CN104363196A - Synchronizing method and receiving end - Google Patents

Abstract

The embodiment of the invention belongs to the technical field of communication, and provides a synchronizing method and a receiving end so that transmission efficiency of a system can be improved. The synchronizing method comprises the steps of obtaining sampling signals of signals sent by an opposite terminal through the receiving end, determining a zero-order self-correlation function and an N-order self-correlation function of the sampling signals, wherein N represents the number of subcarriers, determining coefficients of fourier series of the zero-order self-correlation function of the sampling signals, calculating timing offset statistics according to the coefficients of the fourier series of the zero-order self-correlation function, calculating time offset of the sampling signals according to the timing offset statistics, determining coefficients of fourier series of the N-order self-correlation function of the sampling signals, calculating frequency offset statistics according to the coefficients of the fourier series of the N-order self-correlation function, calculating frequency offset of the sampling signals according to the frequency offset statistics and the time offset, and compensating for time and frequencies of the sampling signals according to the time offset and the frequency offset.

Description

A kind of synchronous method and receiving terminal

Technical field

The present invention relates to communication technical field, particularly relate to a kind of synchronous method and receiving terminal.

Background technology

At present, based on multiplexing (the Orthogonal Frequency DivisionMultiplexing of OFDM, OFDM) Multicarrier Transmission Technology, because it can effectively solve wireless channel frequency Selective intensity, simplified receiver complexity, also can select modulation coding mode flexibly on sub-carriers, significantly improve the frequency efficiency of communication system, be widely used in mobile communication system.

But ofdm system is very high for the synchronous requirement of receiving terminal.Especially, if multicarrier system exists frequency shift (FS), then can cause inter-sub-carrier interference (Inter-Carrier Interference, ICI) when receiving terminal demodulation, reduce received signal to noise ratio, the demodulation performance of severe exacerbation system; If multicarrier system exists timing error, timing estimation can be made to depart from the protection range of Cyclic Prefix (cyclic prefix, CP), the interference between subcarrier can be caused equally.Therefore, in an ofdm system, often need to estimate the time migration of multicarrier system and frequency shift (FS) by synchronized algorithm.

The synchronized algorithm of existing multicarrier system needs the auxiliary of synchronizing sequence usually.Specifically, usually needing to insert at transmitting terminal the synchronizing sequence that a section has good correlation, at receiving terminal, the signal of reception and local synchronization sequence are carried out related operation, obtaining timing and frequency estimation by finding relevant peaks.Because existing synchronous method needs periodically to send synchronizing sequence at transmitting terminal, therefore can take the transfer resource of system, reduce the efficiency of transmission of system.

Therefore, need to seek a kind of synchronous method that can improve the efficiency of transmission of system.

Summary of the invention

Embodiments of the invention provide a kind of synchronous method and receiving terminal, at least to solve the problem that existing synchronous method can reduce system transfers efficiency, can improve the efficiency of transmission of system.

For achieving the above object, embodiments of the invention adopt following technical scheme:

First aspect, provides a kind of synchronous method, comprising:

Receiving terminal obtains the sampled signal of the signal that opposite end sends;

Determine zeroth order auto-correlation function and the N rank auto-correlation function of described sampled signal, wherein, N represents subcarrier number;

Determine the coefficient of the Fourier series of the zeroth order auto-correlation function of described sampled signal, and the coefficient of Fourier series according to described zeroth order auto-correlation function, calculate timing slip statistic;

According to described timing slip statistic, calculate the time offset of described sampled signal;

Determine the coefficient of the Fourier series of the N rank auto-correlation function of described sampled signal, and the coefficient of Fourier series according to described N rank auto-correlation function, calculated rate skew statistic;

According to described frequency shift (FS) statistic and described time offset, calculate the frequency offset of described sampled signal;

According to described time offset and described frequency offset, time and frequency compensation are carried out to described sampled signal.

Unlike the prior art, based on the synchronous method that the embodiment of the present invention provides, do not need by synchronizing sequence, therefore also without the need to periodically sending synchronizing sequence at transmitting terminal, but the zeroth order auto-correlation function of sampled signal of the signal sent according to opposite end and N rank auto-correlation function can carry out timing estimation and Frequency Estimation.Therefore, compared with prior art, the synchronous method that the embodiment of the present invention provides can improve the efficiency of transmission of system.

Second aspect, provides a kind of receiving terminal, comprising: acquiring unit, determining unit, the first performance element, the first computing unit, the second performance element, the second computing unit and compensating unit;

Described acquiring unit, for obtaining the sampled signal of the signal that opposite end sends;

Described determining unit, for determining zeroth order auto-correlation function and the N rank auto-correlation function of described sampled signal, wherein, N represents subcarrier number;

Described first performance element, for determining the coefficient of the Fourier series of the zeroth order auto-correlation function of described sampled signal, and the coefficient of Fourier series according to described zeroth order auto-correlation function, calculate timing slip statistic;

Described first computing unit, for according to described timing slip statistic, calculates the time offset of described sampled signal;

Described second performance element, for determining the coefficient of the Fourier series of the N rank auto-correlation function of described sampled signal, and the coefficient of Fourier series according to described N rank auto-correlation function, calculated rate skew statistic;

Described second computing unit, for according to described frequency shift (FS) statistic and described time offset, calculates the frequency offset of described sampled signal;

Described compensating unit, for according to described time offset and described frequency offset, carries out time and frequency compensation to described sampled signal.

Unlike the prior art, when the receiving terminal using the embodiment of the present invention to provide carries out timing estimation and Frequency Estimation, do not need by synchronizing sequence, therefore also without the need to periodically sending synchronizing sequence at transmitting terminal, zeroth order auto-correlation function and the N rank auto-correlation function of the sampled signal of the signal that receiving terminal is sent by opposite end can carry out timing estimation and Frequency Estimation.Therefore, compared with prior art, the synchronous method that the embodiment of the present invention provides can improve the efficiency of transmission of system.

Accompanying drawing explanation

The schematic flow sheet of a kind of synchronous method that Fig. 1 provides for the embodiment of the present invention;

The structural representation of a kind of receiving terminal that Fig. 2 provides for the embodiment of the present invention.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.

For the ease of the technical scheme of the clear description embodiment of the present invention, in an embodiment of the present invention, have employed the printed words such as " first ", " second " to distinguish the substantially identical identical entry of function and efficacy or similar item, it will be appreciated by those skilled in the art that the printed words such as " first ", " second " do not limit quantity and execution order.

Embodiment one,

The embodiment of the present invention provides a kind of synchronous method, as shown in Figure 1, comprising:

S101, receiving terminal obtain the sampled signal of the signal that opposite end sends.

The zeroth order auto-correlation function of S102, receiving terminal determination sampled signal and N rank auto-correlation function, wherein, N represents subcarrier number.

The coefficient of the Fourier series of the zeroth order auto-correlation function of S103, receiving terminal determination sampled signal, and the coefficient of Fourier series according to zeroth order auto-correlation function, calculate timing slip statistic.

S104, receiving terminal according to timing slip statistic, the time offset of calculating sampling signal.

S105, receiving terminal determine the coefficient of the Fourier series of the N rank auto-correlation function of described sampled signal, and the coefficient of Fourier series according to described N rank auto-correlation function, calculated rate skew statistic.

S106, according to frequency shift (FS) statistic and time offset, the frequency offset of calculating sampling signal.

S107, according to time offset and frequency offset, time and frequency compensation are carried out to sampled signal.

It should be noted that, the synchronous method that the embodiment of the present invention provides, do not limit the computation sequence of timing slip statistic and frequency shift (FS) statistic, that is, according to the order shown in Fig. 1, first timing slip statistic can be calculated, calculated rate skew statistic again, can offset statistic by first calculated rate, then calculate timing slip statistic, the embodiment of the present invention does not do concrete restriction to this yet.

It should be noted that, it is readily appreciated by a person skilled in the art that for multicarrier system, its subcarrier number N > 1; And for single-carrier system, its subcarrier number N=1.In the synchronous method that the embodiment of the present invention provides, do not limit the value (certainly, N should be >=positive integer of 1) of N, the synchronous method that namely embodiment of the present invention provides is not only applicable to multicarrier system, be applicable to single-carrier system, the embodiment of the present invention does not do concrete restriction to this yet.

In addition, also it should be noted that, only for the situation of single antenna transmission and single antenna reception, the synchronous method that the embodiment of the present invention provides is described below.Those of ordinary skill in the art are to be understood that, multiple antennas is sent and multiple antennas receiving system (Multiple-Inputand Multiple-Output, MIMO), the synchronous method that its every a pair dual-mode antenna can adopt the embodiment of the present invention to provide carries out timing estimation and Frequency Estimation.

Concrete, in the synchronous method that the embodiment of the present invention provides, the zeroth order auto-correlation function of receiving terminal determination sampled signal and N rank auto-correlation function (step S102), specifically can comprise:

Receiving terminal according to the first preset formula, the zeroth order auto-correlation function of calculating sampling signal, wherein, the first preset formula is as shown in formula (1):

$r(n;0)=\frac{1}{M}\underset{k=0}{\overset{M-1}{\mathrm{\Σ}}}y(n+\mathrm{kP})y^{*}(n+\mathrm{kP}),n=\mathrm{0,1,2}...(P-1)$ Formula (1)

Wherein, r (n; 0) represent the zeroth order auto-correlation function of sampled signal, y (n) represents sampled signal, y ^*n () represents the conjugate function of y (), M represents positive integer, and P represents the length of a multicarrier symbol.

And,

Receiving terminal according to the second preset formula, the N rank auto-correlation function of calculating sampling signal, wherein, the second preset formula is as shown in formula (2):

$r(n;N)=\frac{1}{M}\underset{k=0}{\overset{M-1}{\mathrm{\Σ}}}y(n+\mathrm{kP})y^{*}(n-N+\mathrm{kP}),n=\mathrm{0,1,2}...(P-1),$ Formula (2)

Wherein, r (n; N) represent the N rank auto-correlation function of sampled signal, y (n) represents sampled signal, y ^*n () represents the conjugate function of y (), M represents positive integer, and P represents the length of a multicarrier symbol.

It should be noted that, M is the enough large positive integer selected according to the needs of practical application.

Preferably, in the implementation step S103 of the synchronous method provided in the invention described above embodiment, receiving terminal, according to the coefficient of the Fourier series of zeroth order auto-correlation function, calculates timing slip statistic, specifically can comprise:

Receiving terminal according to the coefficient of the Fourier series of zeroth order auto-correlation function and the first system intrinsic biased, in conjunction with the 3rd preset formula, calculate timing slip statistic, wherein, the 3rd preset formula comprises formula (3)-formula (5):

M (k ₀; 0)=F ₁(k ₀; 0) R (k ₀; 0) formula (3)

$F_1(k_0;0)={\left(\underset{-0.5}{\overset{0.5}{\∫}}{F}^{*}(\mathrm{\β}-\frac{k_0}{P})F\left(\mathrm{\β}\right)\mathrm{d\β}\right)}^{-1}$ Formula (4)

$F\left(\mathrm{\β}\right)=\underset{n=0}{\overset{\∞}{\mathrm{\Σ}}}f\left(n\right)e^{-j2\mathrm{\πn\β}}$ Formula (5)

Wherein, M (k ₀; 0) timing slip statistic is represented, F ₁(k ₀; 0) represent that the first system is intrinsic biased, R (k ₀; 0) represent the coefficient of the Fourier series of zeroth order auto-correlation function, f (n) is expressed as type function, and F (β) is expressed as the Fourier transform of type function f (n), F ^*() represents the conjugate function of F (), and P represents the length of a multicarrier symbol, k ₀represent any positive integer between 1 to P-1.

Concrete, the coefficients R (k of the Fourier series of zeroth order auto-correlation function ₀; 0) calculate by formula (6):

$R(k_0;0)=\frac{1}{P}\underset{n=0}{\overset{P-1}{\mathrm{\Σ}}}r(n;0)e^{-j\frac{2\mathrm{\π}}{P}{k}_{0}n}$ Formula (6)

Wherein, R (k ₀; 0) represent the coefficient of the Fourier series of zeroth order auto-correlation function, P represents the length of a multicarrier symbol, r (n; 0) the zeroth order auto-correlation function of sampled signal is represented, k ₀represent any positive integer between 1 to P-1.

It should be noted that, in actual applications, owing to there is not ∞, therefore when calculating F (β), more than enough item can be taken fully to variable n according to actual needs and carrying out cumulative.In addition, due to F ₁(k ₀; 0) only relevant with shaping function f (n) of opposite end with F (β), therefore can precalculate F ₁(k ₀; 0) and F (β), and result of calculation is stored in the memory of receiving terminal, thus, directly result of calculation can be called when receiving terminal calculates timing slip statistic, and then shorten the computing time of timing slip statistic, improve the efficiency of synchronous method.

Preferably, in the synchronous method that the embodiment of the present invention provides, receiving terminal according to timing slip statistic, computing time side-play amount, i.e. step S104, specifically can comprise:

According to timing slip statistic, in conjunction with the 4th preset formula, computing time side-play amount, wherein, the 4th preset formula is as shown in formula (7):

${\tilde{n}}_{\mathrm{\ϵ}}=-\frac{P}{2\mathrm{\π}{k}_0}\arg \left\{M\right[k_0;0\left]\right\}$ Formula (7)

Wherein, represent time offset, P represents the length of a multicarrier symbol, k ₀represent any positive integer between 1 to P-1, arg{} represents and asks phase bit arithmetic to plural number, M (k ₀; 0) timing slip statistic is represented.

Preferably, in the implementation step S105 of the synchronous method provided in the invention described above embodiment, receiving terminal is according to the coefficient of the Fourier series of N rank auto-correlation function, and calculated rate skew statistic, specifically can comprise:

According to the coefficient of the Fourier series of N rank auto-correlation function and second system intrinsic biased, in conjunction with the 5th preset formula, calculated rate skew statistic, wherein, the 5th preset formula comprises formula (8)-formula (10):

M (k ₀; N)=F ₁(k ₀; N) R (k ₀; N) formula (8)

$F_1(k_0;N)={\left(\underset{-0.5}{\overset{0.5}{\∫}}{F}^{*}(\mathrm{\β}-\frac{k_0}{P})F\left(\mathrm{\β}\right)e^{-j2\mathrm{\π\βN}}\mathrm{d\β}\right)}^{-1}$ Formula (9)

$F\left(\mathrm{\β}\right)=\underset{n=0}{\overset{\∞}{\mathrm{\Σ}}}f\left(n\right)e^{-j2\mathrm{\πn\β}}$ Formula (10)

Wherein, M (k ₀; N) frequency shift (FS) statistic is represented, F ₁(k ₀; N) represent that second system is intrinsic biased, R (k ₀; N) represent the coefficient of the Fourier series of N rank auto-correlation function, f (n) is expressed as type function, and F (β) is expressed as the Fourier transform of type function f (n), F ^*() represents the conjugate function of F (), and P represents the length of a multicarrier symbol, k ₀represent any positive integer between 1 to P-1.

Concrete, the coefficients R (k of the Fourier series of N rank auto-correlation function ₀; N) calculate by formula (11):

$R(k_0;N)=\frac{1}{P}\underset{n=0}{\overset{P-1}{\mathrm{\Σ}}}r(n;N)e^{-j\frac{2\mathrm{\π}}{P}{k}_{0}n}$ Formula (11)

Wherein, R (k ₀; N) represent the coefficient of the Fourier series of N rank auto-correlation function, P represents the length of a multicarrier symbol, r (n; N) the N rank auto-correlation function of sampled signal is represented, k ₀represent any positive integer between 1 to P-1.

It should be noted that, with F ₁(k ₀; 0) processing method is similar, can precalculate F ₁(k ₀; N), result of calculation is stored to receiving terminal.

Preferably, in the synchronous method that the embodiment of the present invention provides, receiving terminal is according to frequency shift (FS) statistic and time offset, and the frequency offset of calculating sampling signal, i.e. step S106, specifically can comprise:

Receiving terminal according to frequency shift (FS) statistic and time offset, in conjunction with the 6th preset formula, the frequency offset of calculating sampling signal, wherein, the 6th preset formula is as shown in formula (12):

${\stackrel{\‾}{\mathrm{\θ}}}_{\mathrm{\ϵ}}=-\frac{1}{2\mathrm{\πN}}\arg \left\{M\right[k_0;N\left]e^{j2\mathrm{\π}\frac{k_0}{P}{\tilde{n}}_{\mathrm{\ϵ}}}\right\}$ Formula (12)

Wherein, the Tuan commentary on meaning of different diagrams in The Book Changes shows frequency offset, and N represents subcarrier number, and arg{} represents and asks phase bit arithmetic to plural number, M (k ₀; N) represent frequency shift (FS) statistic, P represents the length of a multicarrier symbol, k ₀represent any positive integer between 1 to P-1, represent time offset.

In the synchronous method that the embodiment of the present invention provides, first, receiving terminal obtains the sampled signal of signal that opposite end sends, and according to the zeroth order auto-correlation function of sampled signal determination sampled signal and N rank auto-correlation function; Then, determine the coefficient of the Fourier series of the zeroth order auto-correlation function of sampled signal, and the coefficient of Fourier series according to zeroth order auto-correlation function, calculate timing slip statistic, then according to timing slip statistic, the time offset of calculating sampling signal; Then, determine the coefficient of the Fourier series of the N rank auto-correlation function of described sampled signal, and the coefficient of Fourier series according to described N rank auto-correlation function, calculated rate skew statistic, again according to frequency shift (FS) statistic and time offset, the frequency offset of calculating sampling signal; Finally, according to time offset and frequency offset, time and frequency compensation are carried out to sampled signal.Unlike the prior art, based on the synchronous method that the embodiment of the present invention provides, do not need by synchronizing sequence, therefore also without the need to periodically sending synchronizing sequence at transmitting terminal, but the zeroth order auto-correlation function of sampled signal of the signal sent according to opposite end and N rank auto-correlation function can carry out timing estimation and Frequency Estimation.Therefore, compared with prior art, the synchronous method that the embodiment of the present invention provides can improve the efficiency of transmission of system.

Embodiment two,

The embodiment of the present invention provides a kind of receiving terminal 20, as shown in Figure 2, comprising: acquiring unit 201, determining unit 202, first performance element 203, first computing unit 204, second performance element 205, second computing unit 206 and compensating unit 207.

Wherein, acquiring unit 201, for obtaining the sampled signal of the signal that opposite end sends.

Determining unit 202, for determining zeroth order auto-correlation function and the N rank auto-correlation function of sampled signal, wherein, N represents subcarrier number.

First performance element 203, for determining the coefficient of the Fourier series of the zeroth order auto-correlation function of described sampled signal, and the coefficient of Fourier series according to described zeroth order auto-correlation function, calculate timing slip statistic.

First computing unit 204, for according to described timing slip statistic, calculates the time offset of described sampled signal.

Second performance element 205, for determining the coefficient of the Fourier series of the N rank auto-correlation function of described sampled signal, and the coefficient of Fourier series according to described N rank auto-correlation function, calculated rate skew statistic.

Second computing unit 206, for according to described frequency shift (FS) statistic and described time offset, calculates the frequency offset of described sampled signal.

Compensating unit 207, for according to time offset and frequency offset, carries out time and frequency compensation to sampled signal.

Concrete, in the receiving terminal 20 that the embodiment of the present invention provides, determining unit 202 specifically may be used for:

According to the first preset formula, the zeroth order auto-correlation function of calculating sampling signal, wherein, the first preset formula comprises:

$r(n;0)=\frac{1}{M}\underset{k=0}{\overset{M-1}{\mathrm{\Σ}}}y(n+\mathrm{kP})y^{*}(n+\mathrm{kP}),n=\mathrm{0,1,2}...(P-1),$

Wherein, r (n; 0) represent the zeroth order auto-correlation function of sampled signal, y (n) represents sampled signal, y ^*n () represents the conjugate function of y (), M represents positive integer, and P represents the length of a multicarrier symbol.

Determining unit 202 specifically can also be used for:

According to the second preset formula, the N rank auto-correlation function of calculating sampling signal, wherein, the second preset formula comprises:

$r(n;N)=\frac{1}{M}\underset{k=0}{\overset{M-1}{\mathrm{\Σ}}}y(n+\mathrm{kP})y^{*}(n-N+\mathrm{kP}),n=\mathrm{0,1,2}...(P-1),$

Wherein, r (n; N) represent the N rank auto-correlation function of sampled signal, y (n) represents sampled signal, y ^*n () represents the conjugate function of y (), M represents positive integer, and P represents the length of a multicarrier symbol.

It should be noted that, M is the enough large positive integer selected according to the needs of practical application.

Preferably, in the receiving terminal 20 that the embodiment of the present invention provides, the first performance element 203 specifically may be used for:

According to the coefficient of the Fourier series of zeroth order auto-correlation function and the first system intrinsic biased, in conjunction with the 3rd preset formula, calculate timing slip statistic, wherein, the 3rd preset formula comprises:

M(k ₀；0)＝F ₁(k ₀；0)·R(k ₀；0)

$F_1(k_0;0)={\left(\underset{-0.5}{\overset{0.5}{\∫}}{F}^{*}(\mathrm{\β}-\frac{k_0}{P})F\left(\mathrm{\β}\right)\mathrm{d\β}\right)}^{-1}$

$F\left(\mathrm{\β}\right)=\underset{n=0}{\overset{\∞}{\mathrm{\Σ}}}f\left(n\right)e^{-j2\mathrm{\πn\β}}$

Wherein, M (k ₀; 0) timing slip statistic is represented, F ₁(k ₀; 0) represent that the first system is intrinsic biased, R (k ₀; 0) represent the coefficient of the Fourier series of zeroth order auto-correlation function, f (n) is expressed as type function, and F (β) is expressed as the Fourier transform of type function f (n), F ^*() represents the conjugate function of F (), and P represents the length of a multicarrier symbol, k ₀represent any positive integer between 1 to P-1.

Preferably, in the receiving terminal 20 that the embodiment of the present invention provides, the first computing unit 204 specifically may be used for:

According to timing slip statistic, in conjunction with the 4th preset formula, computing time side-play amount, wherein, the 4th preset formula comprises:

${\tilde{n}}_{\mathrm{\ϵ}}=-\frac{P}{2\mathrm{\π}{k}_0}\arg \left\{M\right[k_0;0\left]\right\},$

Wherein, represent time offset, P represents the length of a multicarrier symbol, k ₀represent any positive integer between 1 to P-1, arg{} represents and asks phase bit arithmetic to plural number, M (k ₀; 0) timing slip statistic is represented.

Preferably, in the receiving terminal 20 that the embodiment of the present invention provides, the second performance element 205 specifically may be used for:

According to the coefficient of the Fourier series of N rank auto-correlation function and second system intrinsic biased, in conjunction with the 5th preset formula, calculated rate skew statistic, wherein, the 5th preset formula comprises:

M(k ₀；N)＝F ₁(k ₀；N)·R(k ₀；N)

$F_1(k_0;N)={\left(\underset{-0.5}{\overset{0.5}{\∫}}{F}^{*}(\mathrm{\β}-\frac{k_0}{P})F\left(\mathrm{\β}\right)e^{-j2\mathrm{\π\βN}}\mathrm{d\β}\right)}^{-1}$

$F\left(\mathrm{\β}\right)=\underset{n=0}{\overset{\∞}{\mathrm{\Σ}}}f\left(n\right)e^{-j2\mathrm{\πn\β}}$

Wherein, M (k ₀; N) frequency shift (FS) statistic is represented, F ₁(k ₀; N) represent that second system is intrinsic biased, R (k ₀; N) represent the coefficient of the Fourier series of N rank auto-correlation function, f (n) is expressed as type function, and F (β) is expressed as the Fourier transform of type function f (n), F ^*() represents the conjugate function of F (), and P represents the length of a multicarrier symbol, k ₀represent any positive integer between 1 to P-1.

Preferably, in the receiving terminal 20 that the embodiment of the present invention provides, the second computing unit 206 specifically may be used for:

According to frequency shift (FS) statistic and time offset, in conjunction with the 6th preset formula, the frequency offset of calculating sampling signal, wherein, the 6th preset formula comprises:

${\stackrel{\‾}{\mathrm{\θ}}}_{\mathrm{\ϵ}}=-\frac{1}{2\mathrm{\πN}}\arg \left\{M\right[k_0;N\left]e^{j2\mathrm{\π}\frac{k_0}{P}{\tilde{n}}_{\mathrm{\ϵ}}}\right\},$

Wherein, represent frequency offset, N represents subcarrier number, and arg{} represents and asks phase bit arithmetic to plural number, M (k ₀; N) represent frequency shift (FS) statistic, P represents the length of a multicarrier symbol, k ₀represent any positive integer between 1 to P-1, represent time offset.

It should be noted that, using the receiving terminal 20 that provides of the embodiment of the present invention to carry out the concrete grammar of timing estimation and Frequency Estimation can the description of reference example one, and the embodiment of the present invention does not repeat them here.

In the receiving terminal that the embodiment of the present invention provides, first, obtain by acquiring unit the sampled signal of signal that opposite end sends, and by the zeroth order auto-correlation function of determining unit determination sampled signal and N rank auto-correlation function; Then, by the coefficient of the Fourier series of the zeroth order auto-correlation function of the first performance element determination sampled signal, and the coefficient of Fourier series according to zeroth order auto-correlation function, calculate timing slip statistic, again by the first computing unit according to timing slip statistic, the time offset of calculating sampling signal; Then, by the coefficient of the Fourier series of the N rank auto-correlation function of the second performance element determination sampled signal, and the coefficient of Fourier series according to N rank auto-correlation function, calculated rate skew statistic, again by the second computing unit according to frequency shift (FS) statistic and time offset, the frequency offset of calculating sampling signal; Finally, by compensating unit according to time offset and frequency offset, time and frequency compensation are carried out to sampled signal.Unlike the prior art, when the receiving terminal using the embodiment of the present invention to provide carries out timing estimation and Frequency Estimation, do not need by synchronizing sequence, therefore also without the need to periodically sending synchronizing sequence at transmitting terminal, zeroth order auto-correlation function and the N rank auto-correlation function of the sampled signal of the signal that receiving terminal is sent by opposite end can carry out timing estimation and Frequency Estimation.Therefore, compared with prior art, the synchronous method that the embodiment of the present invention provides can improve the efficiency of transmission of system.

Those skilled in the art can be well understood to, for convenience and simplicity of description, the device of foregoing description, only be illustrated with the division of above-mentioned each functional module, in practical application, can distribute as required and by above-mentioned functions and be completed by different functional modules, the internal structure by device is divided into different functional modules, to complete all or part of function described above.The specific works process of the system of foregoing description, device and unit, with reference to the corresponding process in preceding method embodiment, can not repeat them here.

In several embodiments that the application provides, should be understood that, disclosed system, apparatus and method, can realize by another way.Such as, device embodiment described above is only schematic, such as, the division of described module or unit, be only a kind of logic function to divide, actual can have other dividing mode when realizing, such as multiple unit or assembly can in conjunction with or another system can be integrated into, or some features can be ignored, or do not perform.Another point, shown or discussed coupling each other or direct-coupling or communication connection can be by some interfaces, and the indirect coupling of device or unit or communication connection can be electrical, machinery or other form.

The described unit illustrated as separating component or can may not be and physically separates, and the parts as unit display can be or may not be physical location, namely can be positioned at a place, or also can be distributed in multiple network element.Some or all of unit wherein can be selected according to the actual needs to realize the object of the present embodiment scheme.

In addition, each functional unit in each embodiment of the present invention can be integrated in a processing unit, also can be that the independent physics of unit exists, also can two or more unit in a unit integrated.Above-mentioned integrated unit both can adopt the form of hardware to realize, and the form of SFU software functional unit also can be adopted to realize.

If described integrated unit using the form of SFU software functional unit realize and as independently production marketing or use time, can be stored in a computer read/write memory medium.Based on such understanding, the part that technical scheme of the present invention contributes to prior art in essence in other words or all or part of of this technical scheme can embody with the form of software product, this computer software product is stored in a storage medium, comprising some instructions in order to make a computer equipment (can be personal computer, server, or the network equipment etc.) or processor (processor) perform all or part of step of method described in each embodiment of the present invention.And aforesaid storage medium comprises USB flash disk, portable hard drive, read-only memory (ROM, Read-OnlyMemory), random access memory (RAM, Random Access Memory), magnetic disc or CD etc. various can be program code stored medium.

The above; be only the specific embodiment of the present invention, but protection scope of the present invention is not limited thereto, is anyly familiar with those skilled in the art in the technical scope that the present invention discloses; change can be expected easily or replace, all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of described claim.

Claims (12)

1. a synchronous method, is characterized in that, described method comprises:

Receiving terminal obtains the sampled signal of the signal that opposite end sends;

Determine zeroth order auto-correlation function and the N rank auto-correlation function of described sampled signal, wherein, N represents subcarrier number;

Determine the coefficient of the Fourier series of the zeroth order auto-correlation function of described sampled signal, and the coefficient of Fourier series according to described zeroth order auto-correlation function, calculate timing slip statistic;

According to described timing slip statistic, calculate the time offset of described sampled signal;

Determine the coefficient of the Fourier series of the N rank auto-correlation function of described sampled signal, and the coefficient of Fourier series according to described N rank auto-correlation function, calculated rate skew statistic;

According to described frequency shift (FS) statistic and described time offset, calculate the frequency offset of described sampled signal;

According to described time offset and described frequency offset, time and frequency compensation are carried out to described sampled signal.

2. method according to claim 1, is characterized in that, described zeroth order auto-correlation function and the N rank auto-correlation function determining described sampled signal, comprising:

According to the first preset formula, calculate the zeroth order auto-correlation function of described sampled signal, wherein, described first preset formula comprises:

$r(n;0)=\frac{1}{M}\underset{k=0}{\overset{M-1}{\mathrm{\Σ}}}y(n+\mathrm{kP})y^{*}(n+\mathrm{kP}),n=\mathrm{0,1,2}...(P-1),$

Wherein, r (n; 0) represent the zeroth order auto-correlation function of sampled signal, y (n) represents sampled signal, y ^*n () represents the conjugate function of y (), M represents positive integer, and P represents the length of a multicarrier symbol;

And,

According to the second preset formula, calculate the N rank auto-correlation function of described sampled signal, wherein, described second preset formula comprises:

$r(n;N)=\frac{1}{M}\underset{k=0}{\overset{M-1}{\mathrm{\Σ}}}y(n+\mathrm{kP})y^{*}(n-N+\mathrm{kP}),n=\mathrm{0,1,2}...(P-1),$

Wherein, r (n; N) represent the N rank auto-correlation function of sampled signal, y (n) represents sampled signal, y ^*n () represents the conjugate function of y (), M represents positive integer, and P represents the length of a multicarrier symbol.

3. method according to claim 1 and 2, is characterized in that, the coefficient of the described Fourier series according to described zeroth order auto-correlation function, calculates timing slip statistic, comprising:

According to the coefficient of the Fourier series of described zeroth order auto-correlation function and the first system intrinsic biased, in conjunction with the 3rd preset formula, calculate timing slip statistic, wherein, described 3rd preset formula comprises:

M(k ₀；0)＝F ₁(k ₀；0)·R(k ₀；0)，

$F_1(k_0;0)={\left(\underset{-0.5}{\overset{0.5}{\∫}}{F}^{*}(\mathrm{\β}-\frac{k_0}{P})F\left(\mathrm{\β}\right)\mathrm{d\β}\right)}^{-1},$

$F\left(\mathrm{\β}\right)=\underset{n=0}{\overset{\∞}{\mathrm{\Σ}}}f\left(n\right)e^{-j2\mathrm{\πn\β}},$

Wherein, M (k ₀; 0) timing slip statistic is represented, F ₁(k ₀; 0) represent that the first system is intrinsic biased, R (k ₀; 0) represent the coefficient of the Fourier series of zeroth order auto-correlation function, f (n) is expressed as type function, and F (β) is expressed as the Fourier transform of type function f (n), F ^*() represents the conjugate function of F (), and P represents the length of a multicarrier symbol, k ₀represent any positive integer between 1 to P-1.

4. according to claim 1) method described in 3 any one, it is characterized in that, described according to described timing slip statistic, calculate the time offset of described sampled signal, comprising:

According to described timing slip statistic, in conjunction with the 4th preset formula, calculate the time offset of described sampled signal, wherein, described 4th preset formula comprises:

${\tilde{n}}_{\mathrm{\ϵ}}=-\frac{P}{2\mathrm{\π}{k}_0}\arg \left\{M\right[k_0;0\left]\right\},$

Wherein, represent time offset, P represents the length of a multicarrier symbol, k ₀represent any positive integer between 1 to P-1, arg{} represents and asks phase bit arithmetic to plural number, M (k ₀; 0) timing slip statistic is represented.

5. method according to claim 1 and 2, is characterized in that, the coefficient of the described Fourier series according to described N rank auto-correlation function, and calculated rate skew statistic, comprising:

According to the coefficient of the Fourier series of described N rank auto-correlation function and second system intrinsic biased, in conjunction with the 5th preset formula, calculated rate skew statistic, wherein, described 5th preset formula comprises:

M(k ₀；N)＝F ₁(k ₀；N)·R(k ₀；N)，

$F_1(k_0;N)={\left(\underset{-0.5}{\overset{0.5}{\∫}}{F}^{*}(\mathrm{\β}-\frac{k_0}{P})F\left(\mathrm{\β}\right)e^{-j2\mathrm{\π\βN}}\mathrm{d\β}\right)}^{-1},$

$F\left(\mathrm{\β}\right)=\underset{n=0}{\overset{\∞}{\mathrm{\Σ}}}f\left(n\right)e^{-j2\mathrm{\πn\β}},$

Wherein, M (k ₀; N) frequency shift (FS) statistic is represented, F ₁(k ₀; N) represent that second system is intrinsic biased, R (k ₀; N) represent the coefficient of the Fourier series of N rank auto-correlation function, f (n) is expressed as type function, and F (β) is expressed as the Fourier transform of type function f (n), F ^*() represents the conjugate function of F (), and P represents the length of a multicarrier symbol, k ₀represent any positive integer between 1 to P-1.

6. method according to claim 1 and 2, is characterized in that, described according to described frequency shift (FS) statistic and described time offset, calculates the frequency offset of described sampled signal, comprising:

According to described frequency shift (FS) statistic and described time offset, in conjunction with the 6th preset formula, calculate the frequency offset of described sampled signal, wherein, described 6th preset formula comprises:

${\stackrel{\‾}{\mathrm{\θ}}}_{\mathrm{\ϵ}}=\frac{1}{2\mathrm{\πN}}\arg \left\{M\right[k_0;N\left]e^{j2\mathrm{\π}\frac{k_0}{P}{\tilde{n}}_{\mathrm{\ϵ}}}\right\},$

Wherein, represent frequency offset, N represents subcarrier number, and arg{} represents and asks phase bit arithmetic to plural number, M (k ₀; N) represent frequency shift (FS) statistic, P represents the length of a multicarrier symbol, k ₀represent any positive integer between 1 to P-1, represent time offset.

7. a receiving terminal, described receiving terminal comprises: acquiring unit, determining unit, the first performance element, the first computing unit, the second performance element, the second computing unit and compensating unit;

Described acquiring unit, for obtaining the sampled signal of the signal that opposite end sends;

Described determining unit, for determining zeroth order auto-correlation function and the N rank auto-correlation function of described sampled signal, wherein, N represents subcarrier number;

Described first performance element, for determining the coefficient of the Fourier series of the zeroth order auto-correlation function of described sampled signal, and the coefficient of Fourier series according to described zeroth order auto-correlation function, calculate timing slip statistic;

Described first computing unit, for according to described timing slip statistic, calculates the time offset of described sampled signal;

Described second performance element, for determining the coefficient of the Fourier series of the N rank auto-correlation function of described sampled signal, and the coefficient of Fourier series according to described N rank auto-correlation function, calculated rate skew statistic;

Described second computing unit, for according to described frequency shift (FS) statistic and described time offset, calculates the frequency offset of described sampled signal;

Described compensating unit, for according to described time offset and described frequency offset, carries out time and frequency compensation to described sampled signal.

8. receiving terminal according to claim 7, is characterized in that, described determining unit specifically for:

According to the first preset formula, calculate the zeroth order auto-correlation function of described sampled signal, wherein, described first preset formula comprises:

$r(n;0)=\frac{1}{M}\underset{k=0}{\overset{M-1}{\mathrm{\Σ}}}y(n+\mathrm{kP})y^{*}(n+\mathrm{kP}),n=\mathrm{0,1,2}...(P-1),$

Wherein, r (n; 0) represent the zeroth order auto-correlation function of sampled signal, y (n) represents sampled signal, y ^*n () represents the conjugate function of y (), M represents positive integer, and P represents the length of a multicarrier symbol;

Described determining unit concrete also for:

According to the second preset formula, calculate the N rank auto-correlation function of described sampled signal, wherein, described second preset formula comprises:

$r(n;N)=\frac{1}{M}\underset{k=0}{\overset{M-1}{\mathrm{\Σ}}}y(n+\mathrm{kP})y^{*}(n-N+\mathrm{kP}),n=\mathrm{0,1,2}...(P-1),$

Wherein, r (n; N) represent the N rank auto-correlation function of sampled signal, y (n) represents sampled signal, y ^*n () represents the conjugate function of y (), M represents positive integer, and P represents the length of a multicarrier symbol.

9. the receiving terminal according to claim 7 or 8, is characterized in that, described first performance element specifically for:

According to the coefficient of the Fourier series of described zeroth order auto-correlation function and the first system intrinsic biased, in conjunction with the 3rd preset formula, calculate timing slip statistic, wherein, described 3rd preset formula comprises:

M(k ₀；0)＝F ₁(k ₀；0)·R(k ₀；0)，

$F_1(k_0;0)={\left(\underset{-0.5}{\overset{0.5}{\∫}}{F}^{*}(\mathrm{\β}-\frac{k_0}{P})F\left(\mathrm{\β}\right)\mathrm{d\β}\right)}^{-1},$

$F\left(\mathrm{\β}\right)=\underset{n=0}{\overset{\∞}{\mathrm{\Σ}}}f\left(n\right)e^{-j2\mathrm{\πn\β}},$

Wherein, M (k ₀; 0) timing slip statistic is represented, F ₁(k ₀; 0) represent that the first system is intrinsic biased, R (k ₀; 0) represent the coefficient of the Fourier series of zeroth order auto-correlation function, f (n) is expressed as type function, and F (β) is expressed as the Fourier transform of type function f (n), F ^*() represents the conjugate function of F (), and P represents the length of a multicarrier symbol, k ₀represent any positive integer between 1 to P-1.

10. according to claim 7) receiving terminal described in 9 any one, it is characterized in that, described first computing unit specifically for:

According to described timing slip statistic, in conjunction with the 4th preset formula, calculate described time offset, wherein, described 4th preset formula comprises:

${\tilde{n}}_{\mathrm{\ϵ}}=-\frac{P}{2\mathrm{\π}{k}_0}\arg \left\{M\right[k_0;0\left]\right\},$

Wherein, represent time offset, P represents the length of a multicarrier symbol, k ₀represent any positive integer between 1 to P-1, arg{} represents and asks phase bit arithmetic to plural number, M (k ₀; 0) timing slip statistic is represented.

11. receiving terminals according to claim 7 or 8, is characterized in that, described second performance element specifically for:

According to the coefficient of the Fourier series of described N rank auto-correlation function and second system intrinsic biased, in conjunction with the 5th preset formula, calculated rate skew statistic, wherein, described 5th preset formula comprises:

M(k ₀；N)＝F ₁(k ₀；N)·R(k ₀；N)，

$F_1(k_0;N)={\left(\underset{-0.5}{\overset{0.5}{\∫}}{F}^{*}(\mathrm{\β}-\frac{k_0}{P})F\left(\mathrm{\β}\right)e^{-j2\mathrm{\π\βN}}\mathrm{d\β}\right)}^{-1},$

$F\left(\mathrm{\β}\right)=\underset{n=0}{\overset{\∞}{\mathrm{\Σ}}}f\left(n\right)e^{-j2\mathrm{\πn\β}},$

Wherein, M (k ₀; N) frequency shift (FS) statistic is represented, F ₁(k ₀; N) represent that second system is intrinsic biased, R (k ₀; N) represent the coefficient of the Fourier series of N rank auto-correlation function, f (n) is expressed as type function, and F (β) is expressed as the Fourier transform of type function f (n), F ^*() represents the conjugate function of F (), and P represents the length of a multicarrier symbol, k ₀represent any positive integer between 1 to P-1.

12. receiving terminals according to claim 7 or 8, is characterized in that, described second computing unit specifically for:

According to described frequency shift (FS) statistic and described time offset, in conjunction with the 6th preset formula, calculate the frequency offset of described sampled signal, wherein, described 6th preset formula comprises:

${\stackrel{\‾}{\mathrm{\θ}}}_{\mathrm{\ϵ}}=\frac{1}{2\mathrm{\πN}}\arg \left\{M\right[k_0;N\left]e^{j2\mathrm{\π}\frac{k_0}{P}{\tilde{n}}_{\mathrm{\ϵ}}}\right\},$

Wherein, represent frequency offset, N represents subcarrier number, and arg{} represents and asks phase bit arithmetic to plural number, M (k ₀; N) represent frequency shift (FS) statistic, P represents the length of a multicarrier symbol, k ₀represent any positive integer between 1 to P-1, represent time offset.