CN105450569A - Intelligent terminal and demodulation method and device for Gaussian frequency-shift keying signal thereof - Google Patents

Abstract

The invention discloses an intelligent terminal and a demodulation method and device for Gaussian frequency-shift keying signal thereof. The method comprises the steps: carrying out the matching filtering of a receiving signal and all possible signal modes in the time period from nT to (n+3)T according to a phase estimated value (shown in the description) of the receiving signal and I<n-1>, and obtaining the optimal matching waveform of the receiving signal in the time period from nT to (n+3)T; judging I<n> according to the optimal matching waveform of the receiving signal in the time period from nT to (n+3)T; obtaining the maximum correlation value angle delta (theta<n>) of the receiving signal in the time period from nT to (n+3)T according to the receiving signal and the optimal matching waveform of the receiving signal in the time period from nT to (n+3)T; calculating the result of the following formula (shown in the description) according to the phase estimated value (shown in the description) of the receiving signal, I<n> and the maximum correlation value angle delta (theta<n>); carrying out the above steps in a circulating manner according to the result of the formula and I<n>; and obtaining all to-be-modulated data through recursion. The method integrates matching filtering and angle iteration, employs the maximum correlation value angle delta (theta<n>) obtained in matching filtering to participate the angle iteration, carries out frequency loop tracking, and reduces the influence caused by frequency changes.

Description

The demodulation method of intelligent terminal and Gaussian frequency shifted key signal thereof and device

Technical field

The present invention relates to wireless communication technology field, particularly relate to demodulation method and the device of a kind of intelligent terminal and Gaussian frequency shifted key signal thereof.

Background technology

Frequency shift keying (FrequencyShiftKeying, FSK) is a kind of digital modulation technique of extensive use in middle slow data transmission, and it utilizes the frequency change of carrier wave to carry out transmitting digital information.

Gaussian Frequency Shift Keying (GaussFrequencyShiftKeying, GFSK) modulation is by signal after the filtering of gauss low frequency filter premodulated, then carries out the digital modulation mode of shift keying modulation.It is while maintenance constant amplitude, can be controlled by the spectrum width of bandwidth to signal changing gauss low frequency filter, the characteristic desired by wireless communication system such as have permanent width envelope, power spectrum is concentrated, frequency spectrum is narrower, is widely used in the fields such as mobile communication, navigation, aviation.

The major parameter that Gaussian frequency shifted key signal relates to when modulating has: BT refers to and modulation index.Wherein, BT refers to it is the bandwidth (bandwidth) of modulated filter and the product of bit duration, is a kind of parameter being used for describing transmitted waveform quality; Modulation index (ModulationIndex) is also called bandwidth efficiency, and its unit is bit/s/Hz, in the angle modulated of being undertaken by sinusoidal signal, is peak (frequency) deviation and the ratio of sinusoidal modulation signal frequency.

As the practical application of Gaussian Frequency Shift Keying modulation technique, bluetooth (Bluetooth) is that a kind of support such as terminals such as mobile terminal of mobile telephone, palmtop PC (PersonalDigitalAssistant, PDA), notebook computer carry out the wireless communication technology of short haul connection.Basic rate (BasicRate) signal of bluetooth is Gaussian frequency shifted key signal.

For the typical Gaussian frequency shifted key signal of the basic rate signal of bluetooth when modulating, usually it is 0.5 that BT can be adopted to refer to, modulation index is 0.3 to modulate, but in actual applications, modulation index is not determine 0.3, but can float in a larger scope, such as 0.28 ~ 0.35 is all possible.

Conventional demodulation method for Gaussian frequency shifted key signal comprises coherent demodulation and differential ference spiral etc., but existing demodulation method all exists certain defect.Such as, for coherent demodulation scheme of the prior art, it is subject to the Rapid Variable Design of frequency deviation, and the uncertainty impact of modulation index is larger; And for differential ference spiral scheme of the prior art, although it can be subject to the Rapid Variable Design of frequency, and probabilistic impact of modulation index comes little relative to coherent demodulation scheme, and its receiving sensitivity can 3 ~ 4dB lower than coherent demodulation scheme.

Consider the feature of the basic rate signal of bluetooth, the uncertainty of its modulation index is comparatively large, as previously mentioned, can float in the scope of 0.28 ~ 0.35, and the related protocol Rapid Variable Design that specifies to limit its frequency and the frequency deviation that causes thus larger.Therefore, usually adopt differential ference spiral scheme to carry out demodulation to it in prior art, but this effective propagation path that result also in its signal is shorter.

The impact that the Rapid Variable Design of uncertainty and frequency how to eliminate or reduce modulation index brings, the major obstacle run into when being and adopting coherent demodulation scheme to carry out Gaussian frequency shifted key signal demodulation.

Summary of the invention

The technical problem that the present invention solves is: when adopting coherent demodulation scheme to carry out Gaussian frequency shifted key signal demodulation, how to eliminate or impact that the Rapid Variable Design of the uncertainty and frequency that reduce modulation index brings.

In order to solve the problems of the technologies described above, the embodiment of the present invention provides a kind of demodulation method of Gaussian frequency shifted key signal, and I represents data to be demodulated, and θ represents the phase place actual value of Received signal strength, represent the phase estimation value of Received signal strength, h represents modulation index, and π represents circumference ratio, comprising:

According to and I _n-1received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, draws the optimum Match waveform of Received signal strength in nT<t< (n+3) T time;

According to the optimum Match waveform of Received signal strength in nT<t< (n+3) T time, judge I _n;

The optimum Match waveform in nT<t< (n+3) T time according to Received signal strength and Received signal strength, draws the maximum related value angle delta θ of Received signal strength in nT<t< (n+3) T time _n;

According to i _nwith Δ θ _n, gone out by following formulae discovery

${\widehat{\mathrm{\&theta;}}}_{n+1}={\widehat{\mathrm{\&theta;}}}_n+I_n\mathrm{h\&pi;}+\mathrm{\&Delta;}{\mathrm{\&theta;}}_n;$

According to and I _n, circulation performs above-mentioned steps, and recursion draws whole data to be demodulated.

Optionally, drawn by following steps and I _n-1initial value i _-1and h:

According to transmitting data, draw I _n-1and h;

According to transmitting data and Received signal strength, gone out by following formulae discovery

${\widehat{\mathrm{\&theta;}}}_0=\mathrm{angle}\left({\&Integral;}_0^{3T}r\left(t\right)v_i^H\left(t\right)\mathrm{dt}\right);$

Wherein, r (t) represents Received signal strength.

Optionally, described basis and I _n-1received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, draw the optimum Match waveform of Received signal strength in nT<t< (n+3) T time specifically: the Received signal strength following form represented carries out matched filtering:

$r\left(t\right)=e^{j2\mathrm{\&pi;h}\underset{-\&infin;}{\overset{t}{\&Integral;}}\underset{n}{\mathrm{\&Sigma;}}{I}_{n}g(\mathrm{\&tau;}-\mathrm{nT})\mathrm{d\&tau;}}.$

Optionally, described basis and I _n-1received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, draw the optimum Match waveform of Received signal strength in nT<t< (n+3) T time specifically: draw optimum Match waveform by following formula:

$I^{`}=\arg \min {\&Integral;}_0^{3T}|\underset{0\&le;i<k}{{r\left(t\right)e}^{-j{\mathrm{\&theta;}}_n}}-v_i\left(t\right)|\mathrm{dt}=\arg \underset{0\&le;i<k}{\max }\left(\mathrm{real}\left({\&Integral;}_0^{3T}r\left(t\right)e^{-j{\mathrm{\&theta;}}_n}{v}_i^H\left(t\right)\mathrm{dt}\right)\right);$

Wherein, v _it () represents matched signal, I` represents optimum Match waveform, and k represents the quantity of Received signal strength all possible signal mode in nT<t< (n+3) T time.

Optionally, described according to Received signal strength and Received signal strength the optimum Match waveform in nT<t< (n+3) T time, draw the maximum related value angle delta θ of Received signal strength in nT<t< (n+3) T time _nspecifically: draw maximum related value angle delta θ according to following formula _n:

$\mathrm{\&Delta;}{\mathrm{\&theta;}}_n=\mathrm{angle}{\left(\mathrm{corr}\right)}_n={\mathrm{\&theta;}}_n-{\widehat{\mathrm{\&theta;}}}_n.$

Optionally, described Gaussian frequency shifted key signal is the basic rate signal of bluetooth, and transmitting data is the synchronous head data of bluetooth.

Optionally, the modulation index of described Gaussian frequency shifted key signal is that 0.28 ~ 0.35, BT refers to be 0.5, and described BT refers to the product for bandwidth sum bit duration.

In order to solve the problems of the technologies described above, the embodiment of the present invention also provides a kind of demodulating equipment of Gaussian frequency shifted key signal, comprising: matched filtering unit, coupling decision unit, the first computing unit and the second computing unit; Wherein:

Matched filtering unit, for basis and I _n-1received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, draws the optimum Match waveform of Received signal strength in nT<t< (n+3) T time;

Coupling decision unit, after drawing optimum Match waveform at described matched filtering unit, according to the optimum Match waveform of Received signal strength in nT<t< (n+3) T time, judges I _n;

First computing unit, after drawing optimum Match waveform at described matched filtering unit, the optimum Match waveform in nT<t< (n+3) T time according to Received signal strength and Received signal strength, draws the maximum related value angle delta θ of Received signal strength in nT<t< (n+3) T time _n;

Second computing unit, for drawing maximum related value angle delta θ at described first computing unit _nafterwards, according to i _nwith Δ θ _n, gone out by following formulae discovery

${\widehat{\mathrm{\&theta;}}}_{n+1}={\widehat{\mathrm{\&theta;}}}_n+I_n\mathrm{h\&pi;}+\mathrm{\&Delta;}{\mathrm{\&theta;}}_n;$

Calculate at described second computing unit afterwards, described matched filtering unit, the circulation of coupling decision unit, the first computing unit and the second computing unit carry out above-mentioned action, and recursion draws whole data to be demodulated.

Optionally, also comprise: initial value computing unit, described initial value computing unit, for according to transmitting data, draws I _n-1and h, also for according to transmitting data and Received signal strength, gone out by following formulae discovery

${\widehat{\mathrm{\&theta;}}}_0=\mathrm{angle}\left({\&Integral;}_0^{3T}r\left(t\right)v_i^H\left(t\right)\mathrm{dt}\right);$

Wherein, r (t) represents Received signal strength.

Optionally, described matched filtering unit according to and I _n-1received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, draw the optimum Match waveform of Received signal strength in nT<t< (n+3) T time specifically: the Received signal strength following form represented carries out matched filtering:

$r\left(t\right)=e^{j2\mathrm{\&pi;h}\underset{-\&infin;}{\overset{t}{\&Integral;}}\underset{n}{\mathrm{\&Sigma;}}{I}_{n}g(\mathrm{\&tau;}-\mathrm{nT})\mathrm{d\&tau;}}.$

Optionally, described matched filtering unit according to and I _n-1received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, draw the optimum Match waveform of Received signal strength in nT<t< (n+3) T time specifically: draw optimum Match waveform by following formula:

$I^{`}=\arg \min {\&Integral;}_0^{3T}|\underset{0\&le;i<k}{{r\left(t\right)e}^{-j{\mathrm{\&theta;}}_n}}-v_i\left(t\right)|\mathrm{dt}=\arg \underset{0\&le;i<k}{\max }\left(\mathrm{real}\left({\&Integral;}_0^{3T}r\left(t\right)e^{-j{\mathrm{\&theta;}}_n}{v}_i^H\left(t\right)\mathrm{dt}\right)\right);$

Wherein, v _it () represents matched signal, I` represents optimum Match waveform, and k represents the quantity of Received signal strength all possible signal mode in nT<t< (n+3) T time.

Optionally, described first computing unit is the optimum Match waveform in nT<t< (n+3) T time according to Received signal strength and Received signal strength, draws the maximum related value angle delta θ of Received signal strength in nT<t< (n+3) T time _nspecifically: draw maximum related value angle delta θ according to following formula _n:

$\mathrm{\&Delta;}{\mathrm{\&theta;}}_n=\mathrm{angle}{\left(\mathrm{corr}\right)}_n={\mathrm{\&theta;}}_n-{\widehat{\mathrm{\&theta;}}}_n.$

Optionally, described Gaussian frequency shifted key signal is the basic rate signal of bluetooth, and transmitting data is the synchronous head data of bluetooth.

Optionally, the modulation index of described Gaussian frequency shifted key signal is that 0.28 ~ 0.35, BT refers to be 0.5, and described BT refers to the product for bandwidth sum bit duration.

In order to solve the problems of the technologies described above, the embodiment of the present invention also provides a kind of intelligent terminal, and described intelligent terminal possesses the function receiving Gaussian frequency shifted key signal, also comprises the demodulating equipment of foregoing Gaussian frequency shifted key signal.

Optionally, described intelligent terminal is smart mobile phone, panel computer or notebook computer.

Compared with prior art, technical scheme of the present invention has following beneficial effect:

Draw optimum Match waveform by matched filtering, draw maximum related value angle delta θ according to Received signal strength and optimum Match waveform thereof _n, in recurrence calculation phase of received signal estimated value time add maximum related value angle delta θ _n, thus ensure that to θ _n+1unbiased esti-mator, reduce the impact that frequency change is brought.

Further, utilization obtains carry out frequency loop tracking, recursion draws I _n+1, and the recursion that circulates is until draw whole data to be demodulated.Especially matched filtering is combined with angle iteration, adopts the Δ θ obtained in matched filtering _nparticipate in angle iteration, carry out frequency loop tracking, thus reduce the impact that frequency change brings.

Meanwhile, above-mentioned demodulating process is insensitive for modulation index, and for existing coherent demodulation scheme, the uncertainty by modulation index affects less.

Accompanying drawing explanation

Fig. 1 is the demodulation method flow chart of the Gaussian frequency shifted key signal in the embodiment of the present invention;

Fig. 2 is that the system algorithm of the demodulation method of Gaussian frequency shifted key signal in the embodiment of the present invention realizes block diagram;

Fig. 3 is the demodulating equipment structured flowchart of the Gaussian frequency shifted key signal in the embodiment of the present invention.

Embodiment

According to the analysis of background technology part, the comparatively large and fast-changing feature of frequency of the uncertainty that there is modulation index usually for the Gaussian frequency shifted key signal of the basic rate signal of bluetooth.In order to the impact that the uncertainty reducing modulation index Rapid Variable Design that is comparatively large and frequency brings, usually differential ference spiral scheme is adopted to carry out the demodulation of Gaussian frequency shifted key signal in prior art, but this can cause the reduction of receiving sensitivity, make the effective propagation path of bluetooth in prior art shorter.

The demodulation method of present inventor to Gaussian frequency shifted key signal improves, while employing coherent demodulation scheme improves and accepts the effective propagation path of sensitivity and signal, the impact that the Rapid Variable Design of the uncertainty and frequency that reduce modulation index brings.

For making those skilled in the art understand better and realize the present invention, referring to accompanying drawing, be described in detail by specific embodiment.

First, the signal after Gaussian Frequency Shift Keying modulation, the numerical expression of its Received signal strength is as follows:

$r\left(t\right)=e^{j2\mathrm{\&pi;h}\underset{-\&infin;}{\overset{t}{\&Integral;}}\underset{n}{\mathrm{\&Sigma;}}{I}_{n}g(\mathrm{\&tau;}-\mathrm{nT})\mathrm{d\&tau;}};$

Wherein, h is modulation index, and for the basic rate signal of bluetooth, modulation index is 0.3, and in practical application, modulation index is usually in the scope of 0.28 ~ 0.35.

For the demodulation of Gaussian frequency shifted key signal, namely the object of demodulation is from Received signal strength, to solve whole data I to be demodulated.

BT refer to for represent the product of bandwidth sum bit duration.The BT of Gaussian frequency shifted key signal refers to it is 0.5, therefore,

Order $q\left(t\right)=\underset{-\&infin;}{\overset{t}{\&Integral;}}g\left(\mathrm{\&tau;}\right)\mathrm{d\&tau;}=\frac{1}{2}(t>2T);$

Then have $\mathrm{\&phi;}(t;I)=2\mathrm{\&pi;h}\underset{k=-\&infin;}{\overset{n}{\mathrm{\&Sigma;}}}{I}_{k}q(t-\mathrm{kT});$

$\mathrm{\&phi;}(t;I)=\mathrm{\&pi;h}\underset{k=-\&infin;}{\overset{n-2}{\mathrm{\&Sigma;}}}{I}_k+2\mathrm{\&pi;h}\underset{k=n-1}{\overset{n}{\mathrm{\&Sigma;}}}{I}_{k}q(t-\mathrm{KT});$

φ(t；I)＝θ _n+2πhI _n-1q(t-(n-1)T)+2πhI _nq(t-nT)；

Each meaning of parameters that the embodiment of the present invention relates to is as follows:

I represents data to be demodulated;

θ represents the phase place actual value of Received signal strength;

represent the phase estimation value of Received signal strength;

H represents modulation index;

π represents circumference ratio;

R (t) represents Received signal strength;

V _it () represents matched signal;

I` represents optimum Match waveform;

K represents the quantity of Received signal strength all possible signal mode in nT<t< (n+3) T time.

As described below, the embodiment of the present invention provides a kind of demodulation method of Gaussian frequency shifted key signal.

With reference to the demodulation method flow chart of the Gaussian frequency shifted key signal shown in Fig. 1, be described in detail below by way of concrete steps:

S101, according to and I _n-1received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, draws the optimum Match waveform of Received signal strength in nT<t< (n+3) T time.

As previously mentioned, the signal after Gaussian Frequency Shift Keying modulation, the numerical expression of its Received signal strength is as follows:

$r\left(t\right)=e^{j2\mathrm{\&pi;h}\underset{-\&infin;}{\overset{t}{\&Integral;}}\underset{n}{\mathrm{\&Sigma;}}{I}_{n}g(\mathrm{\&tau;}-\mathrm{nT})\mathrm{d\&tau;}};$

Wherein, $2\mathrm{\&pi;h}\underset{-\&infin;}{\overset{t}{\&Integral;}}\underset{n}{\mathrm{\&Sigma;}}{I}_{n}g(\mathrm{\&tau;}-\mathrm{nT})\mathrm{d\&tau;}$ Be its angle information, order $\mathrm{\&phi;}(t;I)=2\mathrm{\&pi;h}\underset{-\&infin;}{\overset{t}{\&Integral;}}\underset{n}{\mathrm{\&Sigma;}}{I}_{n}g(\mathrm{\&tau;}-\mathrm{nT})\mathrm{d\&tau;}.$

Order $q\left(t\right)=\underset{-\&infin;}{\overset{t}{\&Integral;}}g\left(\mathrm{\&tau;}\right)\mathrm{d\&tau;}=\frac{1}{2}(t>2T);$

Then have $\mathrm{\&phi;}(t;I)=2\mathrm{\&pi;h}\underset{k=-\&infin;}{\overset{n}{\mathrm{\&Sigma;}}}{I}_{k}q(t-\mathrm{kT});$

$\mathrm{\&phi;}(t;I)=\mathrm{\&pi;h}\underset{k=-\&infin;}{\overset{n-2}{\mathrm{\&Sigma;}}}{I}_k+2\mathrm{\&pi;h}\underset{k=n-1}{\overset{n}{\mathrm{\&Sigma;}}}{I}_{k}q(t-\mathrm{KT});$

φ(t；I)＝θ _n+2πhI _n-1q(t-(n-1)T)+2πhI _nq(t-nT)；

When needing demodulation In, Received signal strength nT<t< (n+3) T during this period of time in, only depend on parameter θ _n, I _n-1, I _n, I _n+1and I _n+2, obtaining θ in advance _nwhen (rear extended meeting provide obtain θ _nmethod), then Received signal strength only has 16 kinds of possible signal modes altogether at nT<t< (n+3) T during this period of time.

Therefore, Received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, the optimum Match waveform of Received signal strength in nT<t< (n+3) T time can be drawn.

During coupling, the form of Received signal strength is waveform.

Particularly, can matched filtering be carried out by following formula and draw optimum Match waveform:

$I^{`}=\arg \min {\&Integral;}_0^{3T}|\underset{0\&le;i<k}{{r\left(t\right)e}^{-j{\mathrm{\&theta;}}_n}}-v_i\left(t\right)|\mathrm{dt}=\arg \underset{0\&le;i<k}{\max }\left(\mathrm{real}\left({\&Integral;}_0^{3T}r\left(t\right)e^{-j{\mathrm{\&theta;}}_n}{v}_i^H\left(t\right)\mathrm{dt}\right)\right);$

Wherein, v _it () represents matched signal, I` represents optimum Match waveform, and k represents the quantity of Received signal strength all possible signal mode in nT<t< (n+3) T time.In the present embodiment, k=16.

S102, according to the optimum Match waveform of Received signal strength in nT<t< (n+3) T time, judges I _n.

After obtaining the optimum Match waveform I` of Received signal strength in nT<t< (n+3) T time, I can be judged _n.

S103, the optimum Match waveform in nT<t< (n+3) T time according to Received signal strength and Received signal strength, draws the maximum related value angle delta θ of Received signal strength in nT<t< (n+3) T time _n.

Certain difference is there is between the phase place actual value of Received signal strength and its estimated value.Directly adopt the estimated value of phase place to carry out computing in prior art, can produce certain error, especially when frequency change is very fast, this error also can be larger.And Gaussian frequency shifted key signal a kind of frequency change signal faster just.

The phase place actual value of Received signal strength is represented with θ, represent the phase estimation value of Received signal strength, Δ θ _nbe difference between the two, that is:

After drawing optimum Match waveform according to Received signal strength, if do not consider noise effect, then both correlations should be real numbers.But due to the angle change that frequency change causes, the actual correlation obtained not is real number.Accordingly, namely according to Received signal strength and its optimum Match waveform, by asking maximum related value angle, the information about frequency change can be obtained.

I.e. Δ θ _n=angle (corr) _n;

Due to Δ θ _nfor θ and between difference, therefore $\mathrm{angle}{\left(\mathrm{corr}\right)}_n={\mathrm{\&theta;}}_n-{\widehat{\mathrm{\&theta;}}}_n.$

Δ θ is added in follow-up recursive operation _n, can realize θ _nunbiased esti-mator, thus reduce the impact that brings of frequency change.

S104, according to i _nwith Δ θ _n, pass through formula calculate

The recurrence formula of phase place is: θ _n+1=θ _n+ I _nh π _n;

In the coherent demodulation scheme of routine, directly with phase estimation value substitute in above-mentioned phase recursion formula as θ, cause error thus.In recursive process, need repeated multiple times above-mentioned use phase recursion formula, therefore, after have passed through successive ignition, error will be increasing.

The present embodiment draws the maximum related value angle delta θ of Received signal strength in nT<t< (n+3) T time in step s 103 _n.

By $\mathrm{\&Delta;}{\mathrm{\&theta;}}_n={\mathrm{\&theta;}}_n-{\widehat{\mathrm{\&theta;}}}_n,$

Therefore ${\widehat{\mathrm{\&theta;}}}_{n+1}={\mathrm{\&theta;}}_n+I_n\mathrm{h\&pi;}={\widehat{\mathrm{\&theta;}}}_n+I_n\mathrm{h\&pi;}+\mathrm{\&Delta;}{\mathrm{\&theta;}}_n;$

Thus, the present embodiment passes through in recurrence calculation phase of received signal estimated value time add maximum related value angle delta θ _n, thus ensure that to θ _n+1unbiased esti-mator, reduce the impact that frequency change is brought.

The present embodiment has drawn in step S104 draw I in step s 102 _n, will and I _nsubstitute in step S101 and I _n-1, circulation performs step S101 to S104, recursion can draw whole data to be demodulated.

The present embodiment utilization obtains carry out frequency loop tracking, recursion draws I _n+1, and the recursion that circulates is until draw whole data to be demodulated.

Especially matched filtering is combined with angle iteration, adopts the Δ θ obtained in matched filtering _nparticipate in angle iteration, carry out frequency loop tracking, thus reduce the impact that frequency change brings.

Meanwhile, above-mentioned demodulating process is insensitive for modulation index, and for existing coherent demodulation scheme, the uncertainty by modulation index affects less.

First perform step S101 time, need to provide in advance modulation index h and and I _n-1initial value i _-1.

Can draw in the following manner modulation index h and and I _n-1initial value i _-1:

When Signal transmissions, if transmit leg carries out modulation and the transmission of signal according to set agreement, then for reciever, directly transmitting data can be determined according to agreement.Namely transmitting data is known, directly can draw I according to transmitting data _n-1and h.

For the basic rate signal of bluetooth, the synchronous head data of bluetooth are known for recipient.

After receiving Received signal strength, the initial value of phase estimation value can be gone out by following formulae discovery

${\widehat{\mathrm{\&theta;}}}_0=\mathrm{angle}\left({\&Integral;}_0^{3T}r\left(t\right)v_i^H\left(t\right)\mathrm{dt}\right);$

It should be noted that, above-mentioned acquisition modulation index h and and I _n-1initial value i _-1mode be not unique, there is the mode that other obtain above-mentioned initial value in prior art.

So far, obtain modulation index h and and I _n-1initial value i _-1afterwards, whole data to be demodulated can be demodulated by abovementioned steps S101 to S104.

The present embodiment from receiving Received signal strength, to demodulating whole data to be demodulated.

Total system algorithm realizes block diagram as shown in Figure 2.Wherein, waveform 1 to waveform 16 is all 16 kinds of possible coupling waveforms.

If frequency departure excessive (such as reaching more than 100kHz), then loop is difficult to work, therefore needs to carry out frequency deviation estimation.

After frequency deviation is estimated, namely can carry out correcting frequency deviation with estimated value.

As described below, the embodiment of the present invention provides a kind of demodulating equipment of Gaussian frequency shifted key signal.

Demodulating equipment structured flowchart with reference to the Gaussian frequency shifted key signal shown in Fig. 3:

The demodulating equipment of described Gaussian frequency shifted key signal comprises: matched filtering unit 301, coupling decision unit 302, first computing unit 303 and the second computing unit 304; Wherein:

Matched filtering unit 301, for basis and I _n-1received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, draws the optimum Match waveform of Received signal strength in nT<t< (n+3) T time;

Coupling decision unit 302, after drawing optimum Match waveform at described matched filtering unit 301, according to the optimum Match waveform of Received signal strength in nT<t< (n+3) T time, judges I _n;

First computing unit 303, after drawing optimum Match waveform at described matched filtering unit 301, the optimum Match waveform in nT<t< (n+3) T time according to Received signal strength and Received signal strength, draws the maximum related value angle delta θ of Received signal strength in nT<t< (n+3) T time _n;

Second computing unit 304, for drawing maximum related value angle delta θ at described first computing unit 303 _nafterwards, according to i _nwith Δ θ _n, gone out by following formulae discovery

${\widehat{\mathrm{\&theta;}}}_{n+1}={\widehat{\mathrm{\&theta;}}}_n+I_n\mathrm{h\&pi;}+\mathrm{\&Delta;}{\mathrm{\&theta;}}_n;$

Calculate at described second computing unit 304 afterwards, above-mentioned action is carried out in described matched filtering unit 301, coupling decision unit 302, first computing unit 303 and the circulation of the second computing unit 304, and recursion draws whole data to be demodulated.

Can be found out by the above description to technical scheme, the present embodiment draws optimum Match waveform by matched filtering, draws maximum related value angle delta θ according to Received signal strength and optimum Match waveform thereof _n, in recurrence calculation phase of received signal estimated value time add maximum related value angle delta θ _n, thus ensure that to θ _n+1unbiased esti-mator, reduce the impact that frequency change is brought.

Further, utilization obtains carry out frequency loop tracking, recursion draws I _n+1, and the recursion that circulates is until draw whole data to be demodulated.Especially matched filtering is combined with angle iteration, adopts the Δ θ obtained in matched filtering _nparticipate in angle iteration, carry out frequency loop tracking, thus reduce the impact that frequency change brings.

Meanwhile, above-mentioned demodulating process is insensitive for modulation index, and for existing coherent demodulation scheme, the uncertainty by modulation index affects less.

In concrete enforcement, can also comprise: initial value computing unit 305, described initial value computing unit 305, for according to transmitting data, draws I _n-1and h, also for according to transmitting data and Received signal strength, gone out by following formulae discovery

${\widehat{\mathrm{\&theta;}}}_0=\mathrm{angle}\left({\&Integral;}_0^{3T}r\left(t\right)v_i^H\left(t\right)\mathrm{dt}\right);$

Wherein, r (t) represents Received signal strength.

In concrete enforcement, described matched filtering unit 301 basis and I _n-1received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, draw the optimum Match waveform of Received signal strength in nT<t< (n+3) T time specifically: the Received signal strength following form represented carries out matched filtering:

$r\left(t\right)=e^{j2\mathrm{\&pi;h}\underset{-\&infin;}{\overset{t}{\&Integral;}}\underset{n}{\mathrm{\&Sigma;}}{I}_{n}g(\mathrm{\&tau;}-\mathrm{nT})\mathrm{d\&tau;}}.$

In concrete enforcement, described matched filtering unit 301 basis and I _n-1received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, draw the optimum Match waveform of Received signal strength in nT<t< (n+3) T time specifically: draw optimum Match waveform by following formula:

$I^{`}=\arg \min {\&Integral;}_0^{3T}|\underset{0\&le;i<k}{{r\left(t\right)e}^{-j{\mathrm{\&theta;}}_n}}-v_i\left(t\right)|\mathrm{dt}=\arg \underset{0\&le;i<k}{\max }\left(\mathrm{real}\left({\&Integral;}_0^{3T}r\left(t\right)e^{-j{\mathrm{\&theta;}}_n}{v}_i^H\left(t\right)\mathrm{dt}\right)\right);$

Wherein, v _it () represents matched signal, I` represents optimum Match waveform, and k represents the quantity of Received signal strength all possible signal mode in nT<t< (n+3) T time.

In concrete enforcement, described first computing unit 303 is the optimum Match waveform in nT<t< (n+3) T time according to Received signal strength and Received signal strength, draws the maximum related value angle delta θ of Received signal strength in nT<t< (n+3) T time _nspecifically: draw maximum related value angle delta θ according to following formula _n:

$\mathrm{\&Delta;}{\mathrm{\&theta;}}_n=\mathrm{angle}{\left(\mathrm{corr}\right)}_n={\mathrm{\&theta;}}_n-{\widehat{\mathrm{\&theta;}}}_n.$

In concrete enforcement, described Gaussian frequency shifted key signal is the basic rate signal of bluetooth, and transmitting data is the synchronous head data of bluetooth, and the modulation index of described Gaussian frequency shifted key signal is 0.28 ~ 0.35, BT refers to be 0.5, and described BT refers to the product for bandwidth sum bit duration.

As described below, the embodiment of the present invention provides a kind of intelligent terminal.

Described intelligent terminal possesses the function receiving Gaussian frequency shifted key signal.Be with the difference of prior art, this intelligent terminal also comprise as in the embodiment of the present invention the demodulating equipment of Gaussian frequency shifted key signal that provides.Thus this intelligent terminal can draw optimum Match waveform by matched filtering, draws maximum related value angle delta θ according to Received signal strength and optimum Match waveform thereof _n, in recurrence calculation phase of received signal estimated value time add maximum related value angle delta θ _n, thus ensure that to θ _n+1unbiased esti-mator, reduce the impact that frequency change is brought.On this basis, utilization obtains carry out frequency loop tracking, recursion draws I _n+1, and the recursion that circulates is until draw whole data to be demodulated, thus the further impact reducing frequency change and bring.Meanwhile, above-mentioned demodulating process is insensitive for modulation index, and for existing coherent demodulation scheme, the uncertainty by modulation index affects less.

In concrete enforcement, described intelligent terminal can be smart mobile phone, panel computer or notebook computer.

One of ordinary skill in the art will appreciate that all or part of step in the various methods of above-described embodiment is that the hardware that can carry out instruction relevant by program has come, this program can be stored in a computer-readable recording medium, and storage medium can comprise: ROM, RAM, disk or CD etc.

Although the present invention discloses as above, the present invention is not defined in this.Any those skilled in the art, without departing from the spirit and scope of the present invention, all can make various changes or modifications, and therefore protection scope of the present invention should be as the criterion with claim limited range.

Claims (16)

1. a demodulation method for Gaussian frequency shifted key signal, I represents data to be demodulated, and θ represents the phase place actual value of Received signal strength, represent the phase estimation value of Received signal strength, h represents modulation index, and π represents circumference ratio, it is characterized in that, comprising:

According to and I _n-1received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, draws the optimum Match waveform of Received signal strength in nT<t< (n+3) T time;

According to the optimum Match waveform of Received signal strength in nT<t< (n+3) T time, judge I _n;

The optimum Match waveform in nT<t< (n+3) T time according to Received signal strength and Received signal strength, draws the maximum related value angle delta θ of Received signal strength in nT<t< (n+3) T time _n;

According to i _nwith Δ θ _n, gone out by following formulae discovery

${\widehat{\mathrm{\&theta;}}}_{n+1}={\widehat{\mathrm{\&theta;}}}_n+I_n\mathrm{h\&pi;}+\mathrm{\&Delta;}{\mathrm{\&theta;}}_n;$

According to and I _n, circulation performs above-mentioned steps, and recursion draws whole data to be demodulated.

2. the demodulation method of Gaussian frequency shifted key signal as claimed in claim 1, be is characterized in that, drawn by following steps and I _n-1initial value i _-1and h:

According to transmitting data, draw I _n-1and h;

According to transmitting data and Received signal strength, gone out by following formulae discovery

${\widehat{\mathrm{\&theta;}}}_0=\mathrm{angle}\left({\&Integral;}_0^{3T}r\left(t\right)v_i^H\left(t\right)\mathrm{dt}\right);$

Wherein, r (t) represents Received signal strength.

3. the demodulation method of Gaussian frequency shifted key signal as claimed in claim 1, is characterized in that, described basis and I _n-1received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, draw the optimum Match waveform of Received signal strength in nT<t< (n+3) T time specifically: the Received signal strength following form represented carries out matched filtering:

$r\left(t\right)=e^{j2\mathrm{\&pi;h}\underset{-\&infin;}{\overset{t}{\&Integral;}}\underset{n}{\mathrm{\&Sigma;}}{I}_{n}g(\mathrm{\&tau;}-\mathrm{nT})\mathrm{d\&tau;}}.$

4. the demodulation method of Gaussian frequency shifted key signal as claimed in claim 1, is characterized in that, described basis and I _n-1received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, draw the optimum Match waveform of Received signal strength in nT<t< (n+3) T time specifically: draw optimum Match waveform by following formula:

$I^{`}=\arg \min {\&Integral;}_0^{3T}|\underset{0\&le;i<k}{{r\left(t\right)e}^{-j{\mathrm{\&theta;}}_n}}-v_i\left(t\right)|\mathrm{dt}=\arg \underset{0\&le;i<k}{\max }\left(\mathrm{real}\left({\&Integral;}_0^{3T}r\left(t\right)e^{-j{\mathrm{\&theta;}}_n}{v}_i^H\left(t\right)\mathrm{dt}\right)\right);$

Wherein, v _it () represents matched signal, I` represents optimum Match waveform, and k represents the quantity of Received signal strength all possible signal mode in nT<t< (n+3) T time.

5. the demodulation method of Gaussian frequency shifted key signal as claimed in claim 1, it is characterized in that, described according to Received signal strength and Received signal strength the optimum Match waveform in nT<t< (n+3) T time, draw the maximum related value angle delta θ of Received signal strength in nT<t< (n+3) T time _nspecifically: draw maximum related value angle delta θ according to following formula _n:

$\mathrm{\&Delta;}{\mathrm{\&theta;}}_n=\mathrm{angle}{\left(\mathrm{corr}\right)}_n={\mathrm{\&theta;}}_n-{\widehat{\mathrm{\&theta;}}}_n.$

6. the demodulation method of Gaussian frequency shifted key signal as claimed in claim 1, it is characterized in that, described Gaussian frequency shifted key signal is the basic rate signal of bluetooth, and transmitting data is the synchronous head data of bluetooth.

7. the demodulation method of Gaussian frequency shifted key signal as claimed in claim 1, it is characterized in that, the modulation index of described Gaussian frequency shifted key signal is that 0.28 ~ 0.35, BT refers to be 0.5, and described BT refers to the product for bandwidth sum bit duration.

8. a demodulating equipment for Gaussian frequency shifted key signal, is characterized in that, comprising: matched filtering unit, coupling decision unit, the first computing unit and the second computing unit; Wherein:

Matched filtering unit, for basis and I _n-1received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, draws the optimum Match waveform of Received signal strength in nT<t< (n+3) T time;

Coupling decision unit, after drawing optimum Match waveform at described matched filtering unit, according to the optimum Match waveform of Received signal strength in nT<t< (n+3) T time, judges In;

First computing unit, after drawing optimum Match waveform at described matched filtering unit, the optimum Match waveform in nT<t< (n+3) T time according to Received signal strength and Received signal strength, draws the maximum related value angle delta θ of Received signal strength in nT<t< (n+3) T time _n;

Second computing unit, for drawing maximum related value angle delta θ at described first computing unit _nafterwards, according to i _nwith Δ θ _n, gone out by following formulae discovery

${\widehat{\mathrm{\&theta;}}}_{n+1}={\widehat{\mathrm{\&theta;}}}_n+I_n\mathrm{h\&pi;}+\mathrm{\&Delta;}{\mathrm{\&theta;}}_n;$

Calculate at described second computing unit afterwards, described matched filtering unit, the circulation of coupling decision unit, the first computing unit and the second computing unit carry out above-mentioned action, and recursion draws whole data to be demodulated.

9. the demodulating equipment of Gaussian frequency shifted key signal as claimed in claim 8, it is characterized in that, also comprise: initial value computing unit, described initial value computing unit, for according to transmitting data, draws I _n-1and h, also for according to transmitting data and Received signal strength, gone out by following formulae discovery

${\widehat{\mathrm{\&theta;}}}_0=\mathrm{angle}\left({\&Integral;}_0^{3T}r\left(t\right)v_i^H\left(t\right)\mathrm{dt}\right);$

Wherein, r (t) represents Received signal strength.

10. the demodulating equipment of Gaussian frequency shifted key signal as claimed in claim 8, is characterized in that, described matched filtering unit according to and I _n-1received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, draw the optimum Match waveform of Received signal strength in nT<t< (n+3) T time specifically: the Received signal strength following form represented carries out matched filtering:

$r\left(t\right)=e^{j2\mathrm{\&pi;h}\underset{-\&infin;}{\overset{t}{\&Integral;}}\underset{n}{\mathrm{\&Sigma;}}{I}_{n}g(\mathrm{\&tau;}-\mathrm{nT})\mathrm{d\&tau;}}.$

The demodulating equipment of 11. Gaussian frequency shifted key signal as claimed in claim 8, is characterized in that, described matched filtering unit according to and I _n-1received signal strength and all possible signal mode in nT<t< (n+3) T time are carried out matched filtering, draw the optimum Match waveform of Received signal strength in nT<t< (n+3) T time specifically: draw optimum Match waveform by following formula:

$I^{`}=\arg \min {\&Integral;}_0^{3T}|\underset{0\&le;i<k}{{r\left(t\right)e}^{-j{\mathrm{\&theta;}}_n}}-v_i\left(t\right)|\mathrm{dt}=\arg \underset{0\&le;i<k}{\max }\left(\mathrm{real}\left({\&Integral;}_0^{3T}r\left(t\right)e^{-j{\mathrm{\&theta;}}_n}{v}_i^H\left(t\right)\mathrm{dt}\right)\right);$

Wherein, v _it () represents matched signal, I` represents optimum Match waveform, and k represents the quantity of Received signal strength all possible signal mode in nT<t< (n+3) T time.

The demodulating equipment of 12. Gaussian frequency shifted key signal as claimed in claim 8, it is characterized in that, described first computing unit is the optimum Match waveform in nT<t< (n+3) T time according to Received signal strength and Received signal strength, draws the maximum related value angle delta θ of Received signal strength in nT<t< (n+3) T time _nspecifically: draw maximum related value angle delta θ according to following formula _n:

$\mathrm{\&Delta;}{\mathrm{\&theta;}}_n=\mathrm{angle}{\left(\mathrm{corr}\right)}_n={\mathrm{\&theta;}}_n-{\widehat{\mathrm{\&theta;}}}_n.$

The demodulating equipment of 13. Gaussian frequency shifted key signal as claimed in claim 8, it is characterized in that, described Gaussian frequency shifted key signal is the basic rate signal of bluetooth, transmitting data is the synchronous head data of bluetooth.

The demodulating equipment of 14. Gaussian frequency shifted key signal as claimed in claim 8, is characterized in that, the modulation index of described Gaussian frequency shifted key signal is that 0.28 ~ 0.35, BT refers to be 0.5, and described BT refers to the product for bandwidth sum bit duration.

15. 1 kinds of intelligent terminals, described intelligent terminal possesses the function receiving Gaussian frequency shifted key signal, it is characterized in that, also comprises the demodulating equipment of the Gaussian frequency shifted key signal according to any one of claim 8 to 14.

16. intelligent terminals as claimed in claim 15, it is characterized in that, described intelligent terminal is smart mobile phone, panel computer or notebook computer.