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WO2001001647A1 - Procede de calcul de sequences de donnees tirees d'un signal reçu - Google Patents

Procede de calcul de sequences de donnees tirees d'un signal reçu Download PDF

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Publication number
WO2001001647A1
WO2001001647A1 PCT/IB2000/000835 IB0000835W WO0101647A1 WO 2001001647 A1 WO2001001647 A1 WO 2001001647A1 IB 0000835 W IB0000835 W IB 0000835W WO 0101647 A1 WO0101647 A1 WO 0101647A1
Authority
WO
WIPO (PCT)
Prior art keywords
received signal
bits
calculated
data
correlations
Prior art date
Application number
PCT/IB2000/000835
Other languages
German (de)
English (en)
Inventor
Franz-Josef Hagmanns
Original Assignee
Marconi Communications Gmbh
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Marconi Communications Gmbh filed Critical Marconi Communications Gmbh
Priority to AU50981/00A priority Critical patent/AU5098100A/en
Publication of WO2001001647A1 publication Critical patent/WO2001001647A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H04B1/7073—Synchronisation aspects
    • H04B1/7075—Synchronisation aspects with code phase acquisition
    • H04B1/70751—Synchronisation aspects with code phase acquisition using partial detection
    • H04B1/70752—Partial correlation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H04B1/7073—Synchronisation aspects
    • H04B1/7075—Synchronisation aspects with code phase acquisition
    • H04B1/7077—Multi-step acquisition, e.g. multi-dwell, coarse-fine or validation
    • H04B1/70775—Multi-dwell schemes, i.e. multiple accumulation times
    • 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
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03006—Arrangements for removing intersymbol interference
    • H04L25/03171—Arrangements involving maximum a posteriori probability [MAP] detection

Definitions

  • the invention relates to a method for calculating data sequences from a received signal according to the preamble of claim 1 and a mobile radio system using such a method.
  • radio channels especially terrestrial ones, behave like time-variant linear filters.
  • a time-dependent transmission signal s (t r a) with a digital data sequence a generates a reception signal when transmitted via a radio channel which has a time-variant channel impulse response h (t, ⁇ )
  • the function w (t) stands for a Gaussian-distributed interference signal of the power density NQ.
  • the transmission signal is divided into short sections, the so-called bursts.
  • the channel impulse response can be regarded as almost constant during the duration of a burst, so that approximately for the received signal
  • the sample values of the channel impulse response h (1) are correlated with one another within a burst according to the Rayleigh channel model. This is described by the following autocorrelation matrix:
  • E [x] is the expected value of a random variable x. h * that conjugates complexes of h.
  • the samples of the interference signal are uncorrelated and have a variance of ⁇ 2 .
  • a receiver In the received signal, which is distorted by the transmission channel, a receiver must recognize the data sequence a, which forms the information to be transmitted. For this purpose, test symbols which are known to the receiver are inserted into the data symbols to be transmitted in the data sequence. Part of the transmission signal thereby becomes a test signal. With the test signal, the receiver can determine the properties of the transmission channel, in particular the channel impulse response. The reception then takes place in two successive steps:
  • This method is already used in mobile radio systems according to the GSM standard (Global System for Mobile Communications) and is also to be used in receivers of the third generation UMTS (Universal Mobile Telephone System) mobile radio system.
  • GSM Global System for Mobile Communications
  • UMTS Universal Mobile Telephone System
  • DE 43 10 852 Cl discloses a method for receiving radio signals which are coded according to the direct sequence spread spectrum method (DS-SS method). With this procedure the two-step procedure for channel impulse response estimation is dispensed with and the following optimized procedure is used instead:
  • DS-SS method direct sequence spread spectrum method
  • a disadvantage of this method is the computational effort for the calculation of the transmission signal for each possible data sequence, which increases exponentially with the length of the data sequence.
  • K bits of the data sequence a 2 ⁇ different data sequences and the associated transmission signals s (k, a) must be calculated.
  • the correlations u (l, a) have to be carried out and the vector u (a) and the quadratic form U (a) have to be calculated.
  • the technical problem on which the invention is based is therefore to specify a method for calculating data sequences from a received signal, the effort for calculating the data sequences only increasing linearly with the length of the data sequences.
  • the invention relates to a method for calculating data sequences from a received signal which has a large number of bursts. Each burst has M test and K data bits, the M test bits being known to a receiver.
  • the process has the following steps: a) correlating a first received signal section, which has M test and QM data bits, Q being less than K, with all possible transmit signals that can be generated with Q bits, b) correlating a second received signal section, which has the Q + lth data bit with all possible transmit signals are generated with the Q + l-th bit) calculating c of the correlations for the composite of the first and second receiving signal portion Emp ⁇ fang signal portion by summing the calculated in a) and b) be ⁇ correlations d ) calculating all 2 + ⁇ - ⁇ ⁇ square shapes with the in c) calculated correlations, e) Find the largest quadracischen shapes and congehö ⁇ membered data sequences from the 2Q + 1 -M square shapes, f
  • step a correlations are advantageously formed only with transmission signals that can be generated with Q bits, ie less than K bits of a burst. This reduces the computing effort in step a). Further, approximately the screened bran nesten square shapes approximation in step e), where ⁇ further reduced by the computing effort for the following steps.
  • u (l, a) l / N - ⁇ r ⁇ k + l) - s * (k, a)
  • r (k + l) the received signal section to be correlated
  • s (k, a) the transmitted signal to be correlated, which is generated by a data sequence a
  • N (M + K) B the number of samples of a burst and k a running parameter are the samples of the received signal section to be correlated.
  • step d) are preferably calculated as follows:
  • the 2 Q_M largest square shapes and the associated data sequences are searched for in step e).
  • a good approximation for calculating data sequences from a received signal is advantageously achieved in this way.
  • the method is particularly preferably used for received signals which are encoded using the direct sequence spread spectrum technique.
  • the burst is sampled in a receiver in such a way that samples are obtained per section B. The transmission signal that forms the burst can then pass through
  • the quantity a m e ⁇ 0,1 ⁇ is the bit of the th section and p m (k) is the spread sequence used to generate the transmission signal if the transmission signal is transmitted by means of spread spectrum technology.
  • the number of vectors to be calculated for all possible transmission signals with Q bits is 2 ° - -M .
  • the test bit is not taken into account in the formation of all possible transmission signals that can be generated with Q bits, since it is already known to the receiver.
  • the vectors u (a +) are recursively calculated from the vectors u (a Q ) for a transmission signal with Q + 1 sections of a burst.
  • the data sequence expanded by one section results from the data sequence with Q bits by appending an additional bit:
  • u Q + 1 (l) 1 / N- ⁇ r (k + l) -p Q + 1 (k) k
  • the number of square shapes is 2 Q + 1-M .
  • the largest of the quadratic forms is interested in the final recognition of the most likely transmitted data sequence.
  • the smallest 2 ⁇ - ⁇ of the total of 2 Q + 1-M square shapes can therefore be disregarded, so that exactly 2 Q ⁇ M square shapes are processed for the next step.
  • the next step is the same for reducing the square shapes to be processed. Overall, the computing effort remains constant in every further step.
  • the second step of the process is now repeated for all further sections Q + 2, Q + 3, ..., M + Kl.
  • the input variables for the nth step are the 2 ° - -M vectors u (a n -) calculated in the previous step, which are the largest quadratic

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Probability & Statistics with Applications (AREA)
  • Power Engineering (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)

Abstract

Procédé de calcul de séquences de données tirées d'un signal reçu qui comporte une pluralité de rafales. Chaque rafale possède M bits de test et K bits de données, les M bits de test étant connus d'un récepteur. Ledit procédé consiste (a) à corréler un premier segment de signal reçu qui possède M bits de test et Q-M bits de données, Q étant inférieur à K, avec tous les signaux d'émission possibles pouvant être produits avec Q bits, (b) à corréler un second segment de signal reçu qui possède le bit de données correspondant à Q+1 avec tous les signaux d'émission possibles pouvant être produits avec le bit correspondant à Q+1, (c) à calculer les corrélations pour le segment de signal reçu composé des premier et second segments de signal reçu par addition des corrélations calculées sous (a) et (b), (d) à calculer toutes les formes quadratiques 2Q+1-M à l'aide des corrélations calculées sous (c), (e) à rechercher les plus grandes formes quadratiques et les séquences de données associées à partir des formes quadratiques 2Q+1-M et (f) à répéter les étapes (b) à (e) avec les séquences de données trouvées à l'étape (e) et pour les segments de signal reçu présentant le bit correspondant à Q+2, Q+3 jusqu'à M+K-1.
PCT/IB2000/000835 1999-06-23 2000-06-08 Procede de calcul de sequences de donnees tirees d'un signal reçu WO2001001647A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU50981/00A AU5098100A (en) 1999-06-23 2000-06-08 Method of calculating data sequences from a received signal

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE1999128667 DE19928667A1 (de) 1999-06-23 1999-06-23 Verfahren zur Berechnung von Datensequenzen aus einem Empfangssignal
DE19928667.1 1999-06-23

Publications (1)

Publication Number Publication Date
WO2001001647A1 true WO2001001647A1 (fr) 2001-01-04

Family

ID=7912204

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2000/000835 WO2001001647A1 (fr) 1999-06-23 2000-06-08 Procede de calcul de sequences de donnees tirees d'un signal reçu

Country Status (3)

Country Link
AU (1) AU5098100A (fr)
DE (1) DE19928667A1 (fr)
WO (1) WO2001001647A1 (fr)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996008881A2 (fr) * 1994-09-12 1996-03-21 Nokia Telecommunications Oy Procede de reception et recepteur

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4310852C1 (de) * 1993-04-02 1994-04-28 Ant Nachrichtentech Verfahren zum burstweisen Empfang von bandbegrenzten Direct-Sequence Spread-Spectrum Signalen
US5506861A (en) * 1993-11-22 1996-04-09 Ericsson Ge Mobile Comminications Inc. System and method for joint demodulation of CDMA signals

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996008881A2 (fr) * 1994-09-12 1996-03-21 Nokia Telecommunications Oy Procede de reception et recepteur

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
HAGMANNS F J ET AL: "DIRECT-SEQUENCE SPREAD-SPECTRUM-UEBERTRAGUNG FUER ZELLULARE CDMA-MOBILFUNKSYSTEME", NACHRICHTENTECHNISCHE BERICHTE,DE,ANT NACHRICHTENTECHNIK GMB. BACKNANG, no. 10, 1 August 1993 (1993-08-01), pages 72 - 81, XP000446110 *
WIJAYASURIYA S S H ET AL: "A NEAR-FAR RESISTANT SLIDING WINDOW DECORRELATING ALGORITHM FOR MULTI-USER DETECTORS IN DS-CDMA SYSTEMS", PROCEEDINGS OF THE GLOBAL TELECOMMUNICATIONS CONFERENCE (GLOBECOM),US,NEW YORK, IEEE, vol. -, 6 December 1992 (1992-12-06), pages 1331 - 1338, XP000390429, ISBN: 0-7803-0608-2 *

Also Published As

Publication number Publication date
DE19928667A1 (de) 2000-12-28
AU5098100A (en) 2001-01-31

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