(19)
(11)EP 2 164 214 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
09.01.2019 Bulletin 2019/02

(21)Application number: 07816853.1

(22)Date of filing:  16.11.2007
(51)International Patent Classification (IPC): 
H04L 25/02(2006.01)
H04L 27/26(2006.01)
(86)International application number:
PCT/CN2007/003247
(87)International publication number:
WO 2009/003327 (08.01.2009 Gazette  2009/02)

(54)

A CHANNEL ESTIMATION METHOD OF THE MOBILE COMMUNICATION SYSTEM BASED ON THE TIME DIVISION PILOT FIELD

KANALSCHÄTZUNGSVERFAHREN EINES MOBILKOMMUNIKATIONSSYSTEMS AUF DER BASIS DES ZEITMULTIPLEX-PILOTFELDS

PROCÉDÉ D'ESTIMATION DE CANAL DU SYSTÈME DE COMMUNICATION MOBILE, BASÉ SUR LE CHAMP PILOTE À RÉPARTITION DANS LE TEMPS


(84)Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC MT NL PL PT RO SE SI SK TR

(30)Priority: 04.07.2007 CN 200710075806

(43)Date of publication of application:
17.03.2010 Bulletin 2010/11

(73)Proprietor: ZTE Corporation
Shenzhen, Guangdong 518057 (CN)

(72)Inventors:
  • XU, Guoping
    Guangdong 518057 (CN)
  • XIN, Yu
    Guangdong 518057 (CN)
  • REN, Liang
    Guangdong 518057 (CN)
  • ZHANG, Xin
    Guangdong 518057 (CN)
  • YANG, Dacheng
    Guangdong 518057 (CN)

(74)Representative: Novagraaf Technologies 
Bâtiment O2 2, rue Sarah Bernhardt CS90017
92665 Asnières-sur-Seine Cedex
92665 Asnières-sur-Seine Cedex (FR)


(56)References cited: : 
CN-A- 1 527 513
CN-A- 1 909 526
KR-A- 20060 001 646
CN-A- 1 747 462
JP-A- 2007 013 310
  
  • TAKEDA K ET AL: "Pilot-assisted Channel Estimation Based on MMSE Criterion for DS-CDMA with Frequency-domain Equalization", IEEE 61ST VEHICULAR TECHNOLOGY CONFERENCE - VTC2005, vol. 1, 30 May 2005 (2005-05-30), - 1 June 2005 (2005-06-01), pages 447-451, XP010855433, NJ, USA DOI: 10.1109/VETECS.2005.1543330 ISBN: 978-0-7803-8887-1
  • ADACHI F ET AL: "Modulation, coding and signal processing for wireless communications - broadband CDMA techniques", IEEE WIRELESS COMMUNICATIONS, vol. 12, no. 2, 1 April 2005 (2005-04-01), pages 8-18, XP011130569, NJ, US ISSN: 1536-1284, DOI: 10.1109/MWC.2005.1421924
  • DAVID FALCONER ET AL: "Frequency Domain Equalization for Single-Carrier Broadband Wireless Systems", IEEE COMMUNICATIONS MAGAZINE, vol. 40, no. 4, 1 April 2002 (2002-04-01), pages 58-66, XP011092809, NJ, US ISSN: 0163-6804
  
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


Description

Field of Invention



[0001] The present invention relates to communication system, and in particular to a channel estimation method of the mobile communication system based on the time division pilot field.

Background of the Invention



[0002] Channel estimation technology can generally be classified into non-blind estimation and blind estimation, and semi-blind estimation derived from them. Generally, using the non-blind estimation can realize better effect with lower calculation complexity, thus it is more facilitated to follow the change of a wireless channel, therefore the receiver performance can be improved. Commonly, a great volume of matrix computation has to be processed while using the traditional channel estimation method, resulting in higher complexity and longer time delay for processing.

[0003] For example, in a Code Division Multiple Access (CDMA) wireless communication system, due to high transmission rate, the Coherent Detection technology is required to be used to obtain comparatively high performance, thus channel estimation becomes an important aspect of the investigation relating to CDMA. Precise channel estimation can improve the performance of a CDMA system, and the results of channel estimation can be applicable to the RAKE receiver, the time domain equalization receiver, and the frequency domain equalization receiver of a CDMA system. However, the prior art does not provide a channel estimation method performing fast and precise calculation.

[0004] TAKEDA K ET AL: "Pilot-assisted channel estimation based on MMSE criterion for DS-CDMA with frequency-domain equalization" IEEE 61ST VEHICULAR TECHNOLOGY CONFERENCE -VEC2005, VOL. 1, 30 MAY 2005; and ADACHI F ET AL: "Modulation, coding and signal processing for wireless communications-broadband CDMA techniques", IEEE WIRELESS COMMUNICATIONS, vol. 12, no.2 1 April 2005, provide respective technical solutions; however, the above mentioned problem still remains unsolved.

Summary of the Invention



[0005] In view of the above problem, the present invention provides a channel estimation method of mobile communication system based on time division pilot field, wherein a pilot sequence having a cyclic prefix (CP) is utilized to perform channel estimation in frequency domain. The channel estimation based on Fast Fourier Transform (FFT)/Inverse Fast Fourier transform (IFFT) module has less complexity in calculation than the conventional time domain channel estimation, so the system delay caused by channel estimation can be reduced.

[0006] The channel estimation method according to the embodiments of the present invention comprises the steps defined in claim 1 and further detailed in the dependent claims.

[0007] The present invention is defined by the appended claims and limited only by their scope.

[0008] In the following, any embodiment(s) referred to and not fully falling within the scope of said appended claims is (are) to be interpreted as example(s) useful for understanding the present invention.

[0009] In the present invention, the linear convolution between the pilot sequence and the channel is transformed into the cyclic convolution between the pilot sequence and the channel by employing the pilot field format with added CP, thus the channel estimation in frequency domain can be performed based on FFT/IFFT module, the computation amount of the channel estimation in frequency domain is substantially less than that of the channel estimation in time domain. In addition, if the whole pilot field is comparatively long while the maximum delay of the channel is comparatively short, the pilot sequence with attached CP can be repeatedly transmitted several times. At the receiving end, the received pilot sequence is averaged (if the pilot sequence with attached CP is transmitted more than 2 times) to obtain an averaged received data of the pilot sequence, thus the effect of Gauss noise on the pilot sequence is reduced.

Brief Description of the Drawings



[0010] The illustrated drawings herein provide a further understanding to the present invention and form a part of the application. The exemplary embodiments and the description thereof are intended to explain the present invention not limit the proper scope of the present invention, which is determined only by the scope of the appended claims, wherein:

Fig.1 is a schematic view of the principle of the time division pilot field employed in the channel estimation method according to the embodiment of the present invention;

Fig.2 is a model diagram of the channel model of M.1225 vehicle-loaded channel A according to the embodiment of the present invention;

Fig.3 is a schematic view of the frame format of the downlink channel physical layer specified in the High Rate Packet Data Protocol (HRPD); and

Fig.4 is a schematic view of the mean square error obtained from the processing by the channel estimation method according to the embodiment of the present invention.


Detailed Description of Embodiments



[0011] The detailed description of the embodiment of the present invention will be provided in connection with the drawings.

[0012] In order to perform channel estimation of the mobile communication system in frequency domain based on FFT/IFFT module, the most important problem is to transform the linear convolution between the pilot field and the channel into the cycle convolution between the pilot field and the channel. The present invention employs the processing method similar to that of the Orthogonal Frequency Division Multiplexing (OFDM) system, i.e., attaching a cyclic prefix (CP) in front of a pilot sequence. A pilot sequence is selected, wherein a plenty of frequency information is demanded in the pilot sequence because that Least Square (LS) Criterion, Linear Maximum Mean square error (LMMSE) Criterion, or Maximum Mean Square Error (MMSE) Criterion is required to be employed to perform channel estimation in frequency domain. That is to say, after the FFT transform, the value of zero is not allowed in the sampling sequence in frequency domain corresponding to the pilot sequence. Generally, the real or complex pseudo-random sequence has such feature. In prior art, the Chu sequence or the Newman sequence has closed-form expressions, and the amplitude of the sampling sequence in time domain and the sampling sequence in frequency domain corresponding to the time domain of the Chu sequence or the Newman sequence are constant, such sequence can prevent the Gauss noise from being amplified by the comparative small sampling amplitude in frequency domain in LS estimation. However, the Chu sequence and the Newman sequence are complex number sequences, thus an additional path of signal is required to transmit such pilots compared to the real pseudo-random sequence.

[0013] As shown in Fig.1, setting the CP of the pilot sequence is not shorter than the maximum delay of the channel, if the length of the pilot field specified in the protocol is long enough, the pilot sequence with an attached CP will be transmitted several times consecutively and thus a pilot field will be formed. The repeatedly transmitted pilot sequence will be averaged to reduce the effect of Gauss noise on the precision of the channel estimation.

[0014] The channel estimation method according to the embodiment of the present invention is the channel estimation based on FFT/IFFT module; the processing method is similar to that in OFDM system. For the purpose of convenience, the present specification will refer to the terminologies in OFDM system, the frequency domain sampling signal derived by transforming the time domain pilot field of general mobile communication system is considered as the signal on an equivalent sub-carrier.

[0015] Assuming that at the transmitting end, the length of the pilot sequence is N, and the length of the set CP is 1, then the length of the pilot sequence attached with a CP is N+l and is transmitted n times . The total length of the pilot field specified by the system is K, then the following equation exists:



[0016] The receiving end sums the repeated pilot sequences correspondingly, then calculates the average value of the sum. From transmitting to receiving, various noise of the channel can be attributed to Gauss white noise; although there is limit to bandwidth, under the assumption of the Central Limit Theorem being satisfied, the sum of the various interferences greatly resembles Gauss white noise. If the Gauss white noise of each pilot sequence follows (0,σ2) distribution, after the averaging of n pilot sequences, the Gauss white noise of the derived average-value sequences follows (0,σ2/n) distribution.

[0017] Assuming that the sampling sequence R = [R(0),R(1),···R(N-1)] in frequency domain can be obtained from the received signal being transformed to frequency domain based on the FFT module. Wherein, N is the number of the equivalent sub-carriers in the communication system, also represents the length of the pilot sequence; the average value of the known pilot sequence is transformed into frequency domain to get the sequence X = [X(0),X(1),···X(N-1)]. The channel estimation in frequency domain based on LS criterion is,

Wherein, LS = [LS(0),ĤLS(1),···,LS(N-1)] represents the LS estimation of the frequency response of each equivalent sub-carrier in the communication system. If the channel estimation is done based on MMSE criterion, the computation amount is comparatively large, so LMMSE criterion with comparatively low complexity can be employed to approach the precision of MMSE channel estimation. Based on the Signal Noise-to-Ratio (SNR) of the channel, LMMSE estimation utilizes one LMMSE modification matrix to modify the result of LS channel estimation using the following computation method:

Wherein, RHH = E{HHH} is the expectancy of the self-correlating matrix of the channel impulse response, β = E{|xk|2}/E{|1/xk|2, k = 1,2,···N-1 is the constant derived from the computation based on the transmitted pilot sequence xk, k = 1,2,···N-1, and SNR is the Signal-to-Noise Ratio.

[0018] After the LS estimation or LMMSE (MMSE) estimation of the channel frequency response is obtained from the computation, the channel estimation will be transformed to time domain via IFFT module with a length of N. If N is larger than L, which is the maximum delay of the channel, the estimation value whose length is larger than L among the obtained result is set to zero, thus the error of the channel estimation will be further reduced, and the LS estimation and LMMSE (MMSE) estimation result of the channel impulse response will be obtained. The impulse response estimation can be directly applied to the time domain equalization of the communication system or the RAKE receiver, and it also can be applied to the frequency domain equalization of the communication system after being transformed back into frequency domain.

[0019] A further embodiment will be provided to explain the channel estimation method according to the embodiment of the present invention. An simulation platform similar to that of High Rate Packet Data (HRPD) downlink is established as follows: the chip rate of the uncoded system is 1.2288 Mcps, and 16-order Walsh code spreaded spectrum is employed. The channel employs a M.1225 vehicle-loaded channel A simulation model, as shown in Fig. 2, the pilot field employs the complex pseudo-random sequence of a length of 16, the length of CP is set as 8, and the pilot sequence attached with CP is repeatedly transmitted 4 times, thus form a pilot field whose total length is 96 . Note that, the length of the pilot field specified by HRPD is 96 chips. As shown in Fig.3, in the frame format of the downlink channel physical layer specified in HRPD protocol, the pilot field is an all "1" chip sequence, after QPSK spreading module processing, the pilot field becomes a PN sequence of complex number. In order to satisfy the requirement on the setting of the pilot field, the portion of the pilot field corresponding to the complex pseudo-random sequence utilized in QPSK spreading is modified into the format same with the format with attached CP shown in Fig.1. After QPSK spreading module processing, the all "1" pilot field will be transformed into the format required by the channel estimation method according to the embodiment of the present invention.

[0020] In order to compare the precision of channel estimation, the defined mean square error of the channel estimation is given below,

Wherein, []* represents the conjugate operator, N represents the number of the HRPD equivalent sub-carriers, also represents the length of FFT/IFFT. H(k),k=0,1,···,N-1 is the real frequency response of the channel, and (k),k=0,1,···,N-1 is the estimated frequency response.

[0021] Fig.4 shows the simulation result through the simulation platform, wherein, the Mean Square Error (MSE) curve represents the mean square error of the frequency response estimation of the channel in frequency domain, the Signal-to-Noise Ratio (SNR) is the SNR during the simulation. Curve of FD LS estimation and Curve of FD LMMSE estimation represents the result utilizing the LS estimation and the LMMSE estimation respectively in frequency domain. As shown in Fig.4, when the computation complexity is less than that of the LS channel estimation in time domain, the LS channel estimation in frequency domain provides a more precise result. LMMSE estimation can further improve the channel estimation precision, and it facilitates to improve the performance of the CDMA equalization algorithm.

[0022] As a summery of the above description, the essence of the present invention is a channel estimation method based on the continuously transmitted time division pilot. The channel estimation in frequency domain for the single carrier system (e.g. , CDMA system) is realized by employing the format of a pilot field attached with a cyclic prefix. For the pilot field attached with a CP, by utilizing the Least Square (LS) criterion, Linear Minimum Mean Square Error (LMMSE) criterion or Minimum Mean Square Error (MMSE) criterion for channel estimation, similar to that in OFDM, the channel estimation for single carrier system is carried out. In connection with the repeatedly transmitting pilot method used for channel estimation according to the embodiment of the present invention, the original calculation formula and the estimation steps of the LS, LMMSE and MMSE channel estimation in OFDM are modified, and the modified LS, LMMSE and MMSE algorithm can further improve the precision of channel estimation in frequency domain. While ensuring comparably high channel estimation precision, the modified algorithm can make the computation burden for channel estimation less than that of channel estimation in time domain with same performance. Moreover, in the CDMA system with similar to HRPD downlink channel, the frequency equalization (or in connection with interference and cancellation) algorithm is more suitable for user signal recovery, and facilitates the result of the channel estimation in frequency domain to be easily applied to frequency domain equalization receiving algorithm.


Claims

1. A channel estimation method in a single carrier mobile communication system based on a time division pilot field; said channel estimation method comprising the following steps:

step 1, transmitting by a transmitting end a time division pilot sequence having a cyclic prefix;

step 2, transforming by a receiving end the time division pilot sequence into frequency domain using a Fast Fourier Transform module, and performing channel estimation to obtain a channel frequency response estimation result;

said channel estimation method being characterized by further comprising:

step 3, transforming by the receiving end the channel frequency response estimation result back into time domain using an Inverse Fast Fourier Transform module, and obtaining a channel impulse response estimation result, wherein when the length of the channel impulse response estimation result is larger than a maximum delay of the channel, the estimation value or values of said channel impulse response estimation result having an index larger than the maximum delay of the channel among the channel impulse response estimation result is set to zero and obtaining thereby a new channel impulse response estimation result; and

step 4, using said new channel impulse response estimation result in an equalization process of the single carrier mobile communication system.


 
2. The channel estimation method of the mobile communication system based on the time division pilot field according to Claim 1 is characterized in that, in step 1, the transmitting end repeatedly transmits the time division pilot sequence having the cyclic prefix, and the following step is included between step 1 and step 2: averaging the time division pilot sequence received at the receiving end.
 
3. The channel estimation method of the mobile communication system based on the time division pilot field according to Claim 1 or 2 is characterized in that, in the said step 2, one or more of the following criterions are employed to perform channel estimation: Least Square criterion, Linear Minimum Mean Square Error criterion, Minimum Mean Square Error criterion.
 
4. The channel estimation method of the mobile communication system based on the time division pilot field according to Claim 1 or 2 is characterized in that step 4 comprises: utilizing the new channel impulse response estimation result in a time domain equalization process of the mobile communication system.
 
5. The channel estimation method of the mobile communication system based on the time division pilot field according to Claim 3 is characterized in that step 4 comprises: utilizing the new channel impulse response estimation result in a time domain equalization process of the mobile communication system.
 
6. The channel estimation method of the mobile communication system based on the time division pilot field according to Claim 1 or 2 is characterized in that step 4 comprises: transforming the new channel impulse response estimation result back into frequency domain, and utilizing the transforming result in a frequency domain equalization process of the mobile communication system.
 
7. The channel estimation method of the mobile communication system based on the time division pilot field according to Claim 3 is characterized in that step 4 comprises: transforming the new channel impulse response estimation result back into frequency domain, and utilizing the transforming result in a frequency domain equalization process of the mobile communication system.
 


Ansprüche

1. Kanalschätzverfahren in einem Einzelträger-Mobilkommunikationssystem, das auf einem Zeitmultiplex-Pilotfeld basiert; wobei das Kanalschätzverfahren die folgenden Schritte umfasst:

Schritt 1, Übertragen, durch ein Übertragungsende, einer Zeitmultiplex-Pilotsequenz, die ein zyklisches Präfix aufweist;

Schritt 2, Transformieren, durch ein Empfangsende, der Zeitmultiplex-Pilotsequenz in Frequenzdomäne unter Verwendung eines Fast Fourier Transform-Moduls, und Durchführen von Kanalschätzung, um ein Kanalfrequenzgang-Schätzergebnis zu erhalten;

wobei das Kanalschätzverfahren dadurch gekennzeichnet ist, dass es weiter umfasst:

Schritt 3, Transformieren, durch das Empfangsende, des Kanalfrequenzgang-Schätzergebnisses zurück in Zeitdomäne unter Verwendung eines Inverse Fast Fourier Transform-Moduls, und Erhalten eines Kanalimpulsgang-Schätzergebnisses, wobei, wenn die Länge des Kanalimpulsgang-Schätzergebnisses größer ist als eine maximale Verzögerung des Kanals, der oder die Schätzwert/-werte des Kanalimpulsgang-Schätzergebnisses, die einen Index aufweisen, der größer ist als die maximale Verzögerung des Kanals aus dem Kanalimpulsgang-Schätzergebnis auf Null gesetzt werden, und dadurch Erhalten eines neuen Kanalimpulsgang-Schätzergebnisses; und

Schritt 4, Verwenden des neuen Kanalimpulsgang-Schätzergebnisses in einem Entzerrprozess des Einzelträger-Mobilkommunikationssystems.


 
2. Auf dem Zeitmultiplex-Pilotfeld basierendes Kanalschätzverfahren des Mobilkommunikationssystems nach Anspruch 1, dadurch gekennzeichnet, dass in Schritt 1 das Übertragungsende wiederholt die das zyklische Präfix aufweisende Zeitmultiplex-Pilotsequenz überträgt, und der folgende Schritt zwischen Schritt 1 und Schritt 2 eingeschlossen ist: Mitteln der am Empfangsende empfangenen Zeitmultiplex-Pilotsequenz.
 
3. Auf dem Zeitmultiplex-Pilotfeld basierendes Kanalschätzverfahren des Mobilkommunikationssystems nach Anspruch 1 oder 2, ist dadurch gekennzeichnet, dass im Schritt 2 eine oder mehrere der folgenden Kriterien eingesetzt werden, um Kanalschätzung durchzuführen: Kriterium des kleinesten Quadrats, Kriterium des linearen minimalen mittleren quadratischen Fehlers, Kriterium des minimalen mittleren quadratischen Fehlers.
 
4. Auf dem Zeitmultiplex-Pilotfeld basierendes Kanalschätzverfahren des Mobilkommunikationssystems nach Anspruch 1 oder 2, ist dadurch gekennzeichnet, dass Schritt 4 umfasst:
Verwenden des neuen Kanalimpulsgang-Schätzergebnisses in einem Zeitdomänen-Entzerrprozess des Mobilkommunikationssystems.
 
5. Auf dem Zeitmultiplex-Pilotfeld basierendes Kanalschätzverfahren des Mobilkommunikationssystems nach Anspruch 3, ist dadurch gekennzeichnet, dass Schritt 4 umfasst:
Verwenden des neuen Kanalimpulsgang-Schätzergebnisses in einem Zeitdomänen-Entzerrprozess des Mobilkommunikationssystems.
 
6. Auf dem Zeitmultiplex-Pilotfeld basierendes Kanalschätzverfahren des Mobilkommunikationssystems nach Anspruch 1 oder 2, ist dadurch gekennzeichnet, dass Schritt 4 umfasst:
Transformieren des neuen Kanalimpulsgang-Schätzergebnisses zurück in Frequenzdomäne, und Verwenden des Transformationsergebnisses in einem Frequenzdomänen-Entzerrprozess des Mobilkommunikationssystems.
 
7. Auf dem Zeitmultiplex-Pilotfeld basierendes Kanalschätzverfahren des Mobilkommunikationssystems nach Anspruch 3, dadurch gekennzeichnet, dass Schritt 4 umfasst:
Transformieren des neuen Kanalimpulsgang-Schätzergebnisses zurück in Frequenzdomäne, und Verwenden des Transformationsergebnisses in einem Frequenzdomänen-Entzerrprozess des Mobilkommunikationssystems.
 


Revendications

1. Procédé d'estimation de canal dans un système de communication mobile à porteuse unique sur la base d'un champ de pilotes par répartition dans le temps ; ledit procédé d'estimation de canal comprenant les étapes suivantes :

étape 1, la transmission, par une extrémité de transmission, d'une séquence de pilotes par répartition dans le temps comportant un préfixe cyclique ;

étape 2, la transformation, par une extrémité de réception, de la séquence de pilotes par répartition dans le temps dans le domaine de fréquence en utilisant un module de transformée rapide de Fourier, et l'exécution d'une estimation de canal pour obtenir un résultat d'estimation de réponse de fréquence de canal ;

ledit procédé d'estimation de canal étant caractérisé en ce qu'il comprend en outre :

étape 3, la transformation, par l'extrémité de réception, du résultat d'estimation de réponse de fréquence de canal dans le domaine de temps en utilisant un module de transformée rapide inverse de Fourier, et l'obtention d'un résultat d'estimation de réponse d'impulsion de canal, dans lequel, lorsque la longueur du résultat d'estimation de réponse d'impulsion de canal est supérieure à un retard maximal du canal, la valeur d'estimation ou les valeurs d'estimation dudit résultat d'estimation de réponse d'impulsion de canal ayant un indice supérieur au retard maximal du canal dans le résultat d'estimation de réponse d'impulsion de canal sont réglées à zéro et l'obtention de ce fait d'un nouveau résultat d'estimation de réponse d'impulsion de canal ; et

étape 4, l'utilisation dudit nouveau résultat d'estimation de réponse d'impulsion de canal dans un processus d'égalisation du système de communication mobile à porteuse unique.


 
2. Procédé d'estimation de canal du système de communication mobile sur la base du champ de pilotes par répartition dans le temps selon la revendication 1, caractérisé en ce que, à l'étape 1, l'extrémité de transmission transmet à répétition la séquence de pilotes par répartition dans le temps ayant le préfixe cyclique, et l'étape suivante est incluse entre l'étape 1 et l'étape 2 : le calcul de la moyenne de la séquence de pilotes par répartition dans le temps reçue à l'extrémité de réception.
 
3. Procédé d'estimation de canal du système de communication mobile sur la base du champ de pilotes par répartition dans le temps selon la revendication 1 ou 2, caractérisé en ce que, à ladite étape 2, un ou plusieurs des critères suivants sont employés pour effectuer une estimation de canal : critère des moindres carrés, critère de l'erreur quadratique moyenne minimale linéaire, critère de l'erreur quadratique moyenne minimale.
 
4. Procédé d'estimation de canal du système de communication mobile sur la base du champ de pilotes par répartition dans le temps selon la revendication 1 ou 2, caractérisé en ce que l'étape 4 comprend :
l'utilisation du nouveau résultat d'estimation de réponse d'impulsion de canal dans un processus d'égalisation dans le domaine de temps du système de communication mobile.
 
5. Procédé d'estimation de canal du système de communication mobile sur la base du champ de pilotes par répartition dans le temps selon la revendication 3, caractérisé en ce que l'étape 4 comprend : l'utilisation du nouveau résultat d'estimation de réponse d'impulsion de canal dans un processus d'égalisation dans le domaine de temps du système de communication mobile.
 
6. Procédé d'estimation de canal du système de communication mobile sur la base du champ de pilotes par répartition dans le temps selon la revendication 1 ou 2, caractérisé en ce que l'étape 4 comprend : la transformation du nouveau résultat d'estimation de réponse d'impulsion de canal dans le domaine de fréquence et l'utilisation du résultat de la transformation dans un processus d'égalisation dans le domaine de fréquence du système de communication mobile.
 
7. Procédé d'estimation de canal du système de communication mobile sur la base du champ de pilotes par répartition dans le temps selon la revendication 3, caractérisé en ce que l'étape 4 comprend :
la transformation du nouveau résultat d'estimation de réponse d'impulsion de canal dans le domaine de fréquence, et l'utilisation du résultat de la transformation dans un processus d'égalisation dans le domaine de fréquence du système de communication mobile.
 




Drawing











Cited references

REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Non-patent literature cited in the description