CN103596260A - Time slot synchronization method and system of multicarrier GSM system - Google Patents

Abstract

The invention relates to a time slot synchronization method and system of a multicarrier GSM system. The method comprises the following steps: carrying out carrier searching on multicarrier GSM base station signals and obtaining carrier information; carrying out base-band treatment for each carrier through software radio technology according to the carrier information; cross-correlating base-band signals of each carrier with local sequences; determining a synchronization channel and a synchronization burst in a broadcast channel according to a correlation peak value obtained by the cross correlation, and employing the position of the synchronization burst in a GSM frame structure to output the time slot synchronization pulses. The time slot synchronization method and system of the multicarrier GSM system realizes multicarrier GSM time slot synchronization function, improves flexibility and scalability of the system, can suit different base station occasions, realizes self-adaptation time slot synchronization, and is simple and practical.

Description

The slotted synchronous method of multicarrier gsm system and system

Technical field

The present invention relates to moving communicating field and signal and process, be specifically related to a kind of slotted synchronous method of multicarrier gsm system, and a kind of slot synchronization system of multicarrier gsm system.

Background technology

Base station is the equipment of power consumption in whole wireless network, and the power amplifier unit power consumption in base station is the more than 70% of base station power consumption, therefore improves power amplifier technology, and the efficiency that improves power amplifier is to reduce the important means of base station power consumption.And base station load is in the course of the work dynamic change, the traffic carrying capacity difference of busy and idle time is very large, as GSM(Global System for Mobile Communications global system for mobile communications) mobile communication system.That gsm mobile communication system adopts is time-division multiplex technology (TDMA), each basic frame comprises 8 time slots, a plurality of basic frames form a multi-frame, user converses and relevant control signal only takies one of them time slot (TimeSlot), therefore to some carrier waves, within some time periods, be not that 8 time slots all have signal, when telephone traffic is many, 8 time slots have signal, and when telephone traffic is few, only have seldom time slot wherein to have signal.If intelligence is turn-offed power amplifier unit in the time slot without business datum, the consumption that so just can save power amplifier, has reduced the power consumption of transmitter unit.And in current GSM repeater, no matter equipment state is busy or not busy, whether each time slot has CU, and the power amplifier unit in equipment is all often opened, and the energy that power amplifier consumes in equipment is maximum, and this has just caused the waste of the energy.But the prerequisite that realizes timeslot shutdown is to realize slot synchronization.After in slot synchronization, just can carry out time slot power detection, thereby judge whether current time slots has service signal, if synchronously accurate not, will cause call drop, thereby affect speech quality.And in the network optimization edge devices such as repeater, owing to lacking the signaling information of base band data, be not easy to realize GSM slot synchronization, thereby realize time slot power accurately, detect and timeslot shutdown.

Summary of the invention

The object of the invention is to overcome shortcomings and deficiencies of the prior art, slotted synchronous method and the system of multicarrier gsm system are provided, can realize the time slot precise synchronization of multicarrier GSM base station signal, solved the error problem that baseband signal frequency deviation is brought, for time slot power detects, provide reference synchronization, the more important thing is that the timeslot shutdown for base station power amplification unit provides synchronizing information.

Technical scheme of the present invention is as follows:

A slotted synchronous method for multicarrier gsm system, comprises the steps:

GSM base station signal to multicarrier carries out searching carrier, obtains carrier information;

According to described carrier information, adopt software and radio technique to carry out Base-Band Processing to each carrier wave;

The baseband signal of described each carrier wave and local sequence are carried out to cross-correlation;

Synchronizing channel and Synchronization Burst sequence in the correlation peak judgement broadcast channel obtaining according to described cross-correlation, utilize the position output time solt lock-out pulse of Synchronization Burst sequence in GSM frame structure.

A slot synchronization system for gsm system, comprising: searching carrier module, baseband processing module, cross-correlation module, slot synchronization module;

Described searching carrier module, for the GSM base station signal of multicarrier is carried out to searching carrier, is obtained carrier information;

Described baseband processing module, for according to described carrier information, adopts software and radio technique to carry out Base-Band Processing to each carrier wave;

Described cross-correlation module is for carrying out cross-correlation by the baseband signal of described each carrier wave and local sequence;

Described slot synchronization module judges synchronizing channel and the Synchronization Burst sequence of broadcast channel for the correlation peak obtaining according to described cross-correlation, utilize the position output time solt lock-out pulse of Synchronization Burst sequence in GSM frame structure.

The present invention compared with prior art tool has the following advantages and beneficial effect:

The present invention is lacking under the prerequisite of base station signaling, by carrier track algorithm from motion tracking GSM carrier information, according to carrier information locking broadcast channel BCH(Broadcast Channel broadcast channel), adopt radiotechnics, solved the problem of bringing due to the frequency deviation of RF down-conversion and Digital Down Convert, adopt real number relevant simultaneously, reduced Digital Signal Processing resource, support different application scenarios the more important thing is and realized multicarrier GSM slot synchronization function, flexibility and the extensibility of system have been improved, can adapt to different base station occasions, realize adaptive slot synchronization, simpler than the slot synchronization algorithm of resolving based on signaling, convenient and practical.

Accompanying drawing explanation

Fig. 1 is the schematic flow sheet in one embodiment of slotted synchronous method of multicarrier gsm system of the present invention.

Fig. 2 is the schematic flow sheet of step S11 in Fig. 1 embodiment.

Fig. 3 is the schematic flow sheet of step S12 in Fig. 1 embodiment.

Fig. 4 is the present invention's correlated results of SDR digital quadrature demodulation in one embodiment.

Fig. 5 is the schematic flow sheet of step S13 in Fig. 1 embodiment.

Fig. 6 is the schematic flow sheet of step S14 in Fig. 1 embodiment.

Fig. 7 is the structured flowchart in one embodiment of slot synchronization system of multicarrier gsm system of the present invention.

Fig. 8 is the structural representation of searching carrier module in Fig. 7 embodiment.

Fig. 9 is the structural representation of baseband processing module in Fig. 7 embodiment.

Figure 10 is the structural representation of cross-correlation module in Fig. 7 embodiment.

Figure 11 is the structural representation of slot synchronization module in Fig. 7 embodiment.

Embodiment

Below in conjunction with embodiment and accompanying drawing, the present invention is described in further detail, but embodiments of the present invention are not limited to this.

Embodiment mono-:

As shown in Figure 1, the schematic flow sheet for the slotted synchronous method of the multicarrier gsm system in the present embodiment of the present invention, comprises the following steps:

S11, the GSM base station signal of multicarrier is carried out to searching carrier, obtain carrier information;

S12, according to described carrier information, adopt software and radio technique to carry out Base-Band Processing to each carrier wave;

S13, the baseband signal of described each carrier wave and local sequence are carried out to cross-correlation;

S14, the correlation peak obtaining according to described cross-correlation judge synchronizing channel and the Synchronization Burst sequence in broadcast channel, utilize the position output time solt lock-out pulse of Synchronization Burst sequence in GSM frame structure.

The present invention is lacking under the prerequisite of base station signaling, by carrier track algorithm, from motion tracking GSM carrier information, according to carrier information, locks broadcast channel BCH(Broadcast Channel broadcast channel).Adopt radiotechnics, solved the problem of bringing due to the frequency deviation of RF down-conversion and Digital Down Convert, adopt real number relevant simultaneously, reduced Digital Signal Processing resource, support different application scenarios the more important thing is and realized multicarrier GSM slot synchronization function, improved flexibility and the extensibility of system, can adapt to different base station occasions, realize adaptive slot synchronization, simpler, convenient and practical than the slot synchronization algorithm of resolving based on signaling.

For more clear technical scheme of the present invention, set forth the preferred embodiment of technical scheme of the slotted synchronous method of multicarrier gsm system of the present invention below.

In a preferred embodiment, for S11, as shown in Figure 2, particularly, can comprise the steps:

S111, intermediate-freuqncy signal is carried out to IF bandpass sampling, obtain digital intermediate frequency real signal;

S112, described digital intermediate frequency real signal is carried out to zero intermediate frequency processing, obtain zero intermediate frequency base band in-phase component I _bwith quadrature component Q _b;

S113, to described zero intermediate frequency base band in-phase component I _bwith quadrature component Q _bcarry out searching carrier, obtain carrier information;

Can adopt in the present embodiment Nyquist bandpass sample theory to carry out bandpass sampling to intermediate-freuqncy signal, obtain digital intermediate frequency real signal S _b, simultaneously to S _bsignal carries out zero intermediate frequency processing, obtains zero intermediate frequency base band in-phase component I _bwith quadrature component Q _b;

Wherein, described zero intermediate frequency is processed and is comprised successively first order numeral NCO(Numerical Controlled Oscillator digital controlled oscillator) process and low-pass filtering treatment; Described S _bsignal carries out first order numeral NCO successively to be processed and low-pass filtering treatment; Described low-pass filtering treatment can be FIR(Finite Impulse Response finite impulse response (FIR)) filtering, IIR(Infinite Impulse Response infinite impulse response) filtering or other forms of filtering processes;

According to known GSM searching carrier algorithm to zero intermediate frequency base band in-phase component I _bwith quadrature component Q _bcarry out searching carrier, obtain carrier information, searching carrier specifically can, with reference to the correlation technique that GSM carrier information can be provided, not repeat them here.

For S12, as shown in Figure 3, particularly, can comprise the steps:

S121, according to described carrier information on current channel number to described zero intermediate frequency base band in-phase component I _bwith quadrature component Q _bcarry out after single pass Digital Down Convert processing, then carry out sampling rate conversion and obtain baseband signal I ₀and Q ₀;

The carrier information that can obtain according to described searching carrier, on current channel number to zero intermediate frequency baseband signal I _band Q _bcarrying out single pass Digital Down Convert (DDC, Digital Down Conversion) processes;

Described single pass Digital Down Convert DDC processes and comprises that second level numeral NCO processes, filtering extraction is processed, shaping filter is processed, after DDC is processed, the high speed sequence of output is carried out sampling rate conversion, according to actual conditions, set relatively and the OSR (Over Sampling Ratio over-sampling rate) of GSM chip rate integral multiple value, obtain the baseband signal I that speed is lower ₀and Q ₀.Owing to having reduced processing speed, for programmable logic device has alleviated burden, be conducive to programmable logic device simultaneously and carry out time division multiplexing, greatly saved the hardware resource of device.The present invention can apply as programmable logic devices such as FPGA, CPLD, DSP, is conducive to digit chip and realizes.

Zero intermediate frequency baseband signal I _band Q _bby second level numeral NCO processing, filtering extraction processing, shaping filter, process successively; Described filtering extraction is treated to the dressing of CIC(Cascaded Integrator Comb integration) extract, HB(HalfBand half band) extract, FIR extracts or other forms of filtering extraction is processed; Described shaping filter is treated to FIR filtering, IIR filtering or other forms of filtering and processes.Owing to adopting the signal processing technology of above-mentioned many speed, relevant parameter can reset according to software, therefore the carrier number of supporting can increase and decrease according to application scenario, the bandwidth of supporting also can be set according to different application scenarios, greatly increased flexibility and the extensibility of system, simpler, convenient and practical than the slot synchronization algorithm of resolving based on signaling.

S122, employing software radio digital quadrature demodulation technology, to described baseband signal I ₀and Q ₀carry out complex demodulation, obtain real number baseband signal;

The lower baseband signal I of speed that step S121 is obtained ₀and Q ₀carry out complex demodulation, obtain real number baseband signal S ₀; Described complex demodulation adopts SDR digital quadrature demodulation technology, and its principle is as follows:

For modulated signal through the logical ADC(Analog Digital Conversion analog-to-digital conversion of midband) after sampling, its mathematic(al) representation can be expressed as

s(n)＝a(n)cos(ω _cn+ψ(n))

=I _bcos (ω _cn)-Q _bsin (ω _cn) (formula 1)

S in formula 1 (n) is the digital medium-frequency signal after ADC sampling, in the same way component I _b, quadrature component Q _bthe baseband signal of resolving for needs.

According to carrier information to signal I _band Q _bextract with filtering and process and obtain baseband signal I ₀and Q ₀, and I ₀and Q ₀it is exactly the baseband signal on current channel number.

According to complex orthogonal signal I ₀and Q ₀can parse modulation signal, for the broadcast channel BCH employing of GSM is Gaussian minimum frequency-shift GMSK(Gaussian Minimum Shift Keying Gaussian minimum frequency-shift) modulation, that phase place is carried out to integration, in order to obtain raw information, need to carry out differential, ψ (n) is carried out to differential,

${\mathrm{<figure-callout\; id="0"\; label="S"\; filenames="HDA00002024935200021.png,HDA00002024935200043.png"\; state="\{\{state\}\}">S</figure-callout>}}_0=\mathrm{\&psi;}{\left(n\right)}^{\&prime;}=\mathrm{\&psi;}\left(n\right)-\mathrm{\&psi;}(n-1)=\arctan \left(\frac{Q_0\left(n\right)}{I_0\left(n\right)}\right)-\arctan \left(\frac{Q_0(n-1)}{I_0(n-1)}\right)$ (formula 2)

S in formula 2 ₀for unmodulated symbol signal, described I ₀and Q (n) ₀(n) be current sampling point, I ₀and Q (n-1) ₀(n-1) be a upper sampled point.

Now it is carried out to mathematic(al) manipulation,

according to mathematical formulae derivative, launch, so formula (2) is just had:

${\mathrm{<figure-callout\; id="0"\; label="S"\; filenames="HDA00002024935200021.png,HDA00002024935200043.png"\; state="\{\{state\}\}">S</figure-callout>}}_0=\mathrm{\&psi;}{\left(n\right)}^{\&prime;}=\frac{I_0\left(n\right){Q^{\&prime;}}_0\left(n\right)-{I^{\&prime;}}_0\left(n\right)Q_0\left(n\right)}{{I^2}_0\left(n\right)+{{\mathrm{<figure-callout\; id="0"\; label="Q"\; filenames="HDA00002024935200021.png,HDA00002024935200043.png"\; state="\{\{state\}\}">Q</figure-callout>}}_0}^2\left(n\right)}$ (formula 3)

The derivative of discrete series is exactly difference, and for the GSM signal of the GMSK modulation of single carrier, signal is permanent envelope, and its amplitude is constant, i.e. I ² ₀(n)+Q ₀ ²(n) be constant.If I ² ₀(n)+Q ₀ ²(n)=1, so have:

S ₀=ψ (n) '=X _i(n-1) X _q(n)-X _i(n) X _q(n-1) (formula 4)

By the mathematic(al) manipulation of formula 1, formula 2, formula 3, show that formula 4 is a real sequence, i.e. real number baseband signal S ₀.Owing to adopting above-mentioned SDR digital quadrature demodulation technology, having solved RF(Radio Frequency) frequency error that causes of down-conversion and Digital Down Convert causes that correlation is poor, the problem of false synchronization.Adopt real number relevant simultaneously, greatly reduced the storage of local sequence, saved the hardware resource of device.

The correlated results of SDR digital quadrature demodulation as shown in Figure 4, due to process sampling rate conversion, the S in the present embodiment ₀data transfer rate be 4 times of GSM spreading rate, in actual application, be not limited only to 4 times.

For step S13, as shown in Figure 5, particularly, can comprise the steps:

S131, the training sequence of Synchronization Burst sequence in GSM frame format in gsm mobile communication system is carried out to interpolation produce local sequence;

S132, described local sequence and described real number base band data are carried out relevantly cumulative drawing correlation, more described correlation is carried out to delivery;

Can be according to the training sequence S of Synchronization Burst sequence in GSM frame format in gsm mobile communication system _tinterpolation produces local sequence S _l; Owing to adopting SDR quadrature demodulation technology, local sequence S _lneed not pass through molding filtration, 4 times of Direct interpolations are correlated with;

Because the autocorrelation of the Synchronization Burst sequence of gsm mobile communication system is very strong, by local sequence S _lwith real number base band data S ₀according to formula 5, be correlated with cumulative, draw correlation R _x, then to R _xdelivery obtains R ₀.

$R_x=\underset{k=-\&infin;}{\overset{\&infin;}{\mathrm{\&Sigma;}}}{S}_L\left(n\right)*S_0(n-k)$ (formula 5)

For S14, as shown in Figure 6, particularly, can comprise the steps:

S141, according to described baseband signal I ₀and Q ₀calculate the signal power of current channel number, according to the size adaptation of described signal power, set threshold value;

S142, described correlation and described threshold value are compared; If described correlation is greater than described threshold value, adjudicating current channel is GSM broadcast channel BCH, and adjudicate current burst is Synchronization Burst sequence simultaneously;

S143, when this secondary burst of judgement is while being described Synchronization Burst sequence, utilize the position of described Synchronization Burst sequence in GSM frame structure to described baseband signal I ₀and Q ₀carry out time delay, output time solt lock-out pulse;

Can be according to baseband signal I ₀and Q ₀calculate the signal power P of current channel number ₀, according to P ₀size adaptation set threshold value G ₀; Threshold value G ₀be stored in a thresholding look-up table P ₀as the input of look-up table, according to P ₀size energy adaptive setting threshold value G ₀;

By described real number baseband signal R ₀with G ₀compare; If R ₀be greater than G ₀adjudicating current channel is GSM broadcast channel BCH, and adjudicate current burst is Synchronization Burst sequence simultaneously;

When this secondary burst of judgement is Synchronization Burst sequence, utilize the position of Synchronization Burst sequence in GSM frame structure to described baseband signal I ₀and Q ₀carry out time delay, output time solt lock-out pulse.

According to the slot synchronization pulse of above-mentioned slotted synchronous method output, for timeslot shutdown provides accurate synchronizing information, can be according to the time slot power of slot synchronization pulse detection GSM base station system, thereby judge whether this time slot has CU, for no user timeslot shutdown power amplifier unit provides key parameter, the consumption of therefore greatly having saved power amplifier, has reduced the power consumption of transmitter unit, reaches the object of green energy resource.Power by 6 pairs of each time slots of GSM signal of formula carries out accurate Calculation, realizes and accurately detects time slot power P _t:

$P_T=\frac{\underset{i=0}{\overset{M}{\mathrm{\&Sigma;}}}({I^2}_0\left(i\right)+{{\mathrm{<figure-callout\; id="0"\; label="Q"\; filenames="HDA00002024935200021.png,HDA00002024935200043.png"\; state="\{\{state\}\}">Q</figure-callout>}}_0}^2\left(i\right))}{M}$ (formula 6)

M in formula 6 counts for calculating signal power point.

Accordingly, below in conjunction with the drawings and specific embodiments, the technical scheme of multicarrier gsm system slot synchronization system of the present invention is described in detail.

Embodiment 2:

As shown in Figure 7, be the structural representation of the slot synchronization system of multicarrier gsm system of the present invention, comprising:

Searching carrier module 21, baseband processing module 22, cross-correlation module 23, slot synchronization module 24;

Described searching carrier module 21 is carried out searching carrier for the GSM base station signal to multicarrier, obtains carrier information;

Described baseband processing module 22, for according to described carrier information, adopts software and radio technique to carry out Base-Band Processing to each carrier wave;

Described cross-correlation module 23 is for carrying out cross-correlation by the baseband signal of described each carrier wave and local sequence;

Described slot synchronization module 24 judges synchronizing channel and the Synchronization Burst sequence of broadcast channel for the correlation peak obtaining according to described cross-correlation, utilize the position output time solt lock-out pulse of Synchronization Burst sequence in GSM frame structure.

Set forth a preferred embodiment of the slot synchronization system of multicarrier gsm system of the present invention below.

As shown in Fig. 8 ~ 11, it is respectively the structured flowchart of searching carrier module 21, baseband processing module 22, cross-correlation module 23 and slot synchronization module 24.

Searching carrier module 21 comprises sampling unit 211, zero intermediate frequency processing unit 212, search unit 213;

Described sampling unit 211, for intermediate-freuqncy signal is carried out to IF bandpass sampling, obtains digital intermediate frequency real signal; Can adopt Nyquist bandpass sample theory to carry out IF bandpass sampling to intermediate-freuqncy signal, obtain digital intermediate frequency real signal S _b;

Described zero intermediate frequency processing unit 212, for described digital intermediate frequency real signal is carried out to zero intermediate frequency processing, obtains zero intermediate frequency base band in-phase component I _bwith quadrature component Q _b;

To described S _bsignal carries out zero intermediate frequency processing, obtains zero intermediate frequency base band in-phase component I _bwith quadrature component Q _b; Described zero intermediate frequency processing unit 212 also comprises that first order numeral NCO processes subelement 2121 and low-pass filtering treatment subelement 2122; Described S _bsignal is processed subelement 2121 and low-pass filtering treatment subelement 2122 by first order numeral NCO successively; Described low-pass filtering treatment subelement 2122 can be processed for FIR filtering, IIR filtering or other forms of filtering;

Described search unit 213 is for to described zero intermediate frequency base band in-phase component I _bwith quadrature component Q _bcarry out searching carrier, obtain carrier information;

Wherein, searching carrier specifically can, with reference to the correlation technique that GSM carrier information can be provided, not repeat them here.

Described baseband processing module 22 comprises: Digital Down Convert processing unit 221 and demodulating unit 222;

Described Digital Down Convert processing unit 221 for according to described carrier information on current channel number to described zero intermediate frequency base band in-phase component I _bwith quadrature component Q _bafter carrying out single pass Digital Down Convert (being DDC) and processing, then carry out sampling rate conversion and obtain baseband signal I ₀and Q ₀;

Described Digital Down Convert processing unit 221 comprises that second level numeral NCO processes subelement 2211, filtering extraction is processed subelement 2212, shaping filter processing subelement 2213, carries out sampling rate conversion and obtains the baseband signal I that speed is lower ₀and Q ₀.Owing to having reduced processing speed, for programmable logic device has alleviated burden, be conducive to programmable logic device simultaneously and carry out time division multiplexing, greatly saved the hardware resource of device.The present invention can apply as programmable logic devices such as FPGA, CPLD, DSP, is conducive to digit chip and realizes.

Zero intermediate frequency baseband signal I _band Q _bby second level numeral NCO, process subelement 2211, filtering extraction processing subelement 2212, shaping filter processing subelement 2213 successively; Described filtering extraction processing subelement 2212 can extract for CIC, HB half band extracts, FIR extracts or the processing of other forms of filtering extraction; Described shaping filter is treated to FIR filtering, IIR filtering or other forms of filtering and processes.Owing to adopting the signal processing technology of above-mentioned many speed, relevant parameter can reset according to software, therefore the carrier number of supporting can increase and decrease according to application scenario, the bandwidth of supporting also can be set according to different application scenarios, greatly increased flexibility and the extensibility of system, simpler, convenient and practical than the slot synchronization algorithm of resolving based on signaling.

Described demodulating unit 222 is for adopting software radio digital quadrature demodulation technology to described baseband signal I ₀and Q ₀carry out complex demodulation, obtain real number baseband signal S ₀.Owing to adopting above-mentioned SDR digital quadrature demodulation technology, having solved RF(Radio Frequency) frequency error that causes of down-conversion and Digital Down Convert causes that correlation is poor, the problem of false synchronization.Adopt real number relevant simultaneously, greatly reduced the storage of local sequence, saved the hardware resource of device.

Described cross-correlation module 23 comprises interpolation unit 231 and relevant cumulative unit 232;

Described interpolation unit 231 is for the training sequence S to synchronization burst SB in gsm mobile communication system GSM frame format _tcarry out interpolation and produce local sequence S _l;

Described relevant cumulative unit 232 is for by described local sequence S _lwith real number base band data S ₀be correlated with cumulative, draw correlation R _x, then to R _xresult delivery obtains correlation R ₀.

Described slot synchronization module 24 comprises setup unit 241, decision unit 242, output unit 243;

Described setup unit 241 is for according to described baseband signal I ₀and Q ₀calculate the signal power P of current channel number ₀, according to P ₀size adaptation set the threshold value G of correlator ₀;

Described decision unit 242 is for exporting R by described relevant accumulation result ₀with described G ₀compare; If R ₀be greater than G ₀adjudicating current channel is GSM broadcast channel BCH, and adjudicate current burst is Synchronization Burst sequence simultaneously;

Described output unit 243, for when this secondary burst of judgement is described Synchronization Burst sequence, utilizes the position of described Synchronization Burst sequence in GSM frame structure to baseband signal I ₀and Q ₀carry out time delay, output time solt lock-out pulse I ₀and Q ₀.

According to the slot synchronization pulse of above-mentioned slot synchronization system output, for timeslot shutdown provides accurate synchronizing information, can be according to the time slot power of slot synchronization pulse detection GSM base station system, thereby judge whether this time slot has CU, for no user timeslot shutdown power amplifier unit provides key parameter, the consumption of therefore greatly having saved power amplifier, has reduced the power consumption of transmitter unit, reaches the object of green energy resource.

The present invention is lacking under the prerequisite of base station signaling, by carrier track algorithm, from motion tracking GSM carrier information, according to carrier information, locks broadcast channel BCH.Adopt SDR digital quadrature demodulation technology algorithm, solved the problem of bringing due to the frequency deviation of RF down-conversion and Digital Down Convert, adopt real number relevant simultaneously, reduced Digital Signal Processing resource; The more important thing is by adopting SDR(Software Defined Radio software radio) signal processing technology of many speed, the carrier number of supporting can increase and decrease according to application scenario, the bandwidth of supporting also can be set according to different application scenarios, flexibility and the extensibility of system have greatly been increased, realized multicarrier GSM slot synchronization function, flexibility and the extensibility of system have been improved, can adapt to different base station occasions, realize adaptive slot synchronization, simpler, convenient and practical than the slot synchronization algorithm of resolving based on signaling.

The above embodiment has only expressed several execution mode of the present invention, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to the scope of the claims of the present invention.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection range of patent of the present invention should be as the criterion with claims.

Claims (10)

1. the slotted synchronous method of multicarrier gsm system, is characterized in that, comprises the steps:

GSM base station signal to multicarrier carries out searching carrier, obtains carrier information;

According to described carrier information, adopt software and radio technique to carry out Base-Band Processing to each carrier wave;

The baseband signal of described each carrier wave and local sequence are carried out to cross-correlation;

Synchronizing channel and Synchronization Burst sequence in the correlation peak judgement broadcast channel obtaining according to described cross-correlation, utilize the position output time solt lock-out pulse of described Synchronization Burst sequence in GSM frame structure.

2. the slotted synchronous method of multicarrier gsm system according to claim 1, is characterized in that, the GSM base station signal of described multicarrier carries out searching carrier, and the step of obtaining carrier information specifically comprises:

Intermediate-freuqncy signal is carried out to IF bandpass sampling, obtain digital intermediate frequency real signal;

Described digital intermediate frequency real signal is carried out to zero intermediate frequency processing, obtain zero intermediate frequency base band in-phase component I _bwith quadrature component Q _b;

To described zero intermediate frequency base band in-phase component I _bwith quadrature component Q _bcarry out searching carrier, obtain carrier information.

3. the slotted synchronous method of multicarrier gsm system according to claim 2, is characterized in that, described according to described carrier information, and the step that adopts software and radio technique to carry out Base-Band Processing to each carrier wave specifically comprises:

According to described carrier information on current channel number to described zero intermediate frequency base band in-phase component I _bwith quadrature component Q _bcarry out after single pass Digital Down Convert processing, then carry out sampling rate conversion and obtain baseband signal I ₀and Q ₀;

Adopt software radio digital quadrature demodulation technology, to described baseband signal I ₀and Q ₀carry out complex demodulation, obtain real number baseband signal.

4. the slotted synchronous method of multicarrier gsm system according to claim 3, is characterized in that, the described step that the baseband signal of described each carrier wave and local sequence are carried out to cross-correlation specifically comprises:

The training sequence of Synchronization Burst sequence in GSM frame format in gsm mobile communication system is carried out to interpolation and produce local sequence;

Described local sequence and described real number base band data are carried out to relevant adding up and draw correlation, more described correlation is carried out to delivery.

5. the slotted synchronous method of multicarrier gsm system according to claim 4, it is characterized in that, synchronizing channel and Synchronization Burst sequence in the described correlation peak judgement broadcast channel obtaining according to described cross-correlation, utilize the step of the position output time solt lock-out pulse of Synchronization Burst sequence in GSM frame structure specifically to comprise:

According to described baseband signal I ₀and Q ₀calculate the signal power of current channel number, according to the size adaptation of described signal power, set threshold value;

Described correlation and described threshold value are compared; If described correlation is greater than described threshold value, adjudicating current channel is GSM broadcast channel BCH, and adjudicate current burst is Synchronization Burst sequence simultaneously;

When this secondary burst of judgement is described Synchronization Burst sequence, utilize the position of described Synchronization Burst sequence in GSM frame structure to described baseband signal I ₀and Q ₀carry out time delay, output time solt lock-out pulse.

6. the slot synchronization system of multicarrier gsm system, is characterized in that, comprising: searching carrier module, baseband processing module, cross-correlation module, slot synchronization module;

Described searching carrier module, for the GSM base station signal of multicarrier is carried out to searching carrier, is obtained carrier information;

Described baseband processing module, for according to described carrier information, adopts software and radio technique to carry out Base-Band Processing to each carrier wave;

Described cross-correlation module is for carrying out cross-correlation by the baseband signal of described each carrier wave and local sequence;

Described slot synchronization module judges synchronizing channel and the Synchronization Burst sequence of broadcast channel for the correlation peak obtaining according to described cross-correlation, utilize the position output time solt lock-out pulse of Synchronization Burst sequence in GSM frame structure.

7. the slot synchronization system of multicarrier gsm system according to claim 6, is characterized in that, described searching carrier module comprises sampling unit, zero intermediate frequency processing unit, search unit;

Described sampling unit, for intermediate-freuqncy signal is carried out to IF bandpass sampling, obtains digital intermediate frequency real signal;

Described zero intermediate frequency processing unit, for described digital intermediate frequency real signal is carried out to zero intermediate frequency processing, obtains zero intermediate frequency base band in-phase component I _bwith quadrature component Q _b;

Described search unit is used for described zero intermediate frequency base band in-phase component I _bwith quadrature component Q _bcarry out searching carrier, obtain carrier information.

8. the slot synchronization system of multicarrier gsm system according to claim 7, is characterized in that, described baseband processing module comprises: Digital Down Convert processing unit and demodulating unit;

Described Digital Down Convert processing unit for according to described carrier information on current channel number to described zero intermediate frequency base band in-phase component I _bwith quadrature component Q _bcarry out after single pass Digital Down Convert processing, then carry out sampling rate conversion and obtain baseband signal I ₀and Q ₀;

Described demodulating unit is used for adopting software radio digital quadrature demodulation technology to described baseband signal I ₀and Q ₀carry out complex demodulation, obtain real number baseband signal.

9. the slot synchronization system of multicarrier gsm system according to claim 8, is characterized in that, described cross-correlation module comprises interpolation unit and relevant cumulative unit;

Described interpolation unit produces local sequence for the training sequence of Synchronization Burst sequence in gsm mobile communication system GSM frame format is carried out to interpolation;

Described relevant cumulative unit carries out relevant adding up by described local sequence and real number base band data and draws correlation, more described correlation is carried out to delivery.

10. the slot synchronization system of multicarrier gsm system according to claim 9, is characterized in that, described slot synchronization module comprises setup unit, decision unit, output unit;

Described setup unit is used for according to described baseband signal I ₀and Q ₀calculate the signal power of current channel number, according to the size adaptation of described signal power, set threshold value;

Described decision unit is for comparing described threshold value; If described correlation is greater than described threshold value, adjudicating current channel is GSM broadcast channel BCH, and adjudicate current burst is Synchronization Burst sequence simultaneously;

Described output unit, for when this secondary burst of judgement is described Synchronization Burst sequence, utilizes the position of described Synchronization Burst sequence in GSM frame structure to described baseband signal I ₀and Q ₀carry out time delay, output time solt lock-out pulse.

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