0019] A setting unit is configured to set the explicit cyclic prefix in the first OFDM symbol, and / or set the implicit cyclic prefix in the second OFDM symbol; wherein the second OFDM symbol is an adjacent symbol of the first OFDM symbol.

[0020] In a third aspect, the embodiments of the present disclosure further provide a communication device, which comprises a memory, a transceiver, and a processor.

[0021] The memory is configured to store a computer program; the transceiver is configured to transceive data under the control of the processor; and the processor is configured to read the computer program in the memory and perform:

[0022] Determine an explicit cyclic prefix and / or an implicit cyclic prefix of the first OFDM symbol; wherein the explicit cyclic prefix is a cyclic prefix with a fixed length, and the implicit cyclic prefix is a cyclic prefix with an adjustable length.

[0023] Set the explicit cyclic prefix in the first OFDM symbol, and / or set the implicit cyclic prefix in the second OFDM symbol; wherein the second OFDM symbol is an adjacent symbol of the first OFDM symbol.

[0024] In a fourth aspect, the embodiments of the present disclosure further provide a processor-readable storage medium, wherein the processor-readable storage medium stores a program, and the program is configured to make the processor execute the cyclic prefix setting method of any one of the embodiments of the first aspect.

[0025] In at least one embodiment of the present disclosure, by determining the explicit cyclic prefix and / or the implicit cyclic prefix of the first OFDM symbol, the explicit cyclic prefix is a fixed-length cyclic prefix, and the implicit cyclic prefix is an adjustable-length cyclic prefix; then, the explicit cyclic prefix is set in the first OFDM symbol, and the implicit cyclic prefix is set in the second OFDM symbol, which is the adjacent symbol of the first OFDM symbol, which can be compatible with the frame structure of the NR system. It can be seen that if the length requirement of the cyclic prefix changes, the length of the implicit cyclic prefix can be directly adjusted, and there is no need to change the length of the cyclic prefix by reconfiguring the subcarrier spacing. While meeting the length requirement of the cyclic prefix and improving the spectral efficiency, the subcarrier spacing remains unchanged, and the subcarrier spacing determines the period of the OFDM symbol (the subcarrier spacing is inversely proportional to the period of the OFDM symbol), so the transmission time of each OFDM symbol remains unchanged, and thus the service transmission delay is not increased. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings needed in the embodiments or related technical descriptions will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and other drawings can also be obtained by those skilled in the art based on these drawings.

[0027] FIG. 1 is a schematic diagram of an OFDM symbol with a cyclic prefix CP added in a non-interference scenario and an interference scenario;

[0028] FIG. 2 is a schematic diagram of a slot and a symbol in a subframe when the subcarrier spacing SCS is 60 kHz;

[0029] FIG. 3 is a flowchart of a cyclic prefix setting method provided by an embodiment of the present disclosure;

[0030] FIG. 4 is a frame structure without an explicit CP with an adjustable length of an implicit CP provided by an embodiment of the present disclosure;

[0031] FIG. 5 is a frame structure with an explicit CP with an adjustable length of an implicit CP provided by an embodiment of the present disclosure;

[0032] FIG. 6 is a schematic diagram of different indication modes of the positions of frequency domain resource elements provided by an embodiment of the present disclosure;

[0033] FIG. 7 is a schematic diagram of a normal symbol and a symbol containing a special signal RE_res indication mode provided by an embodiment of the present disclosure;

[0034] FIG. 8 is a schematic diagram of the inclusion relationship of different lengths (M points) of an implicit CP provided by an embodiment of the present disclosure;

[0035] FIG. 9 is a schematic diagram of the inclusion and the included relationship of adjacent OFDM symbols with different lengths of the implicit CP according to an embodiment of the present disclosure;

[0036] FIG. 10 is a schematic diagram of calculating the communication bandwidth B according to an embodiment of the present disclosure;

[0037] FIG. 11 is a schematic diagram of generating the time-domain waveform of the implicit CP according to an embodiment of the present disclosure;

[0038] FIG. 12 is a schematic diagram of a device for setting the cyclic prefix according to an embodiment of the present disclosure;

[0039] FIG. 13 is a schematic diagram of a communication device according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0040] In order to more clearly understand the above-mentioned purposes, features and advantages of the present disclosure, the present disclosure will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the described embodiments are part of the embodiments of the present disclosure, rather than all the embodiments. The specific embodiments described herein are only used to explain the present disclosure, but not to limit the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure are within the scope of protection of the present disclosure.

[0041] It should be noted that, in this document, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any such actual relationship or order between such entities or actions.

[0042] OFDM is to divide the channel into several orthogonal sub-channels, convert the high-speed data signal into parallel low-speed sub-data streams, modulate each sub-channel to obtain an orthogonal signal. The orthogonal signal can be separated by using correlation technology at the receiving end, so as to reduce the mutual interference between the sub-channels. The signal on each sub-channel has a bandwidth smaller than the correlation bandwidth of the channel, so that each sub-channel can be considered as a flat fading, thereby eliminating the inter-symbol interference, and since the bandwidth of each sub-channel is only a small part of the original channel bandwidth, channel equalization becomes relatively easy.

[0043] FIG. 1 is a schematic diagram of the interference-free scenario and the interference scenario after adding the CP to the OFDM symbol.

[0044] In the interference-free scenario, the time delay d between the multipath 2 and the multipath 1 is less than the CP length, and when the FFT transformation is performed, since the multipath 2 is within the FFT receiving window, there is still a complete periodic signal, so both the multipath signals can recover the original information, and the OFDM symbol 1 has no interference to the OFDM symbol 2.

[0045] In the interference scenario, the delay d between multipath 2 and multipath 1 is greater than the CP length. When performing FFT transformation, multipath 2 cannot form a complete periodic signal in the FFT receiving window, so multipath 2 cannot completely recover the original information. At the same time, the OFDM symbol 1 of multipath 2 interferes with the OFDM symbol 2 of multipath 1.

[0046] The following parameters are defined in the NR standard:

[0047] (1) Sampling rate T c , that is, the sampling rate when the terminal or base station receives a signal.

[0048] T c = 1 / (Δf max × N f ), where Δf max = 480 × 10 3 Hz, N f = 4096.

[0049] (2) Constant k, k = T s / T c = 64, where T s = 1 / (Δf ref × N f,ref ), Δf ref = 15 × 10 3 Hz, N f,ref = 2048.

[0050] (3) Subcarrier spacing SCS and cyclic prefix CP, as shown in Table 1:

[0051] Table 1 Transmission parameter table

[0052] Where Δf is the subcarrier spacing SCS, and μ is the subcarrier width configuration parameter (that is, the index of SCS).

[0053] (4) Frame structure: the length of one radio frame (frame) is 10 ms, containing 10 sub-frames (sub-frame), and the length of each sub-frame is 1 ms. Each sub-frame contains a number of slots (the number of slots contained by different SCS is different), and each slot contains 14 symbols. The frame structure parameters are shown in Table 2:

[0054] Table 2 Frame structure parameters

[0055] Where, is the number of symbols included in each slot (slot), is the number of slots included in each radio frame. is the number of slots included in each sub-frame.

[0056] As can be seen, Table 2 describes the number of slots included in a 10ms radio frame and the number of slots included in each subframe under different SCS. For example, when μ = 4, each subframe includes 16 slots, and each slot includes 14 symbols, i.e., each subframe includes 16 x 14 = 224 symbols.

[0057] (5) Symbol length and CP length

[0058] wherein μ is a subcarrier width configuration parameter, and l is a symbol number.

[0059] FIG. 2 is a schematic diagram of slots and symbols included in a subframe when the subcarrier spacing SCS is 60 kHz, wherein the subcarrier spacing SCS of 60 kHz corresponds to μ = 2 according to Table 1. In FIG. 2, one subframe includes 4 slots, and each slot includes 14 symbols, i.e., one subframe includes 56 symbols, denoted as #0 to #55.

[0060] In FIG. 2, the symbol #8 corresponds to the symbol number l = 8 (i.e., l ≠ 0 and l ≠ 7 x 2 2 ), and thus the CP length corresponding to the symbol #8 is 144k x 2 -2 , wherein k is a constant (i.e., 64), and thus the CP length corresponding to the symbol #8 is 144 x 64 / 4. The symbol length corresponding to the symbol #8 is 2048k x 2 -2 = 2048 x 64 / 4.

[0061] In FIG. 2, the symbol #28 corresponds to the symbol number l = 28 (i.e., l = 7 x 2 2 ), and thus the CP length corresponding to the symbol #8 is 144k x 2 -2 + 16k, wherein k is a constant (i.e., 64), and thus the CP length corresponding to the symbol #28 is 16 x 64 + 144 x 64 / 4. The symbol length corresponding to the symbol #28 is 2048k x 2 -2 = 2048 x 64 / 4.

[0062] As can be seen, the current CP setting is determined by a fixed frame structure, and a CP of fixed length is used in the frame structure. The CP length is different for different subcarrier spacing SCS, as shown in Table 3:

[0063] Table 3: Correspondence between SCS and CP length

[0064] wherein μ is a subcarrier width configuration parameter, 4.68 is the length of a normal CP, and 16.7 is the length of an extended CP.

[0065] However, in actual deployment scenarios, the length requirement of the CP has a large range of variation, such as a minimum requirement of 0.0478us and a maximum requirement of 20.65us. The use of a fixed-length CP cannot meet the length requirements of different terminals for different CPs. Moreover, the use of a fixed-length CP cannot improve the spectral efficiency. For example:

[0066] For SCS=15KHz, the length of the normal CP is 4.68us, and for the minimum requirement scenario, the actual length requirement is 0.0478us, that is, most of the length of the CP (4.68us-0.0478us) is not used, and thus the spectral efficiency is low.

[0067] If the length of the CP is to be changed, the subcarrier spacing SCS in the frame structure can only be reconfigured, and at least two defects exist as follows:

[0068] 1: The change of the SCS can only be configured in a semi-static manner and cannot adapt to the length requirements of different terminals for different CPs.

[0069] 2: The change of the SCS will affect the user experience. For example, the CP is increased by reducing the SCS. Since the SCS determines the period of the OFDM symbol (the SCS is inversely proportional to the period of the OFDM symbol), reducing the SCS will cause the period of the OFDM symbol to increase, that is, the transmission time of each OFDM symbol becomes longer, thereby increasing the service transmission delay.

[0070] FIG. 3 is a flowchart of a method for setting a cyclic prefix provided by an embodiment of the present disclosure, which is applied to a terminal (User Equipment, UE) or a base station. As shown in FIG. 3, the method for setting the cyclic prefix can include but is not limited to steps 301 and 302:

[0071] In step 301, a dominant cyclic prefix and / or a recessive cyclic prefix of a first orthogonal frequency division multiplexing symbol are determined; wherein the dominant cyclic prefix is a fixed-length cyclic prefix, and the recessive cyclic prefix is an adjustable-length cyclic prefix.

[0072] In this embodiment, the CP of each OFDM symbol is composed of a dominant CP and a recessive CP, and the length of the dominant CP can be zero. The dominant CP is embodied in the time domain of the frame structure, and the recessive CP is not embodied in the time domain of the frame structure but in the frequency domain of the OFDM symbol.

[0073] In order to be compatible with the frame structure of the NR system, in the embodiment, the explicit CP is set as a cyclic prefix with a fixed length, so that the explicit CP is similar to the cyclic prefix with a fixed length in the frame structure of the NR system, and the implicit CP is not embodied in the time domain of the frame structure, so that the explicit CP and the implicit CP do not change the frame structure of the NR system.

[0074] In order to be able to adjust the length of the cyclic prefix in time, in the embodiment, the implicit CP is set as a cyclic prefix with an adjustable length, and when it is necessary to change the length of the cyclic prefix, the length of the implicit CP is adjusted to meet the length requirement of the cyclic prefix.

[0075] It can be seen that when the length requirement of the cyclic prefix changes, in the embodiment, the length of the implicit CP is only adjusted to meet the length requirement of the cyclic prefix, and the length of the explicit CP does not need to be adjusted, that is, the length adjustment of the implicit CP does not affect the length of the explicit CP, and the length of the explicit CP is unchanged. Therefore, the length of the cyclic prefix does not need to be changed by reconfiguring the subcarrier spacing SCS, that is, the SCS is unchanged. The SCS determines the period of the OFDM symbol (the SCS is inversely proportional to the period of the OFDM symbol), so the transmission time of each OFDM symbol is unchanged, so that the service transmission delay is not increased.

[0076] In step 302, an explicit cyclic prefix is set in a first orthogonal frequency division multiplexing symbol, and / or an implicit cyclic prefix is set in a second orthogonal frequency division multiplexing symbol; wherein the second orthogonal frequency division multiplexing symbol is an adjacent symbol of the first orthogonal frequency division multiplexing symbol.

[0077] In the embodiment, the explicit CP of the first OFDM symbol is set in the first OFDM symbol, and the implicit CP of the first OFDM symbol is set in the second OFDM symbol. That is, the explicit CP and the implicit CP of the first OFDM symbol are respectively set in different OFDM symbols. Whether the first OFDM symbol increases the explicit CP of the first OFDM symbol or the second OFDM symbol increases the implicit CP of the first OFDM symbol, the frame structure of the NR system is not changed, so that the scheme of the embodiment can be compatible with the frame structure of the NR system.

[0078] It can be seen that, in the embodiment, by determining the explicit CP and / or the implicit CP of the first OFDM symbol, the explicit CP is a cyclic prefix with a fixed length, and the implicit CP is a cyclic prefix with an adjustable length. Then, the explicit CP is set for the first OFDM symbol, and the implicit CP is set for the second OFDM symbol, which is the adjacent symbol of the first OFDM symbol, so that the frame structure of the NR system can be compatible. If the length requirement of the cyclic prefix changes, the length of the implicit CP can be directly adjusted, and it is not necessary to change the length of the cyclic prefix by reconfiguring the subcarrier spacing SCS. In this way, the length requirement of the cyclic prefix is met, the spectral efficiency is improved, and the transmission time of each OFDM symbol is unchanged because the SCS is unchanged, and the SCS determines the period of the OFDM symbol (the SCS is inversely proportional to the period of the OFDM symbol), so that the service transmission delay is not increased.

[0079] In some embodiments, in step 301, the explicit cyclic prefix and / or the implicit cyclic prefix of the first OFDM symbol are determined, including the following (1) and / or (2):

[0080] (1) determining a frame structure parameter, the frame structure parameter including: a subcarrier spacing, a length of the explicit cyclic prefix, and a position of the explicit cyclic prefix.

[0081] In the embodiment, the frame structure parameter can be configured by a protocol indication or high-layer signaling indication.

[0082] The subcarrier spacing SCS in the frame structure parameter can support at least one of the following two cases:

[0083] Case 1: a multiple of 15KHz, wherein the multiple is 2 μ μ is a subcarrier width configuration parameter, and μ is an integer less than, greater than, or equal to zero. That is, the SCS is supported to be expanded by a multiple based on 15KHz.

[0084] For example, the multiple is 0.5, 1, 2, 4, 8, 16, 32, 64, 128, 256, etc. The expanded SCS is: 7.5KHz, 15KHz, 30KHz, 60KHz, 120KHz, 240KHz, 480KHz, 960KHz, 1920KHz, 3840KHz, etc.

[0085] Case 2: a multiple of 17KHz, wherein the multiple is 2 μ μ is a subcarrier width configuration parameter, and μ is an integer less than, greater than, or equal to zero. That is, the SCS is supported to be expanded by a multiple based on 17KHz.

[0086] For example, the multiples are 0.5, 1, 2, 4, 8, 16, 32, 64, 128, etc. The extended SCS are: 8.5KHz, 17KHz, 34KHz, 68KHz, 136KHz, 272KHz, 544KHz, 1088KHz, 2176KHz, etc.

[0087] The explicit CP in the frame structure parameter is a cyclic prefix independent of the OFDM symbol, so the position of the explicit CP can be located before the OFDM symbol or after the OFDM symbol (also known as a cyclic suffix (CS)).

[0088] It should be noted that when there is no explicit CP in the frame structure (i.e., the length of the explicit CP is zero), the configuration of the length of the explicit CP and the position of the explicit CP can not be performed. For example, for SCS = 15KHz, each slot contains 15 OFDM symbols, and each OFDM symbol has no explicit CP; for SCS = 17KHz, each slot contains 16 OFDM symbols, and each OFDM symbol has an explicit CP.

[0089] (2) Determine the length of the implicit cyclic prefix, the position of the implicit cyclic prefix, and the time domain waveform of the implicit cyclic prefix.

[0090] In this embodiment, the length of the implicit CP can be configured by protocol indication, high layer signaling indication, media access control control element (MAC-CE) indication, or dynamic downlink control information (DCI) indication.

[0091] Among them, the length of the implicit CP indicated by the protocol is applicable to all OFDM symbols. The length of the implicit CP indicated by the high layer signaling, MAC-CE or dynamic DCI can indicate different implicit CPs for different OFDM symbols, or different implicit CPs for the OFDM symbols used by the scheduled data.

[0092] For example, FIG. 4 is a frame structure of a non- explicit CP length-adjustable non- explicit CP (i.e., the length of the explicit CP is zero). In FIG. 4, 1 ms includes 15 OFDM symbols, and OFDM symbol (8) is taken as an example. OFDM symbol (8) has no explicit CP, and the implicit CP of OFDM symbol (8) is arranged at the end of OFDM symbol (7). If the data length of OFDM symbol (8) and OFDM symbol (7) is N points (for example, N = 2048), the length of the implicit CP of OFDM symbol (8) is M points. The data of the implicit CP of OFDM symbol (8) is the same as the M-point data at the end of OFDM symbol (8) (i.e., the shaded part in FIG. 4). The time domain data of the implicit CP of OFDM symbol (8) is realized by setting the input point of a specific IFFT (Inverse Fast Fourier Transform) of the data, where the input point of the IFFT refers to the length of the frequency domain signal input when the IFFT operation is performed, that is, the number of FFT points.

[0093] In order to simplify the implementation complexity of the communication device, in some embodiments, the length of the implicit CP is limited to several levels: N / 2 m ; where N is the length of the first OFDM symbol, and m is a positive integer greater than or equal to 2. For example, the length of the implicit CP is divided into 5 levels: N / 4, N / 8, N / 16, N / 32, and N / 64.

[0094] In this embodiment, the position of the implicit CP can be configured as the end of the previous OFDM symbol or the start position of the next OFDM symbol. Wherein the previous OFDM symbol can be understood as the previous OFDM symbol of the OFDM symbol where the explicit CP is located, and similarly, the next OFDM symbol can be understood as the next OFDM symbol of the OFDM symbol where the explicit CP is located.

[0095] In this embodiment, the time domain waveform of the implicit CP includes any one of the following (i) to (iii):

[0096] (i) a time domain signal with zero power (i.e., the amplitude is zero).

[0097] (ii) a preset time domain signal with non-zero power, for example, a linear frequency modulation (LFM) signal.

[0098] (iii) a time domain signal formed by the transmission data of the second OFDM symbol.

[0099] Wherein, the LFM signal is generated in the following manner:

[0100] s(t) is the LFM signal, μ = B / T (B is the bandwidth of the LFM signal; T is the time length of the LFM signal, corresponding to the length of the implicit CP), A is the amplitude of the LFM signal.

[0101] It should be noted that the implicit CPs of different OFDM symbols can adopt the same time domain waveform (for example, the time domain signals of zero power or the preset time domain signals of non-zero power are adopted for different OFDM symbols), or different time domain waveforms (for example, the time domain signals of zero power are adopted for some continuous symbols, and the preset time domain signals of non-zero power are adopted for some continuous symbols).

[0102] It should be noted that for the OFDM symbol of uplink (terminal sending, base station receiving), considering that the terminal does not know the data information at the tail of the previous OFDM symbol (for example, the previous OFDM symbol is sent by another terminal), the base station can agree that the tail of the OFDM symbol (or the front part of the OFDM symbol) is a specific time domain waveform (for example, a time domain signal of zero power or a preset time domain signal of non-zero power), and the terminal can generate a specific time domain waveform at the tail (or the front part) of the sending symbol.

[0103] It should be noted that, optionally, for different terminals multiplexed on one OFDM symbol, the lengths of the implicit CPs are the same.

[0104] It should be noted that if the lengths of the implicit CPs of adjacent symbols are different, the time domain data of the longer-length implicit CP contains the time domain data of the shorter-length implicit CP.

[0105] In some embodiments, in step 302, the explicit CP is arranged at the first OFDM symbol, and / or the implicit CP is arranged at the second OFDM symbol, including (1) or (2) as follows:

[0106] (1) The position of the explicit CP is located before the first OFDM symbol, and the position of the implicit CP is the end of the second OFDM symbol; wherein the second OFDM symbol is the previous symbol of the first OFDM symbol.

[0107] In this embodiment, the explicit CP of the first OFDM symbol is a cyclic prefix independent of the first OFDM symbol, and therefore the explicit CP is arranged before the first OFDM symbol.

[0108] Since the cyclic prefix of the first OFDM symbol includes the explicit CP and the implicit CP, and the explicit CP is located before the first OFDM symbol, the implicit CP is also located before the first OFDM symbol. Considering that the implicit CP is not embodied in the time domain of the frame structure, the implicit CP is set at the end of the second OFDM symbol, that is, the implicit CP is embodied in the frequency domain of the second OFDM symbol. The second OFDM symbol is the next symbol of the first OFDM symbol.

[0109] For example, for a scenario in which the length requirement of the cyclic prefix is the minimum requirement (0.0478us), in this embodiment, the length of the explicit CP can be determined as zero. FIG. 4 is a frame structure without the explicit CP (that is, the length of the explicit CP is zero) in which the length of the implicit CP is adjustable. In FIG. 4, 1ms includes 15 OFDM symbols, each of which has no explicit CP, and the subcarrier spacing SCS in the frame structure parameter is 15KHz. Taking the OFDM symbol (8) as an example, the OFDM symbol (8) has no explicit CP, and the implicit CP of the OFDM symbol (8) is set at the end of the OFDM symbol (7). In the actual data transmission process, if the length requirement of the cyclic prefix increases (for example, the terminal is at the edge of the cell), the length of the implicit CP can be adjusted to meet the increased length requirement.

[0110] For another example, for a scenario in which the length requirement of the cyclic prefix is the normal requirement (for example, 3.676us), in this embodiment, the length of the explicit CP is determined as not zero and is a fixed length. FIG. 5 is a frame structure with the explicit CP (that is, the length of the explicit CP is not zero) in which the length of the implicit CP is adjustable. In FIG. 5, 1ms includes 16 OFDM symbols, the length of the explicit CP of each OFDM symbol is fixed, for example, 128 points, and the subcarrier spacing SCS in the frame structure parameter is 17KHz. Taking the OFDM symbol (8) as an example, the explicit CP of the OFDM symbol (8) is set before the OFDM symbol (8), and the implicit CP of the OFDM symbol (8) is set at the end of the OFDM symbol (7). In the actual data transmission process, if the length requirement of the cyclic prefix increases (for example, the terminal is at the edge of the cell), the length of the implicit CP can be adjusted to meet the increased length requirement.

[0111] (2) The position of the explicit cyclic prefix is located after the first orthogonal frequency division multiplexing symbol, and the position of the implicit cyclic prefix is the start position of the second orthogonal frequency division multiplexing symbol; the second orthogonal frequency division multiplexing symbol is the next symbol of the first orthogonal frequency division multiplexing symbol.

[0112] In this embodiment, the explicit CP of the first OFDM symbol is a cyclic prefix independent of the first OFDM symbol, and therefore, the explicit CP can be set after the first OFDM symbol. At this time, the explicit CP can also be referred to as an explicit CS (cyclic suffix).

[0113] Since the cyclic prefix of the first OFDM symbol includes an explicit CP and an implicit CP, and the explicit CP is located after the first OFDM symbol, the implicit CP is also located after the first OFDM symbol, and at this time, the implicit CP is also called an implicit CS (cyclic suffix). Considering that the implicit CP does not exist in the time domain of the frame structure, the implicit CP is set at the start position of the second OFDM symbol, that is, the implicit CP exists in the frequency domain of the second OFDM symbol. The second OFDM symbol is the next symbol of the first OFDM symbol.

[0114] In some embodiments, the method for setting the cyclic prefix shown in FIG. 3 further includes the following steps not shown in FIG. 3:

[0115] Determining the positions of at least one frequency domain resource element used to generate a time domain waveform of an implicit cyclic prefix.

[0116] In this embodiment, in order to be able to generate a time domain waveform of an implicit CP, the positions of L (L≥1) frequency domain resource elements (REs) used to generate a time domain waveform of an implicit CP need to be determined. That is, when transmitting data, both the receiving end and the transmitting end consider that the REs at these positions cannot be used to transmit communication data. The value of L is related to the length of the implicit CP, and the longer the implicit CP, the greater the value of L.

[0117] In some embodiments, the positions of the at least one frequency domain resource element can be determined by obtaining indication information.

[0118] The indication information is used to indicate the positions of the at least one frequency domain resource element. The indication information is obtained by protocol indication, high layer signaling indication, MAC-CE indication, or dynamic DCI indication.

[0119] In this embodiment, the indication information is comb indication, block indication, or bitmap indication.

[0120] The comb indication is used to indicate the positions of frequency domain resource elements distributed in a comb shape (i.e., discontinuous, such as equidistant discontinuous). The block indication is used to indicate the positions of frequency domain resource elements distributed in a block shape (i.e., continuous). The bitmap indication is used to indicate the positions of frequency domain resource elements distributed irregularly.

[0121] For example, FIG. 6 is a schematic diagram of different ways of indicating the position of the frequency domain resource elements. In FIG. 6, the comb indication indicates that the positions of the frequency domain resource elements are distributed in a comb shape, i.e., equidistantly and discontinuously. The distance is the comb factor. If the comb factor is 15 and n is the position of the first frequency domain resource element, then n+15 is the position of the second frequency domain resource element and n+30 is the position of the third frequency domain resource element. If the comb factor is 30 and n is the position of the first frequency domain resource element, then n+30 is the position of the second frequency domain resource element.

[0122] In FIG. 6, the block indication indicates that the positions of the frequency domain resource elements are distributed in a block shape, i.e., continuously. If the block length is K, then the positions of the frequency domain resource elements indicated by the block indication are K and continuous. If the block length is 2K, then the positions of the frequency domain resource elements indicated by the block indication are 2K and continuous.

[0123] In FIG. 6, the bitmap indication is used to indicate the positions of the frequency domain resource elements that are distributed irregularly. The bitmap indication is a bit map, in which 1 represents a frequency domain resource element used to generate the time domain waveform of the implicit CP.

[0124] It should be noted that for some special signals, such as the primary synchronization (PSS) signal, the secondary synchronization (SSS) signal, the physical broadcast channel (PBCH) signal or the physical downlink control channel (PDCCH) signal used for cell search, some frequency domain resource elements cannot be indicated as RE_res (i.e., a frequency domain resource element used to generate the time domain waveform of the implicit CP). The positions of the RE_res can be additionally indicated to ensure that the length of the implicit CP of the specific time domain waveform is achieved.

[0125] It should be noted that for the downlink (from the base station to the terminal) data transmission, the indication information of the positions of the RE_res can be indicated and determined according to the resources of the physical resource blocks (PRBs). Alternatively, when different terminals multiplex the downlink resources in a frequency division multiplexing (FDM) manner, the positions of the RE_res are the same and are distributed within the channel bandwidth frequency domain resources.

[0126] It should be noted that, for the data transmission in the uplink (terminal to base station), the indication information of the position of RE_res can be indicated and determined according to the resource of the physical resource block. Alternatively, when different terminals multiplex uplink resources in an FDM manner, the positions of RE_res can be different and distributed in the frequency domain resources scheduled for the terminals.

[0127] In some embodiments, the method for setting the cyclic prefix shown in FIG. 3 further includes a step not shown in FIG. 3: determining the multipath delay difference.

[0128] In the communication process, in order to ensure that the length of the cyclic prefix (including the explicit CP and the implicit CP) matches the scenario of the multipath, that is, the sum of the lengths of the explicit CP and the implicit CP is greater than the multipath delay difference, the multipath delay difference needs to be determined.

[0129] The manner of determining the multipath delay difference includes any one of the following (1) to (3):

[0130] (1) sending a multipath measurement signal.

[0131] In this embodiment, the multipath measurement signal is sent by the sending end, and the multipath delay difference is measured by the receiving end based on the multipath measurement signal. The sending end and the receiving end are not the same device.

[0132] For example, the base station sends the multipath measurement signal, the terminal measures the multipath delay difference, and the terminal feeds back the multipath delay difference to the base station. Alternatively, the terminal sends the multipath measurement signal, and the base station measures the multipath delay difference.

[0133] (2) sending a multipath measurement signal and measuring a multipath delay difference based on the multipath measurement signal.

[0134] In this embodiment, the multipath measurement signal is sent by the sending end, and the multipath delay difference is measured by the sending end based on the multipath measurement signal.

[0135] For example, base station A sends a multipath measurement signal, and base station A measures the multipath delay difference. Alternatively, terminal B sends a multipath measurement signal, terminal B measures the multipath delay difference, and terminal B feeds back the multipath delay difference to the base station.

[0136] (3) receiving a multipath measurement signal and measuring a multipath delay difference based on the multipath measurement signal.

[0137] For example, the base station receives the multipath measurement signal sent by the terminal, and measures the multipath delay difference based on the multipath measurement signal. Alternatively, the terminal receives the multipath measurement signal sent by the base station, and measures the multipath delay difference based on the multipath measurement signal, and the terminal feeds back the multipath delay difference to the base station.

[0138] The multipath measurement signal can be any one of the following (1) to (4):

[0139] (1) Downlink channel measurement signal, for example, Channel State Information-Reference Signal (CSI-RS). Or uplink channel measurement signal, for example, Sounding Reference Signal (SRS).

[0140] (2) Measurement signal for positioning, for example, Positioning Reference Signal (PRS).

[0141] (3) Measurement signal for sensing.

[0142] (4) Special waveform signal forming implicit CP, for example, non-zero power preset time domain signal: linear frequency modulation (LFM) signal.

[0143] Embodiment one (setting method of cyclic prefix based on subcarrier spacing SCS of 15KHz)

[0144] In this embodiment, the frame structure design of SCS expansion is based on subcarrier spacing SCS of 15KHz, the explicit CP of OFDM symbol is zero, and the implicit CP is not zero.

[0145] The execution subject of this embodiment is a communication device, which can be a terminal or a base station. The setting method of cyclic prefix of this embodiment includes the following steps 1 to 3:

[0146] Step 1: Determine the frame structure parameters, including: subcarrier spacing (SCS), length of explicit CP and position of explicit CP.

[0147] In this embodiment, the frame structure parameters can be configured by protocol indication or high layer signaling indication.

[0148] The subcarrier spacing SCS in the frame structure parameter is expanded by multiple SCS based on 15KHz, the multiple is 0.5, 1, 2, 4, 8, 16, 32, 64, 128, 256, etc. The expanded SCS is: 7.5KHz, 15KHz, 30KHz, 60KHz, 120KHz, 240KHz, 480KHz, 960KHz, 1920KHz, 3840KHz, etc.

[0149] Based on 15KHz, multiple expansion SCS can be compatible with the frame structure parameters of the NR system, and the implementation process can inherit the frame structure design of the NR system, and the OFDM symbol interval is the same. The disadvantage is that if there is an explicit CP in the frame structure, the length of the explicit CP allocated to the OFDM symbol cannot be the same. That is, not all OFDM symbol intervals are the same, which is a challenge to the growth of future systems and multiple services (such as sensing services, which require equidistant symbol intervals).

[0150] The explicit CP in the frame structure parameter is a cyclic prefix independent of the OFDM symbol, so the position of the explicit CP can be located in front of the OFDM symbol or behind the OFDM symbol (also known as a cyclic suffix (CS)).

[0151] It should be noted that when there is no explicit CP in the frame structure (that is, the length of the explicit CP is zero), the configuration of the length of the explicit CP and the position of the explicit CP can not be performed. In this embodiment, when SCS = 15KHz, each time slot contains 15 OFDM symbols, and each OFDM symbol has no explicit CP, the configuration of the length of the explicit CP and the position of the explicit CP can not be performed.

[0152] The frame structure parameters based on subcarrier spacing SCS of 15KHz are shown in Table Four and Table Five.

[0153] Table Four Subcarrier Spacing SCS (based on SCS of 15KHz)

[0154] Wherein, Δf is the subcarrier spacing SCS, and μ is the index of the SCS.

[0155] Table Five Number of slots or symbols included in each subframe (based on SCS of 15KHz)

[0156] Wherein, is the number of symbols included in each time slot (slot), is the number of slots included in each radio frame. is the number of slots included in each subframe (1ms).

[0157] Step 2: Determine the length of the implicit CP, the position of the implicit CP, and the time domain waveform of the implicit CP.

[0158] The length of the implicit CP can be configured by a protocol indication, a high layer signaling indication, a medium access control control element (MAC-CE) indication, or a dynamic downlink control information (DCI) indication.

[0159] The length of the implicit CP indicated by the protocol is applicable to all OFDM symbols. The length of the implicit CP indicated by high-layer signaling, MAC-CE indication, or dynamic DCI indication can be different for different OFDM symbols or for OFDM symbols used by scheduled data.

[0160] To simplify the implementation complexity of the communication device, the length of the implicit CP can be limited to several levels, for example, five levels, which are N / 4, N / 8, N / 16, N / 32, and N / 64, respectively. N is the length of the OFDM symbol. Table 6 is the length of the implicit CP of different levels based on a subcarrier spacing SCS of 15 KHz.

[0161] Table 6 Length of implicit CP

[0162] NR ECP is the extended CP of the NR system, and NR NCP is the normal CP of the NR system.

[0163] It should be noted that in the communication system, there are some special signals, for example, a primary synchronization (PSS) signal, a secondary synchronization (SSS) signal, a physical broadcast channel (PBCH) signal, or a physical downlink control channel (PDCCH) signal containing a cell search. The implicit CP of these special signals can be indicated separately, such as setting a longer length of the implicit CP, so as to improve the performance of the terminal searching for a cell.

[0164] The position of the implicit CP can be configured as the end of the previous OFDM symbol or the starting position of the next OFDM symbol. The previous OFDM symbol can be understood as the previous OFDM symbol of the OFDM symbol where the explicit CP is located, and similarly, the next OFDM symbol can be understood as the next OFDM symbol of the OFDM symbol where the explicit CP is located.

[0165] For example, in FIG. 4, the implicit CP of OFDM #8 is located at the end of OFDM #7. Assuming that the lengths of OFDM #7 and OFDM #8 are both N (such as N = 2048) points, the length of the implicit CP is M points.

[0166] Assuming that the time domain signal (after Inverse Discrete Fourier Transform (IDFT) transformation) of OFDM #7 is:

[0167] Assuming that the time domain signal (after IDFT transformation) of OFDM #8 is:

[0168] According to the definition of the cyclic prefix, then,

[0169] Similarly, for OFDM#8, if the implicit CP length of M points is also needed, then:

[0170] Assuming that the time-domain waveform data of the implicit CP is a zero-power time-domain signal, the length of the implicit CP is 64 points, i.e., M = 64. The process of determining the M = 64-point data of the implicit CP, all of which are zeros, is as follows (1) and (2):

[0171] (1) Set the time-domain waveform data of the implicit CP (for example, a linear frequency modulation (LFM) signal): LFM-d(0) = 0, LFM-d(1) = 0, LFM-d(2) = 0, …, LFM-d(63) = 0.

[0172] (2) Generate the frequency-domain data X1-data on the RE_res (i.e., the frequency-domain resource elements used to generate the time-domain waveform of the implicit CP), and map X1-data, X2-data (i.e., the communication data to be transmitted on OFDM#7) to the input end of the IDFT, and perform IDFT, to generate wherein the generation process of X1-data is described below.

[0173] It should be noted that the generation of X1-data Analogous methods are used, and will not be described again.

[0174] Step 3: Determine the location of the frequency-domain resource elements (RE_res) used to generate the time-domain waveform of the implicit CP.

[0175] wherein the RE_res cannot be used for communication data transmission.

[0176] In this embodiment, in order to be able to generate the time-domain waveform of the implicit CP, it is necessary to determine the location of L (L ≥ 1) frequency-domain resource elements (Resource Element, RE), and these REs are used to generate the time-domain waveform of the implicit CP. That is, when transmitting data, both the receiving end and the transmitting end consider that these REs cannot be used to transmit communication data. Wherein the value of L is related to the length of the implicit CP, the longer the implicit CP, the greater the value of L.

[0177] The way to determine RE_res is to obtain RE_res through protocol indication, high-layer signaling indication, MAC-CE indication, or dynamic DCI indication.

[0178] ​In this embodiment, the RE_res is also indicated by the protocol through the length M of the implicit CP. The RE_res is also indicated by the high layer signaling through the length M of the implicit CP indicated by the high layer signaling. The RE_res is also indicated by the MAC-CE through the length M of the implicit CP indicated by the MAC-CE. The RE_res is also indicated by the dynamic DCI through the length M of the implicit CP indicated by the dynamic DCI.

[0179] The way of indicating the RE_res includes comb indication, block indication or bitmap indication.

[0180] The comb indication is used to indicate the position of the frequency domain resource elements distributed in a comb shape (i.e. discontinuous, for example, equidistant discontinuous). The block indication is used to indicate the position of the frequency domain resource elements distributed in a block shape (i.e. continuous). The bitmap indication is used to indicate the position of the frequency domain resource elements distributed irregularly.

[0181] In this embodiment, the length N of the OFDM symbol is 2048, the subcarrier spacing SCS is 15KHz, the length M of the implicit CP is 64, and the communication bandwidth B is assumed to be 30.72MHz. FIG. 7 is a schematic diagram of the RE_res indication manner of the normal symbol and the symbol containing special signals, as shown in FIG. 7:

[0182] The comb indication of the RE_res of the normal symbol: the comb factor (M-GAP) is N / M = 2048 / 64 = 32, that is, the comb spacing is 32. Assuming that the position of the first RE_res is RE_index = 0, the positions of the RE_res of the normal symbol are: RE_index = 0, RE_index = 32, RE_index = 64, …, RE_index = 1984, RE_index = 2016.

[0183] The indication of the RE_res of the symbol containing special signals (for example, PSS, SSS, PBCH or PDCCH): as shown in FIG. 7, assuming that the PSS occupies 127 consecutive REs, there cannot be RE_res in the 127 REs of the PSS. It is necessary to supplement the RE_res in other RE positions. For example, there can be at most 4 RE_res positions in the 127 REs of the PSS, then 2 RE resources are reserved at the beginning and the end of the REs occupied by the PSS as additional RE_res.

[0184] In some embodiments, for the additional RE_res of the special signal, the following ways A to C can also be used for indication:

[0185] A: The additional RE_res is only allocated in the RE position adjacent to one end of the RE occupied by the special signal (for example, the RE position adjacent to one end of the RE occupied by the PSS).

[0186] B: Additional RE_res resource allocation at the edge of the bandwidth resource.

[0187] C: Reduce the value of the comb factor (M-GAP).

[0188] In some embodiments, the number of REs for RE_res is calculated in the case of small bandwidth as follows:

[0189] Taking subcarrier spacing SCS = 15KHz as an example, the number of points of FFT used in OFDM modulation is 2048. Then: the maximum bandwidth can be 15KHz x 2048, which is approximately equal to 30MHz. In actual communication design, there is a case where the channel bandwidth is less than 30MHz, and 2048 points are still used for FFT. In this case: the number of REs K for RE_res can be scaled proportionally based on the transmission bandwidth, as shown in the following Table Seven.

[0190] Table Seven Relationship between the number of REs K for RE_res and the transmission bandwidth

[0191] As can be seen, if the channel bandwidth is 20MHz, for the length of the implicit CP M = 128, the number of REs for RE_res is 2048.

[0192] Embodiment Two (Method for setting cyclic prefix based on subcarrier spacing SCS of 17KHz)

[0193] In this embodiment, the frame structure design is based on subcarrier spacing SCS of 17KHz, the explicit CP of OFDM symbol is not zero, and the length of the implicit CP is adjustable.

[0194] The execution subject of this embodiment is a communication device, which can be a terminal or a base station. The method for setting the cyclic prefix of this embodiment includes the following steps 1 to 3:

[0195] Step 1: Determine the frame structure parameters, including: subcarrier spacing (SCS), length of explicit CP, and position of explicit CP.

[0196] In this embodiment, the frame structure parameters can be configured by protocol indication or high layer signaling indication.

[0197] The subcarrier spacing SCS in the frame structure parameters is based on 17KHz, and the multiple of the extended SCS is 0.5, 1, 2, 4, 8, 16, 32, 64, 128, etc. The extended SCS is: 8.5KHz, 17KHz, 34KHz, 68KHz, 136KHz, 272KHz, 544KHz, 1088KHz, 2176KHz, etc.

[0198] The multiple expansion SCS based on 17KHz, although it cannot be compatible with the frame structure parameters of the NR system, but when applied to the explicit CP structure, the length of the explicit CP allocated to all OFDM symbols is the same. That is, all OFDM symbol intervals are the same, which can meet the demand of the symbol equidistant service (such as: sensing service).

[0199] The explicit CP in the frame structure parameter is a cyclic prefix independent of the OFDM symbol, so the position of the explicit CP can be located in front of the OFDM symbol, or located behind the OFDM symbol (also called cyclic suffix CS). For example, for SCS = 17KHz, each time slot contains 16 OFDM symbols, and the explicit CP has a length of 1 / 16 of the OFDM length.

[0200] The frame structure parameters based on the subcarrier spacing SCS of 17KHz are shown in Table Eight and Table Nine.

[0201] Table Eight Subcarrier Spacing SCS (based on SCS of 17KHz)

[0202] Wherein, Δf is the subcarrier spacing SCS, and μ is the index of SCS.

[0203] For a 1ms length subframe, each subframe includes a number of time slots (different SCS contains different number of time slots), and each time slot contains 16 symbols based on the subcarrier spacing of 17KHz. As shown in Table Nine.

[0204] Table Nine Number of time slots or symbols included in each subframe (based on SCS of 17KHz)

[0205] Wherein, is the number of symbols included in each time slot (slot), is the number of time slots included in each radio frame (10ms). is the number of time slots included in each subframe (1ms).

[0206] Length of explicit CP and length of OFDM symbol (based on SCS of 17KHz) are as follows:

[0207] Wherein, μ is the index of SCS (i.e. subcarrier width configuration parameter), l is the symbol number, and k is a constant related to the sampling frequency.

[0208] Step 2: Determine the length of the implicit CP, the position of the implicit CP and the time domain waveform of the implicit CP.

[0209] The length of the implicit CP can be configured by a protocol indication, a high layer signaling indication, a medium access control control element (MAC-CE) indication, or a dynamic downlink control information (DCI) indication.

[0210] To simplify the implementation complexity of the communication device, the length of the implicit CP can be limited to several levels, for example, 5 levels, which are N / 4, N / 8, N / 16, N / 32, and N / 64, respectively. N is the length of the OFDM symbol. Table 10 is the length of the implicit CP of different levels based on a subcarrier spacing (SCS) of 17 KHz.

[0211] Table 10 Length of the implicit CP

[0212] The position of the implicit CP can be configured as the end of the previous OFDM symbol or the start position of the next OFDM symbol. The previous OFDM symbol can be understood as the OFDM symbol before the OFDM symbol where the explicit CP is located, and similarly, the next OFDM symbol can be understood as the OFDM symbol after the OFDM symbol where the explicit CP is located.

[0213] Suppose the position of the implicit CP is the end of the previous OFDM symbol, as shown in FIG. 5, the implicit CP of OFDM #8 is located at the end of OFDM #7. Suppose the length of OFDM #7 and OFDM #8 is N (for example, N = 2048) points, the length of the implicit CP is M points, and the explicit CP is a normal CP.

[0214] Suppose the time domain (after IDFT transformation) signal of OFDM #7 is:

[0215] Suppose the time domain (after IDFT transformation) signal of OFDM #8 is:

[0216] According to the definition of the cyclic prefix, it is:

[0217] Similarly, for OFDM #8, if the length of the implicit CP is also M points, then:

[0218] For the M-point data of the implicit CP: Suppose the time domain waveform data of the implicit CP is a linear frequency modulation (LFM) signal, and suppose the length of the OFDM symbol is N = 2048 points and the length of the implicit CP is M = 64 points. The process of determining the M = 64-point data of the implicit CP is as follows (1) to (3): ​

[0219] (1) The LFM signal is generated in the following way:

[0220] The above formula is decomposed as: s(t) = IQ(t) x f c (t);

[0221] wherein, is the time domain expression of the baseband signal, sampled at the baseband; f c (t) = exp(j x (f0t)), is the time domain expression of the signal at the radio frequency, processed at the radio frequency.

[0222] (2) IQ(t) is sampled to form time domain data LMF-d(0), LMF-d(1), LMF-d(2), …, LMF-d(63).

[0223] (3) Based on the RE_res information (RE_map1) on OFDM#7, and the communication data X2-data to be sent on OFDM#7 and the mapped RE position information RE_map2, the frequency domain data X1-data on RE_res is determined. X1-data, X2-data are mapped to the input end of IDFT, and IDFT is performed, that is, the LFM signal is generated wherein, RE_map1 is described below.

[0224] It should be noted that the LFM signal is generated using a similar method, which will not be described again.

[0225] It should be noted that when the time domain waveform of the implicit CP uses a non-zero power time domain signal (such as a non-zero power linear frequency modulation (LFM) signal), the time domain waveforms of different lengths have a contained relationship, and FIG. 8 is a schematic diagram of the contained relationship of the implicit CP of different lengths (M points).

[0226] In FIG. 8, the LFM signal is used as the time domain waveform of the implicit CP (i.e., CP2 in the figure):

[0227] - When the length of the implicit CP is the longest (such as M = 512), the frequency modulation is from -B / 2 to +B / 2.

[0228] - When the length of the implicit CP is the second longest (such as M = 256), the frequency modulation is from B4 / 2 to +B / 2; here, the linear frequency modulation frequency from B4 / 2 to +B / 2 is contained in -B / 2 to +B / 2.

[0229] - When the length of the implicit CP is the third longest (such as M = 128), the frequency modulation is from B3 / 2 to +B / 2; here, the linear frequency modulation frequency from B3 / 2 to +B / 2 is contained in -B / 2 to +B / 2.

[0230] When the adjacent OFDM symbols need to form different implicit CP lengths, the containing and contained relationship of the time domain waveform described above is needed. FIG. 9 is a schematic diagram of the containing and contained relationship when the implicit CP lengths of adjacent OFDM symbols are different.

[0231] In FIG. 9, the tail implicit CP (i.e. CP2 in the figure) of OFDM2 is the implicit CP of OFDM3, with a length M = 128. The tail implicit CP of OFDM3 is the implicit CP of OFDM4, with a length M = 128. The tail implicit CP of OFDM4 is the implicit CP of OFDM5, with a length M = 512. It can be seen that the time domain waveform of OFDM3 contains the time domain waveform of OFDM2.

[0232] Step 3: Determine the positions of the frequency domain resource elements (RE_res) used to generate the time domain waveform of the implicit CP.

[0233] The RE_res cannot be used for communication data transmission.

[0234] In this embodiment, in order to be able to generate the time domain waveform of the implicit CP, the positions of L (L≥1) frequency domain resource elements (Resource Element, RE) need to be determined, and these REs are used to generate the time domain waveform of the implicit CP. That is, when transmitting data, both the receiving end and the transmitting end consider that these REs cannot be used to transmit communication data. The value of L is related to the length of the implicit CP, and the longer the implicit CP, the greater the value of L.

[0235] For terminal sending uplink data, for example, sending Physical Uplink Shared Channel (PUSCH) data, in order to ensure that terminals do not interfere with each other and meet the low peak-to-average ratio requirement of the uplink waveform, the positions of RE_res are limited within the scheduled frequency domain resources.

[0236] For example, the RE_res of PUSCH is determined in the following two steps (1) and (2):

[0237] (1) Configure the indication form of RE_res and related parameters.

[0238] For example, the indication form is configured as a comb indication, and the comb factor (M-GAP) is N / M = 2048 / 64 = 32, that is, the comb spacing is 32; the resource starting offset offset is configured.

[0239] For another example, the indication form is configured as a block indication, and the continuous block length (unit RE) is configured; the resource starting offset offset is configured.

[0240] (2) Based on the PUSCH resource allocation indication, determine the resource location of RE_res (such as the start location and the end location), including the following A and B:

[0241] A: Determine the number of REs K for RE_res.

[0242] Where M is the length of the implicit cyclic prefix, N is the number of points (i.e. length) of fast Fourier transform (FFT) of OFDM symbols, and B is the number of REs of the communication bandwidth.

[0243] Explanation 1: For uplink scheduling, when the transmission physical resource of PUSCH is continuously allocated, B is the number of actually scheduled REs; when the transmission physical resource of PUSCH is distributedly allocated, B is the distributed bandwidth of the actually scheduled REs. FIG. 10 is a schematic diagram for calculating the communication bandwidth B.

[0244] Explanation 2: For comb indication, based on the comb factor (M-GAP), the resource start offset offset, and the number of FFT points N, the value of M is determined, for example:

[0245] B: Based on the parameters related to RE_res configured in step (1), determine the resource location of RE_res.

[0246] In FIG. 10, it is assumed that the number of RBs of the scheduled PUSCH is 15, and the number of REs of B is: 15x12;

[0247] - For the case of continuous resource block allocation, the physical resource of the scheduled PUSCH is continuous, and B=15x12;

[0248] - For the case of distributed resource block allocation, the physical resource of the scheduled PUSCH is distributed, and there are 4 RBs in the middle of the resource that are not allocated to PUSCH, so B=(15+4)x12.

[0249] Optionally, the resource location of RE_res is determined to be in the actually scheduled resource of PUSCH.

[0250] In embodiment one and embodiment two, the time domain waveform of the implicit CP is generated in the following manner:

[0251] The input data parameters are as follows:

[0252] - Time domain waveform of implicit CP: LFM_t;

[0253] - Dynamic data frequency domain mapping parameter: RE_map1; RE_map1 can also be understood as the location information of RE_res;

[0254] - Communication frequency domain data: X2-data;

[0255] RE location information of communication frequency domain data mapping: RE_map2.

[0256] The OFDM time domain signal s(t) sent by the communication device in one OFDM symbol includes the following two kinds of information:

[0257] -1: predetermined time domain waveform signal at predetermined time domain position (such as LMF_t in the figure). (Note: expressed in time domain form);

[0258] -2: communication data to be transmitted (such as X2-data data). (Note: expressed in frequency domain form).

[0259] Figure 11 is a flowchart of generating a time domain waveform of an implicit CP, including the following steps 1 to step 4:

[0260] Step 1: generate column vector b (M columns).

[0261] Determine the column vector b according to the predetermined time domain waveform signal LMF_t (predetermined time domain position time domain data value), communication frequency domain data (X2-data), and RE location information of communication frequency domain data mapping (RE_map2).

[0262] Step 2: generate matrix A (M x M).

[0263] Determine the matrix A according to the dynamic data frequency domain mapping parameter RE_map1 (i.e. M RE mapping position information) and the M time domain position information of the predetermined time domain waveform.

[0264] Step 3: determine to generate dynamic data X.

[0265] Determine to generate dynamic data X, X = b / A. b / A represents column vector b divided by matrix A.

[0266] Step 4: generate OFDM time domain signal.

[0267] Map the data X1-data to the OFDM symbol generation input according to the dynamic data X1-data and the RE mapping parameter of the X1-data data (i.e. RE_map1).

[0268] Map the data data to the OFDM symbol generation input according to the communication frequency domain data X2-data and the RE mapping parameter of the X2-data data (i.e. RE_map2).

[0269] Perform IDFT / IFFT transformation.

[0270] It should be noted that, for the foregoing method embodiments, in order to simply describe, they are all expressed as a series of action combinations, but those skilled in the art can understand that the embodiments of the present disclosure are not limited by the action sequence described, because according to the embodiments of the present disclosure, certain steps can be performed in other sequences or simultaneously. In addition, those skilled in the art can understand that the embodiments described in the specification all belong to optional embodiments.

[0271] FIG. 12 is a schematic diagram of a cyclic prefix setting device provided by an embodiment of the present disclosure, which is applied to a terminal or a base station, as shown in FIG. 12, the cyclic prefix setting device includes but is not limited to: a determination unit 1201 and a setting unit 1202, and the specific description is as follows:

[0272] The determination unit 1201 is configured to determine an explicit cyclic prefix and / or an implicit cyclic prefix of a first orthogonal frequency division multiplexing symbol; wherein the explicit cyclic prefix is a cyclic prefix with a fixed length, and the implicit cyclic prefix is a cyclic prefix with an adjustable length.

[0273] The setting unit 1202 is configured to set the explicit cyclic prefix in the first orthogonal frequency division multiplexing symbol, and / or set the implicit cyclic prefix in a second orthogonal frequency division multiplexing symbol; wherein the second orthogonal frequency division multiplexing symbol is an adjacent symbol of the first orthogonal frequency division multiplexing symbol.

[0274] In some embodiments, the determination unit 1201 is configured to:

[0275] determine a frame structure parameter, the frame structure parameter including: a subcarrier spacing, a length of the explicit cyclic prefix, and a position of the explicit cyclic prefix; and / or,

[0276] determine a length of the implicit cyclic prefix, a position of the implicit cyclic prefix, and a time domain waveform of the implicit cyclic prefix.

[0277] In some embodiments, the subcarrier spacing is at least one of the following:

[0278] a multiple of 15KHz, a multiple of 17KHz;

[0279] wherein the multiple is 2 μ , μ is a subcarrier width configuration parameter, and μ is an integer less than, greater than, or equal to zero.

[0280] In some embodiments, if the subcarrier spacing is 2 μ ×15KHz, the explicit cyclic prefix is zero, and one subframe includes 15×2 μ orthogonal frequency division multiplexing symbols; or,

[0281] if the subcarrier spacing is 2 μ15 KHz, the length of the explicit cyclic prefix is greater than zero, and one subframe includes 14 x 2 μ orthogonal frequency division multiplexing symbols; or,

[0282] If the subcarrier spacing is 2 μ x 17 KHz, the length of the explicit cyclic prefix is greater than zero, and one subframe includes 16 x 2 μ orthogonal frequency division multiplexing symbols, and the length of the explicit cyclic prefix is N / 16, N being the length of the first orthogonal frequency division multiplexing symbol.

[0283] In some embodiments, the length of the implicit cyclic prefix is:

[0284] N / 2m; where N is the length of the first orthogonal frequency division multiplexing symbol, and m is a positive integer greater than or equal to 2.

[0285] In some embodiments, the time-domain waveform of the implicit cyclic prefix includes any one of the following:

[0286] a time-domain signal with zero power;

[0287] a preset time-domain signal with non-zero power;

[0288] a time-domain signal formed by the transmitted data of the second orthogonal frequency division multiplexing symbol.

[0289] In some embodiments, the position of the explicit cyclic prefix is before the first orthogonal frequency division multiplexing symbol, and the position of the implicit cyclic prefix is the end of the second orthogonal frequency division multiplexing symbol; where the second orthogonal frequency division multiplexing symbol is the previous symbol of the first orthogonal frequency division multiplexing symbol.

[0290] Or, the position of the explicit cyclic prefix is after the first orthogonal frequency division multiplexing symbol, and the position of the implicit cyclic prefix is the starting position of the second orthogonal frequency division multiplexing symbol; where the second orthogonal frequency division multiplexing symbol is the next symbol of the first orthogonal frequency division multiplexing symbol.

[0291] In some embodiments, the determining unit 1201 is further configured to:

[0292] determine the position of at least one frequency domain resource element used to generate the time-domain waveform of the implicit cyclic prefix.

[0293] In some embodiments, the determining unit 1201 determines the position of at least one frequency domain resource element, comprising:

[0294] obtaining indication information; where the indication information is used to indicate the position of at least one frequency domain resource element, and the indication information is comb indication, block indication or bitmap indication.

[0295] In some embodiments, the cyclic prefix setting device further comprises a processing unit configured to:

[0296] transmitting a multipath measurement signal;

[0297] or, transmitting a multipath measurement signal, and measuring a multipath delay difference based on the multipath measurement signal;

[0298] or, receiving a multipath measurement signal, and measuring a multipath delay difference based on the multipath measurement signal.

[0299] In some embodiments, a length of the implicit cyclic prefix and a number of frequency domain resource elements of a time domain waveform used to generate the implicit cyclic prefix satisfy the following formula:

[0300] K≥M×B / N;

[0301] wherein M is the length of the implicit cyclic prefix, K is the number of frequency domain resource elements of the time domain waveform used to generate the implicit cyclic prefix, B is a number of resource elements of a communication bandwidth, and N is a length of the first orthogonal frequency division multiplexing symbol.

[0302] Details of the embodiments of the setting device of the cyclic prefix shown in FIG. 12 can refer to the embodiments of the setting method of the cyclic prefix shown in FIG. 3, and will not be repeated here.

[0303] The embodiments of the present disclosure further provide a processor-readable storage medium, which stores a program for causing a processor to execute the steps of the embodiments of the setting method of the cyclic prefix. The processor-readable storage medium can be any available medium or data storage device that a processor can access, including but not limited to a magnetic storage (such as a floppy disk, a hard disk, a magnetic tape, a magneto-optical disk (MO), etc.), an optical storage (such as a CD, a DVD, a BD, a HVD, etc.), and a semiconductor memory (such as a ROM, an EPROM, an EEPROM, a non-volatile memory (NAND FLASH), a solid state disk (SSD), etc.).

[0304] FIG. 13 is a schematic diagram of a communication device provided by an embodiment of the present disclosure, which is applied to a terminal or a base station. As shown in FIG. 13, the communication device provided by an embodiment of the present disclosure includes a memory 1301, a transceiver 1302, and a processor 1303:

[0305] The memory 1303 is configured to store a computer program; the transceiver 1302 is configured to transceive data under the control of the processor; and the processor 1303 is configured to read the computer program in the memory and perform the following steps:

[0306] determining an explicit cyclic prefix and / or an implicit cyclic prefix of a first orthogonal frequency division multiplexing symbol; wherein the explicit cyclic prefix is a fixed-length cyclic prefix, and the implicit cyclic prefix is an adjustable-length cyclic prefix;

[0307] An explicit cyclic prefix is arranged in the first OFDM symbol, and / or an implicit cyclic prefix is arranged in the second OFDM symbol; wherein the second OFDM symbol is an adjacent symbol of the first OFDM symbol.

[0308] In some embodiments, the explicit cyclic prefix and / or the implicit cyclic prefix of the first OFDM symbol is determined by:

[0309] The frame structure parameters are determined, the frame structure parameters comprising: a subcarrier spacing, a length of the explicit cyclic prefix, and a position of the explicit cyclic prefix; and / or,

[0310] The length of the implicit cyclic prefix, the position of the implicit cyclic prefix, and a time-domain waveform of the implicit cyclic prefix are determined.

[0311] In some embodiments, the subcarrier spacing is at least one of:

[0312] a multiple of 15KHz, a multiple of 17KHz;

[0313] wherein the multiple is 2 μ , μ is a subcarrier width configuration parameter, and μ is an integer less than, greater than, or equal to zero.

[0314] In some embodiments, if the subcarrier spacing is 2 μ ×15KHz, the explicit cyclic prefix is zero, and one subframe comprises 15×2 μ OFDM symbols; or,

[0315] if the subcarrier spacing is 2 μ ×15KHz, the explicit cyclic prefix is greater than zero, and one subframe comprises 14×2 μ OFDM symbols; or,

[0316] if the subcarrier spacing is 2 μ ×17KHz, the explicit cyclic prefix is greater than zero, and one subframe comprises 16×2 μ OFDM symbols, and the length of the explicit cyclic prefix is N / 16, N being the length of the first OFDM symbol.

[0317] In some embodiments, the length of the implicit cyclic prefix is:

[0318] N / 2 m ; N being the length of the first OFDM symbol, and m being a positive integer greater than or equal to 2.

[0319] In some embodiments, the time-domain waveform of the implicit cyclic prefix comprises any one of:

[0320] a time-domain signal of zero power;

[0321] a preset time domain signal of non-zero power;

[0322] a time domain signal formed by the transmitted data of the second OFDM symbol.

[0323] In some embodiments, the position of the explicit cyclic prefix is before the first OFDM symbol, and the position of the implicit cyclic prefix is the end of the second OFDM symbol; wherein the second OFDM symbol is a symbol before the first OFDM symbol.

[0324] Or, the position of the explicit cyclic prefix is after the first OFDM symbol, and the position of the implicit cyclic prefix is the start position of the second OFDM symbol; wherein the second OFDM symbol is a symbol after the first OFDM symbol.

[0325] In some embodiments, the processor 1303 is further configured to determine the position of at least one frequency domain resource element used to generate the time domain waveform of the implicit cyclic prefix.

[0326] In some embodiments, the determination of the position of the at least one frequency domain resource element comprises:

[0327] obtaining indication information; wherein the indication information is used to indicate the position of the at least one frequency domain resource element, and the indication information is comb indication, block indication or bitmap indication.

[0328] In some embodiments, the processor 1303 is further configured to:

[0329] transmit a multipath measurement signal;

[0330] Or, transmit a multipath measurement signal and measure the multipath delay difference based on the multipath measurement signal.

[0331] Or, receive a multipath measurement signal and measure the multipath delay difference based on the multipath measurement signal.

[0332] In some embodiments, the length of the implicit cyclic prefix and the number of frequency domain resource elements used to generate the time domain waveform of the implicit cyclic prefix satisfy the following formula:

[0333] K≥M×B / N;

[0334] wherein M is the length of the implicit cyclic prefix, K is the number of frequency domain resource elements used to generate the time domain waveform of the implicit cyclic prefix, B is the number of resource elements of the communication bandwidth, and N is the length of the first OFDM symbol.

[0335] In the above embodiments, the transceiver 1302 is configured to receive and transmit data under the control of the processor 1303. The bus architecture can include any number of interconnecting buses and bridges, and the various circuitry representative of the processor 1303 and the memory 1301, which can be of various types, including caches and instruction and data memories, linked through one or more buses and bridges, are indicative of the various components of the memory 1301 and processor 1303 that can be used. The bus architecture can further link various other circuits such as peripheral devices, voltage regulators and power management circuitry, which are well known in the art, and therefore, not further described herein. The bus interface provides an interface to the transceiver. The transceiver can be a plurality of elements including a transmitter and a receiver that provide means for communicating with various other apparatus over a transmission medium including wireless channels, wired channels, optical cables, and the like. The processor 1303 is responsible for managing the bus architecture and general processing, and the memory 1301 can store data used by the processor 1303 in executing its operations.

[0336] The processor 1303 can be an integrated circuit chip logic processing capability. In the implementation process, each step of the above method can be completed by the integrated logic circuit of hardware in the processor 1303 or the instruction in the form of software. The processor 1303 can be a general processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component. The general processor can be a microprocessor or the processor can also be any conventional processor.

[0337] It should be noted that in this paper, the term "include", "contain" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the elements defined by the statement "include" do not exclude the presence of other identical elements in the process, method, article or device including the element.

[0338] Those skilled in the art can understand that although some embodiments described herein include certain features included in other embodiments rather than other features, the combination of features of different embodiments means that it is within the scope of the disclosure and forms different embodiments.

[0339] Those skilled in the art will appreciate that the description of various embodiments can emphasize differing features to better describe particular embodiments, and that features described in one embodiment can be applicable or modified to other embodiments.

[0340] While the embodiments of the disclosure have been described in conjunction with the accompanying drawings, various modifications and changes can be suggested to one skilled in the art, and it is intended that the appended claims encompass such modifications and changes as fall within the scope of the present disclosure.

Claims

1. A method for setting a cyclic prefix, the method comprising: Determine the dominant cyclic prefix and / or the implicit cyclic prefix of the first orthogonal frequency division multiplexing symbol; wherein the dominant cyclic prefix is ​​a cyclic prefix of fixed length, and the implicit cyclic prefix is ​​a cyclic prefix of adjustable length; The explicit cyclic prefix is ​​set in the first orthogonal frequency division multiplexing symbol, and / or the implicit cyclic prefix is ​​set in the second orthogonal frequency division multiplexing symbol; wherein the second orthogonal frequency division multiplexing symbol is an adjacent symbol of the first orthogonal frequency division multiplexing symbol.

2. The method of claim 1, wherein, The determination of the dominant cyclic prefix and / or implicit cyclic prefix of the first orthogonal frequency division multiplexing symbol includes: Determine the frame structure parameters, which include: subcarrier spacing, the length of the dominant cyclic prefix, and the position of the dominant cyclic prefix; and / or, Determine the length of the implicit cyclic prefix, the position of the implicit cyclic prefix, and the time-domain waveform of the implicit cyclic prefix.

3. The method of claim 2, wherein, The subcarrier spacing is at least one of the following: Multiples of 15kHz, multiples of 17kHz; wherein the multiple is 2 μ μ is a subcarrier width configuration parameter, and μ is an integer less than, greater than, or equal to zero.

4. The method according to claim 3, wherein, if the subcarrier spacing is 2 μ × 15 KHz, the dominant cyclic prefix is zero, and one subframe includes 15 x 2 μ orthogonal frequency division multiplexing symbols; or, if the subcarrier spacing is 2 μ × 15 KHz, the cyclic prefix is greater than zero, and one subframe includes 14 x 2 μ orthogonal frequency division multiplexing symbols. or, if the subcarrier spacing is 2 μ × 17 KHz, the dominant cyclic prefix is greater than zero, one subframe includes 16 x 2 μ × 2 orthogonal frequency division multiplexing symbols, and the length of the dominant cyclic prefix is N / 16, N being the length of the first orthogonal frequency division multiplexing symbol.

5. The method of claim 2, wherein, The length of the implicit cyclic prefix is: N / 2 m ; wherein N is a length of the first OFDM symbol and m is a positive integer greater than or equal to 2.

6. The method of claim 2, wherein, The time-domain waveform of the implicit cyclic prefix includes any of the following: Zero-power time-domain signal; A preset time-domain signal with non-zero power; The time-domain signal formed by the transmitted data of the second orthogonal frequency division multiplexing symbol.

7. The method according to any one of claims 1 to 6, wherein, The explicit cyclic prefix is ​​positioned before the first orthogonal frequency division multiplexing (OFDM) symbol, and the implicit cyclic prefix is ​​positioned at the end of the second OFDM symbol; wherein the second OFDM symbol is the symbol preceding the first OFDM symbol. Alternatively, the explicit cyclic prefix is ​​located after the first orthogonal frequency division multiplexing (OFDM) symbol, and the implicit cyclic prefix is ​​located at the starting position of the second OFDM symbol; wherein the second OFDM symbol is the next symbol after the first OFDM symbol.

8. The method of claim 1, wherein, The method further includes: The position of at least one frequency domain resource element is determined, the frequency domain resource element being used to generate the time domain waveform of the implicit cyclic prefix.

9. The method of claim 8, wherein, Determining the location of at least one frequency domain resource element includes: Obtain indication information; wherein the indication information is used to indicate the location of at least one frequency domain resource element, and the indication information is a comb indication, a block indication, or a bitmap indication.

10. The method of claim 1, wherein, The method further includes: Send multipath measurement signals; Alternatively, a multipath measurement signal can be sent, and the multipath delay difference can be measured based on the multipath measurement signal; Alternatively, receive a multipath measurement signal and measure the multipath delay difference based on the multipath measurement signal.

11. The method of claim 8, wherein, The length of the implicit cyclic prefix and the number of frequency domain resource elements used to generate the time-domain waveform of the implicit cyclic prefix satisfy the following formula: K≥M×B / N; Where M is the length of the implicit cyclic prefix, K is the number of frequency domain resource elements used to generate the time-domain waveform of the implicit cyclic prefix, B is the number of resource elements for the communication bandwidth, and N is the length of the first orthogonal frequency division multiplexing symbol.

12. A device for setting a cyclic prefix, the device comprising: determining an explicit cyclic prefix and / or an implicit cyclic prefix of a first OFDM symbol; wherein the explicit cyclic prefix is a fixed-length cyclic prefix, and the implicit cyclic prefix is an adjustable-length cyclic prefix; setting the explicit cyclic prefix in the first OFDM symbol, and / or setting the implicit cyclic prefix in a second OFDM symbol; wherein the second OFDM symbol is a neighboring symbol of the first OFDM symbol. 13.A communication apparatus, comprising a memory, a transceiver, and a processor; the memory is configured to store a computer program; the transceiver is configured to transceive data under control of the processor; and the processor is configured to read the computer program in the memory and perform: determining an overt and / or a hidden cyclic prefix of the first OFDM symbol; wherein the explicit cyclic prefix is a fixed-length cyclic prefix, and the implicit cyclic prefix is an adjustable-length cyclic prefix; setting the explicit cyclic prefix in the first OFDM symbol, and / or setting the implicit cyclic prefix in a second OFDM symbol; wherein the second OFDM symbol is a neighboring symbol of the first OFDM symbol.

14. The communication apparatus according to claim 13, wherein, The determination of the explicit cyclic prefix and / or the implicit cyclic prefix of the first OFDM symbol comprises: determining a frame structure parameter, the frame structure parameter comprising: a subcarrier spacing, a length of the explicit cyclic prefix, and a position of the explicit cyclic prefix; and / or determining a length of the implicit cyclic prefix, a position of the implicit cyclic prefix, and a time-domain waveform of the implicit cyclic prefix.

15. The communication apparatus according to claim 14, wherein, The subcarrier spacing is at least one of: a multiple of 15 KHz, a multiple of 17 KHz; wherein the multiple is 2 μ μ is a subcarrier width configuration parameter, and μ is an integer less than, greater than, or equal to zero. 16.A communication apparatus according to claim 3, wherein, if the subcarrier spacing is 2 μ × 15 KHz, the dominant cyclic prefix is zero, and one subframe includes 15 x 2 μ orthogonal frequency division multiplexing symbols; or, if the subcarrier spacing is 2 μ × 15 KHz, the cyclic prefix is greater than zero, and one subframe includes 14 x 2 μ orthogonal frequency division multiplexing symbols. or, if the subcarrier spacing is 2 μ x 17 KHz, the dominant cyclic prefix is greater than zero, one subframe includes 16 x 2 μ orthogonal frequency division multiplexing symbols, and the length of the dominant cyclic prefix is N / 16, N being the length of the first orthogonal frequency division multiplexing symbol.

17. The communication apparatus according to claim 14, wherein, the length of the implicit cyclic prefix is: N / 2 m ; wherein N is a length of the first OFDM symbol and m is a positive integer greater than or equal to 2.

18. The communication apparatus according to claim 14, wherein, the time-domain waveform of the implicit cyclic prefix comprises any one of: a time-domain signal with zero power; a preset time-domain signal with non-zero power; a time-domain signal formed by transmitted data of the second OFDM symbol.

19. The communication apparatus according to any of claims 13 to 18, wherein, The position of the explicit cyclic prefix is before the first OFDM symbol, and the position of the implicit cyclic prefix is the end of the second OFDM symbol; wherein the second OFDM symbol is a previous symbol of the first OFDM symbol; or, the position of the explicit cyclic prefix is after the first OFDM symbol, and the position of the implicit cyclic prefix is the start position of the second OFDM symbol; wherein the second OFDM symbol is a next symbol of the first OFDM symbol.

20. The communication apparatus according to claim 13, wherein, The processor is further configured to: determine a position of at least one frequency-domain resource element, the frequency-domain resource element being used to generate the time-domain waveform of the implicit cyclic prefix.

21. The communication apparatus according to claim 20, wherein, The determination of the position of the at least one frequency-domain resource element comprises: obtaining indication information; wherein the indication information is used to indicate the position of the at least one frequency-domain resource element, and the indication information is comb indication, block indication, or bitmap indication.

22. The communication apparatus according to claim 13, wherein, The processor is further configured to: transmit a multipath measurement signal. Or, a multipath measurement signal is sent, and a multipath delay difference is measured based on the multipath measurement signal. Or, a multipath measurement signal is received, and a multipath delay difference is measured based on the multipath measurement signal.

23. The communication apparatus according to claim 20, wherein, The length of the implicit cyclic prefix satisfies the following formula: K≥M×B / N, where M is the length of the implicit cyclic prefix, K is the number of frequency domain resource elements used to generate the time domain waveform of the implicit cyclic prefix, B is the number of resource elements of a communication bandwidth, and N is the length of the first OFDM symbol. The length of the implicit cyclic prefix satisfies the following formula: K≥M×B / N, where M is the length of the implicit cyclic prefix, K is the number of frequency domain resource elements used to generate the time domain waveform of the implicit cyclic prefix, B is the number of resource elements of a communication bandwidth, and N is the length of the first OFDM symbol.

24. A processor-readable storage medium, wherein, The processor readable storage medium stores a program for causing the processor to perform the method for setting a cyclic prefix according to any one of claims 1 to 11.

Images