WO2004068734A1 - Troncature et reglage de niveau de symboles de sortie de rake - Google Patents

Troncature et reglage de niveau de symboles de sortie de rake Download PDF

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Publication number
WO2004068734A1
WO2004068734A1 PCT/EP2003/014530 EP0314530W WO2004068734A1 WO 2004068734 A1 WO2004068734 A1 WO 2004068734A1 EP 0314530 W EP0314530 W EP 0314530W WO 2004068734 A1 WO2004068734 A1 WO 2004068734A1
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WIPO (PCT)
Prior art keywords
data symbols
level
despread data
despread
bits
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PCT/EP2003/014530
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English (en)
Inventor
Magnus Bengtsson
Elias Jonsson
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Telefonaktiebolaget Lm Ericsson (Publ)
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
Priority claimed from EP03388069A external-priority patent/EP1443668A1/fr
Application filed by Telefonaktiebolaget Lm Ericsson (Publ) filed Critical Telefonaktiebolaget Lm Ericsson (Publ)
Priority to AU2003298210A priority Critical patent/AU2003298210A1/en
Priority to US10/542,671 priority patent/US20060274819A1/en
Publication of WO2004068734A1 publication Critical patent/WO2004068734A1/fr

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H03M1/12—Analogue/digital converters
    • H03M1/18—Automatic control for modifying the range of signals the converter can handle, e.g. gain ranging
    • H03M1/181—Automatic control for modifying the range of signals the converter can handle, e.g. gain ranging in feedback mode, i.e. by determining the range to be selected from one or more previous digital output values
    • H03M1/183—Automatic control for modifying the range of signals the converter can handle, e.g. gain ranging in feedback mode, i.e. by determining the range to be selected from one or more previous digital output values the feedback signal controlling the gain of an amplifier or attenuator preceding the analogue/digital converter
    • H03M1/185—Automatic control for modifying the range of signals the converter can handle, e.g. gain ranging in feedback mode, i.e. by determining the range to be selected from one or more previous digital output values the feedback signal controlling the gain of an amplifier or attenuator preceding the analogue/digital converter the determination of the range being based on more than one digital output value, e.g. on a running average, a power estimation or the rate of change
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/3052—Automatic control in amplifiers having semiconductor devices in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H03M1/12—Analogue/digital converters
    • H03M1/18—Automatic control for modifying the range of signals the converter can handle, e.g. gain ranging
    • 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
    • H04B1/7097—Interference-related aspects
    • H04B1/711—Interference-related aspects the interference being multi-path interference
    • H04B1/7115—Constructive combining of multi-path signals, i.e. RAKE receivers
    • 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
    • H04B1/7097—Interference-related aspects
    • H04B1/711—Interference-related aspects the interference being multi-path interference
    • H04B1/7115—Constructive combining of multi-path signals, i.e. RAKE receivers
    • H04B1/7117—Selection, re-selection, allocation or re-allocation of paths to fingers, e.g. timing offset control of allocated fingers
    • 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
    • H04B1/7097—Interference-related aspects
    • H04B1/711—Interference-related aspects the interference being multi-path interference
    • H04B1/7115—Constructive combining of multi-path signals, i.e. RAKE receivers
    • H04B1/712—Weighting of fingers for combining, e.g. amplitude control or phase rotation using an inner loop

Definitions

  • the invention relates to a method of receiving radio signals in a receiver for a digital wireless communications system, the method comprising the steps of level adjusting a received radio signal by an automatic gain control; and de- spreading the level adjusted signal in a RAKE unit having a number of fingers, thus providing a number of despread data symbols, each despread data symbol being represented by a first number of bits.
  • the invention also relates to a receiver for receiving radio signals in a digital wireless communications system.
  • the physical channel between a transmitter and a receiver is typically formed by a radio link.
  • the transmitter could be a base station, and the receiver could be a mobile station, or vice versa.
  • the transmit antenna is not narrowly focused towards the receiver. This means that the transmitted signals may propagate over multiple paths.
  • the receiver may receive multiple instances of the same signal at different times, i.e. with different delays, because different portions of the signal are reflected from various objects, such as buildings, moving vehicles or landscape details.
  • portions with similar propagation distances combine at the receiver and form a distinct multipath component.
  • the effect of the combining depends on the instantaneous relationship of the carrier wavelength and distance differences, and it may thus for a given multipath component be either enhancing or destructive.
  • the combining leads to significant decrease of the magnitude, or fading, of the path gain for that path.
  • CDMA Code Division Multiple Access
  • WCDMA Wideband Code Division Multiple Access
  • PN pseudo-random noise
  • chips The number of chips used to spread one data bit, i.e. chips/bit, may vary, and it depends, at least in part, on the data rate of the channel and the chip rate of the system.
  • the received signal is despread and demodulated with the same spreading code using the same chip rate to recover the transmitted data.
  • the timing of the demodulation must be synchronized, i.e. the despreading code must be applied to the received signal at the correct instant in time, which can be difficult due to the multipath effects mentioned above.
  • the performance of a CDMA receiver is improved by utilizing the signal energy carried by many multipath components. As mentioned, this is achieved by using a RAKE receiver, where each multipath component is assigned a despreader whose reference copy of the spreading code is delayed equally to the path delay of the corresponding multipath component.
  • the received chip sequence is despread (correlated) with the correspondingly delayed spreading code.
  • the despread output symbols from each RAKE finger are then coherently combined to produce a symbol estimate.
  • the radio signal is first down-converted to base band by a radio interface. Then the analog down-converted signal is scaled by an automatic gain control (AGC), before being quantized by an analog-to-digital (A D) converter. It is noted that the analog signal is complex and thus consists of an / part and a Q part. Once the received signal has been quantized it is despread in the RAKE. As mentioned, a radio signal can have travelled through different paths before arriving at the receiver, which causes the signal to be received at different time delays.
  • AGC automatic gain control
  • a D analog-to-digital
  • the received quantized signal is despread in the RAKE for each path by multiplying the quantized signal, sampled at chip rate, with its corresponding channelization code and scrambling code and sum over the length of the channelization code.
  • the radio channel estimates are then calculated and their conjugates are multiplied with the despread data symbols.
  • the products are then summed over the number of paths. Finally, the bit stream is decoded.
  • the scaling of the signal from the AGC may be performed so that the average power of the sum of the I and O parts is kept as close as possible to a given reference value.
  • the measured power i.e. the feedback to the AGC, can be taken before or after the A/D converter.
  • some kind of control algorithm is involved in finding the optimal scale factor for the AGC. It is assumed that such an algorithm is given.
  • WO 00/69086 shows a WCDMA receiver with a RAKE circuit.
  • the signal level is first adjusted with a relatively coarse gain control at the down-converted and quantized complex chip stream.
  • a refined gain control is then subsequently performed by means of AGC circuits at the individual despread data symbols that are output from the fingers of the RAKE.
  • this two-step level adjustment will often be too slow to follow rapid changes in the received signal.
  • the object is achieved in that the method further comprises the step of truncating the despread data symbols provided from the RAKE unit to obtain truncated data symbols represented by a second number of bits, said second number being smaller than said first number, wherein the second number of bits are selected as the least significant bits of the first number of bits representing a despread data symbol; saturating the truncated data symbols to obtain saturated data symbols by replacing a truncated data symbol with the highest value that can be represented by the second number of bits, if the value of the despread data symbol from which that truncated data symbol was obtained is larger than said highest value, and replacing a truncated data symbol with the lowest value that can be repre- sented by the second number of bits, if the value of the despread data symbol from which that truncated data symbol was obtained is less than said lowest value; and level adjusting the despread data symbols provided from the RAKE unit in dependence of said despread data symbols, so that overflow
  • truncation and saturation reduces the number of bits needed to represent the data symbols from the fingers of the RAKE, but since the level adjustment is performed before the RAKE unit and the output levels from the individual fingers may differ considerably from each other, there would, with the use of truncation and saturation alone, still be a risk of overflow for one or more of the data symbols resulting in loss of information in the truncation and saturation process.
  • This problem is solved when the truncation and saturation is combined with a further level adjustment, so that the level of the symbols provided from the RAKE is adjusted in dependence of the level of the saturated data symbols to prevent overflow.
  • the buffer capacity needed for storing and processing the despread data symbols provided from the RAKE unit could also be reduced by truncating and saturating the quantized signal before it is fed to the RAKE unit, or simply by using an A/D converter with a lower number of output bits, such a solution would be less attractive, because if the signal is then reduced to a level, where the signals from the stronger paths do not saturate, information from the weaker paths might be lost. The signal from very weak paths might even be cancelled so that the corresponding fingers of the RAKE unit would only produce noise, the resulting receiver performance being further deteriorated. Therefore, in order to ensure that the information of the weaker paths is also utilized, it is preferred to maintain a high number of bits to represent the input signals to the RAKE unit.
  • the step of level adjusting the despread data symbols provided from the RAKE unit comprises the step of measuring the level of the despread data symbols.
  • the step of level adjusting the despread data symbols provided from the RAKE unit comprises the step of measuring the level of the saturated data symbols.
  • the level adjusting of the despread data symbols may be performed by adjusting a reference value of said automatic gain control.
  • the level adjusting of the despread data symbols may be performed by adjusting the level of each despread data symbol individually in dependence of that despread data symbol.
  • the level adjusting may be based on the largest of an inphase component and a quadrature component of said despread data symbols.
  • the level adjusting is based on data symbols averaged over time, it is ensured that rapid noise fluctuations do not change the adjustment level.
  • the level adjusting is performed by using a Proportional-Integral control algorithm.
  • a simple embodiment is obtained when the level adjusting is performed by selecting one of two different adjustment levels.
  • the invention also relates to a receiver for receiving radio sig- nals in a digital wireless communications system, the receiver having means for level adjusting a received radio signal by an automatic gain control; and despreading the level adjusted signal in a RAKE unit having a number of fingers, thus providing a number of despread data symbols, each despread data symbol being represented by a first number of bits.
  • the receiver further comprises means for truncating the despread data symbols provided from the RAKE unit to obtain truncated data symbols represented by a second number of bits, said second number being smaller than said first number, wherein the second number of bits are selected as the least significant bits of the first number of bits representing a despread data symbol; saturating the truncated data symbols to obtain saturated data symbols by replacing a truncated data symbol with the highest value that can be represented by the second number of bits, if the value of the despread data symbol from which that truncated data symbol was obtained is larger than said highest value, and replacing a truncated data symbol with the lowest value that can be represented by the second number of bits, if the value of the despread data symbol from which that truncated data symbol was ob- tained is less than said lowest value; and level adjusting the despread data symbols provided from the RAKE unit in dependence of said despread data symbols, so that overflow for the truncated data symbols is
  • the receiver is adapted to adjust the level of the despread data symbols provided from the RAKE unit by means of measuring the level of the despread data symbols.
  • the receiver is adapted to adjust the level of the despread data symbols provided from the RAKE unit by means of measuring the level of the saturated data symbols.
  • the receiver may be adapted to adjust the level of the despread data symbols by adjusting a reference value of said automatic gain control. Alterna- tively, the receiver may be adapted to adjust the level of the despread data symbols by adjusting the level of each despread data symbol individually in dependence of that despread data symbol.
  • the receiver may be adapted to base said level adjusting on the largest of an inphase component and a quadrature component of said de- spread data symbols.
  • the receiver When the receiver is adapted to base said level adjusting on data symbols averaged over time, it is ensured that rapid noise fluctuations do not change the adjustment level.
  • the receiver is adapted to perform said level adjusting by using a Proportional-Integral control algorithm.
  • a simple embodiment is obtained when the receiver is adapted to perform said level adjusting by selecting one of two different adjustment levels.
  • the receiver may be a WCDMA receiver.
  • the invention also relates to a computer program and a computer readable medium with program code means for performing the method described above.
  • figure 1 shows an example of multiple paths between a base station and a mobile station
  • figure 2 shows a power delay profile for the paths illustrated in figure 1 ,
  • figure 3 shows a known receiver structure
  • figure 4 shows the receiver of figure 3 modified with a truncation and saturation unit
  • figure 5 illustrates a situation with saturation of one of the I and Q components of a truncated data symbol
  • figure 6 illustrates a situation with saturation of both the I and Q components of a truncated data symbol
  • figure 7 shows a receiver structure in which the AGC unit is adjusted in dependence of the truncated and saturated data symbols
  • figure 8 shows a flow chart of a part of the structure of figure 7
  • figure 9 shows a receiver structure in which the AGC unit is adjusted in dependence of the despread data symbols
  • figure 10 shows a receiver structure in which the despread data symbols are adjusted in dependence of the truncated and saturated data symbols.
  • Figure 1 shows a situation in which a base station 1 and a mobile station 2 of a wireless communications system communicate with each other.
  • a signal transmitted from the base station 1 is received by the mobile station 2.
  • the transmitted signal travels along multiple paths from the base station to the mobile station.
  • there is a direct and unob- structed propagation path 3 but in addition to this direct path, reflections from objects in the surroundings cause a number of indirect paths to exist. Two such paths are shown in the figure.
  • One indirect path 4 is reflected from a house 5, while another path 6 is caused by reflection from another building 7.
  • the power P received at the mobile station 2 as a function of the time t may look as illustrated in figure 2, which shows an example of a power delay profile.
  • the power delay profile shows all signals received at the mobile station, including noise and interference signals.
  • only the peaks in the power delay profile correspond to the multipath components of the transmitted signal. Together these peaks form the impulse response of the channel.
  • the peak P a received at the time t a corresponds to the direct path 3 in figure 1
  • the peaks P b and P c received at the times tb and t C) respectively correspond to the indirect paths 4 and 6 in figure 1.
  • the delay of the path 6 (corresponding to the peak P c ) is larger than the delay of the path 3 (corresponding to the peak P a ).
  • the mobile station 2 and the base station 1 may be adapted for use in e.g. a Code Division Multiple Access (CDMA) system or a Wideband Code Division Multiple Access (WCDMA) system, and in that case the mobile station 2 may use a RAKE receiver, which is capable of identifying and tracking the various multipath signals for a given channel. In this way the energy or power of several multipath components can be utilized in the receiver. As mentioned above, this may be achieved by using a RAKE receiver, where each multi- path component is assigned a despreader whose reference copy of the spreading code is delayed equally to the path delay of the corresponding multipath component. The outputs of the despreaders, i.e. the fingers of the RAKE receiver, are then coherently combined to produce a symbol estimate.
  • CDMA Code Division Multiple Access
  • WCDMA Wideband Code Division Multiple Access
  • FIG. 3 illustrates an example of a typical receiver structure for a RAKE receiver.
  • the radio signal is first down-converted to base band by a radio inter- face 11.
  • the analog down-converted signal is scaled by an automatic gain control (AGC) unit 12, before being quantized by an analog to digital (A/D) converter 13.
  • AGC automatic gain control
  • A/D analog to digital
  • each reported delay estimate is assigned a RAKE finger, and the received quantized signal is despread for each path by multiplying the quantized signal, sampled at chip rate, with its corresponding channelization code and scrambling code and sum over the length of the channelization code.
  • Each RAKE finger presents a complex de- spread data symbol with the values gj and gg, each represented by N g bits.
  • the radio channel estimates are then calculated and their conjugates are multiplied by the despread data symbols.
  • the products for each RAKE finger are then summed over the number of paths. Finally, the bit stream is decoded in the decoder 16.
  • the scaling of the signal in the AGC unit 12 may be performed so that the average power of the sum of the / and O parts is kept as close as possible to a given reference value.
  • the measured power i.e. the feedback to the AGC, can be taken before or after the A/D converter 13.
  • the optimal scale factor for the AGC is found by means of a control algorithm, of which several algorithms are well known.
  • a high buffer capacity is needed to store and process the despread data symbols that are output from the fingers of the RAKE unit 14.
  • the high buffer capacity requires a larger silicon area and thus a larger size and a higher complexity of the receiver. Therefore, it would be advantageous to be able to reduce the number of bits used to represent each despread data symbol. This can be obtained by trun- eating and saturating the despread data symbols, as illustrated in figure 4, in which a truncation and saturation unit 21 is inserted between the RAKE unit 14 and the combining unit 15.
  • the truncated and saturated values tj and t Q are computed from the values gi and g Q by extracting the N least significant bits, if this still equals gi or Q . Otherwise, there is overflow, and ti or t Q is set to the maximum or minimum value that can be represented by N bits, depending on the sign of gi or go.
  • the function of the truncation and saturation unit 21 can be defined as where x is a number represented by an integer number of bits N x . M x and m x are defined to be the maximum and minimum achievable number using the bit representation of x .
  • y can be represented with N y inte- ger bits, where N y is less than N x , and M y and m y are defined to be the maximum and minimum achievable number using the bit representation of y .
  • Figure 5 illustrates a situation where only one of ti or t Q , in this case t e , saturates.
  • a dotted box shows the maximum values of ti or t Q .
  • the coordinate (gj, go) fall outside the box and will thus be truncated.
  • the result of the truncation and saturation is shown as the coordinate (h t ⁇ ). It is immediately seen that the truncation and saturation introduces a phase error.
  • phase of the complex data symbol is changed from a g to a t . If both / / and t Q saturates, even more phase information is loosed, since only four different phases are possible, which is illustrated in Figure 6. Again the dotted box shows the maximum values of or t Q . In the figure both gi and g Q fall outside the box and will thus be truncated. The result of the truncation and saturation is shown as the coordinate (t It ⁇ Q), which will be located at one of the corners of the box. It is immediately seen that the truncation and saturation introduces a phase error. In both cases, valuable soft information is loosed, which results in a deteriorated performance.
  • the truncation and saturation is combined with an adjustment of the level of the RAKE outputs, i.e. the despread data symbols, with an adaptive factor depending on the level of the individual despread data symbols outputs.
  • This can be done in a number of different ways, which will be de- scribed below.
  • One solution is illustrated in figure 7.
  • the reference value for the AGC unit 12 is adjusted in dependence of the truncated and saturated values ti and tQ.
  • the reference value or factor is calculated in the factor computing unit 22, which will be described in further detail below.
  • step 31 data are taken from the truncation and saturation unit 21 , and measurement quantities are computed for all involved physical channels or paths.
  • the values t H) for each physical path or channel CH are sampled accord- ing to a predetermined pattern. A given number of physical channels can be studied in parallel.
  • the measurement quantity is computed for each physical path or channel CH.
  • means the absolute value of x .
  • step 32 the computed measurement quantities are processed.
  • An expectation value of ⁇ (CT) is computed. This can, for example, be done by filtering
  • the time constant for a i.e. the time it takes to compute the corresponding moving average, should be much larger than the time constant for the AGC loop. Furthermore, the time constant for a should be large enough to filter over a number of fading peaks and dips.
  • PI controller Proportional-Integral controller
  • l H is stored from the last activation of the block, and T, is an integration constant.
  • the new reference power for the AGC for channel CH is taken as
  • M t denotes the maximum value represented by t ⁇ , which is the same for t Q .
  • This algorithm toggles between two states.
  • Having ⁇ ⁇ ⁇ ⁇ 2 introduces a viscosity to the system, which prevents the sys- tern from toggling between the two reference values P x and P 2 from one activation of the block to the other.
  • it is straight forward to generalize to include more than two power reference value levels.
  • the values gf H) and g Q ⁇ H) may be used, because they also contain the necessary information. This is illustrated in figure 9.
  • the individual despread data symbol with the values gj and g Q may be scaled with an adaptive factor before truncation and saturation in the unit 21 , instead of adjusting the AGC control as described above.
  • FIG 10 which corresponds to figure 7, but instead of the factor computing unit 22 connected to the AGC unit 12 this em- bodiment has a factor computing unit 42 connected to the truncation and saturation unit 21.
  • the flow chart of figure 8 is also valid for the factor computing unit 42, but the algorithm used in step 33 is different. An example of an algorithm that can be used here is described below.
  • the new reference scale value for the truncation and saturation unit 21, S* can be computed using a PI controller, i.e.
  • M t denotes the maximum value represented by t ⁇ , which is the same for t Q .
  • This algorithm toggles between two states.
  • Having ⁇ x ⁇ 2 introduces a viscosity to the system, which prevents the system from toggling between the two reference values P x and P 2 from one activation of the unit to the other.
  • the values gf H and g g ⁇ H) may be used for each physical path or channel CH in step 31 instead of the values ⁇ CH and tf H as described above, because they also contain the necessary information.
  • all the gain estimation is performed by the AGC unit 12 on the chip stream, i.e. before the signals are de- spread in the RAKE unit 14.
  • the level adjustment performed by the units 22 or 42 can be considered as a safety check to prevent any overflow at symbol level, i.e. after the despreading, by performing a complementary slow gain adjustment based on the symbol stream.

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  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Theoretical Computer Science (AREA)
  • Circuits Of Receivers In General (AREA)

Abstract

La présente invention porte sur un procédé de réception de signaux radio dans un récepteur pour un système de communication sans fil numérique. Ce procédé consiste à effectuer un réglage de niveau d'un signal radio reçu à l'aide d'une commande automatique de gain (12) ; puis à désétaler le signal dans une unité RAKE (14) comportant un certain nombre de doigts. Les symboles de données désétalées sont tronqués en symboles représentés par un nombre de bits inférieur à celui des symboles de données désétalées par la sélection des bits les moins significatifs des symboles de données désétalées. Les symboles de données tronqués sont saturés et les symboles de données désétalées subissent un réglage de niveau en fonction de ces symboles de données désétalées, ce qui permet d'éviter tout dépassement de capacité pour les symboles de données tronqués. Le nombre de bits utilisés pour représenter les symboles de données désétalées produits par les doigts du RAKE peut ainsi être réduit de façon que la perte de données temporaires soit réduite au minimum.
PCT/EP2003/014530 2003-01-30 2003-12-18 Troncature et reglage de niveau de symboles de sortie de rake WO2004068734A1 (fr)

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Application Number Priority Date Filing Date Title
AU2003298210A AU2003298210A1 (en) 2003-01-30 2003-12-18 Truncation and level adjustement of rake output symbols
US10/542,671 US20060274819A1 (en) 2003-01-30 2003-12-18 Truncation and level adjustment of rake output symbols

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DKPA200300120 2003-01-30
DKPA200300120 2003-01-30
US44477803P 2003-02-04 2003-02-04
US60/444,778 2003-02-04
EP03388069A EP1443668A1 (fr) 2003-01-30 2003-10-29 Troncature et ajustement de niveaux des symboles de sortie d'un récepteur du type RAKE
EP03388069.1 2003-10-29

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Cited By (2)

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Publication number Priority date Publication date Assignee Title
WO2010086404A1 (fr) * 2009-01-29 2010-08-05 Telefonaktiebolaget L M Ericsson (Publ) Commande automatique de gain sur la base d'une bande passante et d'un étalement de retard
US7916773B2 (en) * 2004-12-20 2011-03-29 Telefonaktiebolaget L M Ericsson (Publ) Scaling and truncating in a receiver for coded digital data symbols

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DE19918385A1 (de) * 1999-04-22 2000-11-02 Siemens Ag Verfahren und Schaltungsanordnung zum Regeln des einem Analog/Digital-Wandler zugeführten Signalpegels
WO2000069086A1 (fr) * 1999-05-10 2000-11-16 Sirius Communications N.V. Procede et appareil de communication par acces multiple a repartition de code grande vitesse reconfigurable par logiciel

Patent Citations (2)

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Publication number Priority date Publication date Assignee Title
DE19918385A1 (de) * 1999-04-22 2000-11-02 Siemens Ag Verfahren und Schaltungsanordnung zum Regeln des einem Analog/Digital-Wandler zugeführten Signalpegels
WO2000069086A1 (fr) * 1999-05-10 2000-11-16 Sirius Communications N.V. Procede et appareil de communication par acces multiple a repartition de code grande vitesse reconfigurable par logiciel

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Publication number Priority date Publication date Assignee Title
US7916773B2 (en) * 2004-12-20 2011-03-29 Telefonaktiebolaget L M Ericsson (Publ) Scaling and truncating in a receiver for coded digital data symbols
WO2010086404A1 (fr) * 2009-01-29 2010-08-05 Telefonaktiebolaget L M Ericsson (Publ) Commande automatique de gain sur la base d'une bande passante et d'un étalement de retard
US8731500B2 (en) 2009-01-29 2014-05-20 Telefonaktiebolaget Lm Ericsson (Publ) Automatic gain control based on bandwidth and delay spread

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AU2003298210A1 (en) 2004-08-23

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