CN101098186B - Method for determining random access preamble detection dynamic threshold - Google Patents
Method for determining random access preamble detection dynamic threshold Download PDFInfo
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- CN101098186B CN101098186B CN2006100904497A CN200610090449A CN101098186B CN 101098186 B CN101098186 B CN 101098186B CN 2006100904497 A CN2006100904497 A CN 2006100904497A CN 200610090449 A CN200610090449 A CN 200610090449A CN 101098186 B CN101098186 B CN 101098186B
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Abstract
The invention discloses a method for randomly accessing front check dynamic threshold value, comprising that descrambling input signal, descrambling frequency bias, and coherent non-coherent integration, obtaining the sign power time delay distribution of one front check mission at one access time space, finding the average noise horizontal evaluated value of the front check mission, using the evaluated value and the signal/noise ration set by superior, to interfere the integration length to dynamically real-time find the threshold value of single front check mission, finding the threshold values of all front check missions at the access time space, to select the maximum one as the threshold value of the front check. The invention via the noise level evaluation can dynamically real-time find front check threshold value, with simple, reasonable and effective threshold value setting, to avoid most false alarm, control the false alarm rate in allowed range, and confirm check efficiency.
Description
Technical field
The present invention relates to a kind of method of mobile communication, in particular, the method that a kind of WCDMA system random access channel preamble detects.
Background technology
In the WCDMA system; Travelling carriage communicates in order to want access network, sends a period of time preface information usually earlier, after the base station receives this preface information and confirms; Travelling carriage can be launched the access message of a period of time, has wherein comprised the important parameter information that communication is set up.The base station could successfully set up for the special-purpose communication link of this travelling carriage after receiving these message.Usually, this process is called as random access procedure.
Inserting at random is a very important part in the WCDMA system, is that prerequisite and the basis of setting up dedicated channel when call out the back registered and registered to subscriber equipment in the sub-district, and therefore the performance of access ten minutes is important at random.
Random access guiding detection method comparatively commonly used at present mainly is; Detect leading through setting a changeless thresholding; Every energy will go on record greater than the multipath of this thresholding; If a certain signature has the energy of a multipath at least greater than this thresholding, think that then this signature is effective, otherwise invalid.
This method implements fairly simple, but but is very difficult to the definite of thresholding in fact: if thresholding is too high, detected multipath will be considerably less, and have influence on the demodulation performance that inserts message; If thresholding is too low, then can cause false alarm probability too high, thereby take limited demodulation resource, under the serious situation even can cause blocking, make real effectively signature not have available demodulation resource on the contrary.
And existing dynamic threshold method also is to confirm a threshold value in advance; Readjust this threshold value through behind the message demodulation again through the misjudgment rate; Though this method has certain improvement to front fixed threshold method; But it is long partially to adjust its adjustment cycle of thresholding again behind the process message demodulation, does not really accomplish definite detection of preamble thresholding of dynamic real-time.
Therefore, prior art awaits to improve and development.
Summary of the invention
The method that the purpose of this invention is to provide a kind of accessing randomly front detection dynamic threshold overcomes in the fixed threshold method that exists in the prior art thresholding and selects difficulty, false-alarm too much, and demodulating unit blocks; Shortcomings such as existing dynamic threshold method thresholding adjustment cycle is long; In the hope of propose a kind of can be dynamic, real-time, and realize confirming easily the method for leading thresholding; Can guarantee leading in the effectively detection of signature; There is abundant multipath to be used to insert message demodulation, can prevents that again false alarm rate is too high, prevent that the dynamic threshold of access at random of choking phenomenon appearance from confirming method.
For realizing above-mentioned purpose, technical scheme of the present invention comprises:
A kind of method of definite accessing randomly front detection dynamic threshold, it may further comprise the steps:
A: input signal is carried out descrambling, compensate of frequency deviation, coherent integration, separates signature and non-coherent integration process, and the signature power time delay that obtains one of them detection of preamble task of one of them access slot distributes;
B: confirm this detection of preamble task average noise amplitude estimation value;
C: the thresholding of definite said detection of preamble task that utilizes signal to noise ratio and the coherent integration length dynamic real-time of average noise horizontal estimated value that step B obtains, upper-layer configured;
D: utilize said steps A, B, C to confirm the thresholding of all detection of preamble tasks in this access slot successively, therefrom get the thresholding of maximum threshold value as the detection of preamble of this access slot.
Described method wherein also comprises, configuration signal to noise ratio T
RNC, coherent integration CA, said steps A comprises: the signal to input carries out descrambling, multiply each other relevant with scrambler; Compensate of frequency deviation carries out the CM operation with the frequency shift (FS) factor; Coherent integration is carried out coherent integration according to coherent integration length; Separate signature, separate signature with fast hadamard transform; Non-coherent integration is carried out noncoherent accumulation according to coherent integration length and is handled; The power time delay that obtains 16 signatures of one of them detection of preamble task of one of them access slot distributes.
Described method, wherein, the said signature power time delay distribution results that obtains comprises that the leading search ability discharge amplitude in 16 each comfortable search window scopes of signature got preceding 15 results and 1 noise result according to order from high to low.
Described method, wherein, said step B also comprises: utilize formula Amp=(Amp
0+ Amp
1+ ...+Amp
M-1)/M calculates and reports noise amplitude Amp
0, Amp
1..., Amp
M-1Average obtain the estimated value Amp of the average noise amplitude of this detection of preamble task, M=16, the number of expression noise result.
Described method, wherein, said step C also comprises: utilize the estimated value Amp of the average noise amplitude that obtains, the signal to noise ratio T of upper-layer configured
RNCConfirm the thresholding of single detection of preamble task with coherent integration length CA dynamic real-time.
Described method, wherein, said step C also comprises:
C1: utilize formula a=5-(T
RNC＞＞4)-(T
RNC/ 48) obtain multiplication factor;
C2: utilize formula
to calculate the thresholding of detection of preamble task.
Described method, wherein, said step C2 also comprises: gawPdRncThTab [T
RNC] be by formula
The table that calculates, table look-at when calculating.
The method of a kind of accessing randomly front detection dynamic threshold proposed by the invention; Compared with prior art; Its advantage is: through noise level is estimated; Definite detection of preamble thresholding that can be dynamic, real-time, and thresholding sets simply, and single thresholding just can be accomplished the current leading processing of catching; Simultaneously, when the energy of certain access slot signature was big, the inventive method can correspondingly obtain a bigger amplitude thresholding, thereby reaches the phenomenon of avoiding producing a large amount of false-alarms; Through the test of real system, most of false-alarm can be effectively abandoned in being provided with rationally effectively of this thresholding of the present invention, false alarm probability is controlled in the scope of agreement permission, has guaranteed detection probability simultaneously.
Description of drawings
Fig. 1 is definite method flow diagram of WCDMA of the present invention system accessing randomly front detection dynamic threshold.
Embodiment
Below in conjunction with accompanying drawing, specific embodiments of the invention is proved absolutely, so that technical scheme of the present invention and beneficial effect thereof are more readily understood.
Definite method of a kind of WCDMA of the present invention system accessing randomly front detection dynamic threshold, it may further comprise the steps:
The first step: to input signal carry out descrambling, separate frequency deviation, separate signature, relevant non-coherent integration process, the signature power time delay that obtains certain access slot detection of preamble task distributes.
Second step: confirm this detection of preamble task average noise horizontal estimated value.
The 3rd step: utilize second to go on foot the estimated value of the noise average level that obtains and the signal to noise ratio of upper-layer configured, the coherent integration length dynamic real-time is the thresholding of an order detection of preamble task really.
The 4th step: utilized for the first, the second, the 3rd step confirmed the thresholding of all detection of preamble tasks in this access slot successively, therefrom get the thresholding of maximum threshold value as the detection of preamble of this access slot.When definite detection of preamble thresholding, the noise when it is generally acknowledged the different frequency deviation of same access slot is identical, so the max threshold of only choosing all tasks is as last result.
In this preferred embodiment of the present invention, as shown in Figure 1, suppose the thresholding vitamin T
RNC=36, coherence length CA=1024, specific operation process of the present invention is following:
Step 101: the antenna data to input carries out descrambling (multiply each other relevant with scrambler); Compensate of frequency deviation (carrying out the CM operation) with the frequency shift (FS) factor; Coherent integration (carrying out coherent integration) according to given length; Signatures match (separating signature) with fast hadamard transform, non-coherent integration (carrying out noncoherent accumulation according to given length) is handled, and the power time delay that obtains 16 signatures of certain detection of preamble task of certain access slot distributes.
In this preferred embodiment; The signature power time delay distribution results that obtains comprises the result's (end is hot-tempered to be the summation of this signature other all ability discharge amplitudes except that 15 ceiling capacity amplitudes) that makes an uproar at the bottom of 15 results that the leading search of 16 signatures in each comfortable search window scope are can discharge amplitude maximum and 1; It is not real signal energy; Therefore when definite noise level and thresholding, what obtain also is noise average amplitude and output amplitude thresholding.The hot-tempered amplitude result in the end who supposes 16 signatures that a leading search mission obtains through above-mentioned processing be respectively 10,10,12,11,11,9,10,11,9,10,12,11,10,8,10,11}.
Step 102: utilize formula Amp=(Amp
0+ Amp
1+ ...+Amp
M-1)/M calculates and reports noise amplitude Amp
0, Amp
1..., Amp
M-1Average obtain the estimated value Amp of the average noise amplitude of this detection of preamble task.
Amp=10 in this example.According to formula I
0=(Amp*Amp*c)/(N
AntNCA*CA), can know as coherent integration length CA, non-coherent integration length N CA and antenna number N
AntIn the time of certain, noise level I
0Square Amp with noise amplitude
2Between corresponding relation immobilize.As long as therefore obtain noise amplitude Amp, just equal to obtain noise level.
Step 103: utilize the estimated value Amp of the average noise amplitude that step 102 obtains and the signal to noise ratio T of upper-layer configured
RNC, coherent integration length CA dynamic real-time is confirmed the thresholding of single detection of preamble task.And can be divided into following step:
Step 103.1: utilize formula a=5-(T
RNC＞＞4)-(T
RNC/ 48) obtain multiplication factor.A=3 in this example.In step 103.2, because there are a large amount of square root calculations, in order not influence precision of calculation results, according to signal to noise ratio parameter T
RNCCarried out the amplification of different multiples, need confirm multiplication factor here so that do reduction at last.
Step 103.2: utilize formula
Calculate the detection of dynamic thresholding.GawPdRncThTab [T wherein
RNC] be by formula
The table that calculates, table look-at when calculating, thus improve computational efficiency.Tabling look-up in this example obtains gawPdRncThTab [36]=258, so T
d=40.
Step 104: if T
d＞T, then T=T
dWherein T is used for writing down the maximum threshold of all detection of preamble tasks in the same access slot.
The inventive method is through estimating noise level, definite detection of preamble thresholding that can be dynamic, real-time, and thresholding sets simply, and single thresholding just can be accomplished the current leading processing of catching; Simultaneously, when the energy of certain access slot signature was big, the inventive method can correspondingly obtain a bigger amplitude thresholding, thereby reaches the phenomenon of avoiding producing a large amount of false-alarms; Through the test of real system, most of false-alarm can be effectively abandoned in being provided with rationally effectively of this thresholding of the present invention, false alarm probability is controlled in the scope of agreement permission, has guaranteed detection probability simultaneously.
Should be understood that above-mentioned description to specific embodiment is comparatively detailed, can not therefore be interpreted as the restriction to scope of patent protection of the present invention, scope of patent protection of the present invention should be as the criterion with accompanying claims.
Claims (4)
1. the method for a definite accessing randomly front detection dynamic threshold, it may further comprise the steps:
A: input signal is carried out descrambling, compensate of frequency deviation, coherent integration, separates signature and non-coherent integration process, and the signature power time delay that obtains one of them detection of preamble task of one of them access slot distributes;
B: confirm this detection of preamble task average noise amplitude estimation value;
C: utilize the average noise amplitude estimation value Amp that step B obtains, the signal to noise ratio T of upper-layer configured
RNCThresholding with the definite said detection of preamble task of coherent integration length CA dynamic real-time comprises: C1: utilize formula a=5-(T
RNC＞＞4)-(T
RNC/ 48) obtain multiplication factor; C2: utilize formula
Calculate the thresholding of said detection of preamble task, gawPdRncThTab [T
RNC] be by formula
The table that calculates, table look-at when calculating;
D: utilize said steps A, B, C to confirm the thresholding of all detection of preamble tasks in this access slot successively, therefrom get the thresholding of maximum threshold value as the detection of preamble of this access slot.
2. method according to claim 1 is characterized in that, also comprises configuration signal to noise ratio T
RNCWith coherent integration length CA, said steps A comprises: the signal to input carries out descrambling, multiply each other relevant with scrambler; Compensate of frequency deviation carries out the CM operation with the frequency shift (FS) factor; Coherent integration is carried out coherent integration according to coherent integration length; Separate signature, separate signature with fast hadamard transform; Non-coherent integration is carried out noncoherent accumulation according to coherent integration length and is handled; The power time delay that obtains 16 signatures of one of them detection of preamble task of one of them access slot distributes.
3. method according to claim 2; It is characterized in that; The said signature power time delay distribution results that obtains comprises that the leading search ability discharge amplitude in 16 each comfortable search window scopes of signature got preceding 15 results and 1 noise result according to order from high to low.
4. method according to claim 3 is characterized in that, said step B also comprises: utilize formula Amp=(Amp
0+ Amp
1+ ... + Amp
M-1)/M calculates and reports noise amplitude Amp
0, Amp
1..., Amp
M-1Average obtain the estimated value Amp of the average noise amplitude of this detection of preamble task, M=16, the number of expression noise result.
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Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101478827B (en) * | 2008-01-04 | 2011-09-14 | 华为技术有限公司 | Method, system and apparatus for retransmitting preamble signature |
| CN102006608B (en) * | 2010-11-15 | 2014-10-29 | 上海中兴软件有限责任公司 | Determination method and system as well as detection method and system of access preamble detection threshold |
| CN103108338B (en) * | 2011-11-14 | 2015-06-17 | 京信通信系统（中国）有限公司 | Detection method, device and base station for random access signal |
| CN102355279B (en) * | 2011-11-17 | 2013-10-09 | 中国航天科工信息技术研究院 | Method and system for diversity maximum likelihood spread spectrum communication bit synchronization |
| CN104010377B (en) * | 2013-02-22 | 2018-01-19 | 中兴通讯股份有限公司 | Strengthen the method and apparatus of WCDMA system detection of preamble disposal ability |
| CN104219775B (en) * | 2013-06-04 | 2018-01-19 | 普天信息技术研究院有限公司 | A kind of method for improving Stochastic accessing detection robustness |
| CN105099965B (en) * | 2014-05-12 | 2018-01-02 | 普天信息技术有限公司 | The noise variance estimation method and device of a kind of RACH |
| CN113259024B (en) * | 2021-05-31 | 2021-10-08 | 中国人民解放军空军预警学院 | Threshold prediction adjustment method for amplitude of digital channelized receiver |
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| WO2004049652A1 (en) * | 2002-11-26 | 2004-06-10 | Qualcomm Incorporated | Preamble detection and data rate control in a umts system |
| CN1553607A (en) * | 2003-05-27 | 2004-12-08 | 深圳市中兴通讯股份有限公司南京分公 | Leading search apparatus and realizing method thereof |
| WO2005114893A1 (en) * | 2004-05-21 | 2005-12-01 | Infineon Technologies Ag | Device and method for preamble detection and frame synchronisation in data packet transmission |
| CN1731888A (en) * | 2004-08-04 | 2006-02-08 | 中兴通讯股份有限公司 | Method of dynamic pilot detection threshold for random access of CDMA system |
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|---|---|---|---|---|
| WO2004049652A1 (en) * | 2002-11-26 | 2004-06-10 | Qualcomm Incorporated | Preamble detection and data rate control in a umts system |
| CN1553607A (en) * | 2003-05-27 | 2004-12-08 | 深圳市中兴通讯股份有限公司南京分公 | Leading search apparatus and realizing method thereof |
| WO2005114893A1 (en) * | 2004-05-21 | 2005-12-01 | Infineon Technologies Ag | Device and method for preamble detection and frame synchronisation in data packet transmission |
| CN1731888A (en) * | 2004-08-04 | 2006-02-08 | 中兴通讯股份有限公司 | Method of dynamic pilot detection threshold for random access of CDMA system |
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Application publication date: 20080102 Assignee: SHENZHEN ZTE MICROELECTRONICS TECHNOLOGY CO., LTD. Assignor: ZTE Corporation Contract record no.: 2015440020319 Denomination of invention: Method for determining random access preamble detection dynamic threshold Granted publication date: 20120509 License type: Common License Record date: 20151123 |
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