CN1215667C - Method and device for capturing random cut in channel prefix in base station of WCDMA system - Google Patents
Method and device for capturing random cut in channel prefix in base station of WCDMA system Download PDFInfo
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- CN1215667C CN1215667C CN 02111839 CN02111839A CN1215667C CN 1215667 C CN1215667 C CN 1215667C CN 02111839 CN02111839 CN 02111839 CN 02111839 A CN02111839 A CN 02111839A CN 1215667 C CN1215667 C CN 1215667C
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Abstract
The present invention relates to a method and a device for capturing the prefix of a random access channel in a base station of a WCDMA system. The method comprises the steps: using a method for cooperating a delay wire tap and a scrambling phase to realize relevant calculation under different multi-path deviation for realizing multi-path search; using a 16-path scrambling time division multiplexing mode; using an RAM read-write control mode to finish Hadamard transform; using a mode of occupying RAM in different time segments to store middle calculation results and final judgment results. The present invention provides a device which has high resource utilization rate and low system complexity and is capable of finishing rapid capture by the method.
Description
Technical field
The present invention relates to WCDMA (Wideband Code Division Multiple Access (WCDMA)) mobile communication technology, specifically refer to a kind of method and apparatus that WCDMA mobile communication spread spectrum system uplink random access channel prefix is caught.
Background technology
In mobile communication system, when mobile phone need be conversed, he at first must insert request, and the base station then needs the access request of the user in this sub-district is responded.In the WCDMA mobile communication system, the channel relevant with up access is up access channel, up access channel is made up of prefix (preamble) and information (message) two parts again, wherein, preamble is made up of scrambler, signature and phase factor, the user that the signature representative is different.The purpose of catching is exactly by (signature belongs to a hada code character to 16 possible signatures, comprise 16 different signature sequences) carry out coherent detection, thereby determine whether when the user is just asking to insert and ask to insert which the signature that uses number is, the skew of each the bar multipath that produces when needing simultaneously to obtain the wireless channel propagation is so that utilize multipath information that message is partly carried out demodulation.
Because a purpose of catching is to carry out Multipath searching, so how to realize that fast simple search module is a key issue of catching, general employing is the method for matched filtering at present, adopts this method fairly simple from the angle that realizes, but need take more system resources.
Summary of the invention
The objective of the invention is to catch the middle difficult point that exists, a kind of method and device that is applicable to that broadband CDMA system uplink random access channel preamble catches is provided at preamble.By this method or device, when realization is caught fast and accurately, can reduce the complexity of circuit as far as possible, and save system resource.
To achieve these goals, the technical solution adopted in the present invention, the method that the Random Access Channel prefix is caught in promptly a kind of WCDMA system base-station comprises the following steps:
1) utilize the input signal of 24 delay line tap and 16 outs of phase scrambler go to disturb correlation computations, obtain the correlated results under 384 kinds of multipath drift condition;
2) to going to disturb the processing that later correlated results is removed phase factor;
3) adopt control to read and write the mode of RAM, carry out Hadamard transform, obtain being directed to the correlated results of 16 kinds of signatures;
4) the plural correlated results of above all that obtain is asked mould, obtain amplitude;
5) respectively 384 correlation magnitude of each signature sorted, obtain each signature corresponding several maximum correlation magnitude and multi-path location, and amplitude peak is greater than several signatures of thresholding number, with this as court verdict;
6) deposit court verdict in register so that read.
In above-mentioned WCDMA system base-station in the Random Access Channel prefix catching method, wherein, 24 delay line tap, the time delay that 1/2 chip is arranged between the signal of per two taps, the scrambler of 16 outs of phase is time division multiplexing in 16 system clocks of a chip, phase phasic difference 12 chips of per two scramblers.
According to above technical scheme, the present invention also provides the device that the Random Access Channel prefix is caught in a kind of WCDMA system base-station, comprise the correlator bank unit, the Phase Processing unit, Hadamard transformation element, ask form unit, ordering and decision unit, the court verdict memory cell, buffer unit and code generator, described code generator is connected to the correlator bank unit, described buffer unit respectively with the correlator bank unit, the Phase Processing unit, carry out bidirectional interconnect with Hadamard transformation element, the described form unit of asking, ordering and decision unit link to each other with the court verdict memory cell is unidirectional successively, and ask that form unit and buffer unit are also unidirectional to be connected; Wherein: correlator bank unit and code generator cooperate, be used to calculate the correlation (skew between received signal scrambling code phase and the local scrambling code phase) under the different multipaths skews, wherein code generator produces the scrambler that 16 tunnel time division multiplexinges and phase place differ 12 chips successively; The Phase Processing unit is used for removing the phase factor (adding) that the transmitting terminal modulated process adds when transmitting terminal is modulated; Hadamard transformation element is used to obtain to be directed to the correlation of 16 different signatures number; Buffer unit, be used to store the intermediate object program of data processing, comprise the data behind data after data behind the relevant descrambling, the Phase Processing and the Hadamard transform, and according to the relevant descrambling, Phase Processing and the Hadamard transform that carry out successively, buffer unit is taken successively the different data of i.e. each stage storage of buffer unit; Ask form unit, be used for plural correlated results is asked amplitude; Ordering and decision unit are used for determining whether the multi-path location of each signature and the maximal correlation amplitude of amplitude and signature surpass thresholding; The court verdict memory cell is used to store last result, comprises the signature number that surpasses thresholding, the multi-path location and the amplitude of signature.
The device that the Random Access Channel prefix is caught in the above-mentioned WCDMA system base-station, wherein, the correlator bank unit comprises 24 delay cell that is used for producing the different signals that postpone and 24 correlators that are used for relevant descrambling, utilizes the signal that correlator comes to delay line tap and the scrambler of code generator generation to carry out relevant descrambling computing.
The device that the Random Access Channel prefix is caught in the above-mentioned WCDMA system base-station, wherein, correlator comprise multichannel control selector with two respectively with adding/subtracter that this multichannel control selector links to each other, the scrambler that produces by code generator to add/mode that subtracter is controlled realizes the relevant descrambling of signal, and deposits the intermediate object program that adds up in described buffer unit.
Adopted above-mentioned technical solution, the present invention carries out in the mode that has adopted input data delay tap and scrambling code phase to match aspect the realization Multipath searching, delay line tap has 24, differ 1/2chip (chip) between per two taps, 24 taps time delay be respectively 0chip to 11 1/2chip again, so can produce the various time-delays of 0chip to 191 1/2chip by both cooperations and all differ 12chip between the phase place of 16 road scramblers that code generator produces, its precision is 1/2chip.Since 16 road scramblers of code generator be in 16 clocks of a chip time-division produce, so that the system resource that takies than adopting the mode of delay line tap (or matched filter) to significantly reduce fully.When carrying out fast hadamard transform, adopt the mode of control read-write RAM in addition, and in the use of RAM, adopt the mode of recycling stage by stage, improved resource utilization ratio greatly.
Description of drawings
Fig. 1 is the functional block diagram of acquisition equipment structure of the present invention;
Fig. 2 is the structured flowchart of the correlator bank unit in the acquisition equipment of the present invention;
Fig. 3 a is the memory module of RAM in correlation computations and the Phase Processing stage buffer unit;
Fig. 3 b is the memory module through RAM in the buffer unit behind the Hadamard transform;
Fig. 4 is the structured flowchart of correlator inside;
Fig. 5 is 16 road scrambler time division multiplexing schematic diagrames;
Fig. 6 is Hadamard transformation element and the cut-away view that links to each other with RAM.
Embodiment
The present invention can realize catching fast of preamble under the simple circuit configuration relatively, and it is applicable to that the preamble that WCDMA communication system uplink multi-users inserts at random catches fast.
In the receiver of WCDMA communication system, be directed to the acquisition equipment that Random Access Channel (RACH) has a preamble.The preamble of RACH channel partly be by signature (signature is that a group length is totally 16 of 16 Hadamard, is used to indicate different users) through what form after the scrambler scrambling, as shown in the formula:
pre(n)＝Scrm(n)*Sig(n)*exp(j*(PI/4+n*PI/2))，n＝0，...，4095。
Wherein Scrm (n) represents the scrambler among the up RACH preamble, and Sig (n) represents certain signature, and the back is plural phase bit position.
The scrambler that the channel of WCDMA system uses is quadrature GOLD sign indicating number, length is 38400, it is used for distinguishing different channels or user, such as inserting at random for the multi-user, may have a plurality of users and ask to insert (promptly sending the RACH channel to the base station) simultaneously, we can by their having nothing in common with each other (which scrambler each user uses distributed by the base station unification) of using and mutually orthogonal scrambler be distinguished so.
At the composition of the preamble of WCDMA system RACH, the preamble acquisition equipment need carry out descrambling to received signal and number carry out the computing of Hadamard transform at all possible signature, thereby detects received signature number by result of calculation.Another free-revving engine of Preamble acquisition equipment is to carry out multipath to detect, so this device has adopted correlator bank to carry out correlation computations in the processing of descrambling, by to different skew (phase difference between the scrambler of local scrambler and received signal) thus under result of calculation compare multipath skew and the amplitude of obtaining.
One, the handling process of the present invention's employing is as follows:
1) scrambler of the input signal of 24 delay line tap and 16 outs of phase go to disturb correlation computations, obtain the correlated results under various (384 kinds) possible multipath drift condition.
2) to going to disturb the processing that later correlated results is removed phase factor.
3) adopt control to read and write the mode of RAM, carry out Hadamard transform, obtain being directed to the correlated results of 16 kinds of possible signatures.
4) the plural correlated results of above all that obtain is asked mould, obtain amplitude.
5) respectively 384 correlation magnitude of each signature are sorted, obtain the several correlation magnitude and the multi-path location of the corresponding maximum of each signature, and amplitude peak is greater than several signatures of thresholding number.
6) deposit court verdict in register so that read.
24 above-mentioned delay line tap have the time delay of 1/2 chip between the signal of per two taps, the scrambler of 16 outs of phase is time division multiplexing in 16 system clocks of a chip, phase phasic difference 12 chips of per two scramblers.
Two, acquisition equipment of the present invention
As shown in Figure 1, this device comprises correlator bank unit 1, code generator 2, Phase Processing unit 3, Hadamard transformation element 4, buffer unit 8, asks form unit 5, ordering and decision unit 6, court verdict memory cell 7, described code generator 2 is connected to correlator bank unit 1, between described correlator bank unit 1, Phase Processing unit 3 and Hadamard transformation element 4 threes and the buffer unit 8 all is bidirectional interconnect, described buffer unit 8, asks that form unit 5, ordering and decision unit 6, court verdict memory cell 7 are unidirectional successively to link to each other.
Code generator 2 is used to produce the required local scrambler of descrambling, as shown in Figure 5, it can produce 16 road scramblers time-division, and this 16 road scrambler is time division multiplexing in 16 system clocks of a chip (chip), the phase phasic difference 12chip between the adjacent scrambler of every two-way.Certainly this is a kind of selection at this design, and we also can pass through the parameter of configuration code generator inside, thereby controls the phase place of every road scrambler, can make capture range not be confined to 0 to 192chip like this, increases the flexibility of system acquisition scope.
As shown in Figure 2, correlator bank unit 1 comprises 24 delay cell 11 that is used for producing the different signals that postpone and 24 correlators 12 that are used for relevant descrambling, utilizes the signal that 12 pairs of delay line tap of correlator come and the scrambler of code generator 2 generations to carry out relevant descrambling computing.Owing to differ the phase place of 12chip between 16 road scramblers that code generator 2 produces successively, and 24 delay line tap signals differ the phase place of 1/2chip successively, so we can carry out 384 kinds of correlation computations under the different skews.
The structure of correlator inside as shown in Figure 4, it comprises two and adds/subtracter 121 and a multichannel control selector 122, the scrambler that produces by code generator to add/mode that subtracter is controlled realizes the relevant descrambling of signal, the intermediate object program that adds up deposits buffer unit 8 in.
Comprise 48 RAM81 in the buffer unit 8, storage I, Q circuit-switched data, shown in accompanying drawing 3A, Fig. 3 B, the size of RAM81 all is 256 * 14, each RAM81 is divided into 16 parts, they are in the different data of each of data processing storage in stage, and what deposit in correlation computations and each part of Phase Processing stage RAM81 is 16 correlations after adding up through 256 times on certain deviation post.And finish after the Hadamard transform, what deposit in each part of RAM81 is corresponding to the correlation (being the accumulation result of 4096chip) of 16 signatures on certain deviation post.
Phase Processing unit 3 is used to remove phase factor.
Hadamard transformation element 4 is used for 16 kinds of possible signatures are carried out Hadamard transform, as shown in Figure 6, Hadamard transformation element 4 comprises address generator 41, adder 42 and subtracter 43, and it links to each other with RAM81, adopts the mode of control read-write RAM81 to realize Hadamard transform.Shown in the figure is to be in sequence between two inputs and two output: 1) according to reading address 1 reading of data 1 from address 1; 2) according to reading address 2 reading of data 2 from address 2; 3) with the output of adder 42 be data 1 and data 2 and write in the address 1 of RAM81; 4) be that the difference of data 1 and data 2 writes in the address 2 of RAM81 with the output of subtracter 43.
When carrying out Hadamard transform, the data parallel of each correlator 12 is handled, and the also concurrent operation of IQ two-way of correlator inside so there is circuit 48 as shown in the figure to overlap altogether, that is to say also to comprise 48 RAM81 in buffer unit.To the I or the Q road correlated results of certain correlator, 4 butterfly computations of 16 each needs of Hadamard transform.The processing here is a first order butterfly of once finishing 16 Hadamard transforms, do again second and third, level Four.Each butterfly comprises a sub-addition, a subtraction, finishes in 4 clock cycle.From the angle of adder-subtractor, this four operation of clapping is: read address 1 data, read address 2 data and write address 1, difference writes address 2.It is as follows that read/write address produces: two addresses (4) of each butterfly have 3 identical, 8 butterflies for every grade, in " 000 " to " 111 " 8 count values insert ' 0 ' and ' 1 ' read/write address that promptly obtains each butterfly respectively, for 4 grades of butterfly computations, the insertion position is followed successively by " ^ * * * ", " * ^ * * ", " * * ^ * ", " * * * ^ ".
Ask form unit 5 to be used to ask for the amplitude of complex signal.
Ordering and decision unit 6 are used for the correlation magnitude under 384 kinds of skews of every kind of possible signature is compared, thereby obtain the wherein several amplitudes and the skew thereof of amplitude maximum, need in addition comparing between 16 amplitudes that may sign and between they and the detection threshold, thereby obtain surpassing several signatures number of the maximum of thresholding.
Court verdict memory cell 7 is used for the result that memory sequencing and decision unit obtain.
Claims (5)
1, the method that the Random Access Channel prefix is caught in a kind of WCDMA system base-station comprises the following steps:
1) utilize the input signal of 24 delay line tap and 16 outs of phase scrambler go to disturb correlation computations, obtain the correlated results under 384 kinds of multipath drift condition;
2) to going to disturb the processing that later correlated results is removed phase factor;
3) adopt control to read and write the mode of RAM, carry out Hadamard transform, obtain being directed to the correlated results of 16 kinds of signatures;
4) the plural correlated results of above all that obtain is asked mould, obtain amplitude;
5) respectively 384 correlation magnitude of each signature sorted, obtain each signature corresponding several maximum correlation magnitude and multi-path location, and amplitude peak is greater than several signatures of thresholding number, with this as court verdict;
6) deposit court verdict in register so that read.
2, the method that the Random Access Channel prefix is caught in the WCDMA system base-station as claimed in claim 1, it is characterized in that: described 24 delay line tap, the time delay that 1/2 chip is arranged between the signal of per two taps, the scrambler of 16 outs of phase is time division multiplexing in 16 system clocks of a chip, phase phasic difference 12 chips of per two scramblers.
3, the device that the Random Access Channel prefix is caught in a kind of WCDMA system base-station, it is characterized in that: comprise the correlator bank unit, the Phase Processing unit, Hadamard transformation element, ask form unit, ordering and decision unit, the court verdict memory cell, buffer unit and code generator, described code generator is connected to the correlator bank unit, described buffer unit respectively with the correlator bank unit, the Phase Processing unit, carry out bidirectional interconnect with Hadamard transformation element, the described form unit of asking, ordering and decision unit link to each other with the court verdict memory cell is unidirectional successively, and ask that form unit and buffer unit are also unidirectional to be connected; Wherein:
Correlator bank unit and code generator cooperate, and are used to calculate the correlation under the different multipaths skews, and wherein code generator produces the scrambler that 16 tunnel time division multiplexinges and phase place differ 12 chips successively;
The Phase Processing unit is used for removing the phase factor that the transmitting terminal modulated process adds;
Hadamard transformation element is used to obtain to be directed to the correlation of 16 different signatures number;
Buffer unit, be used to store the intermediate object program of data processing, comprise the data behind data after data behind the relevant descrambling, the Phase Processing and the Hadamard transform, and according to the relevant descrambling, Phase Processing and the Hadamard transform that carry out successively, buffer unit is taken successively the different data of i.e. each stage storage of buffer unit;
Ask form unit, be used for plural correlated results is asked amplitude;
Ordering and decision unit are used for determining whether the multi-path location of each signature and the maximal correlation amplitude of amplitude and signature surpass thresholding;
The court verdict memory cell is used to store last result, comprises the signature number that surpasses thresholding, the multi-path location and the amplitude of signature.
4, the device that the Random Access Channel prefix is caught in a kind of WCDMA system base-station according to claim 3, it is characterized in that: described correlator bank unit comprises 24 delay cell that is used for producing the different signals that postpone and 24 correlators that are used for relevant descrambling, utilizes the signal that correlator comes to delay line tap and the scrambler of code generator generation to carry out relevant descrambling computing.
5, the device that the Random Access Channel prefix is caught in a kind of WCDMA system base-station according to claim 4, it is characterized in that: described correlator comprise multichannel control selector with two respectively with adding/subtracter that this multichannel control selector links to each other, the scrambler that produces by code generator to add/mode that subtracter is controlled realizes the relevant descrambling of signal, and deposits the intermediate object program that adds up in described buffer unit.
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| CN 02111839 CN1215667C (en) | 2002-05-27 | 2002-05-27 | Method and device for capturing random cut in channel prefix in base station of WCDMA system |
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| CN100393168C (en) * | 2004-08-04 | 2008-06-04 | 中兴通讯股份有限公司 | CDMA system random access threshold multi-path selection method |
| CN101098324B (en) * | 2006-06-27 | 2011-06-22 | 中兴通讯股份有限公司 | Method and apparatus for implementing scrambling code phase rapid rotation in WCDMA system |
| CN101505173B (en) * | 2009-04-10 | 2013-01-16 | 华为技术有限公司 | Stochastic access detection method and communication apparatus |
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Owner name: BEIER AERKATE CO., LTD., SHANGHAI Free format text: FORMER NAME: BELL CO.,LTD., SHANGHAI Owner name: SHANGHAI ALCATEL-LUCENT CO., LTD. Free format text: FORMER NAME: BEIER AERKATE CO., LTD., SHANGHAI |
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