CN108632014B

CN108632014B - Data transmission method, data sending device and data receiving device

Info

Publication number: CN108632014B
Application number: CN201810403226.4A
Authority: CN
Inventors: 陈哲
Original assignee: New H3C Technologies Co Ltd Chengdu Branch
Current assignee: New H3C Technologies Co Ltd Chengdu Branch
Priority date: 2018-04-28
Filing date: 2018-04-28
Publication date: 2022-04-08
Anticipated expiration: 2038-04-28
Also published as: CN108632014A

Abstract

The present disclosure relates to the field of wireless communications technologies, and in particular, to a data transmission method, a data transmission apparatus, and a data reception apparatus, which are used to transmit two complex symbols with opposite phases through two subcarriers, so that adjacent channel leakage power caused by the two subcarriers can be mutually suppressed in the two opposite phases, thereby reducing the overall adjacent channel leakage power. The data transmission method comprises the following steps: modulating the acquired transmission data to obtain at least one modulation symbol; each modulation symbol is obtained by modulating at least one bit of data; determining a frequency domain spreading sequence for performing frequency domain spreading on each modulation symbol; the frequency domain spreading sequence comprises complex exponentials with opposite phase directions; multiplying each modulation symbol by a corresponding complex index with opposite phase direction to obtain a frequency domain expanded symbol sequence corresponding to each modulation symbol; the symbol sequence after the frequency domain expansion comprises complex symbols with opposite phases; two subcarriers are used to transmit two complex symbols with opposite phases.

Description

Data transmission method, data sending device and data receiving device

Technical Field

The present disclosure relates to the field of wireless communication technologies, and in particular, to a data transmission method, a data transmission apparatus, and a data reception apparatus.

Background

In a 3rd Generation partnership Project (3 GPP) Long Term Evolution (LTE) system, data transmission between a base station and a User Equipment (UE) may be implemented based on a Time Division Duplex (TDD) mode.

As shown in fig. 1, an exemplary diagram of a TDD frame structure of a power wireless private network communication system is shown, in which a time domain resource is divided into a plurality of radio frames, and each radio frame may have a duration of 10ms, and includes a downlink transmission time (denoted by D in the figure), a Guard Period (GP) and a downlink transmission time (denoted by U in the figure). For a power wireless private network communication system adopting a 230MHz frequency band, a base station uses one or more carriers to provide service for UEs in a TDD mode, one carrier of 25kHz includes 6 or 12 subcarriers, and a subcarrier interval of 3.75kHz or 1.875kHz may be adopted between uplink and downlink.

In order to improve the coverage performance of data transmission, a Narrowband transmission technology is introduced into a 3GPP Narrowband Internet of Things (NB-IoT), and a Narrowband Physical Uplink Shared Channel (NPUSCH) format 2 is specifically designed, which is used for a UE to perform Hybrid Automatic Repeat Request-acknowledgement (HARQ-ACK) feedback for Downlink (DL) transmission of a base station. The NPUSCH format 2 uses 1 subcarrier for data transmission, the transmission power is concentrated in the narrower bandwidth occupied by 1 subcarrier, and the power spectral density is larger.

In the single carrier transmission mode, the power spectral density is high, so that the leakage power of the adjacent channel is improved, and particularly when the sub-carrier closer to the adjacent channel is used for transmitting the HARQ-ACK information, the leakage power of the adjacent channel is high, so that the communication performance of the power wireless private network communication system is poor.

Disclosure of Invention

In view of this, the embodiments of the present disclosure provide a data transmission method, a data transmitting apparatus, and a data receiving apparatus, so as to reduce the adjacent channel leakage power and improve the communication performance of the power wireless private network communication system.

In a first aspect, a data transmission method is provided, where the method includes:

acquiring transmission data to be sent to a receiving end, wherein the transmission data comprises data of at least one bit;

modulating the data of the at least one bit to obtain at least one modulation symbol, wherein each modulation symbol in the at least one modulation symbol is obtained by modulating the data of the at least one bit;

determining a frequency domain spreading sequence for frequency domain spreading of each modulation symbol, the frequency domain spreading sequence comprising complex exponentials with opposite phase directions;

multiplying each modulation symbol by the complex index with opposite phase direction in the corresponding frequency domain spreading sequence respectively to obtain a frequency domain spread symbol sequence corresponding to each modulation symbol, wherein the frequency domain spread symbol sequence comprises complex symbols with opposite phases;

and transmitting the complex symbols with opposite phases to the receiving end by adopting two subcarriers, wherein each subcarrier in the two subcarriers respectively transmits one of the complex symbols with opposite phases.

In a second aspect, a data transmission method is provided, the method including:

receiving a frequency domain spread symbol sequence transmitted by a transmitting end through two subcarriers, wherein the frequency domain spread symbol sequence comprises complex symbols with opposite phases, and each subcarrier respectively transmits one of the complex symbols with opposite phases;

acquiring a conjugate sequence of a frequency domain spreading sequence, wherein the frequency domain spreading sequence is used for the transmitting end to perform frequency domain spreading on a modulation symbol after modulation of transmission data to be transmitted, the frequency domain spreading sequence comprises complex indexes with opposite phases, and the conjugate sequence of the frequency domain spreading sequence comprises conjugate complex indexes respectively corresponding to the complex indexes with opposite phases;

multiplying the frequency domain spread symbol sequence comprising the complex symbol with the opposite phase by the conjugate sequence of the frequency domain spread sequence comprising the conjugate complex index to obtain a modulation symbol after frequency domain de-spreading;

and demodulating the modulation symbols to obtain the transmission data sent by the sending end.

In a third aspect, a data transmission apparatus is provided, which includes: a processor, a memory and a bus, the memory storing machine-readable instructions executable by the processor, the processor and the memory communicating over the bus when the data transmission apparatus is operating, the machine-readable instructions when executed by the processor performing the following:

In a fourth aspect, a data receiving apparatus is provided, the data receiving apparatus comprising: a processor, a memory and a bus, the memory storing machine-readable instructions executable by the processor, the processor and the memory communicating via the bus when the data receiving apparatus is operating, the machine-readable instructions when executed by the processor performing the following:

In the above scheme provided by the embodiment of the present disclosure, a sending end performs frequency domain spreading on at least one modulation symbol after data transmission modulation through a determined frequency domain spreading sequence, and transmits a frequency domain spread symbol sequence by using two subcarriers, where the frequency domain spreading sequence is composed of two complex exponentials with opposite phase directions, and the frequency domain spread symbol sequence is correspondingly composed of two complex symbols with opposite phases. By adopting the scheme, the complex symbols with opposite phases are transmitted by the two subcarriers, so that adjacent channel leakage power on the two subcarriers is mutually inhibited on the two opposite phases, the whole adjacent channel leakage power is reduced, and the communication performance of the electric power wireless private network communication system is better.

In addition, in an embodiment, the frequency-domain extended symbol sequence may be jointly extended in the frequency domain and the time domain based on the determined time-domain extension sequence, so as to map the frequency-domain and time-domain extended symbol sequences to N in the time domain_dAnd the OFDM symbols are mapped to two subcarriers on a frequency domain for transmission, and the reliability of data transmission is further ensured while the adjacent channel leakage power is reduced through the joint expansion of the frequency domain and the time domain.

In order to make the aforementioned objects, features and advantages of the present disclosure more comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present disclosure and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings may be obtained from the drawings without inventive effort.

Fig. 1 illustrates a schematic structure diagram of a TDD frame structure provided in an embodiment of the present disclosure;

fig. 2 shows a flow chart of a data transmission method provided by an embodiment of the present disclosure;

fig. 3 is a flow chart illustrating another data transmission method provided by an embodiment of the present disclosure;

FIG. 4 is a flow chart illustrating another data transmission method provided by an embodiment of the present disclosure;

fig. 5 is a flowchart illustrating a data transmission method according to another embodiment of the disclosure;

fig. 6 shows a flow chart of another data transmission method provided by another embodiment of the present disclosure;

FIG. 7 is a flow chart illustrating a further method of data transmission according to another embodiment of the present disclosure;

fig. 8 is a schematic structural diagram of a data transmission apparatus provided in an embodiment of the present disclosure;

fig. 9 is a schematic structural diagram of a data transmission apparatus provided in an embodiment of the present disclosure;

fig. 10 is a schematic structural diagram of another data transmission apparatus provided in the embodiment of the present disclosure;

fig. 11 shows a schematic structural diagram of a data receiving device provided in an embodiment of the present disclosure.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be described clearly and completely with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, not all of the embodiments. The components of the embodiments of the present disclosure, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present disclosure, presented in the figures, is not intended to limit the scope of the claimed disclosure, but is merely representative of selected embodiments of the disclosure. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the disclosure without making creative efforts, shall fall within the protection scope of the disclosure.

Considering a single carrier transmission mode in the related art, because 1 subcarrier is used for data transmission, the transmission power is concentrated in a narrower bandwidth occupied by 1 subcarrier, the power spectral density is large, and the leakage power of the adjacent channel is increased accordingly, and especially when the subcarrier closer to the adjacent channel is used for transmitting Hybrid Automatic Repeat Request-acknowledgement (HARQ-ACK) information, the leakage power of the adjacent channel is higher, and the communication performance of the power wireless private network communication system is poor. Based on this, the embodiments of the present disclosure provide a data transmission method, which is described in detail in the following embodiments.

It should be noted that the embodiment of the present disclosure may be adapted to an application scenario in which a User Equipment (UE) feeds HARQ-ACK information back to a base station, may also be adapted to an application scenario in which the UE transmits a small data packet to the base station, may also be adapted to an application scenario in which the base station feeds HARQ-ACK information back to the UE, and may also be adapted to an application scenario in which the base station transmits a small data packet to the UE, so as to meet different application requirements.

Fig. 2 is a flowchart of a data transmission method according to an embodiment of the present disclosure. The main execution body of the data transmission method is a data sending device, and the data sending device corresponds to a sending end, and can be a UE or a base station. In this way, when the data transmitting apparatus is a UE, the data receiving apparatus corresponding to the receiving end is a base station, and when the data transmitting apparatus is a base station, the data receiving apparatus corresponding to the receiving end is a UE. The embodiment of the present disclosure introduces a data sending device and a data receiving device for the following discussion, and does not mean that the data sending device is only used for data sending, and the data receiving device is only used for data receiving, and the data transmission method includes the following steps:

s201, acquiring transmission data to be transmitted to a receiving end, where the transmission data includes data of at least one bit.

Specifically, the transmission data may be HARQ-ACK information fed back to the receiving end, or may also be a small data packet sent to the receiving end, which is not specifically limited in this disclosure.

S202, performing modulation processing on the data of at least one bit to obtain at least one modulation symbol, where each modulation symbol in the at least one modulation symbol is obtained by modulating the data of at least one bit.

Specifically, for the obtained transmission data, the embodiment of the present disclosure may divide the data of at least one bit corresponding to the transmission data into a plurality of bit groups according to the division number M, and perform modulation symbol mapping on each bit group to obtain at least one modulation symbol modulated by the transmission data, where each bit group includes data of M bits.

It should be noted that, when the data transmission method is applied to the UE, the division number M of each bit group may be a fixed value preset in a protocol, or may be dynamically indicated to the UE after the base station comprehensively considers relevant factors such as the size of the transmitted data amount and the channel quality of the data transmission channel, for example, when the data amount is large and the channel quality is good, the value of M may be appropriately increased. Similarly, when the above data transmission method is applied to the base station, M may be preset in a protocol or determined by the base station according to the size of the data amount to be transmitted, the channel quality of the data transmission channel, and the like.

S203, determining a frequency domain spreading sequence for performing frequency domain spreading on each modulation symbol, wherein the frequency domain spreading sequence comprises complex exponentials with opposite phase directions.

Specifically, for each modulation symbol obtained by modulation, a frequency domain spreading sequence corresponding to the modulation symbol is determined. In order to achieve mutual suppression of adjacent channel leakage power, the frequency domain spreading sequence selected in the embodiments of the present disclosure may be composed of two complex exponentials with opposite phase directions.

For example, the two complex exponentials may each be β₁exp(jθ_i) And beta₂exp{j(θ_i+ pi). In the above expression of two complex exponentials, the phase directions of the two complex exponentials are different by pi and the amplitude value is beta₁And beta₂May be the same or different. In consideration of the requirement that the receiving end expects each complex symbol after frequency domain spreading to be able to transmit stably, the same amplitude may be selected for the two complex exponentials in the embodiment of the present disclosure.

In addition, the parameter θ_iThe method may be predefined or randomly generated, and the embodiment of the disclosure is not particularly limited thereto. In this way, when the data transmission method is applied to a UE, the frequency domain spreading sequence may be preset in a protocol or may be the UEAccording to the parameter theta indicated by the base station_iAnd a predefined frequency domain spreading sequence and theta_iThe relationship between them is determined.

The base station may indicate θ to the UE through Downlink Control Information (DCI)_i. In addition, the base station can also directly indicate a specific frequency domain spreading sequence to the UE through the DCI, and the dynamic indication mode can indicate different frequency domain spreading sequences for different UEs and also indicate different frequency domain spreading sequences for different data transmissions performed by the same UE; similarly, when the data transmission method is applied to a base station, the frequency domain spreading sequence may be preset in a protocol or may be determined by the base station itself.

And S204, multiplying each modulation symbol by the complex index with the opposite phase direction in the corresponding frequency domain spreading sequence respectively to obtain a frequency domain spread symbol sequence corresponding to each modulation symbol, wherein the frequency domain spread symbol sequence comprises complex symbols with opposite phases.

Specifically, for each modulation symbol, frequency domain spreading may be performed through a frequency domain spreading sequence corresponding to the modulation symbol, so as to obtain a symbol sequence after frequency domain spreading. Thus, when the frequency domain spreading sequence consists of two complex exponentials with opposite phases, the symbol sequence may also consist of two complex symbols with opposite phases.

S205, two subcarriers are used to transmit complex symbols with opposite phases to the receiving end, and each of the two subcarriers transmits one of the complex symbols with opposite phases.

Specifically, the embodiment of the present disclosure may map two complex symbols included in the symbol sequence after Frequency domain spreading onto one Orthogonal Frequency Division Multiplexing (OFDM) symbol in a time domain, and transmit two complex symbols with opposite phases to a receiving end through two subcarriers occupied by the OFDM symbol.

In a specific implementation, when the transmission data is HARQ-ACK information, if the data transmitting apparatus is a UE, two subcarriers on a Narrowband Physical Uplink Shared Channel (NPUSCH) may be used to transmit two complex symbols, and if the data transmitting apparatus is a base station, two subcarriers on a Narrowband Physical Downlink Shared Channel (NPDSCH) may be used to transmit two complex symbols.

It should be noted that the two subcarriers may be two adjacent subcarriers, or may also be two non-adjacent subcarriers. Since the larger the frequency domain interval between two subcarriers is, the smaller the cancellation effect between the phase directions is, in order to suppress the adjacent channel leakage power brought by the two subcarriers to the maximum extent, the embodiment of the present disclosure adopts the two adjacent subcarriers as much as possible.

In the data transmission method provided by the embodiment of the present disclosure, a sending end performs frequency domain spreading on at least one modulation symbol after data transmission modulation through a determined frequency domain spreading sequence, and transmits a frequency domain spread symbol sequence by using two subcarriers, where the frequency domain spreading sequence is composed of two complex indexes with opposite phase directions, and the frequency domain spread symbol sequence is correspondingly composed of two complex symbols with opposite phases. By adopting the scheme, the complex symbols with opposite phases are transmitted by the two subcarriers, so that adjacent channel leakage power on the two subcarriers is mutually inhibited on the two opposite phases, the whole adjacent channel leakage power is reduced, and the communication performance of the electric power wireless private network communication system is better.

The data transmission method provided by the embodiment of the disclosure can not only realize frequency domain expansion, but also realize combined expansion of a frequency domain and a time domain, that is, the embodiment of the disclosure can give consideration to both frequency domain expansion and time domain expansion. Referring to fig. 3, the joint extension method is specifically implemented by the following steps:

s301, determining a time domain spreading sequence for performing time domain spreading on complex symbols with opposite phases included in each symbol sequence after frequency domain spreading, wherein the sum of the lengths of the time domain spreading sequences and the number N of Orthogonal Frequency Division Multiplexing (OFDM) symbols for data transmission_dThe same is true.

In particular, to achieve the maximum likelihood of spreading over time domain resources, various of the embodiments of the present disclosureSum of length of time domain spreading sequences and number of OFDM symbols N used for data transmission_dThe same is true. The length of each time domain spreading sequence may be the same or different. In consideration of the requirement that the data transmission performance of each symbol sequence after frequency domain and time domain spreading can meet the requirement of consistency, the time domain spreading sequences with the same length are adopted as much as possible in the embodiment of the disclosure.

The time domain spreading sequence may be a hadamard sequence, a Zadoff-chu (zc) sequence, or another sequence capable of performing time domain spreading, which is not specifically limited in the embodiments of the present disclosure.

When the data transmission method is applied to the UE, the time domain spreading sequence in the embodiment of the present disclosure may be preset in a protocol, or may be dynamically indicated to the UE by the base station through DCI, and the dynamic indication manner may indicate different time domain spreading sequences for different UEs, or may indicate different time domain spreading sequences for the same UE when performing different data transmission; similarly, when the data transmission method is applied to a base station, the time domain spreading sequence may be preset in a protocol or may be determined by the base station.

And S302, multiplying the complex symbols with opposite phases with the corresponding time domain spreading sequences to obtain the symbol sequences after the frequency domain spreading and the time domain spreading, wherein the symbol sequences after the frequency domain spreading and the time domain spreading comprise the complex symbols with opposite phases after the time domain spreading.

Specifically, for each modulation symbol, a frequency-domain and time-domain spread symbol sequence is obtained based on a product result of a complex symbol with an opposite phase and a time-domain spread sequence. The sequence numbers after the frequency domain and the time domain expansion may be complex symbols with opposite phases after the time domain expansion, that is, the symbol sequence is obtained by performing the time domain expansion on the complex symbols with opposite phases corresponding to the symbol sequence after the frequency domain expansion. In this way, after each modulation symbol is subjected to frequency domain and time domain spreading, the number of groups of two complex symbols with opposite phases corresponding to each modulation symbol is the same as the length of the time domain spreading sequence corresponding to the modulation symbol.

S303, mapping the complex symbol with opposite phase after time domain expansion to N in the time domain_dOver one OFDM symbol, and N_dAnd transmitting on two subcarriers in the frequency domain corresponding to the OFDM symbols.

The embodiment of the disclosure further performs time domain mapping and frequency domain mapping on the symbol sequences after the frequency domain and the time domain are spread respectively. Wherein, in time domain mapping, each of the symbol sequences after frequency domain and time domain spreading can be mapped to N_dOne or more OFDM symbols, the number of which is the same as the length of the time domain spreading sequence adopted by each frequency domain and time domain spread symbol sequence, so that the sum of the lengths of the time domain spreading sequences and the number N of OFDM symbols is based on_dThe peer-to-peer relationship between the two sets of the frequency domain and the frequency domain realizes the extension of the time domain resources to the maximum extent possible, and the mapping mode is similar to the mapping mode of only performing the frequency domain extension when performing the frequency domain mapping, and is not repeated here.

It should be noted that the number of OFDM symbols N in the embodiment of the present disclosure_dRepresenting the number of OFDM symbols used for data transmission. Considering that one modulation symbol corresponds to one OFDM symbol when frequency domain spreading is performed, and thus when a plurality of modulation symbols are obtained by modulating transmission data, the corresponding OFDM symbols are also multiple, the number of OFDM symbols occupied by the embodiments of the present disclosure after modulation is less than N_dAnd then, performing time domain expansion, namely performing combined expansion of a frequency domain and a time domain so as to realize maximization of time domain resource utilization.

In the embodiment of the present disclosure, when the data transmission method is applied to the UE, the number N of OFDM symbols is_dThe data transmission method may be preset in a protocol, or the base station may dynamically indicate to the UE after comprehensively considering the size of the transmitted data volume and the channel quality of the data transmission channel, for example, when the data volume is large, N may be appropriately increased_dA value of (d); when the data transmission method is applied to a base station, the number of OFDM symbols is N_dIt may be preset in the protocol, or it may be determined by the base station by comprehensively considering the size of the transmitted data volume and the channel quality of the data transmission channel, and the like, for example, in the data volumeWhen the size is larger, N can be properly increased_dThe value of (c).

In order to better implement modulation on transmission data, referring to fig. 4, in the data transmission method provided in the embodiment of the present disclosure, data modulation is implemented according to a constellation mapping policy, and the modulation process is implemented by the following steps:

s401, a constellation mapping strategy is obtained, wherein the constellation mapping strategy comprises a division number M, and the division number M is the number of bits which are intercepted from transmission data and used for mapping to a modulation symbol;

when the data transmission method is applied to the UE, the constellation mapping policy may be preset in a protocol, or may be dynamically indicated to the UE by the base station after comprehensively considering the size of the transmitted data volume and the channel quality of the data transmission channel. When the data transmission method is applied to a base station, the constellation mapping policy may be preset in a protocol, or may be determined by the base station by comprehensively considering the size of the transmitted data volume, the channel quality of a data transmission channel, and other relevant factors.

S402, sequentially dividing at least one bit included in the transmission data into a plurality of bit groups according to the division number M;

and S403, mapping each bit group into a corresponding modulation symbol, wherein each bit group comprises M bits of data.

Specifically, the embodiments of the present disclosure may sequentially divide data of at least one bit included in transmission data by using data of M bits as a division unit based on the division number M indicated by the obtained constellation mapping policy to obtain a plurality of bit groups. Each bit group is mapped to a corresponding modulation symbol, so that at least one bit of data included in the transmission data is modulated to obtain at least one modulation symbol.

In correspondence with the above-mentioned data transmission device performing data transmission, another embodiment of the present disclosure provides a process of performing data reception by the data reception device, which is described in detail in the following embodiments.

As shown in fig. 5, a flowchart of a data transmission method according to another embodiment of the present disclosure is provided, where an execution main body of the data transmission method is a data receiving apparatus, and the data receiving apparatus corresponds to a receiving end, and may be a UE, or may be a base station, so that when the data receiving apparatus is a UE, a data transmitting apparatus corresponding to a transmitting end of the data receiving apparatus is a base station, and when the data receiving apparatus is a base station, a data transmitting apparatus corresponding to the transmitting end is a UE, and the data transmission method includes the following steps:

s501, receiving a symbol sequence after frequency domain expansion transmitted by a transmitting end through two subcarriers, wherein the symbol sequence after frequency domain expansion comprises complex symbols with opposite phases, and each subcarrier transmits one of the complex symbols with opposite phases respectively.

In the embodiment of the present disclosure, after the transmitting end transmits the symbol sequence after frequency domain expansion to the receiving end through two subcarriers, the receiving end receives the symbol sequence after frequency domain expansion.

S502, acquiring a conjugate sequence of a frequency domain spreading sequence, wherein the frequency domain spreading sequence is used for a transmitting end to perform frequency domain spreading on a modulation symbol after modulation of transmission data to be transmitted, the frequency domain spreading sequence comprises complex indexes with opposite phases, and the conjugate sequence of the frequency domain spreading sequence comprises conjugate complex indexes respectively corresponding to the complex indexes with opposite phases.

In the embodiment of the present disclosure, regardless of whether the data receiving apparatus is a UE or a base station, the embodiment of the present disclosure performs a reverse operation based on a specific operation performed by a data transmitting apparatus corresponding to a transmitting end.

When the data transmission method is applied to the UE, the frequency domain spreading sequence in the embodiment of the present disclosure may be a parameter θ indicated by the UE according to the base station_iAnd a predefined frequency domain spreading sequence and theta_iWith respect to the relation therebetween, the base station may indicate θ to the UE through DCI_i。

In addition, the base station can also directly indicate a specific frequency domain spreading sequence to the UE through the DCI, and the dynamic indication mode can indicate different frequency domain spreading sequences for different UEs and also indicate different frequency domain spreading sequences for the same UE when different data transmission is performed; similarly, when the data transmission method is applied to a base station, the frequency domain spreading sequence may be preset in a protocol or may be determined by the base station. Correspondingly, the conjugate sequence of the frequency domain spreading sequence may be conjugate complex exponents corresponding to two complex exponents with opposite phase directions in the frequency domain spreading sequence, and the phase directions of the two conjugate complex exponents are also opposite.

S503, multiplying the symbol sequence after the frequency domain spreading including the complex symbol with the opposite phase with the conjugate sequence of the frequency domain spreading sequence including the conjugate complex index to obtain the modulation symbol after the frequency domain de-spreading.

The embodiment of the present disclosure may obtain the modulation symbol after frequency domain despreading based on the result of the product of the frequency domain spread symbol sequence including the complex symbol with opposite phase and the obtained conjugate sequence of the frequency domain spread sequence.

And S504, demodulating the modulation symbols to obtain transmission data sent by the sending end.

For the modulation symbols after frequency domain despreading, the embodiment of the present disclosure may further determine data of M bits mapped by each modulation symbol based on the division number included in the constellation mapping policy, so as to demodulate and obtain transmission data sent by the sending end. In the embodiment of the present disclosure, for the symbol sequences after the frequency domain and the time domain spreading transmitted by two subcarriers, frequency domain despreading may be performed first, and then time domain despreading may be performed to obtain a despread modulation symbol, as shown in fig. 6, the despreading process is specifically implemented by the following steps:

s601, receiving a frequency domain and time domain expanded symbol sequence transmitted by a transmitting end through two subcarriers, wherein the frequency domain and time domain expanded symbol sequence comprises complex symbols with opposite phases after time domain expansion.

In the embodiment of the disclosure, after the transmitting end transmits the symbol sequence after the frequency domain and the time domain expansion to the receiving end through the two subcarriers, the receiving end receives the symbol sequence after the frequency domain and the time domain expansion.

S602, multiplying the complex symbol with the opposite phase after the time domain spreading by the obtained time domain spreading sequence to obtain a time domain de-spread symbol sequence, wherein the time domain spreading sequence is used for the sending end to perform time domain spreading on the symbol sequence after the frequency domain spreading.

The embodiment of the present disclosure may obtain a time domain despread symbol sequence based on a result of a product of the complex symbol with an opposite phase after the time domain spreading and the obtained time domain spreading sequence.

When the data transmission method is applied to the UE, the time domain spreading sequence in the embodiment of the present disclosure may be preset in a protocol, or may be dynamically indicated to the UE by the base station through DCI, and the dynamic indication manner may indicate different time domain spreading sequences for different UEs, or may indicate different time domain spreading sequences for the same UE during each data transmission; when the data transmission method is applied to a base station, the time domain spreading sequence may be preset in a protocol.

S603, multiplying the symbol sequence after time domain de-spreading by a conjugate sequence of a frequency domain spreading sequence comprising a conjugate complex index to obtain a modulation symbol after frequency domain de-spreading.

For a time-domain despread symbol sequence, embodiments of the present disclosure may also determine a frequency-domain despread modulation symbol based on a product result of the symbol sequence and a conjugate sequence of a frequency-domain spreading sequence. The above frequency domain despreading process is similar to the method used when only frequency domain despreading is performed, and is not described herein again.

In order to better implement demodulation of transmission data, the data transmission method provided in the embodiment of the present disclosure performs demodulation according to a constellation mapping strategy, as shown in fig. 7, the demodulation process is implemented by the following steps:

s701, a constellation mapping strategy is obtained, wherein the constellation mapping strategy comprises a division number M, and the division number M is the number of bits which are intercepted from transmission data and used for being mapped to a modulation symbol;

s702, according to the division number M, mapping each modulation symbol after frequency domain de-spreading into data of M bits to obtain transmission data.

Similar to the modulation process, the embodiments of the present disclosure may also be based on the number of divisions M included in the constellation mapping strategy when performing the demodulation process. Specifically, in the embodiment of the present disclosure, mapping of M bits of data is performed on each modulation symbol after frequency domain despreading based on the division number M, and after mapping of all modulation symbols is completed, transmission data sent by a sending end is obtained through demodulation.

When the data transmission method is applied to a base station, the constellation mapping strategy can be preset in a protocol, and can also be determined by the base station after comprehensively considering the size of transmitted data volume, the channel quality of a data transmission channel and other relevant factors; when the data transmission method is applied to the UE, the constellation mapping policy may be preset in a protocol, or may be dynamically indicated to the UE by the base station after comprehensively considering the size of the transmitted data volume and the channel quality of the data transmission channel.

In order to further understand the data transmission method provided in the above embodiments, a specific example is described below.

In the embodiment of the present disclosure, the data transmitting apparatus first transmits at least one bit [ b (0), b (1), …, b (M) of the transmission data according to the constellation mapping policy_bit-1)]Modulation to obtain M_symbModulation symbols [ d (0), d (1), …, d (M)_symb-1)](ii) a The modulation symbol d (i) corresponds to M bits of data, and the modulation symbol d (i) may be a complex symbol, such as 1+ j.

Secondly, for each modulation symbol d (i), it can be determined according to the parameter θ_iTo determine a frequency domain spreading sequence r_i＝[r_i(0),r_i(1)]^T＝[exp(jθ_i),exp{j(θ_i+π)}]^T。

Thirdly, the modulation symbols d (i) and the corresponding frequency domain spreading sequence r_iMultiplying to obtain a symbol sequence after frequency domain expansion:

then, for each of the frequency domain spread symbol sequences y_iDetermining a time-domain spreading sequence w_i＝[w_i(0),w_i(1),…,w_i(N_SF,i-1)]^TWherein the length N of the time domain spreading sequence_SF,iIs a positive integer and satisfies:

finally, each frequency domain expanded symbol sequence y_iWith corresponding time domain spreading sequences w_iMultiplying to obtain a symbol sequence after frequency domain and time domain expansion:

the data transmission device obtains all the sequences

One-to-one mapping to N_dOne OFDM symbol and

the 2 complex symbols are placed on two sub-carriers on the corresponding OFDM symbol for transmission to realize transmission of transmission data.

Correspondingly, in the embodiment of the present disclosure, the data receiving apparatus first receives the symbol sequences after the frequency domain and the time domain spreading sent by the two subcarriers:

secondly, the symbol sequence after the frequency domain and the time domain are expanded

And a time domain spreading sequence w_iMultiplying to obtain a symbol sequence after time domain despreading:

thirdly, the symbol sequence after time domain de-spreading and the r of the frequency domain spreading sequence are processed_iOf (2) a conjugated sequence r_i′＝[exp(-jθ_i),exp{-j(θ_i+π)}]^TMultiplying to obtain modulation symbol d (i)', after frequency domain de-spreading.

Finally, according to the constellation mapping strategy, the modulation symbols d (i)' are demodulated into transmission data.

In conclusion, the frequency domain and the time domain are jointly expanded through the cooperation of the data sending device and the data receiving device, the overall adjacent channel leakage power is reduced, and meanwhile the coverage performance of data transmission is further improved.

Based on the same inventive concept, the embodiments of the present disclosure provide a data transmission apparatus corresponding to a data transmission method, and since the principle of solving the problem of the apparatus in the embodiments of the present disclosure is similar to the data transmission method in the embodiments of the present disclosure, the implementation of the apparatus may refer to the implementation of the method, and repeated details are not described again.

As shown in fig. 8, the data transmission apparatus provided in the embodiment of the present disclosure includes:

a transmission data obtaining module 801, configured to obtain transmission data to be sent to a receiving end, where the transmission data includes data of at least one bit;

a data modulation module 802, configured to perform modulation processing on data of at least one bit to obtain at least one modulation symbol, where each modulation symbol in the at least one modulation symbol is obtained by modulating the data of the at least one bit;

a first sequence determining module 803, configured to determine a frequency domain spreading sequence used for performing frequency domain spreading on each modulation symbol, where the frequency domain spreading sequence includes complex exponentials with opposite phase directions;

a first symbol sequence generating module 804, configured to multiply each modulation symbol with a complex index in a corresponding frequency domain spreading sequence, where the phase directions of the complex indexes are opposite, to obtain a frequency domain spread symbol sequence corresponding to each modulation symbol, where the frequency domain spread symbol sequence includes complex symbols in opposite phases;

a transmission module 805, configured to transmit complex symbols with opposite phases to a receiving end by using two subcarriers, where each of the two subcarriers transmits one of the complex symbols with opposite phases.

In one embodiment, the data transmission apparatus further includes:

a second sequence determining module 806, configured to determine a time domain spreading sequence for performing time domain spreading on complex symbols with opposite phases included in each frequency domain spread symbol sequence, where a sum of lengths of the time domain spreading sequences and a number N of Orthogonal Frequency Division Multiplexing (OFDM) symbols used for data transmission_dThe same;

a second symbol sequence generating module 807, configured to multiply the complex symbols with opposite phases with a corresponding time domain spreading sequence to obtain a frequency domain and time domain spread symbol sequence, where the frequency domain and time domain spread symbol sequence includes the complex symbols with opposite phases after time domain spreading;

a transmission module 805, specifically configured to map the time-domain spread complex symbols with opposite phases to N in the time domain_dOver one OFDM symbol, and N_dAnd transmitting on two subcarriers in the frequency domain corresponding to the OFDM symbols.

In another embodiment, the data transmission apparatus further includes:

a policy obtaining module 808, configured to obtain a constellation mapping policy, where the constellation mapping policy includes a division number M, where the division number M is a number of bits that are intercepted from transmission data and used for mapping to one modulation symbol;

a data modulation module 802, specifically configured to sequentially divide at least one bit included in the transmission data into a plurality of bit groups according to the division number M; and mapping each bit group into a corresponding modulation symbol, wherein each bit group comprises M bits of data.

In a specific implementation, the two subcarriers are two adjacent subcarriers.

As shown in fig. 9, which is a schematic structural diagram of a data transmitting apparatus provided in an embodiment of the present disclosure, the data transmitting apparatus includes: a processor 901, a memory 902 and a bus 903, where the memory 902 stores machine-readable instructions executable by the processor 901, when the network-side device operates, the processor 901 and the memory 902 communicate with each other through the bus 903, and when the processor 901 executes the following processing:

modulating the data of at least one bit to obtain at least one modulation symbol, wherein each modulation symbol in the at least one modulation symbol is obtained by modulating the data of at least one bit;

determining a frequency domain spreading sequence for performing frequency domain spreading on each modulation symbol, wherein the frequency domain spreading sequence comprises complex exponentials with opposite phase directions;

multiplying each modulation symbol by a complex index with an opposite phase direction in a corresponding frequency domain spreading sequence respectively to obtain a frequency domain spread symbol sequence corresponding to each modulation symbol, wherein the frequency domain spread symbol sequence comprises complex symbols with opposite phases;

two subcarriers are adopted to transmit complex symbols with opposite phases to a receiving end, and each subcarrier in the two subcarriers respectively transmits one of the complex symbols with opposite phases.

In one embodiment, the processor 901 is further configured to perform the following processes:

determining a time domain spreading sequence for time domain spreading complex symbols with opposite phases included in each frequency domain spread symbol sequence, wherein the sum of the lengths of the time domain spreading sequences and the number N of Orthogonal Frequency Division Multiplexing (OFDM) symbols for data transmission_dThe same;

multiplying the complex symbols with opposite phases with the corresponding time domain spreading sequence to obtain a symbol sequence after frequency domain and time domain spreading, wherein the symbol sequence after the frequency domain and the time domain spreading comprises the complex symbols with opposite phases after the time domain spreading;

processor 901 performs a process for transmitting complex symbols with opposite phases to a receiving end using two subcarriers, comprising:

mapping the time-domain-spread complex symbols with opposite phases to N in the time domain_dOver one OFDM symbol, and N_dAnd transmitting on two subcarriers in the frequency domain corresponding to the OFDM symbols.

In another embodiment, the processor 901 is further configured to perform the following processes:

acquiring a constellation mapping strategy, wherein the constellation mapping strategy comprises a division number M which is the number of bits which are intercepted from transmission data and are used for mapping to a modulation symbol;

sequentially dividing at least one bit included in transmission data into a plurality of bit groups according to the division number M;

and mapping each bit group into a corresponding modulation symbol, wherein each bit group comprises M bits of data.

In a specific implementation, the two subcarriers are two adjacent subcarriers.

The disclosed embodiments also provide a computer-readable storage medium having stored thereon a computer program, which, when executed by a processor, performs the steps of the data transmission method.

Specifically, the storage medium can be a general storage medium, such as a mobile disk, a hard disk, and the like, and when a computer program on the storage medium is executed, the data transmission method can be executed, so that the problem of high adjacent channel leakage power caused by the current single carrier transmission mode is solved, and the effects of reducing the adjacent channel leakage power and improving the communication performance of the electric power wireless private network communication system are achieved.

Based on the same inventive concept, another data transmission device corresponding to the data transmission method is also provided in the embodiments of the present disclosure, and since the principle of solving the problem of the device in the embodiments of the present disclosure is similar to the data transmission method in the embodiments of the present disclosure, the implementation of the device may refer to the implementation of the method, and repeated details are not described.

Referring to fig. 10, a data transmission device provided in an embodiment of the present disclosure includes:

a symbol sequence receiving module 1001, configured to receive a frequency domain extended symbol sequence transmitted by a transmitting end through two subcarriers, where the frequency domain extended symbol sequence includes complex symbols with opposite phases, and each subcarrier transmits one of the complex symbols with opposite phases;

a conjugate sequence obtaining module 1002, configured to obtain a conjugate sequence of a frequency domain spreading sequence, where the frequency domain spreading sequence is used for a sending end to perform frequency domain spreading on a modulation symbol after modulation of transmission data to be sent, the frequency domain spreading sequence includes complex indexes with opposite phases, and the conjugate sequence of the frequency domain spreading sequence includes conjugate complex indexes respectively corresponding to the complex indexes with opposite phases;

a modulation symbol generation module 1003, configured to multiply a frequency domain spread symbol sequence including complex symbols with opposite phases by a conjugate sequence of the frequency domain spread sequence including conjugate complex exponentials to obtain a frequency domain despread modulation symbol;

the demodulation module 1004 is configured to demodulate the modulation symbol to obtain transmission data sent by the sending end.

In an embodiment, the symbol sequence receiving module 1001 is specifically configured to receive a frequency-domain and time-domain spread symbol sequence transmitted by a transmitting end through two subcarriers, where the frequency-domain and time-domain spread symbol sequence includes complex symbols with opposite phases after time-domain spreading;

a modulation symbol generation module 1003, specifically configured to multiply the complex symbol with an opposite phase after time domain spreading by the obtained time domain spreading sequence to obtain a time domain despread symbol sequence, where the time domain spreading sequence is used to send an end to perform time domain spreading on the frequency domain spread symbol sequence; and multiplying the symbol sequence after the time domain de-spreading by a conjugate sequence of a frequency domain spreading sequence comprising a conjugate complex index to obtain a modulation symbol after the frequency domain de-spreading.

In another embodiment, the demodulation module 1004 is specifically configured to obtain a constellation mapping policy, where the constellation mapping policy includes a division number M, where the division number M is a number of bits that are extracted from transmission data and used for mapping to one modulation symbol; and mapping each modulation symbol subjected to frequency domain despreading into data with M bits according to the division number M to obtain transmission data.

As shown in fig. 11, which is a schematic structural diagram of a data receiving device according to an embodiment of the present disclosure, the data receiving device includes: the network side device comprises a processor 1101, a memory 1102 and a bus 1103, wherein the memory 1102 stores machine-readable instructions executable by the processor 1101, when the network side device runs, the processor 1101 communicates with the memory 1102 through the bus 1103, and the machine-readable instructions are executed by the processor 1101 to perform the following processing:

receiving a frequency domain expanded symbol sequence transmitted by a transmitting end through two subcarriers, wherein the frequency domain expanded symbol sequence comprises complex symbols with opposite phases, and each subcarrier respectively transmits one of the complex symbols with opposite phases;

acquiring a conjugate sequence of a frequency domain spreading sequence, wherein the frequency domain spreading sequence is used for carrying out frequency domain spreading on a modulation symbol after modulating transmission data to be transmitted by a transmitting end, the frequency domain spreading sequence comprises complex indexes with opposite phases, and the conjugate sequence of the frequency domain spreading sequence comprises conjugate complex indexes respectively corresponding to the complex indexes with opposite phases;

multiplying a frequency domain spread symbol sequence comprising complex symbols with opposite phases by a conjugate sequence of a frequency domain spread sequence comprising conjugate complex exponentials to obtain a modulation symbol after frequency domain de-spreading;

and demodulating the modulation symbols to obtain transmission data sent by the sending end.

In an embodiment, the processor 1101 performs a process of receiving a symbol sequence after frequency domain spreading transmitted by a transmitting end through two subcarriers, including:

receiving a symbol sequence which is transmitted by a transmitting end through two subcarriers after frequency domain and time domain expansion, wherein the symbol sequence after the frequency domain and the time domain expansion comprises complex symbols which are subjected to time domain expansion and have opposite phases;

processor 1101 performs a process for multiplying a frequency-domain spread symbol sequence comprising complex symbols in opposite phase with a conjugate sequence of a frequency-domain spread sequence comprising conjugate complex exponentials to obtain a frequency-domain despread modulation symbol, comprising:

multiplying the complex symbol with opposite phase after time domain expansion by the acquired time domain expansion sequence to obtain a time domain de-expanded symbol sequence, wherein the time domain expansion sequence is used for transmitting the symbol sequence subjected to the end-to-frequency domain expansion to perform time domain expansion;

and multiplying the symbol sequence after the time domain de-spreading by a conjugate sequence of a frequency domain spreading sequence comprising a conjugate complex index to obtain a modulation symbol after the frequency domain de-spreading.

In another embodiment, the processing executed by the processor 1101 to demodulate the modulation symbols and obtain the transmission data transmitted by the transmitting end includes:

and mapping each modulation symbol subjected to frequency domain despreading into data with M bits according to the division number M to obtain transmission data.

The computer program product of the data transmission method provided in the embodiments of the present disclosure includes a computer-readable storage medium storing a program code, where instructions included in the program code may be used to execute the method in the foregoing method embodiments, and specific implementation may refer to the method embodiments, and details are not described herein again.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the system and the apparatus described above may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present disclosure may be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present disclosure. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The above is only a specific embodiment of the present disclosure, but the scope of the present disclosure is not limited thereto, and any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the present disclosure, and shall be covered by the scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims

1. A method of data transmission, the method comprising:

if the data of the OFDM symbol occupied by the modulation symbol is less than the number N of the OFDM symbols for data transmission_dThen, thenDetermining a time domain spreading sequence for performing time domain spreading on complex symbols with opposite phases included in each frequency domain spread symbol sequence, wherein the sum of the lengths of the time domain spreading sequences and the N_dThe time domain spreading sequence is w_i＝[w_i(0),w_i(1),…,w_i(N_SF,i-1)]^TWherein N is_SF,iIs the length of the time domain spreading sequence and is a positive integer and satisfies:

M_symbis the number of modulation symbols;

spreading each frequency domain symbol sequence y_iWith corresponding time domain spreading sequences w_iMultiplying to obtain a symbol sequence after frequency domain and time domain expansion:

，

the symbol sequences after the frequency domain and the time domain expansion comprise complex symbols with opposite phases after the time domain expansion;

transmitting the complex symbols with opposite phases after the time domain expansion to the receiving end by adopting two subcarriers, wherein each subcarrier in the two subcarriers respectively transmits one of the complex symbols with opposite phases after the time domain expansion;

the transmitting the complex symbol with the opposite phase after the time domain expansion to the receiving end by adopting two subcarriers comprises the following steps:

mapping the time-domain-spread complex symbols with opposite phases to N in a time domain_dOver one OFDM symbol, and with said N_dAnd transmitting on two subcarriers in the frequency domain corresponding to the OFDM symbols.

2. The method of claim 1, wherein prior to the modulation processing of the at least one bit of data, the method further comprises:

obtaining a constellation mapping strategy, wherein the constellation mapping strategy comprises a division number M, and the division number M is the number of bits which are intercepted from the transmission data and used for mapping to a modulation symbol;

the modulating the data of the at least one bit to obtain at least one modulation symbol includes:

sequentially dividing at least one bit included in the transmission data into a plurality of bit groups according to the division number M;

3. The method of claim 1, wherein the two subcarriers are two adjacent subcarriers.

4. A method of data transmission, the method comprising:

receiving a frequency domain and time domain spread symbol sequence transmitted by a transmitting end through two subcarriers, wherein the frequency domain and time domain spread symbol sequence comprises complex symbols with opposite phases after time domain spreading;

acquiring a conjugate sequence of a frequency domain spreading sequence, wherein the frequency domain spreading sequence is used for carrying out frequency domain spreading on a modulation symbol to be transmitted after transmission data to be transmitted is modulated by the transmitting terminal, and comprises complex exponentials with opposite phases;

multiplying the complex symbol with the opposite phase after the time domain expansion by the acquired time domain expansion sequence to obtain a time domain de-spread symbol sequence, wherein the time domain expansion sequence is used for the sending end to perform time domain expansion on the symbol sequence after the frequency domain expansion, and the sum of the length of the time domain expansion sequence and the number N of Orthogonal Frequency Division Multiplexing (OFDM) symbols for data transmission_dThe same;

multiplying the time domain despread symbol sequence with a conjugate sequence of the frequency domain spreading sequence comprising conjugate complex indexes to obtain a frequency domain despread modulation symbol, wherein the conjugate sequence of the frequency domain spreading sequence comprises conjugate complex indexes respectively corresponding to the complex indexes with opposite phases;

demodulating the modulation symbol after the frequency domain de-spreading to obtain the transmission data sent by the sending end;

the method for transmitting the complex symbols with opposite phases after time domain expansion by the transmitting end is as follows: acquiring transmission data to be sent to a receiving end, wherein the transmission data comprises data of at least one bit; modulating the data of the at least one bit to obtain at least one modulation symbol, wherein each modulation symbol in the at least one modulation symbol is obtained by modulating the data of the at least one bit; determining a frequency domain spreading sequence for frequency domain spreading of each modulation symbol, the frequency domain spreading sequence comprising complex exponentials with opposite phase directions; multiplying each modulation symbol by the complex index with opposite phase direction in the corresponding frequency domain spreading sequence respectively to obtain a frequency domain spread symbol sequence corresponding to each modulation symbol, wherein the frequency domain spread symbol sequence comprises complex symbols with opposite phases; if the data of the OFDM symbol occupied by the modulation symbol is less than the number N of the OFDM symbols for data transmission_dDetermining a time domain spreading sequence for time domain spreading complex symbols with opposite phases included in each of the frequency domain spread symbol sequences, wherein the sum of the lengths of the time domain spreading sequences and the number N of Orthogonal Frequency Division Multiplexing (OFDM) symbols for data transmission_dThe time domain spreading sequence is w_i＝[w_i(0),w_i(1),…,w_i(N_SF,i-1)]^TWherein N is_SF,iIs the length of the time domain spreading sequence and is a positive integer and satisfies:

M_symbis the number of modulation symbols; spreading each frequency domain symbol sequence y_iWith corresponding time domain spreading sequences w_iMultiplying to obtain a symbol sequence after frequency domain and time domain expansion:

，

the symbol sequences after the frequency domain and the time domain expansion comprise complex symbols with opposite phases after the time domain expansion; transmitting the complex symbols with opposite phases after the time domain expansion to the receiving end by adopting two subcarriers, wherein each subcarrier in the two subcarriers respectively transmits one of the complex symbols with opposite phases after the time domain expansion; the method for transmitting the complex symbols with opposite phases after time domain expansion to the receiving end by adopting two subcarriers comprises the following steps: mapping the time-domain-spread complex symbols with opposite phases to N in a time domain_dOver one OFDM symbol, and with said N_dAnd transmitting on two subcarriers in the frequency domain corresponding to the OFDM symbols.

5. The method as claimed in claim 4, wherein the demodulating the modulation symbols after the frequency domain despreading to obtain the transmission data sent by the sending end comprises:

and mapping each modulation symbol subjected to frequency domain despreading into data with M bits according to the division number M to obtain the transmission data.

6. A data transmission apparatus, characterized in that the data transmission apparatus comprises: a processor, a memory and a bus, the memory storing machine-readable instructions executable by the processor, the processor and the memory communicating over the bus when the data transmission apparatus is operating, the machine-readable instructions when executed by the processor performing the following:

if the data of the OFDM symbol occupied by the modulation symbol is less than the number N of the OFDM symbols for data transmission_dDetermining a time domain spreading sequence for time domain spreading complex symbols with opposite phases included in each of the frequency domain spread symbol sequences, wherein the sum of the lengths of the time domain spreading sequences and the number N of Orthogonal Frequency Division Multiplexing (OFDM) symbols for data transmission_dThe time domain spreading sequence is w_i＝[w_i(0),w_i(1),…,w_i(N_SF,i-1)]^TWherein N is_SF,iIs the length of the time domain spreading sequence and is a positive integer and satisfies:

M_symbis the number of modulation symbols;

，

in the processing executed by the processor, the transmitting the complex symbols with opposite phases after the time domain spreading to the receiving end by using two subcarriers includes:

7. A data receiving apparatus, characterized in that the data receiving apparatus comprises: a processor, a memory and a bus, the memory storing machine-readable instructions executable by the processor, the processor and the memory communicating via the bus when the data receiving apparatus is operating, the machine-readable instructions when executed by the processor performing the following:

，