WO2016188273A1

WO2016188273A1 - Frequency offset estimation method and apparatus

Info

Publication number: WO2016188273A1
Application number: PCT/CN2016/079755
Authority: WO
Inventors: 周海军; 李媛媛
Original assignee: 电信科学技术研究院
Priority date: 2015-05-25
Filing date: 2016-04-20
Publication date: 2016-12-01
Also published as: CN106302284A; CN106302284B

Abstract

A frequency offset estimation method and device, used to estimate a frequency offset under a high-speed movement environment. A first-class pilot symbol of embodiments of the present invention corresponds to a plurality of first-class short symbols, and a sending device sends the first-class short symbols to a receiving device; and the receiving device estimates, according to the first-class short symbols, a frequency offset. Compared with a mode of directly estimating, by a receiving device, a frequency offset according to a first-class pilot symbol in the prior art, the embodiments of the present invention can improve, due to frequency offset estimation using first-class short symbols, the detection performance of a signal and can better meet a requirement for frequency offset estimation under a high-speed movement environment.

Description

Method and device device for performing frequency offset estimation

The present application claims priority to Chinese Patent Application No. 201510272354.6, entitled "A Method and Apparatus for Frequency Offset Estimation", filed on May 25, 2015, the entire contents of In this application.

Technical field

The present invention relates to the field of wireless communication technologies, and in particular, to a method and device for performing frequency offset estimation.

Background technique

In the LTE (Long Term Evolution) system, the centralized control mode of the network is adopted, that is, the uplink and downlink data of the user equipment (UE) are transmitted and received under the control of the network. The communication between the UE and the UE is forwarded and controlled by the network. There is no direct communication link between the UE and the UE, and the UE is also not allowed to send uplink data by itself, see FIG. 1A.

D2D (Device-to-Device), that is, the user equipment pass-through technology, refers to a method in which neighboring user equipment can transmit data through a direct link in a short range without passing through a central node (ie, a base station). ) Forwarding, as shown in Figure 1B.

In 3GPP (3rd Generation Partnership Project), D2D proximity services include the following two categories:

D2D discovery: The UE uses E-UTRAN (Evolution-Universal Terrestrial Radio Access Network) to confirm that another UE is in its vicinity. For example, the D2D UE can use the service to find nearby taxis, find friends nearby, and the like;

D2D communication: UEs that are close to each other, by directly establishing a link between two UEs, thus converting a communication link originally transmitted through the network into a local direct communication link, saving a large amount of bandwidth and network efficiency; UEs that are close to each other can use direct link communication to obtain stability High-speed and low-cost communication services. Proximity service communication is generally performed under the control or assistance of the network side, and the eNB (Evolved Base Station) may even dynamically allocate resources for the UE performing the proximity service communication.

Currently D2D communication is divided into two types of links:

D2D link: refers to the link between the device and the device for direct communication;

D2N (Device-to-Node) link: A link between a device and a network node.

UEs participating in D2D discovery/communication are divided into two roles:

D2D transmitting UE: a UE that transmits a D2D discovery/communication message;

The D2D receives the UE: that is, the UE that receives the discovery/communication message sent by the D2D transmitting UE.

In D2D of 3GPP, data is SC-FDMA (Single-Carrier Frequency-Division Multiple Access) modulation. The basic transmission unit (TTI) of the data is 1 ms, and the conventional CP (Cyclic Prefix) contains 14 symbols, where symbols 4 and 11 are used to carry demodulation pilots, and symbols 14 are used as symbols. GP (Guard Period).

At present, the working scene of 3GPP's D2D is mainly a low-speed environment, and does not consider the need in a high-speed mobile environment.

In the high-speed mobile environment, assuming a carrier frequency of 5.9 GHz, a crystal stability of 0.1 ppm, and a maximum moving speed of a bicycle of 160 km/h, the maximum relative Doppler shift of the two vehicles is 2.9 kHz, which is used to estimate the frequency. The time interval between the two columns of pilots should not exceed 171 us. The time interval between the three symbols is 214us, and the time interval between the two symbols is 143us.

In summary, there is currently no solution for frequency offset estimation in high-speed mobile environments.

Summary of the invention

The present invention provides a method and apparatus for performing frequency offset estimation for frequency offset estimation in a high speed mobile environment.

A method for performing frequency offset estimation according to an embodiment of the present invention includes:

The transmitting end determines each first type short symbol corresponding to the first type of pilot symbols;

For a transmission, the transmitting end selects a first type of short symbol from all the first type of short symbols;

The transmitting end sends the selected first type of short symbol according to the transmission position corresponding to the first type of pilot symbol, so that the receiving end performs frequency offset estimation according to the first type of short symbol.

Optionally, the sending end determines, according to the following manner, a transmission location corresponding to the first type of pilot symbols:

The transmitting end uses at least one symbol in the same subframe as a transmission location corresponding to the first type of pilot symbol.

Optionally, in the same subframe, at least one symbol is a sixth symbol and at least one symbol is an eleventh symbol; or

In the same subframe, at least one symbol is a third symbol, at least one symbol is a seventh symbol, and at least one symbol is an eleventh symbol; or

In the same subframe, at least one symbol is a third symbol, at least one symbol is a sixth symbol, at least one symbol is a ninth symbol, and at least one symbol is a twelfth symbol.

Optionally, the sending end determines each first type of short symbol corresponding to the first type of pilot symbol, including:

The transmitting end determines each first type short code corresponding to the first type of pilot symbols;

For a first type of short code, the transmitting end generates a first type of short symbol according to the first type of short code.

Optionally, the first type of pilot symbols correspond to S group short codes, and each group of short codes includes R first type short codes; or

The first type of pilot symbols include R first type short codes;

Where S and R are positive integers.

Optionally, the sending end sends the selected first type of short symbol, and further includes:

Determining, by the sending end, a scrambling code corresponding to the selected first type of short symbol;

The transmitting end scrambles data transmitted together with the first type of short symbols by the determined scrambling code.

Optionally, the method further includes:

The transmitting end determines each second type short symbol corresponding to the second type of pilot symbols;

For a transmission, the transmitting end selects a second type of short symbol from all of the second type of short symbols;

And transmitting, by the transmitting end, the selected second type short symbol according to the transmission position corresponding to the second type of pilot symbol, so that the receiving end performs automatic gain control according to the second type of short symbol.

Optionally, the transmission location corresponding to the second type of pilot symbol is the first symbol in the subframe.

Optionally, the method further includes:

The transmitting end determines each third type short symbol corresponding to the third type of pilot symbols;

For a transmission, the transmitting end selects a third type of short symbol from all of the third type of short symbols;

The transmitting end sends the selected third type short symbol according to the transmission position corresponding to the third type of pilot symbol, so that the receiving end performs time synchronization and frequency offset calibration according to the third type short symbol.

Optionally, the transmission location corresponding to the second type of pilot symbol is the second symbol in the subframe.

Optionally, the sending end determines each third type short symbol corresponding to the third type of pilot symbol, including:

The transmitting end determines each third type short code corresponding to the third type of pilot symbols;

For a third type of short code, the transmitting end generates a third type of short symbol according to the third type of short code.

Optionally, any two third type short code cross-correlation values corresponding to the third type of pilot symbols are less than a set threshold; or

Each of the third type of pilot symbols is derived based on different time offsets of the same sequence.

Receiving, by the receiving end, a first type of short symbol from the transmitting end, where the first type of short symbol is selected by the sending end from all first type short symbols corresponding to the first type of pilot symbols;

The receiving end performs frequency offset estimation according to the first type of short symbols.

Optionally, the receiving end receives the first type of short symbol from the sending end, including:

The receiving end receives the first type of short symbol from the transmitting end according to at least one symbol carrying the first type of short symbol in the subframe.

Optionally, at least one symbol in the subframe is a sixth symbol and at least one symbol is an eleventh symbol; or

In the subframe, at least one symbol is a third symbol, at least one symbol is a seventh symbol, and at least one symbol is an eleventh symbol; or

In the subframe, at least one symbol is a third symbol, at least one symbol is a sixth symbol, at least one symbol is a ninth symbol, and at least one symbol is a twelfth symbol.

Optionally, before the receiving end receives the first type of short symbols from the sending end, the method further includes:

The receiving end receives a second type of short symbol from the transmitting end, where the second type of short symbol is selected by the transmitting end from all second type short symbols corresponding to the second type of pilot symbols;

The method also includes:

The receiving end performs automatic gain control according to the second type of short symbols.

Receiving, by the receiving end, a third type of short symbol from the transmitting end, where the third type of short symbol is selected by the transmitting end from all third type short symbols corresponding to the third type of pilot symbol;

The method also includes:

The receiving end performs time synchronization and frequency offset calibration according to the third type of short symbols.

Optionally, after the receiving end receives the first type of short symbol from the sending end, the method further includes:

The receiving end determines the group sequence number according to the third type of short symbol, where the group corresponding to the group sequence number includes the first type short code corresponding to the first type of pilot symbol, and the first type short code is used. Generating the first type of short symbols;

The receiving end performs time domain correlation on the first type short code in the group corresponding to the group sequence number, and determines to generate the first type short code used in the received first type short symbol.

A sending device for performing frequency offset estimation according to an embodiment of the present invention, where the sending device includes:

a determining module, configured to determine each first type of short symbol corresponding to the first type of pilot symbols;

a selection module, configured to, for one transmission, the sender selects a first type of short symbol from all of the first type of short symbols;

And a sending module, configured to send, according to the transmission location corresponding to the first type of pilot symbols, a selected first type of short symbol, so that the receiving end performs frequency offset estimation according to the first type of short symbol.

Optionally, the sending module is further configured to determine, according to the following manner, a transmission location corresponding to the first type of pilot symbols:

At least one symbol in the same subframe is used as a transmission location corresponding to the first type of pilot symbol.

Optionally, the determining module is specifically configured to:

Determining each first type of short code corresponding to the first type of pilot symbols; and for a first type of short code, generating a first type of short symbols according to the first type of short codes.

The first type of pilot symbols include R first type short codes;

Where S and R are positive integers.

Optionally, the sending module is further configured to:

Determining a scrambling code corresponding to the selected first type of short symbols; scrambling data transmitted with the first type of short symbols by the determined scrambling code.

Optionally, the determining module is further configured to:

Determining each second type of short symbol corresponding to the second type of pilot symbol;

The selection module is also used to:

The sending module is further configured to:

And selecting, according to the transmission position corresponding to the second type of pilot symbols, the selected second type of short symbols, so that the receiving end performs automatic gain control according to the second type of short symbols.

Optionally, the determining module is further configured to:

Determining each third type of short symbol corresponding to the third type of pilot symbols;

The selection module is also used to:

Selecting a third type of short symbol from all of the third type of short symbols for one transmission;

The sending module is further configured to:

And transmitting, according to the transmission position corresponding to the third type of pilot symbols, the selected third type of short symbols, so that the receiving end performs time synchronization and frequency offset calibration according to the third type of short symbols.

Optionally, the determining module is specifically configured to:

Determining each third type short code corresponding to the third type of pilot symbols; and for a third type of short code, generating a third type of short symbols according to the third type of short codes.

A receiving device for performing frequency offset estimation according to an embodiment of the present invention, the receiving device includes:

a receiving module, configured to receive a first type of short symbol from a transmitting end, where the first type of short symbol is selected by the sending end from all first type short symbols corresponding to the first type of pilot symbols;

And a processing module, configured to perform frequency offset estimation according to the first type of short symbols.

Optionally, the receiving module is specifically configured to:

Receiving the first from the transmitting end according to at least one symbol carrying the first type of short symbol in the subframe Class short symbol.

Optionally, the receiving module is further configured to:

Receiving a second type of short symbol from the transmitting end before receiving the first type of short symbol from the transmitting end, wherein the second type of short symbol is that the transmitting end is from all second type short symbols corresponding to the second type of pilot symbol Selected;

The processing module is further configured to:

Automatic gain control is performed according to the second type of short symbols.

Optionally, the receiving module is further configured to:

Receiving a third type of short symbol from the transmitting end before receiving the first type of short symbol from the transmitting end, wherein the third type of short symbol is the third terminal short symbol corresponding to the transmitting end from the third type of pilot symbol Selected;

The processing module is further configured to:

Time synchronization and frequency offset calibration are performed according to the third type of short symbols.

Optionally, the processing module is further configured to:

Determining a group sequence number according to the third type of short symbol, where the group corresponding to the group sequence number includes a first type of short code corresponding to the first type of pilot symbols, and the first type of short code is used to generate the a first type of short symbol; performing time domain correlation on the first type of short code in the group corresponding to the group number, and determining to generate the received first type short code used in the first type of short symbol.

The first type of pilot symbols in the embodiment of the present invention correspond to a plurality of first type short symbols, and the transmitting device sends the first type of short symbols to the receiving device; the receiving device performs frequency offset estimation according to the first type of short symbols. Compared with the prior art, the receiving device directly performs frequency offset estimation according to the first type of pilot symbols, and the present invention In the embodiment, the frequency offset estimation is performed by using the first type of short symbols, so that the detection performance of the signal can be improved, and the frequency offset estimation requirement in the high-speed mobile environment can be better adapted.

DRAWINGS

1A is a schematic diagram of data of user equipment communication in a cellular network in the background art;

1B is a schematic diagram of data of direct connection communication of user equipment in the background art;

2 is a schematic structural diagram of a system for performing frequency offset estimation according to an embodiment of the present invention;

3 is a schematic structural diagram of a first D2D data sub-frame according to an embodiment of the present invention;

4 is a schematic diagram of a first data intercepting window according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a second data intercepting window according to an embodiment of the present invention; FIG.

6 is a schematic structural diagram of a second D2D data sub-frame according to an embodiment of the present invention;

7 is a schematic structural diagram of a third D2D data sub-frame according to an embodiment of the present invention;

8 is a schematic structural diagram of a fourth D2D data sub-frame according to an embodiment of the present invention;

9 is a schematic structural diagram of a fifth D2D data sub-frame according to an embodiment of the present invention;

10 is a schematic structural diagram of a sixth D2D data sub-frame according to an embodiment of the present invention;

FIG. 11 is a schematic structural diagram of a first sending device according to an embodiment of the present invention;

12 is a schematic structural diagram of a first receiving device according to an embodiment of the present invention;

FIG. 13 is a schematic structural diagram of a second sending device according to an embodiment of the present invention;

FIG. 14 is a schematic structural diagram of a second receiving device according to an embodiment of the present invention;

FIG. 15 is a schematic flowchart of a method for performing frequency offset estimation according to an embodiment of the present invention; FIG.

FIG. 16 is a schematic flowchart diagram of another method for performing frequency offset estimation according to an embodiment of the present invention.

detailed description

The first type of pilot symbols in the embodiment of the present invention correspond to a plurality of first type short symbols, and the transmitting device sends the first type of short symbols to the receiving device; the receiving device performs frequency offset estimation according to the first type of short symbols. Compared with the method for performing frequency offset estimation according to the first type of pilot symbols in the prior art, the embodiment of the present invention can improve the signal detection performance by using the first type of short symbols for frequency offset estimation, which can be better. Adapt to the frequency offset estimation requirements in high-speed mobile environments.

The embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

As shown in FIG. 2, the system for performing frequency offset estimation in the embodiment of the present invention includes:

The transmitting device 10 is configured to determine each first type of short symbol corresponding to the first type of pilot symbols, and select, for one transmission, a first type of short symbol from all of the first type of short symbols; a transmission position corresponding to the class pilot symbol, and transmitting the selected first type of short symbol;

The receiving device 20 is configured to receive a first type of short symbol from the transmitting end, where the first type of short symbol is selected by the sending end from all first type short symbols corresponding to the first type of pilot symbols; The first type of short symbols are used for frequency offset estimation.

The sending end determines each first type short code corresponding to the first type of pilot symbols;

Specifically, the first type of short code length in the first type of pilot symbols in the embodiment of the present invention is equal to the occupant of the data symbols in the subframe (such as the PUSCH (Physical Uplink Shared Channel) symbol of the LTE). The carrier has a K of 1.

The first type of short code of the embodiment of the present invention may be constructed by using a zadoff-chu sequence, or may be constructed by using an M sequence or other sequences.

For the specific construction mode, refer to the 3GPP TS 36.211 protocol, and details are not described herein again.

After obtaining the first type of short code, each element in the first type of short code is equally spaced into the subcarrier occupied by the sub-frame (equal to the subcarrier used by the data symbol), and the interval is K, and W The point IFFT (Inverse Fast Fourier Transform) operation obtains the first type of short symbols corresponding to the first type of short codes.

The first type of short code is repeated K times, and then a cyclic prefix of length L(i) is added to form a first type of pilot symbol.

For example, K=4, W=1024, L(1)=1104.

Ta(1) = STa (4, 177), ..., STa (4, 256), STa (1), STa (2), STa (3), STa (4), where STa (i) = STa.

Where Tx(m) refers to the mth Tx in the subframe; Tx represents the symbol of type x, such as the first The class symbol, x is 1; Tx(m, n) refers to the nth element of the mth Tx in the subframe. Different values of i indicate different time domain locations, or numbers.

In the process of performing frequency offset estimation in the embodiment of the present invention, only the first type of pilot symbols may be used, or may be performed together with other pilot symbols, which are respectively introduced below.

Solution 1: The first type of pilot symbols and other pilot symbols are involved in the process of performing frequency offset estimation.

Other pilot symbols of the embodiments of the present invention include a second type of pilot symbol and a third type of pilot symbol.

For the second type of pilot symbols, the sending device determines each second type of short symbol corresponding to the second type of pilot symbols;

For a transmission, the sending device selects a second type of short symbol from all the second types of short symbols; and sends a selected second type of short symbol according to the transmission position corresponding to the second type of pilot symbols, The receiving end is caused to perform automatic gain control according to the second type of short symbols.

Correspondingly, the receiving device automatically gains control according to the second type of pilot symbols.

In addition to being used for automatic gain control, the second type of short symbols can also be used to assist in coarse-accuracy synchronization or coarse-precision frequency offset estimation.

In an implementation, the sending end determines each second type short code corresponding to the second type of pilot symbols;

For a second type of short code, the transmitting end generates a second type of short symbol according to the second type of short code.

Specifically, the length of the second type of short code in the second type of pilot symbols in the embodiment of the present invention is equal to one N of the subcarrier occupied by the data symbols in the subframe (such as the PUSCH symbol of LTE).

The second type of short code of the embodiment of the present invention may be constructed by using a zadoff-chu sequence, or may be constructed by using an M sequence or other sequences.

After obtaining the second type of short code, each element in the second type of short code is equally spaced into the subcarrier occupied by the sub-frame (equal to the subcarrier used by the data symbol), and the interval is N, and W The point IFFT operation obtains the second type of short symbols corresponding to the second type of short codes.

The second type of short code is repeated N times, and then a cyclic prefix of length L(i) is added to form a second type of pilot symbol.

For the third type of pilot symbols, the transmitting end determines each third type of short symbol corresponding to the third type of pilot symbols;

For a transmission, the transmitting end selects a third type of short symbol from all the third types of short symbols; and according to the transmission position corresponding to the third type of pilot symbols, sends the selected third type of short symbol to The receiving end is configured to perform time synchronization and frequency offset calibration according to the third type of short symbols.

Correspondingly, the receiving end performs time synchronization and frequency offset calibration according to the third type of short symbols.

Among them, the first type of short symbols can also be used for time synchronization. Compared to the third type of short symbols, the first type of short symbols can perform finer time synchronization.

In an implementation, the sending end determines each third type short code corresponding to the third type of pilot symbols;

Specifically, the third type of short code length in the third type of pilot symbols in the embodiment of the present invention is equal to one-half of the sub-carrier occupied by the data symbols in the subframe (such as the PUSCH symbol of the LTE).

The third type of short code of the embodiment of the present invention may be constructed by using a zadoff-chu sequence, or may be constructed by using an M sequence or other sequences.

After obtaining the third type of short code, each element in the third type of short code is equally spaced into the subcarrier occupied by the sub-frame (equal to the subcarrier used by the data symbol), and the interval is M, and W The point IFFT operation obtains the third type of short symbol corresponding to the third type of short code.

The third type of short code is repeated M times, and then a cyclic prefix of length L(i) is added to form a third type of pilot symbol.

Optionally, for the first scheme, the first type of pilot symbols correspond to the S group short codes, and each group of short codes includes R first type short codes.

When the transmitting device performs one transmission, a set of short codes may be selected from the S group short codes, and one first type short code is selected from the R first type short codes in the selected group.

The third type of pilot symbols correspond to S different third type short symbols.

Optionally, the above S can be the same as the synchronization level that needs to be performed, so that synchronization is not required. Level receiving device. It is also possible to set S to a preset value, such as 1, and the synchronization level needs to be indicated by control information.

In an implementation, control information can be sent in the third symbol of the subframe.

Optionally, for the purpose of better synchronization and reducing inter-user interference, any two types of third-type short-code cross-correlation values corresponding to the third type of pilot symbols in the embodiment of the present invention (ie, cross-correlation of time domain forms of signals) The value is less than the set threshold; or each of the third type of pilot symbols in the third type of pilot symbols of the embodiment of the present invention is obtained based on different time offsets of the same sequence.

The transmitting device, when determining the transmission location corresponding to the first type of pilot symbols, uses at least one symbol in the same subframe as the transmission location corresponding to the first type of pilot symbols.

The first type of short code length in the first type of pilot symbols is equal to one thousand of the subcarriers occupied by the data symbols in the subframe, and the second type of short code length in the second type of pilot symbols is equal to the data symbols in the subframe. The N-division of the occupied sub-carrier is 1. The third-type short code length in the third-type pilot symbol is equal to 1 M of the sub-carrier occupied by the data symbol in the sub-frame. In specific implementation, K, N, and M may be It is custom, and the better value of K is 2. In general practice, it can be N>M>K.

Optionally, at least one of the symbols in the same subframe is a sixth symbol and at least one symbol is an eleventh symbol.

The transmitting device determines, as the transmission location corresponding to the second type of pilot symbol, the first symbol in the subframe as the transmission location corresponding to the second type of pilot symbol.

The transmitting device determines, as the transmission location corresponding to the third type of pilot symbol, the second symbol in the subframe as the transmission location corresponding to the third type of pilot symbol.

For details, the transmission location corresponding to the first type of pilot symbols, the transmission location corresponding to the second type of pilot symbols, and the transmission location corresponding to the third type of pilot symbols can be seen in FIG. 3.

It should be noted that the transmission position in FIG. 3 is only an example, and other transmission positions are also applicable to the embodiment of the present invention. The transmission location corresponding to each type of pilot symbol may be determined according to a channel environment or the like, or may be specified in a protocol.

For the receiving device, when the receiving device detects that the signal power is greater than the set threshold, AGC (Automatic Gain Control) is activated.

After the received signal power value continues to be greater than the set threshold value, the time length is greater than the threshold value (the threshold value may be the time when the automatic gain is too vertical and horizontal), and the second type short symbol or the third type short symbol is used for correlation to determine the arrival of the signal. time.

Use the second type of short symbol to do the correlation:

The time domain signal of the second type of short symbol is correlated with the received data in the time domain, and after obtaining the first correlation peak, the data of 13 symbols including the first short symbol of the correlation peak is intercepted. The length of the data interception window can be adjusted according to the coarse synchronization precision, and needs to include the complete symbols 2 to 13 data, as shown in FIG. 4 .

If the second type of short symbol is used for the coarse precision frequency offset estimation, it can be realized by the following formula:

F=angle(Pda)/Tb;

Where F is the initial value of the frequency estimate; angle is the phase offset value; Tb is the length of the second type of short symbol; Pda is the correlation value, Pda = sum(conj(STb(1)).*STb(2)) Where STb(1) and STb(2) represent two adjacent second-type short symbols; Sum() is summed, conj() is conjugated, and ** is the product of two vectors.

Use the third type of short symbol to do the correlation:

The third type of short symbol is correlated with the received data in the time domain. After the first correlation peak is obtained, the data of 13 symbols including the first half of the correlation peak is intercepted. For details, refer to FIG. 5.

When there are multiple third-type short symbols, each third-type short symbol needs to be correlated with the received data in the time domain, and the third-type short symbol with the largest correlation peak is used as the third short symbol used for transmitting the signal.

In an implementation, the receiving device may use the third type of short symbols for time synchronization.

Specifically, the receiving device correlates the time domain signal of the cascaded third type symbol with the data in the data intercepting window, so that a fine clock can be obtained. If the third type of short symbol is placed in the second symbol of the subframe, the correlation peak position is the starting position of symbol 2, and the data in each symbol is intercepted based on the clock for subsequent processing.

If the receiving device uses the coarse synchronization of the second type of short symbols, and the number S of the second type of short symbols is greater than 1, the data in the data intercepting window may be correlated in parallel, and the short symbol of the largest correlation peak is obtained as the transmission data. The short symbol actually used.

In an implementation, the receiving device may perform a coarser frequency offset estimation (ie, a first frequency offset estimation) using the third type of short symbols.

It is assumed that the transmitting device transmits the third type of short symbol in the second symbol in the subframe, and the receiving device performs a W-point FFT on the second type of short symbol in the second symbol to obtain frequency domain data. By correlating the obtained frequency domain data with the frequency domain data of the third type short code, frequency offset fobs of integer multiples of the subcarriers can be estimated. Use fobs to compensate the time domain data of the second symbol to the 13th symbol, that is, multiply each time domain data point exp(-j*2*pi*fobs*n*ts), exp() is the index of e , n is the number of the time domain point, and ts is the time interval of two adjacent time domain points.

After determining the received third type short symbol, the receiving device determines the group sequence number according to the third type short symbol, and performs time domain correlation on the first type short code in the group corresponding to the group sequence number to determine the generated data. The first type of short code adopted by the first type of short symbol received.

Specifically, the receiving device performs time domain correlation on the first type short code in the group corresponding to the group serial number, and determines the short code used by the sending device to send data according to the correlation peak position. After determining the adopted short code, frequency offset and channel estimation are performed according to the determined short code. Further, after determining the adopted short code, the scrambling code used by the data can be known, and then the received data is descrambled.

Optionally, according to the correlation peak position, the arrival time of the signal can be further estimated, and the fine adjustment of the time is realized.

When the receiving device performs frequency offset estimation according to the third type of short symbols, the correlation value Pdb can be estimated by using two adjacent third type short symbols:

Pdb=sum(conj(STb(1)).*STb(2)), Sum() is summed, conj() is conjugated, and ** represents the inner product of two vectors.

According to the above formula, the correlation value Pdc can also be determined using the first type of short symbols.

The frequency offset estimate can be calculated by the following formula:

Foffset=angle(Pdb+Pdc)/T, where T is the length of time of 1 short symbol; angle is the phase offset.

When the receiving device performs channel estimation according to the first type of short symbols, the Foffset is used to perform frequency offset compensation on the data, and the latest signal arrival time estimation is used to intercept the first type of short symbols, which is short for the first type. The symbol performs an FFT (Fast Fourier Transform) operation to obtain a channel estimation value of the subcarrier with interval K. Interpolating these subcarriers, such as linear interpolation, can obtain channel estimates for all subcarriers.

Optionally, when performing linear interpolation, assuming channel estimates d(i) and d(i+k) of subcarrier i and subcarrier i+k are known, then the channel estimation value of subcarrier i+x is d(i) )+(d(i+k)-d(i))/K*x.

In the implementation, the above W can take 1024, S can take 3, and R can take 4.

The first embodiment of the present invention will be described below by taking the bandwidth of 10 Mhz as an example.

The transmitting device can construct the first type short code, the second type short code, and the third type short code by using the method in LTE.

Specific method:

Is satisfied

The largest prime number.

The setting of the second type of short code related parameters:

Is the number of subcarriers occupied by the service data, N=4.

u=0;

v=0;

The setting of the third type of short code related parameters:

u=0/10/20;

v=0;

The setting of the first type of short code related parameters:

u = 0/10/20; the first type of short code and the third type of short code use the same u value in one subframe.

v=0.

For the above-mentioned letters and the physical meaning of the public, refer to the 3GPP TS 36.211 protocol, and details are not described herein again.

In the implementation, the subcarriers occupied by the first type of short code, the second type of short code, and the third type of short code are included in the subcarrier occupied by the data, and the subcarrier spacing is K, N, and M, as shown in FIG. 6. Shown.

In order to better perform channel estimation, the subcarrier positions occupied by symbols 2, 6, and 11 can be interleaved in the frequency domain.

The frequency domain signal of the first type of short code, the frequency domain signal of the second type of short code, and the frequency domain signal of the third type of short code are written into each subcarrier as shown in FIG. 3, and then 1024/N, 1024/ respectively. M, 1024 / K IFFT operation, the corresponding short code time domain signal is obtained.

The short code time domain signals are repeated N, M, and K times, respectively, and a cyclic prefix of length L(i)-1024 is added to obtain a complete time domain symbol.

The second type of short symbols generated by the second type of short codes are placed in the symbol 1, the second type of short symbols generated by the second type of short codes are placed in the symbol 2, and the second type of short symbols generated by the second type of short codes are placed in the symbol Symbols 6 and 11.

Solution 2: The first type of pilot symbols are involved in the process of performing frequency offset estimation.

In the second scheme, the synchronization and frequency subcarrier level synchronization of the system has been established, and then some first type short symbols are inserted in the subframe for frequency offset estimation and channel estimation.

The generation process of the first type of pilot symbols is the same as that of the first scheme, except that the time domain symbol positions of the first type of short symbol insertion subframes are different.

When the transmitting end uses at least one symbol in the same subframe as the transmission location corresponding to the first type of pilot symbol, at least one symbol in the same subframe is the third symbol and at least one symbol. The seventh symbol and the at least one symbol are the eleventh symbol. For details, refer to FIG. 7. In the same subframe, at least one symbol is the third symbol, and at least one symbol is the sixth symbol. At least one symbol is the ninth symbol and at least one symbol is the twelfth symbol, See Figure 8 for the body.

Optionally, the first type of pilot symbols includes R first type short codes; where R is a positive integer.

In an implementation, the terminal randomly selects one of the R basic symbols when transmitting data. The scrambling code used by the data is in one-to-one correspondence with the first type of pilot symbols. This can effectively reduce the terminal.

Specifically, the sending end determines the selected scrambling code corresponding to the first type of short symbol, and scrambles the data sent together with the first type of short symbol by using the determined scrambling code.

The receiving device intercepts the data containing symbols 1 to 13

The time-domain correlation is performed with the data in the symbol X and all possible third-type short codes, and the short code actually used for transmitting the data can be determined according to the correlation peak position.

The Pdc can be estimated by using the third type of short code in the sub-frame. The process of estimating Pdc is similar to that of the first one, and is not described here.

Calculate the frequency offset estimate: Foffset=angle(Pdc)/T, where T is the length of time of one short symbol.

For the processing procedure of the receiving device, refer to the scheme for processing a third type of short symbol by the receiving device, and details are not described herein again.

The second embodiment of the present invention will be described below by taking the bandwidth of 10 Mhz as an example.

The sending device can construct the first type of short code by using the method in the LTE. The specific process is similar to the first one, and is not described here.

The subcarriers occupied by the first type of short codes are included in the subcarriers occupied by the data, and the subcarrier spacing is K. For details, refer to FIG. 9 or FIG.

The process of generating the third type of short symbol by the sending device according to the time domain signal of the first type of short code is the same as that in the first embodiment, and details are not described herein again. The difference is that the third type of short symbols are added to symbols 3, 7, and 11, or 3, 6, 9, and 12 in scheme 2.

As shown in FIG. 11, the first sending device of the embodiment of the present invention includes:

a determining module 1100, configured to determine each first type of short symbol corresponding to the first type of pilot symbols;

The selecting module 1101 is configured to: for one transmission, the sending end selects a first type of short symbol from all the first type of short symbols;

The sending module 1102 is configured to send, according to the transmission location corresponding to the first type of pilot symbols, a selected first type of short symbol, so that the receiving end performs frequency offset estimation according to the first type of short symbol.

Optionally, the sending module 1102 is further configured to determine, according to the following manner, a transmission location corresponding to the first type of pilot symbols:

Optionally, the determining module 1100 is specifically configured to:

The first type of pilot symbols include R first type short codes;

Where S and R are positive integers.

Optionally, the sending module 1102 is further configured to:

Optionally, the determining module 1100 is further configured to:

The selection module 1101 is further configured to:

The sending module 1102 is further configured to:

Optionally, the determining module 1100 is further configured to:

The selection module 1101 is further configured to:

The sending module 1102 is further configured to:

Optionally, the determining module 1100 is specifically configured to:

As shown in FIG. 12, the first receiving device of the embodiment of the present invention includes:

The receiving module 1200 is configured to receive a first type of short symbol from the transmitting end, where the first type of short symbol is selected by the sending end from all first type short symbols corresponding to the first type of pilot symbols;

The processing module 1201 is configured to perform frequency offset estimation according to the first type of short symbols.

Optionally, the receiving module 1200 is specifically configured to:

Receiving the first type of short symbols from the transmitting end according to at least one symbol carrying the first type of short symbols in the subframe.

Optionally, at least one symbol in the subframe is a sixth symbol and at least one symbol Is the 11th symbol; or

Optionally, the receiving module 1200 is further configured to:

The processing module 1201 is further configured to:

Optionally, the receiving module 1200 is further configured to:

The processing module 1201 is further configured to:

Optionally, the processing module 1201 is further configured to:

It should be noted that the embodiment of the present invention can be applied to a D2D scenario, and the sending device and the receiving device are terminals. In different cases, the transmitting device may also act as a receiving device, and the receiving device may also act as a transmitting device. Based on this, the functions of the sending device and the receiving device in the embodiments of the present invention may be implemented in one entity, that is, the modules in FIG. 11 and FIG. 12 may select a function of the transmitting device or a receiving device according to requirements in one entity. Features.

As shown in FIG. 13, the second sending device of the embodiment of the present invention includes:

The processor 1301 is configured to read a program in the memory 1304 and perform the following process:

Determining each first type of short symbol corresponding to the first type of pilot symbols; for one transmission, the transmitting end selects a first type of short symbol from all of the first type of short symbols; according to the first type of The transmission position corresponding to the frequency symbol is transmitted by the transceiver 1302 to select the first type of short symbol, so that the receiving end performs frequency offset estimation according to the first type of short symbol.

The transceiver 1302 is configured to receive and transmit data under the control of the processor 1301.

Optionally, the processor 1301 is further configured to determine, according to the following manner, a transmission location corresponding to the first type of pilot symbols:

Optionally, the processor 1301 is specifically configured to:

The first type of pilot symbols include R first type short codes;

Where S and R are positive integers.

Optionally, the processor 1301 is further configured to:

Determining each second type of short symbol corresponding to the second type of pilot symbols; for one transmission, the transmitting end selects a second type of short symbol from all of the second type of short symbols; according to the second type of The transmission position corresponding to the frequency symbol transmits the selected second type of short symbol, so that the receiving end performs automatic gain control according to the second type of short symbol.

Optionally, the processor 1301 is further configured to:

Determining each of the third type of short symbols corresponding to the third type of pilot symbols; for a single transmission, selecting a third type of short symbols from all of the third types of short symbols; corresponding to the third type of pilot symbols And transmitting a selected third type of short symbol, so that the receiving end performs time synchronization and frequency offset calibration according to the third type of short symbol.

Optionally, the processor 1301 is specifically configured to:

In FIG. 13, a bus architecture (represented by bus 1300), bus 1300 can include any number of interconnected buses and bridges, and bus 1300 will include one or more processors represented by processor 1301 and memory represented by memory 1304. The various circuits are linked together. The bus 1300 can also link various other circuits, such as peripherals, voltage regulators, and power management circuits, as is known in the art, and therefore, will not be further described herein. Bus interface 1303 provides an interface between bus 1300 and transceiver 1302. Transceiver 1302 can be an element or a plurality of elements, such as a plurality of receivers and transmitters, providing means for communicating with various other devices on a transmission medium. Data processed by processor 1301 passes through antenna 1305 The transmission is performed on a wireless medium, and further, the antenna 1305 also receives data and transmits the data to the processor 1301.

The processor 1301 is responsible for managing the bus 1300 and the usual processing, and can also provide various functions including timing, peripheral interfaces, voltage regulation, power management, and other control functions. The memory 1304 can be used to store data used by the processor 1301 in performing operations.

Optionally, the processor 1301 may be a CPU (Central Embedded Device), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a CPLD (Complex Programmable Logic Device). , complex programmable logic devices).

As shown in FIG. 14, the second receiving device of the embodiment of the present invention includes:

The processor 1401 is configured to read a program in the memory 1404 and perform the following process:

Receiving, by the transceiver 1402, a first type of short symbol from the transmitting end, wherein the first type of short symbol is selected by the transmitting end from all first type short symbols corresponding to the first type of pilot symbols; A type of short symbol is used for frequency offset estimation.

The transceiver 1402 is configured to receive and transmit data under the control of the processor 1401.

Optionally, the processor 1401 is specifically configured to:

Optionally, the processor 1401 is further configured to:

Receiving a second type of short symbol from the transmitting end before receiving the first type of short symbol from the transmitting end, wherein the second type of short symbol is that the transmitting end is short from all second types corresponding to the second type of pilot symbol Selected in the symbol; automatic gain control is performed according to the second type of short symbols.

Optionally, the processor 1401 is further configured to:

Receiving a third type of short symbol from the transmitting end before receiving the first type of short symbol from the transmitting end, wherein the third type of short symbol is the third terminal short symbol corresponding to the transmitting end from the third type of pilot symbol Selected; time synchronization and frequency offset calibration according to the third type of short symbols.

Optionally, the processor 1401 is further configured to:

In FIG. 14, a bus architecture (represented by bus 1400), bus 1400 can include any number of interconnected buses and bridges, and bus 1400 will include one or more processors represented by processor 1401 and memory represented by memory 1404. The various circuits are linked together. The bus 1400 can also link various other circuits, such as peripherals, voltage regulators, and power management circuits, as is known in the art, and therefore, will not be further described herein. Bus interface 1403 provides an interface between bus 1400 and transceiver 1402. Transceiver 1402 may be an element or a plurality of elements, such as multiple receivers and transmitters, providing means for communicating with various other devices on a transmission medium. Data processed by processor 1401 is transmitted over the wireless medium via antenna 1405. Further, antenna 1405 also receives the data and transmits the data to processor 1401.

The processor 1401 is responsible for managing the bus 1400 and the usual processing, and can also provide various functions including timing, peripheral interfaces, voltage regulation, power management, and other control functions. The memory 1404 can be used to store data used by the processor 1401 in performing operations.

Optionally, the processor 1401 may be a CPU, an ASIC, an FPGA, or a CPLD.

It should be noted that the embodiment of the present invention can be applied to a D2D scenario, and the sending device and the receiving device are terminals. In different cases, the transmitting device may also act as a receiving device, and the receiving device may also act as a transmitting device. Based on this, the functions of the transmitting device and the receiving device in the embodiments of the present invention It can be implemented in a physical entity, that is to say, the modules of FIG. 13 and FIG. 14 can be selected in one entity, and the function of the transmitting device or the function of the receiving device can be selected as needed. For example, the processor 1301 and the processor 1401 may be combined into one processor; the transceiver 1302 and the transceiver 1402 may be combined into one transceiver; and the memory 1304 and the memory 1404 may be combined into one memory. Other entities in Figures 13 and 14 can also synthesize an entity. Of course, the entities in FIG. 13 and FIG. 14 may also not synthesize an entity, such as two processors, two transceivers, and the like; or may be partially combined into one entity, and some may not be combined into one entity.

Based on the same inventive concept, a method for performing frequency offset estimation is also provided in the embodiment of the present invention. The principle of solving the problem is similar to the system for performing frequency offset estimation in the embodiment of the present invention. Therefore, the implementation of the method can refer to the implementation of the method. , the repetition will not be repeated.

As shown in FIG. 15, a method for performing frequency offset estimation according to an embodiment of the present invention includes:

Step 1500: The transmitting end determines each first type short symbol corresponding to the first type of pilot symbols.

Step 1501: For a transmission, the sending end selects a first type short symbol from all the first type short symbols;

Step 1502: The sending end sends the selected first type short symbol according to the transmission position corresponding to the first type of pilot symbol, so that the receiving end performs frequency offset estimation according to the first type of short symbol.

Optionally, the sending end determines each first type short symbol corresponding to the first type of pilot symbol, and the packet include:

The first type of pilot symbols include R first type short codes;

Where S and R are positive integers.

Optionally, the method further includes:

Optionally, the sending end determines each third type short symbol corresponding to the third type of pilot symbol, and the packet include:

As shown in FIG. 16, another method for performing frequency offset estimation according to an embodiment of the present invention includes:

Step 1600: The receiving end receives the first type of short symbols from the sending end, where the first type of short symbols is selected by the sending end from all first type short symbols corresponding to the first type of pilot symbols;

Step 1601: The receiving end performs frequency offset estimation according to the first type of short symbol.

Preferably, the receiving end receives the first type of short symbols from the transmitting end, including:

Preferably, at least one symbol in the subframe is a sixth symbol and at least one symbol is an eleventh symbol; or

Preferably, before the receiving end receives the first type of short symbols from the transmitting end, the method further includes:

The method also includes:

Preferably, after receiving the first short symbol from the transmitting end, the receiving end further includes:

It can be seen from the foregoing that the first type of pilot symbols in the embodiment of the present invention correspond to multiple first type short symbols, and the sending device sends the first type of short symbols to the receiving device; the receiving device performs frequency according to the first type of short symbols. Partial estimate. Compared with the method for performing frequency offset estimation according to the first type of pilot symbols in the prior art, the embodiment of the present invention can improve the signal detection performance by using the first type of short symbols for frequency offset estimation, which can be better. Adapt to the frequency offset estimation requirements in high-speed mobile environments.

It is apparent that those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and modifications of the invention

Claims

A method for performing frequency offset estimation, characterized in that the method comprises:

The transmitting end determines each first type short symbol corresponding to the first type of pilot symbols;

For a transmission, the transmitting end selects a first type of short symbol from all the first type of short symbols;

The transmitting end sends the selected first type of short symbol according to the transmission position corresponding to the first type of pilot symbol, so that the receiving end performs frequency offset estimation according to the first type of short symbol.
The method according to claim 1, wherein the transmitting end determines a transmission location corresponding to the first type of pilot symbols according to the following manner:

The transmitting end uses at least one symbol in the same subframe as a transmission location corresponding to the first type of pilot symbol.
The method according to claim 2, wherein in the same subframe, at least one symbol is a sixth symbol and at least one symbol is an eleventh symbol; or

In the same subframe, at least one symbol is a third symbol, at least one symbol is a seventh symbol, and at least one symbol is an eleventh symbol; or

In the same subframe, at least one symbol is a third symbol, at least one symbol is at least one symbol is a sixth symbol, at least one symbol is a ninth symbol, and at least one symbol is a 12th symbol. Symbols.
The method according to claim 1, wherein the transmitting end determines each first type of short symbol corresponding to the first type of pilot symbols, including:

The transmitting end determines each first type short code corresponding to the first type of pilot symbols;

For a first type of short code, the transmitting end generates a first type of short symbol according to the first type of short code.
The method according to claim 4, wherein said first type of pilot symbols correspond to S sets of short codes, and each set of short codes comprises R first type short codes; or

The first type of pilot symbols include R first type short codes;

Where S and R are positive integers.
The method according to claim 1, wherein the transmitting end sends the selected first type of short symbols, and further includes:

Determining, by the sending end, a scrambling code corresponding to the selected first type of short symbol;

The transmitting end scrambles data transmitted together with the first type of short symbols by the determined scrambling code.
The method of claim 1 further comprising:

The transmitting end determines each second type short symbol corresponding to the second type of pilot symbols;

For a transmission, the transmitting end selects a second type of short symbol from all of the second type of short symbols;

And transmitting, by the transmitting end, the selected second type short symbol according to the transmission position corresponding to the second type of pilot symbol, so that the receiving end performs automatic gain control according to the second type of short symbol.
The method according to claim 7, wherein the transmission position corresponding to the second type of pilot symbols is the first symbol in the subframe.
The method according to any one of claims 1 to 8, wherein the method further comprises:

The transmitting end determines each third type short symbol corresponding to the third type of pilot symbols;

For a transmission, the transmitting end selects a third type of short symbol from all of the third type of short symbols;

The transmitting end sends the selected third type short symbol according to the transmission position corresponding to the third type of pilot symbol, so that the receiving end performs time synchronization and frequency offset calibration according to the third type short symbol.
The method according to claim 9, wherein the transmission position corresponding to the second type of pilot symbols is the second symbol in the subframe.
The method according to claim 9, wherein the transmitting end determines each third type of short symbol corresponding to the third type of pilot symbols, including:

The transmitting end determines each third type short code corresponding to the third type of pilot symbols;

For a third type of short code, the transmitting end generates a third type of short symbol according to the third type of short code.
The method according to claim 11, wherein any two third type short code cross-correlation values corresponding to the third type of pilot symbols are less than a set threshold; or

Each of the third type of pilot symbols is derived based on different time offsets of the same sequence.
A method for performing frequency offset estimation, characterized in that the method comprises:

Receiving, by the receiving end, a first type of short symbol from the transmitting end, where the first type of short symbol is selected by the sending end from all first type short symbols corresponding to the first type of pilot symbols;

The receiving end performs frequency offset estimation according to the first type of short symbols.
The method according to claim 13, wherein the receiving end receives the first type of short symbols from the transmitting end, including:

The receiving end receives the first type of short symbol from the transmitting end according to at least one symbol carrying the first type of short symbol in the subframe.
The method according to claim 14, wherein at least one of said symbols is a sixth symbol and at least one symbol is an eleventh symbol; or

In the subframe, at least one symbol is a third symbol, at least one symbol is a seventh symbol, and at least one symbol is an eleventh symbol; or

In the subframe, at least one symbol is a third symbol, at least one symbol is a sixth symbol, at least one symbol is a ninth symbol, and at least one symbol is a twelfth symbol.
The method according to claim 14, wherein before the receiving end receives the first type of short symbols from the transmitting end, the method further includes:

The receiving end receives a second type of short symbol from the transmitting end, where the second type of short symbol is selected by the transmitting end from all second type short symbols corresponding to the second type of pilot symbols;

The method also includes:

The receiving end performs automatic gain control according to the second type of short symbols.
The method according to claim 14, wherein before the receiving end receives the first type of short symbols from the transmitting end, the method further includes:

The receiving end receives a third type of short symbol from the transmitting end, wherein the third type of short symbol is The transmitting end is selected from all third type short symbols corresponding to the third type of pilot symbols;

The method also includes:

The receiving end performs time synchronization and frequency offset calibration according to the third type of short symbols.
The method according to claim 17, wherein after receiving the first type of short symbols from the transmitting end, the receiving end further comprises:

The receiving end determines the group sequence number according to the third type of short symbol, where the group corresponding to the group sequence number includes the first type short code corresponding to the first type of pilot symbol, and the first type short code is used. Generating the first type of short symbols;

The receiving end performs time domain correlation on the first type short code in the group corresponding to the group sequence number, and determines to generate the first type short code used in the received first type short symbol.
A transmitting device for performing frequency offset estimation, wherein the transmitting device includes:

a determining module, configured to determine each first type of short symbol corresponding to the first type of pilot symbols;

a selection module, configured to, for one transmission, the sender selects a first type of short symbol from all of the first type of short symbols;

And a sending module, configured to send, according to the transmission location corresponding to the first type of pilot symbols, a selected first type of short symbol, so that the receiving end performs frequency offset estimation according to the first type of short symbol.
The transmitting device according to claim 19, wherein the sending module is further configured to: determine, according to the following manner, a transmission location corresponding to the first type of pilot symbols:

At least one symbol in the same subframe is used as a transmission location corresponding to the first type of pilot symbol.
The transmitting device according to claim 20, wherein in the same subframe, at least one symbol is a sixth symbol and at least one symbol is an eleventh symbol; or

In the same subframe, at least one symbol is a third symbol, at least one symbol is a seventh symbol, and at least one symbol is an eleventh symbol; or

In the same subframe, at least one symbol is a third symbol, at least one symbol is a sixth symbol, at least one symbol is a ninth symbol, and at least one symbol is a twelfth symbol.
The transmitting device according to claim 19, wherein said determining module is specifically used to:

Determining each first type of short code corresponding to the first type of pilot symbols; and for a first type of short code, generating a first type of short symbols according to the first type of short codes.
The transmitting device according to claim 22, wherein said first type of pilot symbols correspond to S group short codes, and each group of short codes comprises R first type short codes; or

The first type of pilot symbols include R first type short codes;

Where S and R are positive integers.
The transmitting device according to claim 19, wherein the sending module is further configured to:

Determining a scrambling code corresponding to the selected first type of short symbols; scrambling data transmitted with the first type of short symbols by the determined scrambling code.
The transmitting device according to claim 19, wherein the determining module is further configured to:

Determining each second type of short symbol corresponding to the second type of pilot symbol;

The selection module is also used to:

For a transmission, the transmitting end selects a second type of short symbol from all of the second type of short symbols;

The sending module is further configured to:

And selecting, according to the transmission position corresponding to the second type of pilot symbols, the selected second type of short symbols, so that the receiving end performs automatic gain control according to the second type of short symbols.
The transmitting device according to claim 25, wherein the transmission position corresponding to the second type of pilot symbols is the first symbol in the subframe.
The transmitting device according to any one of claims 19 to 26, wherein the determining module is further configured to:

Determining each third type of short symbol corresponding to the third type of pilot symbols;

The selection module is also used to:

Selecting a third type of short symbol from all of the third type of short symbols for one transmission;

The sending module is further configured to:

Transmitting the selected third type of short symbol according to the transmission position corresponding to the third type of pilot symbol, So that the receiving end performs time synchronization and frequency offset calibration according to the third type of short symbols.
The transmitting device according to claim 27, wherein the transmission position corresponding to the second type of pilot symbols is the second symbol in the subframe.
The transmitting device according to claim 27, wherein the determining module is specifically configured to:

Determining each third type short code corresponding to the third type of pilot symbols; and for a third type of short code, generating a third type of short symbols according to the third type of short codes.
The transmitting device according to claim 29, wherein any two third type short code cross-correlation values corresponding to the third type of pilot symbols are smaller than a set threshold; or

Each of the third type of pilot symbols is derived based on different time offsets of the same sequence.
A receiving device for performing frequency offset estimation, characterized in that the receiving device comprises:

a receiving module, configured to receive a first type of short symbol from a transmitting end, where the first type of short symbol is selected by the sending end from all first type short symbols corresponding to the first type of pilot symbols;

And a processing module, configured to perform frequency offset estimation according to the first type of short symbols.
The receiving device according to claim 31, wherein the receiving module is specifically configured to:

Receiving the first type of short symbols from the transmitting end according to at least one symbol carrying the first type of short symbols in the subframe.
The receiving device according to claim 32, wherein at least one of said symbols is a sixth symbol and at least one symbol is an eleventh symbol; or

In the subframe, at least one symbol is a third symbol, at least one symbol is a seventh symbol, and at least one symbol is an eleventh symbol; or

In the subframe, at least one symbol is a third symbol, at least one symbol is a sixth symbol, at least one symbol is a ninth symbol, and at least one symbol is a twelfth symbol.
The receiving device according to claim 32, wherein the receiving module is further configured to:

Receiving a second type of short symbol from the transmitting end before receiving the first type of short symbol from the transmitting end, The second type of short symbol is selected by the sending end from all second type short symbols corresponding to the second type of pilot symbols;

The processing module is further configured to:

Automatic gain control is performed according to the second type of short symbols.
The receiving device according to claim 32, wherein the receiving module is further configured to:

Receiving a third type of short symbol from the transmitting end before receiving the first type of short symbol from the transmitting end, wherein the third type of short symbol is the third terminal short symbol corresponding to the transmitting end from the third type of pilot symbol Selected;

The processing module is further configured to:

Time synchronization and frequency offset calibration are performed according to the third type of short symbols.
The receiving device according to claim 35, wherein the processing module is further configured to:

Determining a group sequence number according to the third type of short symbol, where the group corresponding to the group sequence number includes a first type of short code corresponding to the first type of pilot symbols, and the first type of short code is used to generate the a first type of short symbol; performing time domain correlation on the first type of short code in the group corresponding to the group number, and determining to generate the received first type short code used in the first type of short symbol.