CN102377702A - Channel estimation processing system in digital wireless communication and method - Google Patents
Channel estimation processing system in digital wireless communication and method Download PDFInfo
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- CN102377702A CN102377702A CN201010264151XA CN201010264151A CN102377702A CN 102377702 A CN102377702 A CN 102377702A CN 201010264151X A CN201010264151X A CN 201010264151XA CN 201010264151 A CN201010264151 A CN 201010264151A CN 102377702 A CN102377702 A CN 102377702A
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Abstract
The invention provides a channel estimation processing microsystem in digital wireless communication and a realization method. The processing microsystem composed of an FFT (Fast Fourier Transform) module, a descrambling module and a channel estimation module is newly designed; and transmission data processed by FFT are not subjected to reverse data operation and data descrambling processing and directly enter the channel estimation module. In the channel estimation module, the data are subjected to interpolation estimation on one hand and are subjected to reverse processing on the other hand. While the reverse processing operation is finished, the data are delayed. After the completion of reverse processing, the data are subjected to descrambling operation. The channel estimation processing microsystem and the method can ensure that storage units are reduced under the situation that the performance of the whole system is not changed and effectively solve the delay problem of data processing in the system.
Description
Technical field
The present invention relates to the digital wireless communication field, relate in particular to channel estimation process system and implementation method in the digital wireless communication.
Background technology
CMMB (China Mobile Multimedia Broadcasting, Chinese DMB) is the China Mobile multimedia broadcasting industry standard of China national General Bureau of Radio, Film and Television in October, 2006 promulgation, and this standard was in formal enforcement on November 1 in 2006.It is a kind of based on multi-carrier OFDM (Orthogonal Frequency Division Multiplexing; Orthogonal frequency division multiplexi) wireless broadcast system of technology; Adopt advanced channel error correction coding and multi-carrier OFDM modulation technique; Improved antijamming capability and, adopted the time slot radiation pattern to reduce the power consumption at terminal ambulant support.
The CMMB signal adopts the OFDM modulation technique, and the transmitting terminal signal carries out the quadrature modulation of IFFT (FFT) operation carrying out subcarrier, and the receiving terminal response will be carried out FFT (FFT) operation carrying out quadrature demodulation to signal.The terrestrial wireless transmit stage of signal; Because the wireless transmission environment is more abominable; Can produce the signal distortion of a property taken advantage of to transmission signals;, can adopt channel estimation technique to carry out channel response and estimate in order to eliminate this channel disturbance at receiving terminal, and and then eliminate and be superimposed upon the channel property the taken advantage of interference on the signal.At the receiving terminal of CMMB, FFT and channel estimating are two indispensable signal processing modules.
Traditional FFT module adopts carries out signal processing based on butterfly computation.Before signal output,, need carry out could recovering the proper data order and exporting after the data inverted order handles because butterfly computation makes the data sequence entanglement of a FFT processed frame.The inverted order processing needs to use the RAM of frame sign to realize, in the CMMB system, the RAM that accomplishing the processing of data inverted order needs is 4096* word length (Wordlength).Secondly, in the CMMB receiver, the pilot tone of using frequency domain to insert is carried out the estimation of channel response.At first according to local pilot tone with receive the channel response that signal obtains pilot frequency locations, then according to the channel response result of pilot frequency locations carry out successively inserting in the time domain with frequency domain in insert, obtain the channel response result of whole all carrier positions of signal frame.When carrying out inserting in the time domain; The signal frame of current operation need use before and after it adjacent signal frame to carry out channel response to estimate, so when in time domain, inserting, signal is according to the number of the front and back signal frame that uses; Need delay time accordingly; For example insert a signal frame that uses front and back adjacent in the time domain, then 4096 clocks of signal lag need the FIFO of 4096*Wordlength to realize.So the two total needs the memory cell of 2*4096* word length (Wordlength).
The whole process of the signal processing of CMMB receiver please refer to shown in the accompanying drawing 1.Wherein the structure chart of the channel estimation process micro-system of traditional design please refer to shown in the accompanying drawing 2, is made up of FFT module, descrambling module and channel estimation module.This kind implementation adopts a plurality of memory cell to carry out data inverted order and data delay process, and design is complicated, and in implementation procedure, has prolonged the time of data processing.
Summary of the invention
The object of the invention provides channel estimation process system and implementation method new in a kind of wireless communication field.Employing designs the treatment system that FFT module, descrambling module and channel estimation module constitute again, under the constant situation of the performance of guaranteeing whole system, reduces memory cell, and can effectively reduce the time-delay that system data is handled.
Channel estimation process system in a kind of digital wireless communication is made up of FFT module and channel estimation module.
The FFT module is used for the transmission data are carried out Fourier transform, and signal becomes frequency domain by time domain.
Channel estimation module is made up of interior slotting estimation unit, data inverted order memory cell, descrambling unit and delay process unit.
The interior estimation unit of inserting carries out the interior estimation of inserting to the out of order data of FFT output;
Data inverted order memory cell is carried out inverted order to the out of order data of FFT output and is handled;
The descrambling unit carries out the descrambling computing to the data after the inverted order processing;
The delay process unit is used for the data delay process.
Interior inserting comprises slotting processing module and interior each part of processing module of inserting of frequency domain in preparatory inverted order pilot frequency locations matrix, preparatory scrambling pilot frequency sequence, pilot frequency locations channel response computing module, pilot tone inverted order module, the time domain in the estimation unit.
Among the present invention, after the transmission data are handled through FFT, do not carry out operation of data inverted order and data de-scrambling and handle, directly get into channel estimation module.In channel estimation module, insert in data are carried out on the one hand and estimate that data are carried out the inverted order processing on the other hand.The inverted order operation of data is based on the operation of data block, handles operation in the completion inverted order and simultaneously data is delayed time.After inverted order was finished dealing with, data were carried out the descrambling computing.Synchronous for guaranteeing with interior slotting estimation unit output, the data after the descrambling computing need be carried out the delay process of a weak point.
The present invention also proposes the method for channel estimation process in a kind of digital wireless communication, comprises following content:
(1) the transmission data directly get into channel estimation module after FFT handles;
(2) according to the number sequence of the out of order data of FFT output, the position of the preparatory inverted order pilot tone of calculated off-line in advance;
(3) off-line carries out preparatory scrambling process with pilot data according to the scrambling mode of transmitting terminal data;
(4) channel response on the out of order pilot frequency locations is estimated to calculate;
(5) the channel response result of pilot tone carries out inserting in inverted order, the time domain and interior slotting processing of frequency domain;
(6) handle through the data entering descrambling unit of inverted order and delay process;
(7) data behind the output descrambling and channel response result of calculation are imported back level module into.
The signal frame body that relates among the present invention program is the multi-carrier signal frame symbol that meets the CMMB standard, adopts the signal modulation system of multicarrier.
Through technical scheme provided by the present invention; In the data communication of wireless communication field; Can guarantee under the constant situation of whole system performance, reduce the memory cell in the inverted order operation that has FFT module in the design now, can effectively reduce the time-delay that system data is handled simultaneously.
Description of drawings
The overall architecture sketch map of Fig. 1 CMMB receiver system
The structural representation of the channel estimation process system in Fig. 2 traditional design
The structural representation of Fig. 3 channel estimation process provided by the present invention system
Insert the estimation unit structural representation in Fig. 4 channel estimation process provided by the present invention system
Channel estimation process method basic flow sheet in Fig. 5 digital wireless communication provided by the present invention
Embodiment
Below in conjunction with each accompanying drawing the channel estimation process system and method in a kind of digital wireless communication provided by the present invention is carried out detailed description.
Fig. 1 is the integrated stand composition of CMMB receiver, and its whole system operation principle is that radiofrequency signal gets into receiver through antenna, at first carries out demodulating unit 100 and carries out demodulation process, changes radio frequency analog signal into baseband digital signal.Baseband digital signal carries out signal Synchronization through lock unit 200 to be handled, comprise sampling clock synchronously, frame synchronization and Frequency Synchronization.Data after synchronously get into FFT FFT module 300 signal are become frequency domain by time domain.Frequency domain data gets into descrambling module 400 and carries out the data de-scrambling processing.Data behind the descrambling get into channel estimation module 500, and the channel of estimated signal when transmission is corresponding to get into channel-decoding unit 600 together with data, decoding output.
Fig. 2 is the structural representation of channel estimation process system in the traditional design.This micro-system is made up of FFT module 300, descrambling module 400 and channel estimation module 500.Transmission mode with 4K is an example; Because in the FFT module that adopts pipeline organization; At first pile line operation unit 310 carries out butterfly computation; The result who obtains after the pipeline operation will use the memory cell 320 of 4096 degree of depth to accomplish the operation of data inverted order, and the data after handling through inverted order get into descrambling module 400 and carry out the descrambling computing with the pseudo random sequence that produces in real time, get into channel estimation module 500 afterwards.In channel estimation module; Interior slotting estimation unit 510 through pilot tone carries out the channel response estimation on the one hand; Because when in the pilot tone time domain, inserting; Need the time-delay of 1 OFDM symbol just can obtain the result according to present embodiment, thus need to use 520 pairs of data of memory cell of 4096 degree of depth to carry out caching process, synchronous to keep data and channel response result's.This traditional design framework because the demand of FFT inverted order and channel estimating time-delay, take the more and data processing of memory cell and delay time bigger.In addition, owing between the two, there is the data de-scrambling operation, be difficult for the two combination.
Fig. 3 is the structural representation of channel estimation process provided by the present invention system.This micro-system adopts the pretreated thought of data, walks around the restriction of descrambling module, and eliminates the influence that out of order data are handled data, can in design, save memory cell.Micro-system is made up of FFT module 300 and channel estimation module 500.In FFT module 300, after finishing dealing with in pile line operation unit 310, out of order data are handled without inverted order, directly see off.The out of order data of seeing off need not passed through descrambling module 400 and handled directly entering channel estimation module 500.In channel estimation module 500 provided by the present invention; Data are inserted in interior slotting estimation unit 510 carries out on the one hand and are estimated that data are carried out the inverted order processing through data inverted order memory cell 320 on the other hand, owing to when the data inverted order is operated, be based on the operation of data block; Therefore inverted order is handled and is accomplished data inverted order function simultaneously; Also data have been carried out 4096 time-delay, thus can reach data inverted order and time-delay two aspect effects simultaneously, after inverted order is handled; Data 400 are carried out the descrambling computing through the descrambling unit, the data behind the descrambling just with conventional method in the data exported of channel estimation module be identical.The new channel estimation system framework that the present invention proposes has saved the memory cell of one 4096 degree of depth, has only increased the delay process unit 520 (this is for synchronous with interior slotting estimation unit 510) of " 512 degree of depth ".So in the new channel estimating structure that proposes, the memory cell that the contrast conventional method can be saved is: 4096-512-512=3072.In the present embodiment, the data bit width of FFT output adopts 12bit, and total bit number of then saving is: 3072*12bit ≈ 37kbit.For the interior slotting estimation module 510 of the channel response in the channel estimation module 500, need corresponding change just can satisfy and insert estimation in the channel response of out of order data.The structural representation of interior slotting estimation module 510 as shown in Figure 4.
Out of order and do not have the data of descrambling to insert estimation unit 510 in getting into after; The 511st, according to the rule of the inverted order preparatory inverted order pilot frequency locations matrix that obtains of off-line in advance; The 512nd, according to pseudo random sequence when pilot frequency locations original pilots is carried out the preparatory scrambling pilot frequency sequence after the preparatory scrambling; 512 are driven by 511 signs that provide when the pilot frequency locations, see corresponding scrambling pilot value in advance off.511 preparatory inverted order pilot frequency locations and 512 preparatory scrambling pilot value are all sent into pilot frequency locations channel response computing module 513 when work; Calculate the channel response result of out of order pilot frequency locations; Send into pilot tone inverted order module 514 then; Because the pilot tone number is 1/8 of a subcarrier number in the CMMB standard; So pilot tone inverted order module is accomplished by the memory cell of " 512 degree of depth ", then with traditional interior slotting estimation carry out equally inserting in the time domain with frequency domain in insert and handle, obtain the channel response result of all sub-carrier positions.
Claims (6)
1. channel estimation process system in the digital wireless communication is made up of FFT module and channel estimation module, and it is characterized in that: said channel estimation module is made up of interior slotting estimation unit, data inverted order memory cell, descrambling unit and delay process unit.
2. channel estimation process system in a kind of digital wireless communication as claimed in claim 1 is characterized in that: do not carry out data inverted order operational processes in the said FFT module.
3. channel estimation process system in a kind of digital wireless communication as claimed in claim 1 is characterized in that: insert estimation unit in said and comprise preparatory inverted order pilot frequency locations matrix, insert processing module in scrambling pilot frequency sequence, pilot frequency locations channel response computing module, pilot tone inverted order module, the interior slotting processing module of time domain and the frequency domain in advance.
4. channel estimation process method in the digital wireless communication is characterized in that: comprise following steps:
(1) the transmission data directly get into channel estimation module after FFT handles;
(2) according to the number sequence of the out of order data of FFT output, the position of the preparatory inverted order pilot tone of calculated off-line in advance;
(3) off-line carries out preparatory scrambling process with pilot data according to the scrambling mode of transmitting terminal data;
(4) channel response on the out of order pilot frequency locations is estimated to calculate;
(5) the channel response result of pilot tone carries out inserting in inverted order, the time domain and interior slotting processing of frequency domain;
(6) handle through the data entering descrambling unit of inverted order and delay process;
(7) data behind the output descrambling and channel response result of calculation are imported back level module into.
5. channel estimation process method in a kind of digital wireless communication as claimed in claim 4 is characterized in that: the frame position of said transmission of data signals meets the multi-carrier signal frame symbol of CMMB standard.
6. like channel estimation process method in claim 4 or the 5 described a kind of digital wireless communications, it is characterized in that: the frame of said transmission of data signals adopts multi-carrier modulation.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111711493A (en) * | 2020-06-16 | 2020-09-25 | 中国电子科技集团公司第三研究所 | Underwater communication equipment with encryption and decryption capabilities, transmitter and receiver |
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| US20050124297A1 (en) * | 2003-12-05 | 2005-06-09 | Eilts Henry S. | Low overhead transmit channel estimation |
| CN1984109A (en) * | 2006-04-24 | 2007-06-20 | 华为技术有限公司 | Channel estimater and channel estimating method in telecommunication system |
| CN101345730A (en) * | 2007-07-23 | 2009-01-14 | 清华大学 | Method and device for frequency decision feedback equalizer in TDS-OFDM receiver |
| CN101645733A (en) * | 2008-08-07 | 2010-02-10 | 中兴通讯股份有限公司 | Rake receiving device of hardware and receiving method thereof |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050124297A1 (en) * | 2003-12-05 | 2005-06-09 | Eilts Henry S. | Low overhead transmit channel estimation |
| CN1984109A (en) * | 2006-04-24 | 2007-06-20 | 华为技术有限公司 | Channel estimater and channel estimating method in telecommunication system |
| CN101345730A (en) * | 2007-07-23 | 2009-01-14 | 清华大学 | Method and device for frequency decision feedback equalizer in TDS-OFDM receiver |
| CN101645733A (en) * | 2008-08-07 | 2010-02-10 | 中兴通讯股份有限公司 | Rake receiving device of hardware and receiving method thereof |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111711493A (en) * | 2020-06-16 | 2020-09-25 | 中国电子科技集团公司第三研究所 | Underwater communication equipment with encryption and decryption capabilities, transmitter and receiver |
| CN111711493B (en) * | 2020-06-16 | 2022-03-11 | 中国电子科技集团公司第三研究所 | Underwater communication equipment with encryption and decryption capabilities, transmitter and receiver |
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