CN100438385C - Baseband receiving synchronous acquiring method and apparatus for CDMA system - Google Patents
Baseband receiving synchronous acquiring method and apparatus for CDMA system Download PDFInfo
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Abstract
The present invention discloses a synchronous acquirement method for baseband reception of a CDMA system. The method comprises the steps: receiving an RF signal and converting the RF signal into a baseband signal; processing the baseband signal to acquire an I-path orthogonal data sequence and a Q-path orthogonal data sequence corresponding to each sampling phase; acquiring the energy sequences of the I-path orthogonal data and the Q-path orthogonal data corresponding to each sampling phase; comparing the acquired phase energy to find out the corresponding maximal energy value and the minimal energy value of the same sampling phase and acquire the distance sequence of each sampling phase, wherein the distance is the difference of the corresponding maximal energy value and the minimal energy value; judging multi-path positions according to the acquired distance sequence to acquire the phase information of each multi-path. The present invention can solve contradiction between false alarm probability and detection leakage probability, and acquire stabile rapid multi-path tracing judgment results.
Description
Technical field
The present invention relates to the synchronization gain method and apparatus that the base band of the receiving synchronous method and the device, particularly cdma system of wireless telecommunication system receives.
Background technology
Signal between wireless telecommunication system subscriber equipment and the base station is propagated by wireless channel.Because the relative wire message way of wireless channel, character is comparatively abominable, has many interference such as decline, multipath, so the wireless signal receiving handling method of wireless telecommunication system is a decisive factor that directly influences systematic function always.
CDMA (Code Division Multiple Access, code division multiple access) system has the above feature of wireless telecommunication system as a kind of wireless telecommunication system.And, owing to itself have the advantages that with same frequency a plurality of users transmit at the same time, so this system also has self-interference, it is the mutual interference of different user phase, multiple access disturbs (MAI, MultipleAccess Interference) characteristics, the reception of its wireless signal are difficulty more.But because this system has that power system capacity is big, the availability of frequency spectrum is high, to characteristics such as good inhibition of background noise and good confidentiality, it becomes one of mainstream technology of wireless telecommunications gradually.
In order to reach the good reception of cdma system wireless signal, thereby increase the capacity of system, adopting technology such as time diversity, antenna diversity traditionally.The employing of these technology has obtained good effect to a certain extent, but the development of technology and practical application are had higher requirement for the reception of system wireless signal.In recent years, the development of Multiuser Detection (MUD, MultiUser Detection) technology, adaptive equalization technique and smart antenna (SmartAntenna) technology may for further improving that cdma system provides for the receptivity of wireless signal.
The phenomenon that has the multipath transmission in mobile communication, promptly signal arrives receiver from the transmitter emission through too much transmission paths.Every there is different transmission delays in the footpath, different declines and different phase places, and its multipath reception signal mixes when arriving receiver can cause the multipath fading phenomenon.The situation of multipath is a time orientation vertically among the figure as shown in Figure 1, and each peak value 101-106 represents time and the intensity that multipath occurs.Wherein, the peak of each multipath (time among the figure relatively) is very easy identification.
In the cdma system of reality, because the combined influence of the factors such as non-synchronous fully and noise of the non-ideal characteristic of the length of sign indicating number, sign indicating number, system.The situation of real system multipath as shown in Figure 2.Be time orientation laterally among the figure, each desirable peak value 101-106 represents time and the intensity that multipath occurs.And the energy that obtains in the reality in time situation of change be shown in the pattern 20.Situation for 20, multipath peak then are difficult to differentiate.Particularly, for 104,106 two less peak values of energy, then can distinguish hardly.And, then rule out to possible errors and have multipath for the higher position of some noise energies.
Because cdma system belongs to the exigent system of signal correlation, so it requires very high to the synchronism between base station and the subscriber equipment (UE).When the frame head position of base station transmit signals frame head position and subscriber equipment (UE) received signal differs 1 chip when above, the just noise signal that subscriber equipment then can obtain, but not expectation information.General Rake (RAKE) the receiver technology that adopts is carried out time diversity and merging to the multipath interval greater than a chip in code division multiple access (CDMA) system, obtains better receptivity.
General existing C DMA system receiver structure as shown in Figure 3.Wireless signal obtains base band place signal through the processing of antenna 31, radio-frequency channel 32, shaping filter unit 33 and down-converter unit 34, input RAKE receiver 35; RAKE receiver 35 is the symbol level signal with base band signal process, exports to decoding unit 36; And decoding unit 36 the most at last the symbol level signal processing be Bit data with actual physics meaning, export to later cell processing.
For the system synchronization preparation method, General System adopts two-stage synchronous: Multipath searching and multipath tracking.The scope that Multipath searching can obtain multipath is big, but the retention time is long and time precision is relatively poor relatively; Multipath tracking handle rapidly and also time precision high, but its, scope was little action time.General System utilizes Multipath searching to obtain the rough position of multipath peak value, utilizes the precision of multipath tracking adjusting multipath phase place and overcomes possible the moving of multipath peak value in the Multipath searching cycle.We can say that Multipath searching is a kind of thick simultaneous techniques that obtains the multipath home position in big time range, and multipath tracking is the fine synchronization technology of accurately modulating the multipath phase place in little scope.
The general structure of Multipath searching unit as shown in Figure 4.Baseband signal is after despreading descrambling unit/unit group (41) is handled, and the power spectrum (the despreading descrambling output energy of corresponding different time position) that obtains delaying time outputs to each phase place smooth unit (42).Each phase place smooth unit (42) is finished the smoothing function of each corresponding phase, reaches the effect that suppresses noise, and it exports peak filter (43) to.Peak filter (43) detects the position and the corresponding energy of the peak value of input time delay power spectrum, exports threshold judgement unit/unit group (44) to.Threshold judgement unit/unit group (44) utilizes whether the corresponding peak value of some rule judgements is the multi-path location of signal, as judges that whether corresponding peak value is greater than predetermined power.If be multi-path location then export its phase information, possible threshold judgement unit/unit group also needs phase despreading descrambling unit/unit group (41) to transmit control signal.In the Multipath searching unit, the processing speed is-symbol level (perhaps slower speed step) of each phase place smooth unit (42), peak filter (43) and threshold judgement unit/unit group (44), the back-end processing part can be called; Corresponding despreading descrambling unit/unit group (41) processing speed is very fast, can be described as the front-end processing part.
The front-end processing part that despreading descrambling unit/unit group (41) constitutes generally has two kinds of architectures again according to structure: sliding correlation detector/correlator bank and matched filter.Its structure respectively as shown in Figure 5 and Figure 6.
Fig. 5 is the sliding correlation detector schematic diagram of the front-end processing part that constitutes of despreading descrambling unit/unit group (41), and it is made up of correlator (51), add up zero clearing unit (52) and local PN code generator (53).
Fig. 6 is the schematic diagram of the front-end processing matched filter partly of despreading descrambling unit/unit group (41) formation, and matched filter is the different taps that baseband signal is passed through time delay chain (61), carries out relevant treatment with the correlator bank that has scrambler (62); All results added devices (63) carry out after the addition, obtain required time-delay power spectrum.
The structures shape of the front-end processing part of different structure obtains the length of the time of power on a time location.
After the power spectrum that obtains delaying time, carry out back-end processing, comprise each phase place smooth unit (42), peak filter (43) and threshold judgement unit/unit group (44).
The main effect of each phase place smooth unit (42) is: suppress the influence of ubiquitous noise to multi-path judging, and the big noise of burst is had restriction.In the General System, this part adopts linear filter (FIR: finite impulse respective filter or IIR: infinitely impact respective filter).The most frequently used is the first order IIR filtering device, and its structure as shown in Figure 7.The output of this part by input and the product (finishing) of filter coefficient a and output with multiplier 71 through time-delay (finishing) and coefficient 1-a (finishing) with multiplier 72 by delay register 73 with (carrying out computing) by adder 74.The parameter of this part is filter coefficient a, so this part also becomes a filter.Coefficient a is bigger, system stability then, and false alarm probability is lower, but corresponding capture time for the multipath that occurs is also long; Coefficient a is less, system's sensitivity then, and corresponding capture time for the multipath that occurs is also short, but false alarm probability is also corresponding higher, occurs erroneous judgement easily.
Figure 8 shows that the structure of common peak filter, peak filter (43) mainly be do not search out with making any distinction between time-delay in the energy spectrum the position that has peak value and the energy of peak value.In the General System, this part is to utilize the both sides derived indice difference of peak to adjudicate, and its structure as shown in Figure 8.The time-delay power spectrum is through the phase place of parallel serial conversion unit (81) output energy and previous energy.Its output energy is through logical decision (forming by delay unit (821 and 822), Difference Calculation unit (831 and 832), symbol comparing unit (841 and 842) and with door (85)), and whether export is the judgement of peak value.When phase place, energy output unit (86) are set up in judgement, peak phase and peak energy that output is corresponding.
Whether the peak value of threshold judgement unit/unit group (44) conclusive judgement search is multi-path location.The simplest a kind of threshold judgement unit as shown in Figure 9, its function is for thinking then that this peak value is a multi-path location when peak energy during greater than some prior threshold value T.The threshold judgement unit is made up of threshold judgement (91) and phase place, (92) two parts of energy output unit.The size of the threshold value T of regulation is determining the reliability of judgement in advance.T is bigger, and then false alarm probability is less, but false dismissal probability is also bigger; T is bigger, and then false dismissal probability is less, but false alarm probability is also bigger.
Because Multipath searching is the synchronous basis of dedicated channel demodulation, its performance quality directly influences the overall performance of receiver system.False-alarm is merged for the multipath of RAKE receiver and be brought unnecessary noise, and the resource of waste despreading descrambling unit; Omission then can reduce the effect of system's diversity gain, and systematic function degenerates.
System is in Filtering Processing at present, and what generally adopt is the first order IIR filtering device, and its structure as shown in Figure 7.The parameter of this part is filter coefficient a, so this part also becomes a filter.Coefficient a is bigger, system stability then, and false alarm probability is lower, but corresponding capture time for the multipath that occurs is also long; Coefficient a is less, system's sensitivity then, and corresponding capture time for the multipath that occurs is also short, but false alarm probability is also corresponding higher, occurs erroneous judgement easily.
In the actual environment, the appearance of multipath and the multiple situation of possibility that disappears.A kind of situation is so-called static channel, and promptly fixedly there is multipath in this phase place, just owing to fade-out, and the appearance and the disappearance of the multipath multipath that causes.For this situation, adopt coefficient a more suitable.Also having a kind of typical case is the so-called life channel that goes out, and the phase place of promptly originally not depositing/existing in multipath has occurred stronger multipath/multipath suddenly and disappeared.This phenomenon generally because the user moves away/enters the shadow region and causes, adopts less being beneficial to of coefficient a to catch.Owing to can't determine the multipath appearance/nonvolatile mode on each phase place in the General System, so generally adopt a kind of a coefficient of compromise.All can't reach best search effect for different multipath appearance/nonvolatile mode like this.
Summary of the invention
The objective of the invention is to overcome the synchronization gain method that the characteristics of prior art provide a kind of base band of cdma system to receive, may further comprise the steps:
Receive the RF signal and be converted to baseband signal;
Handle described baseband signal, with I, the Q two-way orthogonal data sequence that obtains each sampling phase correspondence;
Obtain the I of described each sampling phase correspondence, the energy sequence of Q two-way orthogonal data;
The energy of each phase place of more described acquisition, find out the energy value and the minimum energy value of the maximum of corresponding same sampling phase correspondence, and obtaining each sampling phase signal set distance sequence, described distance is the poor of the energy value of maximum of described correspondence and minimum energy value;
According to the distance sequence of described acquisition, carry out the multi-path location judgement, obtain the phase information of each multipath.
Alternatively, method comprises that also step exports the phase information of each multipath of described acquisition.
Preferably, also comprise step: the described distance sequence of filtering, to eliminate the noise of described distance sequence.
Alternatively, the described distance sequence of described filtering comprises: utilize infinite impulse response filter IIR or the described distance sequence of finite impulse response filtering FIR filtering.
Preferably, the step of the described baseband signal of described processing also comprises: relevant add up described I, Q data;
The energy sequence of the I of described each sampling phase correspondence of described acquisition, Q two-way orthogonal data also comprises described relevant I, the Q data that add up, and carries out the square operation of I road and Q road signal, and summation obtains the energy of corresponding each sampling phase.
Alternatively, comprise that also step carries out the irrelevant of rear end to the energy of each sampling phase of described acquisition and add up, obtain each sampling phase energy accumulation result;
Wherein, the described energy value of finding out maximum energy value and minimum comprises step: add up each sampling phase energy accumulation of described acquisition result, obtain maximum I
MaxWith minimum value L
Min, and calculate this sampling phase signal set distance D=L
Max-L
Min
Preferably, described step of carrying out the multi-path location judgement comprises:
Compare sampling phase signal set distance and predetermined threshold;
If described sampling phase signal set distance judges that greater than described predetermined threshold there is multipath in phase place; Otherwise there is not multipath in this phase place; Described sampling phase signal set is added up each sampling phase energy accumulation of described acquisition result apart from being, obtains maximum Lmax and minimum value Lmin, and calculates this sampling phase signal set distance D=Lmax-Lmin.
The present invention also provides the device of the synchronization gain that a kind of base band of cdma system receives, and comprising:
Baseband signal despreading descrambling unit is used for baseband signal despreading descrambling, with I, the Q two-way restituted signal that obtains each phase place;
Energy calculation unit is coupled to described baseband signal despreading descrambling unit, is used to obtain the I of each phase place, the energy of Q signal;
The signal set metrics calculation unit, be used for result according to described energy calculation unit, the energy of each phase place by more described acquisition, find out the energy value and the minimum energy value of the maximum of corresponding same sampling phase correspondence, the difference that obtains described maximum energy value and minimum energy value obtains the distance of corresponding phase signal set as the distance of corresponding phase signal set; With
Judging unit is used for the distance according to described corresponding phase signal set, judges the position of multipath.
Alternatively, described energy calculation unit also comprises:
The relevant energy calculation unit that adds up is calculated the energy of corresponding each phase place of signal of the described despreading descrambling unit output of each phase place;
The irrelevant unit that adds up, the I of irrelevant described each phase place that adds up, the energy of Q.
Preferably, also comprise: signal set is used for the distance of the corresponding phase signal set of the described signal set metrics calculation unit acquisition of filtering apart from low-pass filter unit.
Above-mentioned signal set is iir filter or FIR filter apart from low-pass filter unit.
Alternatively, also comprise peak filter, be used for the signal of the described low-pass filter unit output of filtering, to export to described judging unit.
Preferably, described signal set metrics calculation unit comprises comparing unit, memory cell and computing unit;
Wherein, described comparing unit successively comparator input signal with at the previous maximum or the minimum value signal of described cell stores, and the signal storage that satisfies condition gone into described memory cell, to obtain maximum or the minimum value in the input signal sequence; Described computing unit is by calculating the poor of maximum in the described acquisition input signal sequence and minimum value, the distance value of picked up signal set; Describedly the signal storage that satisfies condition is gone into described memory cell be, the smaller in the greater in storage input signal and the preceding maximum of having stored and input signal and the preceding minimum value of having stored.
Alternatively, described comparing unit comprises the maximum comparator, the maximum multi-channel gating device, wherein, and described maximum comparator comparator input signal and the preceding maximum of having stored, the maximum multi-channel gating device is exported maximum according to result relatively;
Described comparing unit comprises the minimum value comparator, the minimum value multi-channel gating device, and described minimum value comparator comparator input signal and the preceding minimum value of having stored, the minimum value multi-channel gating device is exported minimum value according to result relatively.
The present invention can obtain to make the Multipath searching cycle that is used for a user shorten to giving birth to the rapidity of the channel multi-path searching that goes out under the prerequisite that searches out with the multipath of the same intensity of conventional method.For a user, this rapidity can reduce the cycle of Multipath searching, increases the adaptive capacity to emergent multipath.For a plurality of users, thisly exercise to such an extent that a Multipath searching unit becomes possibility to a plurality of user's time division multiplexinges fast, can reduce the overall cost of receiver system.
Description of drawings
Fig. 1 describes the schematic diagram that each peak value of multipath fading phenomenon is represented the perfect condition of multipath;
Fig. 2 is a schematic diagram of describing the multipath situation of real system;
Fig. 3 is a schematic block diagram of describing existing C DMA system receiver;
Fig. 4 is the theory diagram of existing Multipath searching unit;
Fig. 5 is the schematic diagram of 41 1 kinds of embodiment sliding correlation detectors of front-end processing part among Fig. 4;
Fig. 6 is the schematic diagram of the front-end processing matched filter partly of despreading descrambling unit among Fig. 4/unit group (41) formation;
Figure 7 shows that the structure chart of common first order IIR filtering device;
Figure 8 shows that common peak filter structure chart;
Figure 9 shows that the structure chart of common threshold judgement unit;
Figure 10 shows that the synchronization keeping method flow chart of the base band reception of the cdma system in the embodiments of the invention;
Figure 11 shows that the theory diagram of the synchronous holding device that the base band of the cdma system in the embodiments of the invention receives;
Figure 12 shows that the concrete structure figure of the signal set metrics calculation unit 112 among Figure 11;
Figure 13 shows the simulation result about SIR and Multipath searching of the contrast of the present invention and prior art.
Embodiment
Prior art and the present invention for convenience of description used many abbreviations in description, table 1 has provided the definition of these abbreviations.
Table 1
| Abbreviation | English full name | Chinese |
| WCDMA | Wideband Code Division Multiple Access | Wideband Code Division Multiple Access (WCDMA) inserts |
| 3GPP | 3th Generation Partnership Project | Third generation partnership projects |
| STTD | Space Time Block Coding Based Transmit Diversity | The space-time block coding transmit diversity |
| TSTD | Time Switched Transmit Diversity | The time switched transmit diversity |
| CPICH | Common Pilot Channel | Common pilot channel |
| PCCPCH | Primary Common Control Physical Channel | Primary Common Control Physical Channel |
| SCH | Synchronisation Channel | Synchronizing channel |
| PICH | Page Indication Channel | Page Indication Channel |
| DPCH | Dadicated Physical Channel | DPCH |
| PSCH | Primary Synchronisation Channel | Primary synchronization channel |
| SSCH | Second Synchronisation Channel | Secondary synchronization channel |
| CL | Closed Loop | Closed loop |
| OCNS | Orthogonal Channel Noise Simulator | Orthogonal channel disturbs |
| FBI | FeedBack Information | Feedback information |
| FSM | Feedback Signaling Message | Feedback signaling message |
| SIR | Signal Interference Rate | Signal-to-jamming ratio |
| BER | Bit Error Ratio | Bit error rate |
| BLER | Block Error Ratio | Block Error Rate |
For those skilled in the art better understands the present invention, the specific embodiment of the present invention is described below in conjunction with accompanying drawing.
With reference to accompanying drawing 10, Figure 10 shows that the synchronization keeping method flow chart of the base band reception of the cdma system in the embodiments of the invention.
In step 1: baseband signal is carried out I, the Q two paths of data that front-end processing obtains each sampling phase correspondence; The method that obtains these data is as follows,
In system, the baseband signal of establishing the input that the frame head with respect to a frame begins is { (r
I1, r
Q1), (r
I2, r
Q2) ..., r wherein
IjAnd r
QjBe respectively j the data on the I road and the Q road of input signal, the sampling rate of system is 2
KSpreading rate.Then data are after the processing of corresponding the 1st sampling phase:
With
Wherein, C
IiWith C
QiBe respectively the I road of sign indicating number and i the data on Q road, M is the number of the sign indicating number of a symbol correspondence of signal.
In step 2: the filtered data of each sampling phase correspondence that the first step is obtained are carried out the relevant of rear end and are added up, and obtain each sampling phase signal accumulation result; In fact can select to add up or do not add up, in an embodiment of the present invention, adopt relevant adding up.
It is operating as: to the S that obtains
IljAnd S
QljCarry out following operation:
With
Wherein, N
t(〉=0) is the coherent accumulation number of setting in advance (being determined according to the performance requirement for system by system emulation).
Step 3: to each sampling phase signal accumulation result that second step obtained, carry out the square operation of I road and Q road signal, two result's summations are obtained the energy of corresponding each sampling phase;
For the t that obtains
IljAnd t
QljCarry out following operation:
Step 4: the energy of each sampling phase that obtains for the 4th step carries out irrelevant the adding up (can select to add up or do not add up) of rear end, obtains each sampling phase energy accumulation result;
For the Q that obtains
LjCarry out following operation:
Wherein, N
2(〉=0) is the noncoherent accumulation number of setting in advance (being determined according to the performance requirement for system by system emulation).
Can obtain 1 each sampling phase energy accumulation result according to above step.Repeat aforesaid operations N time, obtain N output signal.
Step 5: the energy result for step 4, ask for energy difference;
For the sampling phase l that obtains (l=0,1,2 ..., M
s, M
sFor the number of the sampled point of needs search according to requirement to systematic function, obtain by system requirements) N export P
Lj(j=1,2 ... N) carry out following operation:
L
max，l＝max{P
l1，P
l2，...，P
lN}
With
L
min，j＝min{P
l1，P
l2，...，P
lN}
And
D
l＝L
max，l-L
min，l
Step 7: for each sampling phase signal set distance results that obtains in the step 6, carry out first order IIR filtering respectively, the α (requirement according to systematic function is obtained by emulation) that filter coefficient is determined obtains the filtered signal set distance of each sampling phase correspondence;
For the sampling phase l that obtains (l=0,1,2 ..., M
s, M
sFor the number of the sampled point of needs search according to requirement to systematic function, obtain by system requirements) the output distance D
1Carry out following operation:
D′
1 ∮(K)＝αD′
1 ∮(k-1)+(1-α)D
1
Wherein, D '
1Value for the filter storage.
Step 8: the filtered signal set distance of each sampling phase correspondence that obtains for the 7th step, carry out the multi-path location judgement, obtain the phase information of each multipath.Wherein, the rule of the judgement of present embodiment is: if filtered signal set distance is then adjudicated this phase place and had multipath greater than definite threshold value (requirement according to systematic function is obtained by emulation); Otherwise adjudicate this phase place and do not have multipath.Though embodiment has adopted should rule, should be understood that and also may adopt the additive method judgement.
The judgement mode of this step is:
if(D′
1＞T)
{
There is multipath signal in 1 sampling point position;
}
else
{
There is not multipath signal in 1 sampling point position;
}
Wherein, T is a threshold value.
At last, in step 9, the phase information of each multipath that output obtains.
Figure 11 shows that the theory diagram of the synchronous holding device that the base band of the cdma system in the embodiments of the invention receives.This device comprises: apparatus of the present invention comprise successively: despreading descrambling unit 41, the relevant energy calculation unit 110 that adds up, relevant add up unit 111, signal set metrics calculation unit 112, each phase place IIR filter unit 113, peak filter 43, threshold judgement unit 44 constitutes.
Wherein, I, the Q two-way restituted signal function that is obtained each phase place by baseband signal finished in despreading descrambling unit 41, is input as the baseband signal of system, exports each phase signal to ground floor low-pass filter unit 120.The relevant energy calculation unit 110 that adds up is finished the energy computing function to corresponding each phase place of each phase place despreading descrambling unit 41 output signal, inputs to the relevant unit 111 that adds up.The irrelevant accumulation function of each phase place energy is finished in the relevant unit 111 that adds up, and is input as the output of the relevant energy calculation unit 110 that adds up, and exports signal set metrics calculation unit 112 to.Signal set metrics calculation unit 112 is finished the distance calculation function of corresponding phase signal set, is input as the irrelevant accumulated value of relevant unit 111 each the phase place energy that add up, each phase place IIR low-pass filter unit 113 of output valve.The signal set distance value that each phase place IIR low-pass filter unit 113 is finished corresponding phase carries out the IIR filter function.Be input as the distance (serial) of the corresponding phase signal set that signal set metrics calculation unit 112 obtains, export filtered time-delay power spectrum to peak filter 43.Peak filter 43 is finished the peak value decision function, imports each phase place second layer low-pass filter unit 42, can comprise the time-delay power spectrum behind the irrelevant unit filtering that adds up, and the phase place of output peak value and energy are to threshold judgement unit 44.Whether the threshold value threshold judgement timesharing position that threshold judgement unit 44 is finished according to peak energy and calculating is the function of multi-path location, the threshold value thresholding that is input as peak phase and energy and calculates, be output as the multipath phase place to the Multipath searching device, and control command is to front-end processing unit 41.
Figure 12 shows that the concrete structure figure of the signal set metrics calculation unit 112 among Figure 11.
Wherein, corresponding maximum obtains part, is made up of comparator 121, first multi-channel gating device 122 and a RAM123.Whether comparator 121 comparator input signal numerical value greater than the former maximum of having stored: if greater than output " 1 ", otherwise output " 0 "; First multi-channel gating device 122 is selected the numerical value of current maximum value signal according to the output of comparator 121: if be input as " 1 ", then select input signal numerical value as output; If be input as " 0 ", the former maximum of then selecting to have stored is as output; The one RAM123 is used to store the maximum of current input and the former maximum that output has been stored.
Corresponding minimum value obtains part, is made up of comparator 124, second multi-channel gating device 125 and the 2nd RAM126.Whether comparator 124 comparator input signal numerical value less than the former minimum value of having stored: if greater than output " 1 ", otherwise output " 0 "; Second multi-channel gating device 125 is selected the numerical value of current minimum value signal according to the output of comparator 124: if be input as " 1 ", then select input signal numerical value as output; If be input as " 0 ", the former minimum value of then selecting to have stored is as output; The 2nd RAM126 is used to store the minimum value of current input and the former minimum value that output has been stored.
The present invention has adopted the signal set distance detection method, can determine the multipath appearance/disappearance of each phase place quickly and efficiently, makes Multipath searching reach rapidity and stable unification.
The stability that the present invention obtains can guarantee the gain of RAKE receiver overall system.
The present invention can obtain to make the Multipath searching cycle that is used for a user shorten to giving birth to the rapidity of the channel multi-path searching that goes out under the prerequisite that searches out with the multipath of the same intensity of conventional method.For a user, this rapidity can will be lacked the cycle of Multipath searching, increases the adaptive capacity to emergent multipath.For a plurality of users, thisly exercise to such an extent that a Multipath searching unit becomes possibility to a plurality of user's time division multiplexinges fast, can reduce the overall cost of receiver system.
Figure 13 shows the simulation result about SIR and Multipath searching of the contrast of the present invention and prior art.This shows corresponding and conventional method (corresponding parameter is 1 among the figure), the inventive method is the gain that (choose and miss decision rate 10%) had 6dB in 11 o'clock in parameter.
The above, only be embodiments of the invention, wherein described apparatus and method all just are used as for example, and are non-so promptly limit to interest field of the present invention, the equivalence of all utilizations specification of the present invention and accompanying drawing content changes, and all is contained in the claim scope of the present invention.
Claims (14)
1, the synchronization gain method of a kind of base band of cdma system reception is characterized in that, may further comprise the steps:
Receive the RF signal and be converted to baseband signal;
Handle described baseband signal, with I, the Q two-way orthogonal data sequence that obtains each sampling phase correspondence;
Obtain the I of described each sampling phase correspondence, the energy sequence of Q two-way orthogonal data;
The energy of each phase place of more described acquisition, find out the energy value and the minimum energy value of the maximum of corresponding same sampling phase correspondence, and obtaining each sampling phase signal set distance sequence, described distance is the poor of the energy value of maximum of described correspondence and minimum energy value;
According to the distance sequence of described acquisition, carry out the multi-path location judgement, obtain the phase information of each multipath.
2. the synchronization gain method of the base band of cdma system as claimed in claim 1 reception is characterized in that, also comprises step: the phase information of exporting each multipath of described acquisition.
3. the synchronization gain method of the base band of cdma system as claimed in claim 1 reception is characterized in that, also comprises step: the described distance sequence of filtering, and to eliminate the noise of described distance sequence.
4. the synchronization gain method of the base band of cdma system as claimed in claim 3 reception is characterized in that the described distance sequence of described filtering comprises: utilize infinite impulse response filter IIR or the described distance sequence of finite impulse response filtering FIR filtering.
5. the synchronization gain method of the base band of cdma system as claimed in claim 1 reception is characterized in that,
The step of the described baseband signal of described processing also comprises: relevant add up described I, Q data;
The energy sequence of the I of described each sampling phase correspondence of described acquisition, Q two-way orthogonal data also comprises described relevant I, the Q data that add up, and carries out the square operation of I road and Q road signal, and summation obtains the energy of corresponding each sampling phase.
6. the synchronization gain method that receives of the base band of cdma system as claimed in claim 5 is characterized in that, comprises that also step carries out the irrelevant of rear end to the energy of each sampling phase of described acquisition and add up, and obtains each sampling phase energy accumulation result;
Wherein, the described energy value of finding out maximum energy value and minimum comprises step: add up each sampling phase energy accumulation of described acquisition result, obtain maximum L
MaxWith minimum value L
Min, and calculate this sampling phase signal set distance D=L
Max-L
Min
7. the synchronization gain method that receives as the base band of claim 1 or 6 described cdma systems is characterized in that, described step of carrying out the multi-path location judgement comprises:
Compare sampling phase signal set distance and predetermined threshold;
If described sampling phase signal set distance judges that greater than described predetermined threshold there is multipath in phase place; Otherwise there is not multipath in this phase place;
Described sampling phase signal set is added up each sampling phase energy accumulation of described acquisition result apart from being, obtains maximum Lmax and minimum value Lmin, and calculates this sampling phase signal set distance D=Lmax-Lmin.
8. the device of the synchronization gain that receives of the base band of a cdma system comprises:
Baseband signal despreading descrambling unit is used for baseband signal despreading descrambling, with I, the Q two-way restituted signal that obtains each phase place;
Energy calculation unit is coupled to described baseband signal despreading descrambling unit, is used to obtain the I of each phase place, the energy of Q signal;
The signal set metrics calculation unit, be used for result according to described energy calculation unit, the energy of each phase place by more described acquisition, find out the energy value and the minimum energy value of the maximum of corresponding same sampling phase correspondence, the difference that obtains described maximum energy value and minimum energy value obtains the distance of corresponding phase signal set as the distance of corresponding phase signal set; With
Judging unit is used for the distance according to described corresponding phase signal set, judges the position of multipath.
9. the synchronization gain device that receives of the base band of cdma system according to claim 8 is characterized in that described energy calculation unit also comprises:
The relevant energy calculation unit that adds up is calculated the energy of corresponding each phase place of signal of the described despreading descrambling unit output of each phase place;
The irrelevant unit that adds up, the I of irrelevant described each phase place that adds up, the energy of Q.
10. the synchronization gain device that receives of the base band of cdma system according to claim 8, it is characterized in that, also comprise: signal set is used for the distance of the corresponding phase signal set of the described signal set metrics calculation unit acquisition of filtering apart from low-pass filter unit.
11. the synchronization gain device that the base band of cdma system according to claim 10 receives is characterized in that described signal set is iir filter or FIR filter apart from low-pass filter unit.
12. the synchronization gain device that the base band of cdma system according to claim 10 receives is characterized in that, also comprises peak filter, is used for the signal of the described low-pass filter unit output of filtering, to export to described judging unit.
13. the synchronization gain device that the base band of cdma system according to claim 8 receives is characterized in that described signal set metrics calculation unit comprises comparing unit, memory cell and computing unit;
Wherein, described comparing unit successively comparator input signal with at the previous maximum or the minimum value signal of described cell stores, and the signal storage that satisfies condition gone into described memory cell, to obtain maximum or the minimum value in the input signal sequence; Described computing unit is by calculating the poor of maximum in the described acquisition input signal sequence and minimum value, the distance value of picked up signal set; Describedly the signal storage that satisfies condition is gone into described memory cell be, the smaller in the greater in storage input signal and the preceding maximum of having stored and input signal and the preceding minimum value of having stored.
14. the synchronization gain device that the base band of cdma system according to claim 13 receives is characterized in that,
Described comparing unit comprises the maximum comparator, the maximum multi-channel gating device, wherein, and described maximum comparator comparator input signal and the preceding maximum of having stored, the maximum multi-channel gating device is exported maximum according to result relatively;
Described comparing unit comprises the minimum value comparator, the minimum value multi-channel gating device, and described minimum value comparator comparator input signal and the preceding minimum value of having stored, the minimum value multi-channel gating device is exported minimum value according to result relatively.
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| CN101167287B (en) * | 2005-10-11 | 2011-05-18 | 中兴通讯股份有限公司 | A mixed-path processing method in CDMA system |
| CN101136687B (en) * | 2006-08-22 | 2011-05-11 | 中兴通讯股份有限公司 | Multi-path tracing method and apparatus used for WCDMA system digital baseband |
| CN102223173B (en) * | 2010-04-16 | 2014-03-12 | 中兴通讯股份有限公司 | Method and device for coarse synchronizing sub-frame |
| CN112953614B (en) * | 2021-03-10 | 2022-08-05 | 广东富宇鸿通讯有限公司 | Wireless signal enhancement method, device and storage medium |
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|---|---|---|---|---|
| CN1309843A (en) * | 1998-07-16 | 2001-08-22 | 艾利森电话股份有限公司 | Adaptive path selection threshold setting for DS-CDMA receivers |
| CN1315792A (en) * | 2000-03-30 | 2001-10-03 | 华为技术有限公司 | Multi-path search method and device of CDMA communication system |
| US20020075946A1 (en) * | 2000-12-19 | 2002-06-20 | Lg Electronics Inc | Method and apparatus for searching multipaths of mobile communication system |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1309843A (en) * | 1998-07-16 | 2001-08-22 | 艾利森电话股份有限公司 | Adaptive path selection threshold setting for DS-CDMA receivers |
| CN1315792A (en) * | 2000-03-30 | 2001-10-03 | 华为技术有限公司 | Multi-path search method and device of CDMA communication system |
| US20020075946A1 (en) * | 2000-12-19 | 2002-06-20 | Lg Electronics Inc | Method and apparatus for searching multipaths of mobile communication system |
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