CN1527517A - Demodulation method and device for unipolar modulated signal - Google Patents
Demodulation method and device for unipolar modulated signal Download PDFInfo
- Publication number
- CN1527517A CN1527517A CNA031071767A CN03107176A CN1527517A CN 1527517 A CN1527517 A CN 1527517A CN A031071767 A CNA031071767 A CN A031071767A CN 03107176 A CN03107176 A CN 03107176A CN 1527517 A CN1527517 A CN 1527517A
- Authority
- CN
- China
- Prior art keywords
- cpich
- signal
- channel
- pich
- fading
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Mobile Radio Communication Systems (AREA)
Abstract
The demodulation method of unipolar modulated signal includes first obtaining the unipolar demodulation signal of paging indication channel (PICH) by utilizing the information of common pilot channel (CPICH); estimating the fading period of the propagation channel with Doppler frequency in the same time; obtaining CPICH reference level based on the fading period; determining the PICH hard judgment threshold with the power bias of CPICH and PICH and the reference level; and finally judging the unipolar demodulation signal with the threshold to obtain demodulated unipolar signal. The said method can overcome the effect of fading on the statistical threshold precision of unipolar modulation signal to raise the demodulation performance and reliability of unipolar modulation signal. The present invention also provides one kind of unipolar modulation signal demodulating device.
Description
Technical field
The present invention relates to the signal processing method in a kind of communication system, especially the demodulation method of signal and device.
Background technology
In Wideband Code Division Multiple Access (WCDMA) (WCDMA) system, for the common down channel of Page Indication Channel (PICH) and so on, the maximum characteristics of such channel be exactly its most paging index signal be 0, its paging index signal is 1 when having only minority.Because the method modulation signal of applying double pole modulation signal in the present system, paging indication is being just to indicate relevant terminal to read S-CCPCH (Secondary Common Control Physical Channel) signal with the road at 1 o'clock only, have only paging at this moment indication just meaningful in other words, therefore under this modulator approach many times this channel all be in emission garbage 0.Promptly many times this channel is all being launched garbage.
In order to save the down transmitting power of system base-station, expect that usually modulated terminal can indicate Pq not transmit at 0 o'clock in paging, at 1 o'clock just Pq transmitted.This just needs to adopt method modulation signal of unipolar signal modulation, so that the base station is not transmit in 0 o'clock at paging indication Pq, Pq just transmitted in 1 o'clock.The patent No. is the thought that patent documentation that CN 01126233.8, name are called " a kind of call indication channel transmission method " has just proposed the PICH channel is carried out the unipolar signal modulation.But, this method is compared with the bipolar signal modulator approach, decoding performance will descend, the 6dB that to descend of the decoding performance when source data signals 0,1 equiprobability distributes for example, therefore the unipolar signal modulator approach is had higher requirement to demodulating end, not only need can effectively demodulation destination channel received signal, and because the randomness that declines in the actual fading channel, the level that has determined the unipolarity restituted signal also is that decline changes, and can estimate the best exactly when also just needing restituted signal to declare firmly and declare thresholding firmly.
As the demodulation of unipolar signal being adopted the demodulation method of bipolar signal, owing to also contain the Common Pilot Channel (CPICH) that adopts the bipolarity modulator approach in the common down channel simultaneously, therefore can estimate the channel fading of CPICH according to the frequency pilot sign that this locality produces at demodulating end, because to change is identical in the decline of CPICH and PICH in wireless fading channel, decline that so just can the corresponding PICH of obtaining channel also obtains the restituted signal of PICH by decline correction, multipath merging.But for the unipolarity modulation signal, because the influence of channel fading randomness, can not be 0 by declaring threshold setting simply firmly, can declare the paging indication that the PICH channel firmly as the demodulation of bipolarity modulation signal.
One as said method substitutes, if adopt certain index of at first obtaining reference channel, signal level as SIR or needs, the method that deducts the power bias of destination channel and reference channel is then removed the signal of demodulation unipolarity method modulation, because the unipolarity modulation signal is a fluctuations, and declare firmly that each symbol all needs to do, if directly adopt said method, just need two interchannels will transmit signal continually, and because each symbol that the reference channel demodulation is come out is subjected to noise jamming bigger, the accuracy of threshold judgement is descended, thereby can influence the accuracy of whole demodulation result.
Summary of the invention
The object of the present invention is to provide a kind of demodulation method of enough accurate demodulation unipolarity modulation signals, use this method can overcome the influence of decline, thereby improve demodulation performance and reliability the unipolarity modulation signal to unipolar signal statistics thresholding accuracy.The present invention also provides a kind of unipolarity modulation signal demodulating device simultaneously.
For achieving the above object, the demodulation method of unipolarity modulation signal provided by the invention comprises:
Utilize the information of Common Pilot Channel (CPICH) to obtain the unipolarity restituted signal of Page Indication Channel (PICH);
Obtain the fading period of propagation channel, according to the reference level that obtains CPICH described fading period;
Utilize the reference level of the power bias of CPICH and PICH and above-mentioned CPICH to determine that PICH's declares thresholding firmly;
Utilize and describedly declare thresholding firmly the unipolarity restituted signal is adjudicated, obtain the unipolar signal after the demodulation.
Be the fading period of Common Pilot Channel (CPICH) fading period of described propagation channel.
The method that the information of the described CPICH of utilization is obtained the unipolarity restituted signal of PICH is:
Signal receiver carries out channel fading to CPICH to be estimated, according to estimated result CPICH is declined after correction and the multipath merging, obtains the restituted signal of CPICH;
PICH utilizes the decline correction, multipath of the channel fading estimated information of CPICH to merge and obtain the unipolarity restituted signal.
In aforesaid operations, utilize the local common pilot symbols that produces of signal receiver to estimate the channel fading of CPICH.
Described method also comprises:
Signal receiver extracts the signal of CPICH and PICH channel according to different code words.
The Doppler frequency of utilizing the Doppler frequency estimation approach to obtain estimating obtains the fading period of CPICH according to said frequencies.
The reference level of described CPICH is the level average of the CPICH signal in the interference fading cycle.
Unipolarity modulation signal demodulating device provided by the invention comprises:
The reference channel estimation module, the common pilot symbols that is used for producing according to this locality is estimated the channel fading of CPICH;
First correction merges module, is used for CPICH signal decline correction and multipath merging;
Second correction merges module, and the channel fading information of utilizing CPICH is to PICH signal decline correction and multipath merging;
Also comprise Doppler frequency estimation module, level statistical module, level adjusting module and declare module firmly, wherein:
The Doppler frequency estimation module is used to obtain the Doppler frequency estimated value;
The level statistical module is used for obtaining according to the Doppler frequency estimated value signal fadeout cycle of CPICH;
The level adjusting module is used for according to the signal fadeout cycle of CPICH and the reference level in the relevant cycle of the acquisition of the power bias between CPICH and PICH;
Declare module firmly, be used for the unipolarity restituted signal being adjudicated, obtain the unipolar signal after the demodulation according to the said reference reference level.
Because the present invention adopts Doppler frequency to estimate to determine the method in channel fading cycle, therefore can obtain reference data level conduct comparatively accurately and declare thresholding firmly, thereby can improve the accuracy of unipolarity modulation signal demodulation in the fading channel greatly, and the Performance And Reliability that improves system, the while has reduced the amount of transmitted information of interchannel again.
Description of drawings
Fig. 1 is the embodiment flow chart of the method for the invention;
Fig. 2 is the embodiment block diagram of device of the present invention.
Embodiment
Under traditional bipolar signal modulation system, signal is modulated into+(just) 1 and-(bearing) 1 signal, for example raw information 1 is modulated into-1, raw information 0 is modulated into+and 1, no matter positive negative signal, + 1 or-1 all is the required power emission, because most of paging index signal of PICH is 0, causes the emission of the garbage of this channel in most time inevitably.Therefore adopt the method for unipolar signal modulation, be not modulate in 0 o'clock promptly in the paging index signal, being to be equivalent to without transmitting power in 0 o'clock in the paging index signal in other words, is this signal to be modulated into+1 or-1 emission the transmitting power that just can save PICH greatly at 1 o'clock.For example, for consistent as far as possible, select to be modulated to-1 with 1 with original system.
Above-mentioned unipolarity modulator approach is had higher requirement to demodulating end, this not only show need can effectively demodulation destination channel signal, it is the signal of the channel of PICH and so on, and in the reality because the randomness that declines in the fading channel, the level that has determined the unipolarity modulation signal is that decline changes, can obtain the best when this just needs restituted signal exactly and declare thresholding firmly, could guarantee accuracy the demodulation of unipolarity modulation signal.But the demodulation to the demodulation of unipolarity modulation signal and bipolarity modulation signal is different.In demodulating process to the bipolarity modulation signal, as in spread spectrum system, restituted signal before declaring firmly is positive negative signal, such as+200, + 300,-200, owing to declare firmly and will select a middle thresholding exactly, all restituted signals greater than this thresholding adjudicate into 0, adjudicate into 1 less than all restituted signals of this thresholding, therefore if recover raw information 0,1, therefore in the bipolarity modulating system, can serve as the hard thresholding of determining with 0, to become 0 greater than 0 signal decision, the signal decision less than 0 becomes 1, has so just recovered raw information; And in the unipolarity system, if not having the signal that demodulation is come out under the decline situation at channel is 0,0 ,-300,-400, or the like, and need become 1 to signal decision less than-150, the judgement greater than-150 becomes 0, but the restituted signal in the actual fading channel may be from negative tens to negative several thousand, therefore 0 also may be because noise and in positive and negative tens fluctuations, need find one to declare thresholding preferably firmly and declare firmly when declaring each symbol firmly, and this demodulation for the unipolarity modulation signal is difficult.Essence of the present invention, be exactly in the process at the demodulation of unipolarity modulation signal, fading characteristic at propagation channel, adopt the Doppler frequency results estimated to estimate to declare firmly thresholding exactly, with the fading characteristic that overcomes propagation channel to declaring the influence of thresholding accuracy firmly, thereby demodulation exactly, rule out the unipolarity modulation signal, improve the Performance And Reliability of system.
With the WCDMA system is example, if the PICH in the existing down emission system adopts the method modulation signal of unipolarity modulation, owing to also contain the CPICH that adopts the bipolarity modulator approach in the common down channel simultaneously, can think that in wireless fading channel it is identical that the decline of CPICH and PICH changes, that is to say, can be with the reference channel of CPICH, to obtain the decline change information of PICH as destination channel PICH; Simultaneously, can estimate the channel fading of CPICH according to the frequency pilot sign that this locality produces at demodulating end, decline that so just can the corresponding PICH of obtaining channel also merges the restituted signal that obtains PICH by decline correction, multipath, at last come the restituted signal of PICH is adjudicated, obtain PICH restituted signal accurately according to the Doppler frequency results estimated.
The present invention is described in further detail below in conjunction with accompanying drawing.
Fig. 1 is the embodiment flow chart of the method for the invention.According to Fig. 1, at first signal receiver is distinguished the received signal of reference channel CPICH and destination channel PICH according to different code words in step 1, this is because CPICH adopts different orthogonal codes with PICH, so CPICH and PICH can be made a distinction fully according to different orthogonal codes.The common pilot symbols that produces according to this locality in step 2 estimates the channel fading of reference channel CPICH then, reference channel is declined rectify a deviation and the multipath merging then, obtains the restituted signal of CPICH.Owing to think that the decline variation of CPICH and PICH is identical in the wireless fading channel, therefore with the channel fading information of the reference channel channel fading information as PICH, decline correction, multipath merging obtains the unipolarity restituted signal of PICH to the channel fading information of utilizing above-mentioned reference channel in step 3 to PICH.Because being decline, actual channel changes, the level that causes the restituted signal of reference channel PICH also is a fluctuations, therefore separate timing at the unipolarity modulation signal and need reference channel level statistics accurately, be exactly to require specifically the reference channel level that counts can adaptive channel the variation of fading period, can adjust statistical length according to the periodicity that signal fluctuation changes, thereby the level statistical value of reference channel and the decline variation of channel are adapted.So at first utilize the Doppler frequency estimation approach to obtain the Doppler frequency estimated value of reference channel in step 4, obtain the fading period of CPICH again according to the Doppler frequency of estimating.In the reality, owing in less than 1/8 or 1/4 fading period, can think that the variation of received signal level is very little, therefore utilize the fading period of above-mentioned CPICH in step 5, the average of the relevant cycle internal reference channel signal level of statistics, obtain one and be subjected to the less reference level of noise jamming, in order to the reference level of firmly declaring thresholding of conduct the PICH restituted signal.Its statistical length of the accuracy requirement of level average is less than the relevant cycle, and the above-mentioned relevant cycle is generally 1/4 or 1/8 of fading period, specifically determines according to the situation of channel fading.The reference level that power bias and step 5 obtain between step 6 is according to reference channel CPICH under the upper layer transfers and destination channel PICH estimates the reference level of destination channel restituted signal, multiply by a corresponding coefficient (as 0.5) of adjusting according to the actual requirement of destination channel again and obtains declaring thresholding at the PICH restituted signal firmly in the relevant cycle.Utilize in step 7 at last and above-mentionedly declare thresholding firmly the PICH restituted signal is adjudicated output,, be judged to 1, finally obtain the echo signal of PICH, promptly obtain useful paging indication less than the signal of declaring thresholding firmly as being judged to 0 greater than the signal of declaring thresholding firmly.
Fig. 2 is the embodiment block diagram of device of the present invention.Comprise in the described device of Fig. 2 that reference channel estimation module 11, first correction merge module 12, second correction merges mould 13, Doppler frequency estimation module 14, level statistical module 15, level adjusting module 16 and declares module 17 firmly, wherein:
Reference channel estimation module 11 is used for the common pilot symbols according to this locality generation, utilizes the received signal of the local reference channel CPICH that produces of signal receiver, estimates the channel fading information of CPICH;
First correction merges module 12, is used for CPICH signal decline correction and multipath merging are obtained the restituted signal of CPICH;
Second correction merges module 13, and the channel fading information of utilizing the CPICH that reference channel estimation module 11 estimates is to PICH signal decline correction and multipath merging, obtains the PICH unipolar signal after the demodulation;
Doppler frequency estimation module 14 is used to obtain the Doppler frequency estimated value of CPICH, and this estimated value is sent to level statistical module 15, is obtained the signal fadeout cycle of CPICH according to the Doppler frequency estimated value by level statistical module 15; This signal fadeout cycle information is sent to level adjusting module 16, the level estimated value that CPICH that is transmitted according to signal fadeout cycle and the upper strata of CPICH by level adjusting module 16 and the power bias between the PICH obtain PICH in the relevant cycle, it is just passable promptly directly to deduct power bias with each reference level of importing, this level estimated value be multiply by corresponding an adjustment behind the coefficient as declaring thresholding firmly according to the actual requirement of destination channel PICH to be delivered to and declares module 17 firmly, declare thresholding by it firmly according to this unipolarity restituted signal that second correction merges module 13 outputs is adjudicated, obtain the unipolar signal after the demodulation.
In said apparatus, the measurement period of level statistical module is relevant with actual fading period, estimates to determine on the basis of fading period in Doppler frequency, and the concrete measurement period length selection principle and the realization of system require to be closely related.When decline changes slowly, fading period is longer, timing statistics is also corresponding longer, then the transinformation of CPICH and PICH interchannel significantly reduces in the unit interval, timing statistics length can be level and smooth effectively to noise simultaneously, also can extract a small amount of sample in measurement period length in the reality and average.Because when channel fading changes when very fast, Doppler frequency is estimated can this variation of fast reaction, thereby the control level statistical module carries out the adjustment of statistical length, guarantees the level statistical accuracy, and then has guaranteed the accuracy to the demodulation of PICH unipolarity modulation signal.
Claims (8)
1, a kind of demodulation method of unipolarity modulation signal is characterized in that comprising:
Utilize the information of Common Pilot Channel (CPICH) to obtain the unipolarity restituted signal of Page Indication Channel (PICH);
Obtain the fading period of propagation channel, according to the reference level that obtains CPICH described fading period;
Utilize the reference level of the power bias of CPICH and PICH and above-mentioned CPICH to determine that PICH's declares thresholding firmly;
Utilize and describedly declare thresholding firmly the unipolarity restituted signal is adjudicated, obtain the unipolar signal after the demodulation.
2, the demodulation method of unipolarity modulation signal according to claim 1 is characterized in that, be the fading period of Common Pilot Channel (CPICH) fading period of described propagation channel.
3, the demodulation method of unipolarity modulation signal according to claim 1 is characterized in that, the method that the information of the described CPICH of utilization is obtained the unipolarity restituted signal of PICH is:
Signal receiver carries out channel fading to CPICH to be estimated, according to estimated result CPICH is declined after correction and the multipath merging, obtains the restituted signal of CPICH;
PICH utilizes the decline correction, multipath of the channel fading estimated information of CPICH to merge and obtain the unipolarity restituted signal.
4, the demodulation method of unipolarity modulation signal according to claim 3 is characterized in that, utilizes the local common pilot symbols that produces of signal receiver to estimate the channel fading of CPICH.
5, the demodulation method of unipolarity modulation signal according to claim 4 is characterized in that, described method also comprises: signal receiver extracts the signal of CPICH and PICH channel according to different code words.
According to the demodulation method of claim 3,4 or 5 described unipolarity modulation signals, it is characterized in that 6, described method also comprises: the Doppler frequency of utilizing the Doppler frequency estimation approach to obtain estimating obtains the fading period of CPICH according to said frequencies.
7, the demodulation method of unipolarity modulation signal according to claim 6 is characterized in that, the reference level of described CPICH is the level average of the CPICH signal in the interference fading cycle.
8, a kind of unipolarity modulation signal demodulating device comprises:
The reference channel estimation module, the common pilot symbols that is used for producing according to this locality is estimated the channel fading of CPICH;
First correction merges module, is used for CPICH signal decline correction and multipath merging;
Second correction merges module, and the channel fading information of utilizing CPICH is to PICH signal decline correction and multipath merging;
It is characterized in that, also comprise Doppler frequency estimation module, level statistical module, level adjusting module and declare module firmly, wherein:
The Doppler frequency estimation module is used to obtain the Doppler frequency estimated value;
The level statistical module is used for obtaining according to the Doppler frequency estimated value signal fadeout cycle of CPICH;
The level adjusting module is used for according to the signal fadeout cycle of CPICH and the reference level in the relevant cycle of the acquisition of the power bias between CPICH and PICH;
Declare module firmly, be used for the unipolarity restituted signal being adjudicated, obtain the unipolar signal after the demodulation according to the said reference reference level.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03107176 CN1268082C (en) | 2003-03-06 | 2003-03-06 | Demodulation method and device for unipolar modulated signal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03107176 CN1268082C (en) | 2003-03-06 | 2003-03-06 | Demodulation method and device for unipolar modulated signal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1527517A true CN1527517A (en) | 2004-09-08 |
| CN1268082C CN1268082C (en) | 2006-08-02 |
Family
ID=34282905
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 03107176 Expired - Fee Related CN1268082C (en) | 2003-03-06 | 2003-03-06 | Demodulation method and device for unipolar modulated signal |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1268082C (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101106397B (en) * | 2006-07-10 | 2010-08-18 | 华为技术有限公司 | Method, system and device for improving demodulation performance of public indication channel |
| CN102090015A (en) * | 2008-07-11 | 2011-06-08 | 高通股份有限公司 | Flash position signaling: multiplexing and interference management |
| CN102348262A (en) * | 2010-07-26 | 2012-02-08 | 中兴通讯股份有限公司 | Transmission method and device for paging indicator channel frames |
-
2003
- 2003-03-06 CN CN 03107176 patent/CN1268082C/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101106397B (en) * | 2006-07-10 | 2010-08-18 | 华为技术有限公司 | Method, system and device for improving demodulation performance of public indication channel |
| CN102090015A (en) * | 2008-07-11 | 2011-06-08 | 高通股份有限公司 | Flash position signaling: multiplexing and interference management |
| CN102090015B (en) * | 2008-07-11 | 2014-04-23 | 高通股份有限公司 | Flash position signaling: multiplexing and interference management |
| CN102348262A (en) * | 2010-07-26 | 2012-02-08 | 中兴通讯股份有限公司 | Transmission method and device for paging indicator channel frames |
| CN102348262B (en) * | 2010-07-26 | 2014-12-10 | 中兴通讯股份有限公司 | Transmission method and device for paging indicator channel frames |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1268082C (en) | 2006-08-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1156179C (en) | Dynamic regulation method and device of channel estimation everage region | |
| CN1178411C (en) | Pilot strength measurement and multipath delay searcher for CDMA receiver | |
| US6614857B1 (en) | Iterative channel estimation and compensation based thereon | |
| CN1286878A (en) | Device and method for controlling initial transmission power of forward link channel in mobile communication system | |
| CN1192567C (en) | Determination of data rate based on power spectral density estimates | |
| CN101042429A (en) | Method and apparatus for increasing the sensitivity of a global positioning satellite receiver | |
| CN1550119A (en) | System and method of estimating earliest arrival of CDMA forward link signals | |
| CN1267439A (en) | Method for identifying base station of time division cellular network in mobile station and mobile station | |
| CN1148925C (en) | Dynamic temp compensation and stage selection in pilot signal acquisition | |
| EP2257016A3 (en) | Incremental pilot insertion for channel and interference estimation | |
| CN1750425A (en) | Forward link power control in a cellular system using Nt/Io values | |
| CN1805426A (en) | Method of correcting channel quality indication in high-speed downlink grouped data packet access | |
| CN1672340A (en) | Power measurement of received CDMA signals using soft threshold preprocessing after correlation | |
| CN1192109A (en) | CDMA radio transmission system | |
| CN1226840C (en) | Method for regulating to reach signal quality target and relevant transceiver | |
| CN1268082C (en) | Demodulation method and device for unipolar modulated signal | |
| CN1371552A (en) | Dynamic control of search duration in wireless communication device | |
| CN1251482A (en) | Timed estimation to GSM pulse train according to past records | |
| CN1457152A (en) | Wireless communication device and wireless communication method | |
| CN1474528A (en) | Channel evaluation method in wide band CDMA communication system | |
| CN1138365C (en) | Signal/interference ratio (SIR) measuring method | |
| CN1910828A (en) | Method of and apparatus for computation of unbiased power delay profile | |
| CN1190976C (en) | Dynamic time interval structure regulating method in channel estimation | |
| CN101060671A (en) | A downlink synchronous pilot frequency time slot search method | |
| CN1561006A (en) | Correlated receiver and signal receiving method for super-broad band radio communication system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20060802 Termination date: 20200306 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |