CN1206972A - Multi-stage iteration multi-subscriber test method - Google Patents
Multi-stage iteration multi-subscriber test method Download PDFInfo
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Abstract
The multi-level iterative multi-user detection method used in CDMA communication system includes the following steps: making external signal r(t) pass through matched filter group (1) to output signal "y", feeding the signal "y" into the multi-level iterative multi-user signal processing module B(2), through first iterative processing, its output is Dy, secondary iterative output is D(2)y, and nth-level iterative output is D(n)y; finally, feeding the output into accumulator to make decision to obtain the processed result B. Said invented method can obviously raise the capacity of DS/CDMA communication system, eliminate multiaddress interference between users,raise the far and near effect of system and easily implement hardward real-time operation.
Description
The present invention is the method that the multi-stage iteration multi-subscriber in a kind of DS/CDMA of being applied to communication system detects, and belongs to the multi-access interference suppression technical field in the DS/CDMA communication technology.
The cdma communication technology will occupy absolute advantage in the development of Communication Technique of making rapid progress.Yet a deficiency the most significant of CD-MA communication system is exactly the multiple access interference between the user.Therefore, great amount of manpower and material resources have been dropped in countries in the world on the multi-access interference suppression Study on Technology.
The multi-access interference suppression Study on Technology has had the history of more than ten years in the world, and the method for many in theory Multiuser Detection is suggested.In moving towards practical application, these detection methods all exist some shortcomings that make whole system be difficult to accept, particularly real-time requirement.Therefore (, IS-665) also do not adopt multiuser detection as yet in the existing C DMA communication system as IS-95.In recent years, how take up research in the world pushes multiuser detection to use to.Wherein do to such an extent that be preferably the polynomial expansion detector that the S.Moshavi of U.S. Bellcore communication experiment chamber finds out, his this detector arrangement is simple, and there are not the data delay and the edge effect of traditional linear detector (decorrelation and MMSE), can realize easily with hardware, and can the adaptive system requirement of processing in real time.We find that under study for action there are following three shortcomings in the multinomial detector of Moshavi: the progression of (1) needs is many; (2) need to estimate in advance several parameters (with progression as many), the acquisition of these parameters needs a large amount of complicated calculations and emulation; (3) system has the user to increase and when reducing, parameter is wanted corresponding change.Therefore, need storage in large quantities to estimate good parameter in advance.
The purpose of this invention is to provide a kind of multi-stage iteration multi-subscriber test method that can eliminate the interference of the multiple access between the user in the cdma communication system.
Multi-stage iteration multi-subscriber test method of the present invention be with outer signal r (t) through matched filter banks output signal " y ", " y " sends into the multi-stage iteration multi-subscriber signal processing module with signal, is output as Dy through first order iteration, second level iteration is output as D
2Y, n level iteration is output as D
nY sends into accumulator at last and adjudicates and obtain result
Every grade of iteration D is by a spread spectrum and despread unit α R and a vectorial delay cell T
bAnd adder A constitutes spread spectrum and despread unit α R and vectorial delay cell T
bInput be the input of every grade of iteration D, spread spectrum and despread unit α R and vectorial delay cell T
bOutput termination adder A, the output of adder A is the output of every grade of iteration D.Spectrum-spreading unit multiply by a predetermined constant α more respectively to addition behind each subscriber signal spread spectrum among each spread spectrum and the despread unit α R, sends into the despread unit with respect to each subscriber signal at last.
The thought of Multiuser Detection is to utilize all users' spreading code, information such as amplitude, position phase, timing.Angle with integral body is carried out signal processing, eliminate the purpose that multiple access disturbs thereby reach, its basic ideas are to add a multiple user signals processing module in the matched filter banks back, this module is handled the output of matched filter banks, its output has been eliminated the multiple access interference fully, its operation principle and the course of work are: the output of matched filter banks represents that with vectorial y y imports " multiple user signals processing module ", and the output of this module promptly gets end product through judgement.And " multiple user signals processing module " be made of some levels, and concrete progression decide on used spreading code of user and spreading gain, and each grade is made up of " D " module.In the first order, " D " module is handled its input y, obtains new vectorial Dy, and Dy sends into vectorial accumulator and y adduction storage mutually, and Dy is admitted to second " D " module simultaneously, obtains partial output D
2Y, D
2Y sends into the vectorial y+Dy adduction storage mutually of vectorial accumulator and the inside, D simultaneously
2Y is admitted to the 3rd module, continues to establish and passed through the M level through the processing identical with the first order or the second level, and then the storage vector of accumulator the inside is (I+D+ ... + D
M) y.At last in this accumulator and vector adjudicate, promptly get last judgement vector
Wherein each " D " module is by a vectorial delay cell " T
bWith a α R " the composing in parallel of module.
The output of matched filter banks is sent to the unit of " α R " module, and " α R " is made of one group of spread spectrum and despread unit.For example user 1 matched filter is output as y
1, y
1By user 1 employed spreading code S
1(t-τ
1) spread spectrum once more, the spreading code that the output of other user's matched filter is also used by them respectively separately is spread spectrum once more, carry out the addition of chip sheet according to their the time delay delay of nature then, to on each chip sheet with multiplication by constants α (α determines in advance a good positive constant), then the data of a chip speed obtaining are like this carried out matched filtering (being despreading) with separately spreading code again, obtain the output of module α R, each user's of this module the output and the output result of its corresponding matched filtering are subtracted each other, will differ from the judgement accumulator of delivering to this user and existing amount (being the output of matched filter) addition.,, the amount in the judgement accumulator is adjudicated like this, promptly get end product through some grades processing.
This invents the base station receiver of available DS/CDMA communication system, and the phase mutual interference of its effect between can the cancellation different user obtains better receptivity, thereby improve the message capacity and the communication quality of whole system.The main following points of its advantage:
1. can significantly improve the DS/CDMA capability of communication system.Because the multiple access of having eliminated between the user disturbs, can be so that the number of users that system can hold has significant increase.Studies show that, in each sub-district of a mobile DS/CDMA communication system, use this multi-user detector after, the number of users that the sub-district is held increases original more than one times;
2. can improve the anti-near-far interference of system, the reduction system is to the requirement of power control.When certain user's power increases (walking out as mobile phone) suddenly in elevator, power control system has little time reaction again, and this user will produce strong interference to other user, makes that other user can't operate as normal; In addition, when certain user's power reduces (as entering elevator) suddenly, because other user's interference, this user's signal can't normally be detected, therefore with regard to cisco unity malfunction.This detector can effectively suppress both of these case;
This detector to system without any additional requirement.As long as existing traditional detection energy operate as normal, this detector is the energy operate as normal just;
4. be easy to the hardware real-time implementation.Because this detector only contains spread spectrum and despread unit, that therefore can have no difficulty uses the ASIC real-time implementation.This is a remarkable advantage of this detector;
5. detect performance and be equivalent to that decorrelation detects and MMSE detects, but overcome the shortcoming that the edge effect that exists in the present treating method and data stop over;
6. compare with the multinomial detector that the Moshavi of U.S. Bellcore company proposes, have its all advantages, and overcome its wretched insufficiency---need to carry out a large amount of emulation, estimate very many parameters in advance according to the employed spreading code of user.Here, we only need estimate a parameter easily.
Fig. 1 is the vector structure schematic diagram of multi-stage iteration multi-subscriber test method of the present invention.Input signal r (t) is wherein arranged, matched filter banks 1, multi-stage iteration multi-subscriber signal processing module B2, output signal
This figure only illustrates the secondary iterative processing.
Fig. 2 is a structure principle chart of the present invention, only shows 1 grade among the figure.
Fig. 3 is the whole system module connection diagram of making the multi-stage iteration multi-subscriber detector.
Embodiment of the present invention are as follows:
Its signal processing method is: at first external input signal r (t) is sent into matched filter banks 1, signal through matched filter banks output is y, then signal y is sent into multi-stage iteration multi-subscriber signal processing module 2, in this module, every grade of iteration D is by a spread spectrum and despread unit α R and a vectorial delay cell T
bAdder A constitute spread spectrum and despread unit α R and vectorial delay cell T
bWith input be the input of every grade of iteration, promptly signal y at first sends into this end, spread spectrum and despread unit α R and vectorial delay cell T
bOutput termination adder A, the output of adder A is the output of every grade of iteration D, is output as Dy through first order iteration, iteration is output as D through the second level
2Y is output as D through n level iteration
nY sends into accumulator at last and adjudicates and obtain result
The embodiment that realizes the application specific processor of above processing method have multiple simply introduce a kind of way of utilizing general digital signal processing (DSP) chip to realize this multi-user detector here.Concrete performing step is as follows:
The first step: the dsp chip of selecting to be suitable for realizing this multi-user detector.Here the TMS320C50 chip that select U.S. Ti company to produce.
Second step: purchase the TMS320C50 chip of Ti company and the developing instrument on the supporting PC thereof.Its detailed explanation of the TMS320C50 chip of purchasing can be referring to the interrelated data of any TMS320C50 that provides about Ti company.
The 3rd step: utilize the development environment on the PC of purchasing, write corresponding assembler.The spreading gain of our supposing the system is 64, three users is arranged in work.The connection of whole system module is as shown in Figure 3: suppose that the TMS320C50 chip is connected by control bus, address bus, data/address bus with " A/D " analog to digital converter, three users' PN code generator and decoder, concrete handling process is as follows:
1. finished the sampling of 64 chip data when " A/D " analog to digital converter, the notice that sends instructions TMS320C50 chip reads this 64 data, and data is delivered to the data-interface of TMS320C50;
2.TMS320C50 obtain read data instruction, data read in appointed its memory;
3. three PN code generators are finished chip synchronization, and 64 PN code datas of each self-generating send instructions successively and notify TMS320C50 chip reading of data, and data are delivered to the data-interface of TMS320C50;
4.TMS320C50 obtain the read data instruction, three users' PN sign indicating number read in the memory of appointment;
5.TMS320C50 by the Multiuser Detection principle that provides here, the data in the memory are handled, are obtained three users' bit decision result;
Notify the decoder read data 6.TMS320C50 send instructions, and data are delivered to the data-interface of decoder;
7. decoder is read away data;
8. repeat the step of 1-7, intact up to the data processing that all antennas receive.
Top flow process is the flow process of whole system work, is write the instruction that TMS320C50 need carry out as corresponding assembler.The 5th step write as a subprogram, and this subprogram is write by the theory diagram of multi-user detector just.
The 4th step: utilize the assembler in the TMS320C50 developing instrument, the assembler of finishing is generated the COFF file destination;
The 5th step: utilize the linker in the TMS320C50 developing instrument, the COFF file destination is converted into executable coff file;
The 6th step: utilize the simulator (simulator) in the TMS320C50 developing instrument, artificial debugging can be carried out coff file;
The 7th step: utilize the hexadecimal crossover tool (hex conversionutility) in the TMS320C50 developing instrument, can carry out coff file and be converted into the hexadecimal file destination;
The 8th step: utilize among the EPROM of burned device with the burned TMS320C50 of hexadecimal file destination.
Like this, we have just obtained a TMS320C50 chip that the Multiuser Detection scheme that we are proposed is solidified.The good element of pertinent regulations in this chip and " the 3rd step " described system is connected, and this chip is the energy operate as normal just, receives principle by the multi-user that we proposed and finishes the function that the multi-user receives.
Claims (3)
1. multi-stage iteration multi-subscriber test method, it is characterized in that this detection method is through matched filter banks (1) output signal " y " with outer signal r (t), signal " y " is sent into multi-stage iteration multi-subscriber signal processing module (2), be output as Dy through first order iteration, second level iteration is output as D
2Y, n level iteration is output as D
nY sends into accumulator at last and adjudicates and obtain result
2. multi-stage iteration multi-subscriber test method according to claim 1 is characterized in that every grade of iteration D is by a spread spectrum and despread unit α R and a vectorial delay cell T
bAnd adder A constitutes spread spectrum and despread unit α R and vectorial delay cell T
bInput be the input of every grade of iteration D, spread spectrum and despread unit α R and vectorial delay cell T
bOutput termination adder A, the output of adder A is the output of every grade of iteration D.
3. multi-stage iteration multi-subscriber test method according to claim 2, it is characterized in that spectrum-spreading unit is respectively to addition behind each subscriber signal spread spectrum among each spread spectrum and the despread unit α R, multiply by a predetermined constant α again, send into despread unit at last with respect to each subscriber signal.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN98111378A CN1059998C (en) | 1998-06-22 | 1998-06-22 | Multi-stage iteration multi-subscriber test method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN98111378A CN1059998C (en) | 1998-06-22 | 1998-06-22 | Multi-stage iteration multi-subscriber test method |
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| CN1206972A true CN1206972A (en) | 1999-02-03 |
| CN1059998C CN1059998C (en) | 2000-12-27 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100338932C (en) * | 2002-12-06 | 2007-09-19 | 冯志强 | Signal processor for suppressing multiuser interference in DS-CDMA system |
| CN100423470C (en) * | 2002-01-09 | 2008-10-01 | 诺基亚公司 | Method and receiver for receiving composite signals |
| CN104301267A (en) * | 2014-11-11 | 2015-01-21 | 山东大学 | Multi-stage iterative detection method and device of MIMO wireless communication receiver |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB9317604D0 (en) * | 1993-08-24 | 1993-10-06 | Philips Electronics Uk Ltd | Receiver for ds-cdma signals |
| US5757791A (en) * | 1996-04-18 | 1998-05-26 | American Wireless Technology, Inc. | Multistage linear receiver for DS-CDMA systems |
| US5831977A (en) * | 1996-09-04 | 1998-11-03 | Ericsson Inc. | Subtractive CDMA system with simultaneous subtraction in code space and direction-of-arrival space |
-
1998
- 1998-06-22 CN CN98111378A patent/CN1059998C/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100423470C (en) * | 2002-01-09 | 2008-10-01 | 诺基亚公司 | Method and receiver for receiving composite signals |
| CN100338932C (en) * | 2002-12-06 | 2007-09-19 | 冯志强 | Signal processor for suppressing multiuser interference in DS-CDMA system |
| CN104301267A (en) * | 2014-11-11 | 2015-01-21 | 山东大学 | Multi-stage iterative detection method and device of MIMO wireless communication receiver |
| CN104301267B (en) * | 2014-11-11 | 2017-07-04 | 山东大学 | The multistage iteration detection method and device of a kind of mimo wireless communication receiver |
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| CN1059998C (en) | 2000-12-27 |
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