CN1385017A - Channel estimating method - Google Patents
Channel estimating method Download PDFInfo
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- CN1385017A CN1385017A CN 00813603 CN00813603A CN1385017A CN 1385017 A CN1385017 A CN 1385017A CN 00813603 CN00813603 CN 00813603 CN 00813603 A CN00813603 A CN 00813603A CN 1385017 A CN1385017 A CN 1385017A
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- frequency pilot
- different frequency
- signs
- pilot sign
- channel
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/0224—Channel estimation using sounding signals
- H04L25/0228—Channel estimation using sounding signals with direct estimation from sounding signals
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Mobile Radio Communication Systems (AREA)
- Noise Elimination (AREA)
Abstract
The present invention discloses a channel estimating method using in the cellular mobile communication system, which transmits different pilot symbols having the correction in both interference and fading in the same subframe at the transmitter side, at the receiver side, performs the difference operation on the received adjacent different pilot symbols, so as to eliminate interference and obtain the exact channel estimating value. The channel estimating method provided by the present invention can effectively eliminate the affect of the interference, give accurate channel parameter estimating value, avoid complex multi-users detection and reduce the complexity of the system.
Description
Channel estimation methods
Technical field
The present invention relates to cell mobile communication systems, more particularly to a kind of effective reduction or the channel estimation methods for eliminating cell mobile communication systems interference.Background of invention
In Modern cellular mobile communication, in order to which the transmission for eliminating channel transfer characteristic and channel fading etc. influences, user service data is more accurately received, generally using channel estimation technique.Such as, QualCom company（Qualcomm the Combined estimator of) the continuous pilot channel estimation proposed in 3G (Third Generation) Moblie standard IS-2000, European Nokia, CP continuous pilot channel that Errisson is proposed in wcdma and special pilot channel（The concrete scheme of Qualcomm CP continuous pilots see Physical Layer Standard for ANSI/TIA/EIA-95-B;Joint pilot channel estimation scheme in WCDMA see 3GPPTS25.211).Because these channel estimation methods are all that, with noisy estimation, thus must carry out Multiuser Detection, accurate channel estimation results otherwise can not be provided, so as to influence the performance of communication system.But Multiuser Detection largely substantially increases the complexity of system again.The content of the invention
A kind of channel estimation methods applied to cell mobile communication systems proposed by the present invention, in multi cell cellular environment, under conditions of no use Multiuser Detection, still can effectively eliminate the influence of interference, provide accurate channel estimation results.
A kind of channel estimation methods of the present invention, are to transmit different frequency pilot signs in the same subframe of transmitting terminal, and the interference between the different frequency pilot signs has correlation, and decline also has correlation；The Bu Sudden Xia receiving terminal progress Ru：
(a) the different frequency pilot signs received are de-spread respectively, in-phase solution is adjusted and serioparallel exchange and despreading, quadrature demodulation and serioparallel exchange；
(b) carry out additive operations to the adjacent different frequency pilot signs after above-mentioned serioparallel exchange respectively to eliminate interference, and to subtracting each other after result of calculation carry out average calculating operation respectively and eliminate interference with further；
(c) result of calculation obtained by step b is divided by, obtains channel phase offset estimate；It is squared to step b result of calculation and, obtain channel magnitude decline estimate.
According to the invention described above technical scheme, described different frequency pilot signs can be made up of the 2N frequency pilot sign that 2N/K groups are transmitted for one group K different frequency pilot signs, and wherein K, Ν is positive integer.
When Κ is 2, transmission Ν groups totally 2 Ν frequency pilot sign when, the additive operations that carried out to the adjacent different frequency pilot signs after serioparallel exchange described in step b refer to difference between the frequency pilot sign of calculating odd bits and the frequency pilot sign of neighbouring even-numbered.
When K is 2N, the adjacent different frequency pilot signs progress additive operations after serioparallel exchange are referred to calculate the difference between M frequency pilot signs and M -1 frequency pilot signs described in Bu Sudden b when transmitting 1 group of common 2N different frequency pilot signs, wherein M is the positive even numbers less than or equal to 2N.
Just blunt according to the invention described above technical scheme, described different frequency pilot signs can also be to be made up of as one group K identical frequency pilot sign, transmits the common 2N frequency pilot sign of different 2N/K groups, wherein, N be positive integer.
When K is 2, during the common 2N frequency pilot sign of the different N groups of transmission, the difference adjacent different frequency pilot signs progress additive operations after serioparallel exchange referred between the difference between the adjacent pilot symbols of calculating odd bits and the adjacent pilot symbols of even bit described in step b.
When K is N, when transmitting the common 2N frequency pilot sign of different 2 Group, the frequency pilot sign that the adjacent different frequency pilot signs progress additive operations after serioparallel exchange are referred to calculating M described in step 13 and the（N+M) position frequency pilot sign between difference, wherein M be less than or equal to
N positive integer.
Above-mentioned different frequency pilot signs, are most preferably to take its correlation properties value to be minimum.
A kind of channel estimating apparatus applied to cellular communication system provided according to the inventive method, including despreading in-phase solution adjust device, despreading orthogonal demodulation device, deserializer, subtracter, divider, divider and quadratic sum arithmetic unit.Wherein, receiving the despread in-phase solution of signal difference adjusts device and despreading orthogonal demodulation device to carry out despread-and-demodulation；Serioparallel exchange respectively is carried out through a deserializer to the signal after despread-and-demodulation；Carry out difference operation to the adjacent different frequency pilot signs after serioparallel exchange respectively to eliminate interference by subtracter；Cumulative be averaging is carried out to difference operation result respectively by divider to disturb with further eliminate；The output of divider is subjected to division arithmetic in divider, to obtain the phase offset estimate of channel；The output of divider is subjected to quadratic sum computing in quadratic sum arithmetic unit, to obtain the amplitude fading estimate of channel.
The channel estimation methods of the present invention, it is to transmit interference in transmitting terminal and decline to be respectively provided with various forms of frequency pilot signs of correlation, interference is eliminated by the computing to adjacent multi-form frequency pilot sign in receiving terminal, make under the conditions of multiple cell interference etc., do not use Multiuser Detection, the influence of interference still can be effectively eliminated, the blue or green true channel parameter estimation information of ^ is provided, reduces the complexity of system.Brief Description Of Drawings
Fig. 1 is the basic schematic block diagram of a wireless communication system.
Fig. 2 is frame structure schematic diagram.
Fig. 3 is four kinds of frequency pilot sign design embodiment schematic diagrames of the present invention.
Fig. 4 is a kind of channel estimating apparatus schematic block diagram according to the inventive method.Implement the mode of the present invention
Below by formula statement and with reference to accompanying drawing, the present invention will be described in detail.
Accompanying drawing 1 is refer to, in k-th of sampling instant, the signal that reception device 105 is received is： rk =aksk +Ik+nk (1)
R in formulat,^ ,/A, k-th of sampling instant, the signal that reception device 105 is received, the signal that dispensing device 101 is launched, the fading factor of fading channel 102, the interference signal 106 from same cell and other cells, and white noise signal 107 are illustrated respectively in.
Estimate signal or channel parameter by frequency pilot sign, and using the estimated result of frequency pilot sign as the reference of subsequent data symbol, and these estimated results keep constant in a frame in, now the frame structure refer to the attached drawing 2 of system.
Realize that the core of the inventive method is in the design of pilot configuration.Traditional pilot configuration design is all transmission identical frequency pilot sign, and the present invention is then that different frequency pilot signs are transmitted in same subframe, so-called difference can refer to its position difference on signal constellation (in digital modulation) figure, it is optimal when the correlation properties value between two different frequency pilot signs is minimum and planisphere distance is the bigger the better.Interference between the different frequency pilot signs of the same subframe is in related area, and decline is also in related area.
Refer to the attached drawing 3, accompanying drawing 3 shows the structure design of several frequency pilot signs of the present invention.Wherein, (a) and（B) frequency pilot sign shown is You Duo Group frequency pilot signs Chong Fu Group into mutually different between every group of frequency pilot sign.（A) it is illustrated that by 2 different frequency pilot signs, Ρ2One group is constituted, Ν groups is had and constitutes 2 Ν frequency pilot signs.（B) it is illustrated that by 1 group of 2N mutually different frequency pilot sign Ρ7、 Ρ2、 Ρ3、 Ρ4"-·'Ρ2Ν-ι、 Ρ2ΝComposition.Here N value, which should be met, makes interference and decline between different frequency pilot signs be respectively provided with correlation.
(c) and（D) frequency pilot sign shown is made up of multigroup frequency pilot sign, and every group is made up of identical frequency pilot sign, and different frequency pilot signs is used between group and group.（C) it is illustrated that respectively by 2 identical frequency pilot signs and ^, P2With P2, ····· ·ΡΝ- ι and PN-!, PNOne group is constituted with PN, N groups is had and constitutes 2N frequency pilot sign, P2, ·····
PNFor！^ mutually different frequency pilot signs.（D) it is illustrated that by N number of identical frequency pilot sign P7One group is separately constituted with A, 2N frequency pilot sign of 2 groups of compositions is had, and2Led for different two
Frequency symbol.Here N value, which should also be met, makes interference and decline between different frequency pilot signs be respectively provided with correlation.
Below by taking Fig. 3-(a) as an example, great convenience and the effectively elimination interference that channel estimation is brought are transformed to by this pilot configuration of derivation explanation.
It is located at the frequency pilot sign within a frame and has 2N, transmits signal A in even number frequency pilot sign in odd number frequency pilot sign transmission signal, i.e., k-th frequency pilot sign is：
{ ( 2 )
Wherein：
Pi = cos(fi)t + 0)-Qk sinOt + 0) = Akcos(6¾ + . + ^ ) ( ） p2 = Ik cos(ot + + sm(ot + φ0) = Α!( cos( + φ0- φ ^ pass through after fading channel, addition of the interference of fading factor and white noise, receive the form and formula of signal（1) expression is somewhat like.Now have：
, j」 k cos(6)t + φ0 +φά1ι +φΙ[) + ΙΙζ + nk k=l,3,-- ·,2Ν-1 ( Λ、 rk = kpkd +Ik +nk =< t 、、 ( 4 )
[ak cos(iyt + φ0+ φΛ -^) + //c + nkK=2,4, ', the phase offset introduced for decline in 2 Ν formulas.
Because the interval time between adjacent pilot symbols is shorter, and interference between the different frequency pilot signs has correlation, and decline also has correlation, thus has a between the adjacent frequency pilot signk =ak_x , pdk =(pdw, Ik =Ik_x(k=l, 2, ···, N ).Therefore, to 2k-l, 2k frequency pilot sign has：
r2k =
+n2k ( 6 ) k=l, 2, ··', N
Shown in refer to the attached drawing 4, the signal that now receiving terminal is received completes in-phase solution by despread-and-demodulation device 401 and adjusted, and is exported by deserializer 403；Completed just by despread-and-demodulation device 402
Demodulation is handed over, is exported by deserializer 404, respectively obtains following signal：
(7) d(2k-l)o =
+ (24-1) + n 0(2k-l) (8) diks = a2k A2k COSOQ + φ21ίOne φά2Ιί ) + Is2k + ns2k ( 9 ) dike = ^2kA2k sin(^0 + u― <Pd2k) + I。u + nolk ( 10) k=l, 2, ···, N
Arithmetic unit 405 is used for completing（7)-(9), have：
Ch = -2α, Λ sin + φ& ) sin( ) + n、skK=l, 3,5,2N- 1 (11) arithmetic units 406 are used for completing（8)-(10), have：
Cks = 2akAk cos(^0 + ^)sin(^) + n、okIn k=l, 3,5,2N-1 (12) formula：
k=l,3,5 , 2N-1 ( 13) k = nok - κ=1' 3, 5,…… , 2N-1 ( 14) n k , n kIt is the white Gaussian noise of zero-mean.
From（11), the expression of (12) can be seen that noise and be essentially eliminated, and is the energy of accurate estimation signal, also to remove the influence of white noise.Needs pair for this（ 11 )、（12) formula is averaged.
Divider 407,408 is right respectively（11), (12) formula is averaged.Due to having 2N frequency pilot sign, the derivation more than, by taking additive operation between adjacent pilot symbols,
(11)、（12) it is only remaining N in formula, therefore can be right（11)、（12) formula takes N averagely： fsk ( 15 )
cko =— ∑2^ cos(^0 + φά(ί ) sin(^, ) +—∑ n k(16) pass through（15), the average calculating operation of (16), largely eliminates the influence of noise,
And due to P2Reception interference and have correlation essentially identical by the decline of transmission channel, therefore have：
cfa = 2 kAk sin + ^)sin(^) + n ( 17 ) cko = 2 kAk cosO0 + ¾) sin(^ ) + n'0(18) ^ now, the very little become after average.
Calculated by quadratic sum arithmetic unit 409（17) * (17)+(18) * (18), is obtained：
Because frequency pilot sign is known signal, so 4, sitin is known signal, while n " value very little, can be neglected herein, thus formula（Divided by the sin of constant term 4 19)2(^), so that it may obtain the estimate c of signal amplitude fading factork。
Divider 410 is used for carrying out formula（17) computing of/(18), is obtained：
tg9sp=tg+(20) are similarly, since frequency pilot sign is known signal, so being Given information, n " value very little can be neglected, so that we can obtain phase pushing figure ^ estimate.
Due to largely having eliminated interference and the influence of noise when estimating channel parameter ^ ,+^, so the estimate that the precision of estimation will from far away higher than the presence interference of prior art and during noise, thus be a kind of effective channel estimation methods.The present invention is the different frequency pilot signs that transmission interference and decline are respectively provided with correlation in the same subframe of transmitting terminal, in receiving terminal by carrying out computing to the different frequency pilot signs received to eliminate interference, obtains the exact value of channel estimation.The channel estimation methods provided using the present invention, can be in the case of multiple cell multi-user interference, provide accurate channel estimation value, and avoid the Multiuser Detection of complexity, the complexity of system is reduced, is a kind of efficient channel method of estimation for being applied to cellular mobile communication or noisy communication system.Above only with a preferred embodiment of the present invention
To illustrate, not to limit the present invention, any any modification, equivalent substitution and improvements within the spirit and principles in the present invention, made etc., it should be included within scope of the presently claimed invention.
Claims (1)
- Claims1st, a kind of channel estimation methods applied to cell mobile communication systems, it is characterised in that this method includes：Different frequency pilot signs are transmitted in the same subframe of transmitting terminal, the interference between the different frequency pilot signs has correlation, decline also has correlation；Following steps are carried out in receiving terminal：(a) the different frequency pilot signs received are de-spread respectively, in-phase solution is adjusted and serioparallel exchange and despreading, quadrature demodulation and serioparallel exchange；Except interference, and to subtracting each other after result of calculation carry out respectively average calculating operation with it is further eliminate disturb；(c) result of calculation obtained by step b is divided by, obtains channel phase offset estimate；It is squared to step b result of calculation and, obtain channel magnitude decline estimate.2nd, channel estimation methods according to claim 1, it is characterised in that：Described different frequency pilot signs refer to be made up of as one group K different frequency pilot signs, transmission2N/K Group 2N frequency pilot sign, wherein K, Ν are positive integer.3rd, channel estimation methods according to claim 2, it is characterised in that：Described Κ is 2, transmits Ν groups totally 2 Ν frequency pilot sign；The described difference adjacent different frequency pilot signs progress additive operations after serioparallel exchange referred between the frequency pilot sign for the frequency pilot sign and neighbouring even-numbered position for calculating odd bits.4th, the channel estimation methods described in claim 2 are occupied, it is characterised in that：Described Κ is 2 Ν, transmits 1 group of totally 2 Ν different frequency pilot sign；Described refers to calculate the difference between Μ frequency pilot signs and Μ -1 frequency pilot signs to the adjacent different frequency pilot signs progress additive operations after serioparallel exchange, and wherein Μ is the positive even numbers less than or equal to 2 Ν.5th, channel estimation methods according to claim 1, it is characterised in that： Described different frequency pilot signs refer to be made up of as one group K identical frequency pilot sign, the common 2N frequency pilot sign of the different 2N/K groups of transmission, and wherein K, Ν is positive integer.6th, channel estimation methods according to claim 5, it is characterised in that：Described Κ is 2, transmits different Ν groups totally 2 Ν frequency pilot sign；The described difference for referring to calculate to the adjacent different frequency pilot signs progress additive operations after serioparallel exchange between the difference between the adjacent pilot symbols of odd bits and the adjacent pilot symbols of even bit.7th, channel estimation methods according to claim 5, it is characterised in that：Described Κ is Ν, transmits the totally 2 Ν frequency pilot sign of different 2 groups；The described frequency pilot sign for referring to calculate mat woven of fine bamboo strips Μ to the adjacent different frequency pilot sign Jin Hang Xiang Minus computings after serioparallel exchange and the（Ν+Μ) position frequency pilot sign between difference, wherein Μ is positive integer less than or equal to Ν.8th, according to any described channel estimation methods of claim 1 to 7, it is characterised in that：Its correlation properties value that is most preferably set to of described different frequency pilot signs is minimum.9th, a kind of channel estimating apparatus applied to cellular communication system, it is characterised in that：The device includes despreading in-phase solution and adjusts device, despreading orthogonal demodulation device, deserializer, subtracter, divider, divider and quadratic sum arithmetic unit；Wherein, receiving the despread in-phase solution of signal difference adjusts device and despreading orthogonal demodulation device to carry out despread-and-demodulation；Serioparallel exchange respectively is carried out through a deserializer to the signal after despread-and-demodulation；Carry out difference operation to the adjacent different frequency pilot signs after serioparallel exchange respectively to eliminate interference by subtracter；Cumulative be averaging is carried out to difference operation result respectively by divider to disturb with further eliminate；The output of divider is subjected to division arithmetic in divider, to obtain the phase offset estimate of channel；The output of divider is subjected to quadratic sum computing in quadratic sum arithmetic unit, to obtain the amplitude fading estimate of channel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB008136033A CN1152537C (en) | 2000-12-14 | 2000-12-14 | Channel estimating method |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/CN2000/000576 WO2002049301A1 (en) | 2000-12-14 | 2000-12-14 | A channel estimating method |
| CNB008136033A CN1152537C (en) | 2000-12-14 | 2000-12-14 | Channel estimating method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1385017A true CN1385017A (en) | 2002-12-11 |
| CN1152537C CN1152537C (en) | 2004-06-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB008136033A Expired - Fee Related CN1152537C (en) | 2000-12-14 | 2000-12-14 | Channel estimating method |
Country Status (4)
| Country | Link |
|---|---|
| CN (1) | CN1152537C (en) |
| AU (1) | AU2001221413A1 (en) |
| HK (1) | HK1050783A1 (en) |
| WO (1) | WO2002049301A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101505495B (en) * | 2008-02-05 | 2013-12-11 | 夏普株式会社 | Interference coordination method and base station for uplink FDM cellular communication system |
| CN113518048B (en) * | 2020-04-10 | 2022-06-14 | 华为技术有限公司 | Channel parameter calculation method and device |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3237628B2 (en) * | 1998-11-02 | 2001-12-10 | 日本電気株式会社 | Channel characteristics estimator |
| US6452917B1 (en) * | 1999-04-08 | 2002-09-17 | Qualcomm Incorporated | Channel estimation in a CDMA wireless communication system |
| US6614857B1 (en) * | 1999-04-23 | 2003-09-02 | Lucent Technologies Inc. | Iterative channel estimation and compensation based thereon |
-
2000
- 2000-12-14 CN CNB008136033A patent/CN1152537C/en not_active Expired - Fee Related
- 2000-12-14 WO PCT/CN2000/000576 patent/WO2002049301A1/en active Application Filing
- 2000-12-14 AU AU2001221413A patent/AU2001221413A1/en not_active Abandoned
-
2003
- 2003-04-24 HK HK03102926A patent/HK1050783A1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| HK1050783A1 (en) | 2003-07-04 |
| WO2002049301A1 (en) | 2002-06-20 |
| CN1152537C (en) | 2004-06-02 |
| AU2001221413A1 (en) | 2002-06-24 |
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