DE10303912B4 - Method and apparatus for determining energy delay profiles in a data stream transmission over multiple data transmission paths - Google Patents

Abstract

Method for determining energy delay profiles of a received data stream (102) from a data stream transmitter (200) to at least one data stream receiver (100) via at least one data transmission path (101) in which transmission properties of the at least one data transmission path (102) can be determined, comprising the following steps:
a) forming a first correlation function between a receive signal (301) and a first pilot sequence signal (303a) having a predetermined symbol sequence in a correlation device (103), the first correlation having a variable correlation length;
b) forming in the correlation means (103) at least a second correlation function between the received signal (301) and a second pilot sequence signal (303b) having a symbol sequence sign-modulated with respect to the first pilot sequence signal (303a), the second correlation having a variable correlation length;
c) determining a energy delay profile (300) of the at least one data transmission path (102) by means of the first and second correlation functions in a determination device (104), wherein
d) the first and second correlation functions are provided by a formation of partial correlations;
e) at least one partial correlation for a ...

Description

The The present invention relates to a method and an apparatus for receiving data streams over multiple Data transmission paths and more particularly relates to a method of receiving a data stream from a data stream transmitter to at least one data stream receiver over at least a data transmission path, at the transmission properties the at least one data transmission path are determinable.

at a data transmission system, for example, a CDMA modem, for example, for use in a 3GPP WCDMA FDD device, a so-called "rake" receiver is used, which consists of different "fingers", each one Finger a path of the delay profile corresponds to a received signal. The number of fingers and the delay in every "finger" in a rake receiver based on a data transfer path search unit assigned. The operating parameters of the data transfer path search unit become by a "finger" management unit assigned.

In wireless data transmission systems overflow signals different data transmission paths, which can be subjected to a different "fading". Because every data transmission path a different length and the data stream signals are approximately the same Data transmission speed spread, the data stream signal arrival times differ at the data stream receiver for the different data transmission paths sometimes considerably.

These delayed Arrival times of the different propagation paths lead to an overlay at different times of transmitted data symbols at the receiver, a Effect referred to as Inter-Symbol Interference (ISI) and without suitable countermeasures adversely affects data reception.

to Compensation of the ISI and the advantageous exploitation of the diversity of the different ones Propagation paths is usually a technique used in CDMA systems, with which the data stream signals of all relevant data transmission paths are received, which are then combined. this will in the prior art in a rake receiver carried out, the one data stream receiver which receives as many multipath data stream signals as possible. Of the Rake receiver combines the signals from all These paths to a possible "trouble-free" data stream signal to produce that stronger than the individual components. Individual paths are through Cross correlating a reference pattern with the received signal found.

The appraisal of so-called energy delay profiles (PDP = Power Delay Profile) is for functionality a rake receiver essential. An estimate the energy delay profile different data transmission streams is through a UMTS receiver carried out, about the amplitude and the delayed Timing of the data transmission paths of data streams in terms of a receiver timing reference to determine.

The Data transmission path searching unit now serves to provide an arrival time and reception energy of the data stream signals from the different data transfer paths to determine. This energy delay profile determination is determined by a correlation using a so-called (primary or secondary) pilot channel (CPICH = Common Pilot Channel) performed a predetermined Symbol sequence transmits.

According to the 3GPP standard (UMTS) are the data streams, e.g. of the pilot channel, frames and slots (data frames and Data slots). For example, a data frame a period of 10 milliseconds (ms) and contains 15 data slots. Each data slot has 2560 chips, which means that the Chip frequency in this example is 3.84 MHz.

Conventionally, a complex correlation of the incoming signal (r (i)) sampled, for example, at twice the chip rate, is provided with a known conjugate complex pilot sequence signal p * (2i) according to the general relationship, where N _corr Represents correlation length.

In the case of the UMTS standard possible different pilot signal sequences via Anten ne 1 and 2 antenna emitted. Here, the terms "antenna 1" and "antenna 2" two different transmitting devices in a data stream transmitter, such as antennas, so that at least two different data transmission paths arise. In order to determine the energy delay profile in the data stream receiver, in the case of transmission diversity, the correlation must be performed for both the data transmission paths of an "antenna 1" and an "antenna 2".

The correlation length N _corr is an even multiple of a pilot sequence symbol length, ie an even multiple of a CPICH symbol length of 256 chips. Although increasing the correlation _length N _corr desirably increases the signal-to-noise ratio in an energy delay profile estimation, on the other hand, this energy delay profile estimation then becomes more sensitive to a sampling clock error. For this reason, an energy delay profile estimation needs to be averaged over time.

That is, an energy delay profile estimate must be averaged over blocks of length N _corr . Since the required correlation _length N _{corr can become} very large, a large buffer memory is needed to store the signals before correlation, which means an increased circuit complexity.

A major disadvantage of conventional systems is that the correlation _length N _{corr is} not constant and can vary in a wide range from one to several symbols.

Unfortunately, the system architecture must be designed such that a maximum correlation _{length Ncorr can be} processed, so that the available hardware is not optimally utilized.

Because usually a large hardware requirement for large correlation lengths N _corr is, is set in conventional data transmission systems, the maximum value of the correlation length Ncorr using this concept to not greater than 2, which means that the correlation is limited disadvantageously to 512 chips.

In the DE 196 14 543 C1 For example, an equalizer with an extended channel estimation is described in order to obtain a higher degree of impulse response of the transmission channel and to always perform the channel estimation with as great a quality as possible. A disadvantage of the equalizer is that hardware resources are not optimally utilized.

The DE 100 04 874 C2 discloses a device for performing search procedures in a mobile radio receiver comprising a two-section correlator for correlating a digital receive data sequence with a digital correlation data sequence, the digital correlation data sequence being pre-stored in a read-only memory.

The EP 0 551 803 A1 describes a method for synchronizing and estimating a channel in a TDMA radio communication system. In the method, a first vector comprising M correlation values between a synchronization sequence and M parts of a signal frame is calculated for its center energy using a correlation value k in the first vector, the calculated value W rounded to the nearest integer, and N consecutive ones Correlation values are distributed around the tentative window central position to form a second vector.

The DE 199 19 545 A1 discloses a method for generating or determining a signal sequence, wherein partial correlations are calculated, stored and reused several times in the processing device.

The EP 0 701 334 A1 finally, describes a method and apparatus for measuring the impulse response of a radio channel in a cellular radiotelephone system comprising a plurality of base stations. The method is characterized in that at least two correlations are formed which are performed with respect to the received signal, wherein at least one correlation sequence of a training sequence of the received signal and a reference sequence known in the receiver is shifted relative to each other for at least one correlation. The at least two correlations are combined to form the impulse response of the channel.

The The object of the present invention is therefore a method for determining energy delay profiles of a receive received data stream, wherein the transmission characteristics at least a data transfer path under optimal utilization of hardware resources are determinable.

These Task is achieved by a specified in the patent claim 1 solved.

Further This object is achieved by a device with the characteristics of Patent claim 19 solved.

Further Embodiments of the invention will become apparent from the dependent claims.

One The essential idea of the invention is to calculate of energy delay profiles different correlation functions between received signals and a pilot sequence signal representing a predetermined symbol sequence has, execute, where the correlation functions in partial correlations of a variable correlation length are divisible.

It is thus an advantage of the present invention that correlation functions or partial correlation functions with a limited correlation length can be calculated and partly reusable.

One Another advantage of the present invention is that the complexity the filter assemblies used can be reduced.

• a) Bilden einer ersten Korrelationsfunktion zwischen einem Empfangssignal und einem ersten Pilotsequenzsignal, das eine vorgegebene Symbolsequenz aufweist, in einer Korrelationseinrichtung, wobei die erste Korrelation eine variable Korrelationslänge aufweist;
• b) Bilden mindestens einer zweiten Korrelationsfunktion zwischen dem Empfangssignal und einem zweiten Pilotsequenzsignal in der Korrelationseinrichtung, wobei die zweite Korrelation eine variable Korrelationslänge aufweist; und
• c) Bestimmen eines Energieverzögerungsprofils des mindestens einen Datenübertragungspfads mittels der ersten und zweiten Korrelationsfunktionen in einer Bestimmungseinrichtung.

The inventive method for determining energy delay profiles of a data stream from a data stream transmitter to a data stream receiver via at least one data transmission path in which transmission properties of the at least one data transmission path can be determined essentially comprises the following steps:

• a) forming a first correlation function between a received signal and a first pilot sequence signal having a predetermined symbol sequence in a correlator, the first correlation having a variable correlation length;
• b) forming at least one second correlation function between the received signal and a second pilot sequence signal in the correlator, the second correlation having a variable correlation length; and
• c) determining an energy delay profile of the at least one data transmission path by means of the first and second correlation functions in a determination device.

In the dependent claims find advantageous developments and improvements of respective subject of the invention.

According to one preferred embodiment of the present invention are the first and second correlation functions after the steps a) and b) provided above by a formation of partial correlations.

In Advantageously, the correlation length of the partial correlations can be variable be specified.

According to one Another preferred embodiment of the present invention for the formation of the first and second correlation functions the subcorrelations provided in steps c) and d) above accumulated.

According to one more Another preferred embodiment of the present invention will the determination of an energy delay profile the correlation functions after the above step e) by a summation the absolute squares of the first and second correlation functions provided.

According to one more Another preferred embodiment of the present invention will the determination of the energy delay profile the correlation functions after the above step e) by the Calculation of the total energy of the corresponding data streams provided.

It is furthermore advantageous if the at least one partial correlation for a sub-symbol length to be led. Conveniently, the correlation length of the at least one partial correlation is provided independently of the total correlation length.

According to one more Another preferred embodiment of the present invention the partial correlations are provided at a rate which the Sampling frequency of the received data stream corresponds.

According to one more Another preferred embodiment of the present invention the partial correlations for either the over the first transmitting device or the transmitted via the second transmitting device Data stream provided.

According to one more Another preferred embodiment of the present invention the partial correlations within the processing device multiple times reused.

in this connection it is advantageous that those partial correlations that the first Sending device, within the processing device can be reused several times.

According to one more Another preferred embodiment of the present invention the real part and the imaginary part of complex results of subcorrelations in separate buffers saved. Furthermore, it is advantageous that the correlation length can be predetermined is.

According to one more Another preferred embodiment of the present invention is the correlation length of Correlation functions an integer multiple of the symbol length. According to one more Another preferred embodiment of the present invention the partial correlations to obtain the overall correlation function averaged by a running average.

According to one more Another preferred embodiment of the present invention will one of the length the partial correlations corresponding length of the input buffer memory provided.

• a) eine Korrelationseinrichtung zur Bildung einer ersten Korrelationsfunktion zwischen einem Empfangssignal und einem ersten Pilotsequenzsignal, das eine vorgegebene Symbolsequenz aufweist, und zur Bildung mindestens einer zweiten Korrelationsfunktion zwischen dem Empfangssignal und einem zweiten Pilotsequenzsignal; und
• b) eine Bestimmungseinrichtung zur Bestimmung eines Energieverzögerungsprofils des mindestens einen Datenübertragungspfads mittels der ersten und zweiten Korrelationsfunktionen.

Furthermore, the device according to the invention for determining energy delay profiles of a data stream via at least one data transmission path essentially comprises:

• a) a correlation device for forming a first correlation function between a received signal and a first pilot sequence signal having a predetermined symbol sequence, and for forming at least a second correlation function between the received signal and a second pilot sequence signal; and
• b) a determination device for determining a energy delay profile of the at least one data transmission path by means of the first and second correlation functions.

According to one more further preferred embodiment of the present invention has the correlator has an input buffer which advantageously one of the correlation length of the partial correlations corresponding Has size.

According to one more further preferred embodiment of the present invention has the determination device separate buffer memory for storage of the real part and the imaginary part of complex results of partial correlations.

According to one more further preferred embodiment of the present invention has the determining means a two's complement inverter, a Adder, an accumulator and a squarer.

embodiments The invention is illustrated in the drawings and in the following Description closer explained. In the drawings show:

1 a schematic block diagram of a data transmission system with multiple data transmission paths;

2 a schematic structure of a pilot channel, via which a pilot sequence signal having a predetermined symbol sequence is transferable;

3 a block diagram of the device according to the invention for transmitting a data stream via at least one data transmission path;

4 a flowchart of a method for forming partial correlations according to a preferred embodiment of the present invention;

5 a schematic flow diagram showing a method with the coherent accumulation over four partial correlation lengths and a subsequent averaging over two correlations according to a preferred embodiment of the present invention; and

6 a schematic flow diagram showing a method with the coherent accumulation over two partial correlation lengths and a subsequent averaging over three correlations according to a preferred embodiment of the present invention.

In the same reference numerals designate the same or functionally identical Components or steps.

1 shows a schematic block diagram of a data transmission system in which different data transmission paths 101 namely direct data transmission paths 101 and indirect data transmission paths 101b . 101c to a transmission of a data stream 102 contribute. There is a direct data transmission path 101 and data transmission paths that run over reflections on buildings, surveys, and other facilities, etc., such as the data transmission paths 101b and 101c , A data stream transmitter 200 here has one or more, typically two, transmitting devices (antennas) 201 and 202 on while a stream recipient 100 typically a receiving device 109 having.

As from the block diagram of 1 As can be seen, the transit times are on the data stream 102 transmitting data transmission paths 101 - 101c differently. In a "worst case" the delay time is typically 30 μs, which corresponds to a distance difference of up to 9 km. This "worst-case" delay time is specified by test cases in the 3GPP standard. In order to calculate an energy delay profile, a number L of values is set which is set to, for example, L = 240 at twice the chip rate resolution for this "worst case".

2 schematically shows the structure of a pilot channel with a predetermined pilot sequence. As shown, a data stream is made up of individual data frames 203a ... 203i ... 203N built up. Each data frame has a time duration of T _f = 10 ms (milliseconds) in the exemplary embodiment according to the invention. Each data frame is in individual slots 204a ... 204i ... 204n divided.

In the embodiment of the invention, a data frame is divided into n = 15 slots. In each slot 10 symbols are transmitted which are in 2 are denoted by A and -A, respectively. The for a first antenna 1 and a first transmitting device 201 under the reference number 205 indicated first symbols or for a second antenna 2 and a second transmitting device 202 under the reference number 206 given second symbols for a specific slot form a first pilot sequence signal 303a or a second pilot sequence signal 303b ,

A symbol is constructed in the embodiment of 256 chips, wherein a chip represents a smallest digital unit. This means that a timeslot T _slot consists of 2560 chips, with one providing 2 bits per symbol - for real and imaginary part, ie (1 + j) - for each one slot 204a - 204n 20 bits are provided. At the specified duration of a data frame 203 and the predetermined number of 15 slots, each containing 10 symbols or 2560 chips, results in a chip rate of 3.84 Mchip / s.

To form correlation functions, the data stream is now sampled at at least twice the chip rate (Nyquist sampling frequency), ie at 7.68 × 10 ⁶ sampling steps per second.

Hereby, a correlation function can be determined, for example, with a resolution of half a chip. Advantageously, a correlation length N _{corr is set} to a multiple of the symbol length (x1, x2, x4...). The quantity L given in the above equation thus denotes a maximum shift in the formation of the correlation functions, ie n runs from 0, 1, 2... L-1. If L is set equal to 240, the result is a sufficient even for the "worst-case" delay time of 31.25 μs at Nyquist sampling frequency.

According to the above equation, both for an antenna 1 and for an antenna 2, ie transmitting devices result 201 respectively. 202 different correlation functions as a function of n, wherein the sum of the absolute squares of the individual correlation functions is formed to determine a total energy delay profile.

In this way, a power delay profile PDP is obtained as a function of n

In equations (1) to (3), the received complex signal is denoted by r (n), while C (i) is the complex product code.

Here, the shift is indicated by n = 0, 1, 2... L-1. The energy delay profile PDP thus results from the sum of the absolute squares according to equation (3) and is designated as PDP (n). The energy _{delay profile} determination can be averaged over several blocks of a correlation _length N _corr .

As explained below with reference to 5 and 6 will be explained, N _{avg denotes} a number of blocks to be averaged over. This quantity N _avg can vary depending on the network conditions and assume any integer value, but this is usefully limited to a maximum value, eg 16.

According to the example according to the invention, the correlation _length N _corr and thus the number of averagings N _{avg can now be} changed without having to change or adapt hardware designs.

3 shows a block diagram of a device for determining energy delay profiles of a data stream 102 according to a preferred embodiment of the present invention. In a correlation device 103 , which is a partial correlation device 103a and an input buffer 304 contains correlation functions or Teilkorrelationsfunktionen over a sub-symbol length of, for example, 128 chips formed, the correlation results (real and imaginary part) in a processing device 105 are processed. The input buffer 304 becomes the received received signal 301 fed.

The processing device 105 receives a determination device 104 with which the energy delay profile (result of equation 3) is determined by at least one data transmission path. Furthermore, the processing device contains 105 Between storage devices 105a and post-processing equipment 106 , The functionality of post-processing equipment 106 corresponds to the general state of the art and is therefore not described in detail below.

According to the invention, a partial correlation is carried out for a sub-symbol length (smaller than 256 chips), wherein the sub-symbol length is preferably 128 chips. That is, correlation functions are formed which have a correlation length less than N _corr . The in 3 shown input buffer memory 304 Thus, for the correlation only 128 chips must be buffered and is advantageously independent of the total correlation _length N _corr .

4 shows an inventive embodiment with reference to a flow chart for forming a correlation function of the partial correlations. First, a _{partial correlation} X _ant1 (n = 0) is calculated over 128 chips, whereupon the _{partial correlation} X _ant1 (n = 1) is calculated, etc. Processing continues until the _{partial correlation} X _ant1 (n = L-1) where L in this example is 240.

These partial correlations are then accumulated, with complex partial results (I for real part and Q for imaginary part) with the corresponding sampling rate, the buffer memory 107 for the I component and 108 cached for the Q component ( 3 ). According to the invention, the partial correlations are reusable, so that a partial correlation is provided only for the above equation (1), ie only for the first antenna 1 is the partial correlation implemented, which advantageously reduces complexity of the hardware design.

Now, a partial correlation for the first antenna 1, which is in the buffer memory 107 respectively. 108 is used to derive the associated partial correlation of the second antenna 2. Subsequently, a coherent accumulation of the partial correlations is performed to obtain results according to equations (1) and (2). Once the results are calculated according to equations (1) and (2), equation (3) can be used to give an energy delay profile (result of equation 3) for a block k. An accumulation of the individual energy delay profiles PDPk (n) obtained for the individual blocks k is calculated by an accumulation, wherein a temporary buffering of all PDPk (n) is not required.

5 _{FIG. 15} shows an example of delay time determination in which the correlation _length N _{corr is set} to 512 chips (two symbols), and the number of blocks N _{avg is} two, that is, N _avg = 2 × N _corr .

In Step S1 becomes a coherent one Correlation over 128 chips started while in step S2, two coherent ones Accumulations over 128 chips each. In step S3, the end of coherent Accumulation of the first block k = 0 (512 chips). The energy delay profile PDPk (n) for this Block k = 0 is also calculated and stored in step S3.

The same process is repeated with steps S1 ', S2' and S3 'for the second correlation _length N _corr of 512 chips. After performing step S3 ', the coherent accumulation of the second block is completed. The energy delay profile PDPk (n) for this block k = 1 is also calculated. In addition, the calculated energy _{delay profile of} the current block k = 1 is now accumulated to the stored energy _{delay profile} of block k = 0 and thus gives the energy _{delay profile} PDP _avg (n).

6 shows a further embodiment of the inventive method in which a correlation _length N _corr of 256 chips (1 symbol) is set, and in which N _avg three correlation _lengths . In step S11, 128 chips begin the coherent correlation and are completed in step S12 for the first 128-chip block. Then, the coherent correlation is started in the step S21 for the second block and ended in the step S22 for the second block. Likewise, the coherent correlation in the third block proceeds (steps S31 and S32).

In Steps 512, S22 and S32 additionally become the energy delay profiles for the blocks k = 0, 1 and 2 are calculated.

The accumulation of the energy delay profiles takes place in steps S22 and S32. The final PDP _avg (n) is available after the accumulation in step S32.

The present invention thus provides a method of reducing the correlation length to a sub-symbol length instead of an overall correlation length N _corr . This advantageously leads to a reduction in the size of the input buffer memory 304 and simplifies the circuit design.

Furthermore, the partial correlation has a fixed predeterminable partial correlation length independent of a total _{correlation length} N _corr .

As a result, the overall architecture of the circuit structure also acts independently of N _corr and N _avg with regard to a memory _size , as a result of which the circuit _{arrangement is} advantageously designed to be flexible for parameter changes.

By sharing hardware resources in the processing device 105 ( 3 ), the circuit complexity is further reduced in an advantageous manner.

The invention of the processing device 105 ( 3 ) is still applicable to Very Long Instruction Word (VLIW) based DSP cores.

Even though the present invention above based on preferred embodiments It is not limited to this, but in many ways modifiable.

Also the invention is not limited to the aforementioned applications limited.

100

Data stream receiver

101

Data transfer path

101

direct Data transfer path

101b, 101c

indirect Data transmission paths

102

data stream

103

correlation means

104

determiner

105

processing device

105a

Latch means

106

postprocessing

107

buffer memory for the I component

108

buffer memory for the Q-component

109

First receiver

200

Stream channels

201

First Antenna, transmitting device

202

Second Antenna, transmitting device

203

data frames

203a ... 203i ... 203N

data frames

204a ... 204i ... 204n

slots

205

First symbols

206

Second symbols

300

Power delay profile

301

receive signal

303a

first Pilot sequence signal

303b

second Pilot sequence signal

304

Input buffer

Claims (18)

Method for determining energy delay profiles of a received data stream ( 102 ) from a data stream transmitter ( 200 ) to at least one data stream receiver ( 100 ) via at least one data transmission path ( 101 ), in the transmission characteristics of the at least one data transmission path ( 102 ) are determinable with the following steps: a) forming a first correlation function between a received signal ( 301 ) and a first pilot sequence signal ( 303a ) having a predetermined symbol sequence, in a correlation device ( 103 ), wherein the first correlation has a variable correlation length; b) forming at least one second correlation function between the received signal ( 301 ) and a second pilot sequence signal ( 303b ), one opposite to the first pilot sequence signal ( 303a ) has sign-modulated symbol sequence, in the correlation device ( 103 ), the second correlation having a variable correlation length; c) determining an energy delay profile ( 300 ) of the at least one data transmission path ( 102 ) by means of the first and second correlation functions in a determination device ( 104 ), wherein d) the first and second correlation functions are provided by a formation of partial correlations; e) performing at least a partial correlation for a sub-symbol length and provided independently of the total correlation length; and f) providing the partial correlations at a rate that corresponds to the sampling rate. Method according to claim 1, characterized in that the determination of the energy delay profile ( 300 ) of the correlation function after step c) is provided by a summation of the magnitude squares of the first and second correlation functions. A method according to claim 1, characterized in that the partial correlations for either the over a first transmitting device ( 201 ) or via a second transmitting device ( 202 ) of the data stream transmitter ( 200 ) transmitted data stream ( 102 ) to be provided. Method according to claim 1, characterized in that that the partial correlations within the processing device be reused several times. Method according to Claim 1, characterized in that the partial correlations which the first transmitting device ( 201 ) are reused several times within the processing device. Method according to Claim 1, characterized in that the first pilot sequence signal ( 303a ) in the correlation device ( 103 ) and that the second pilot sequence signal ( 303b ) in the determination device ( 104 ) provided. Method according to Claim 1, characterized in that the real part and the imaginary part of complex results of the partial correlations are stored in separate buffer memories ( 107 . 108 ) get saved. Method according to claim 1, characterized in that that the correlation length without hardware changes freely selectable is. Method according to claim 1, characterized in that the correlation length is an integer multiple of the symbol length. Method according to claim 1, characterized in that that the partial correlations are accumulated up to the correlation length. Method according to claim 1, characterized in that that the energy delay profile over a specifiable Number of magnitude squares of the correlations is averaged. Method according to claim 1, characterized in that the executed partial correlations are multiply used in the calculation of the energy delay profile ( 300 ) are used. Method according to claim 1, characterized in that a size of an input buffer memory corresponding to the length of the partial correlation ( 304 ) provided. Device for determining energy delay profiles of a via a data transmission path ( 102 ) transmitted data stream ( 102 ), with a) a correlation device ( 103 ) for forming a first correlation function between a received signal ( 301 ) and a first pilot sequence signal ( 303a ) having a predetermined symbol sequence; and b) a determination device ( 104 ) for determining a second correlation function by reusing the first correlation function and determining at least one energy delay profile ( 300 ) of the transmitted data stream ( 101 ) by means of the first and second correlation functions, wherein c) the first and second correlation functions are provided by a formation of partial correlations; d) performing at least a partial correlation for a sub-symbol length and provided independently of the total correlation length; and e) providing the partial correlations at a rate that corresponds to the sampling rate. Device for determining energy delay profiles of a data stream ( 102 ) according to claim 14, characterized in that the correlation device ( 103 ) an input buffer memory ( 304 ) having. Device for determining energy delay profiles of a data stream ( 102 ) according to claim 14, characterized in that the input buffer memory ( 304 ) has a correlation length corresponding to a size of partial correlations. Device for determining energy delay profiles of a data stream ( 102 ) according to claim 14, characterized in that the determining device ( 104 ) separate buffer memories ( 107 . 108 ) for storing the real part and the imaginary part of complex results of the partial correlations. Device for determining energy delay profiles of a data stream ( 102 ) according to claim 14, characterized in that the determining device ( 104 ) comprises a two's complement inverter, an adder, an accumulator and a squarer.