Method for quasi-coherent receipt of multi-beam signal and device for realization of said method

FIELD: radio engineering.

SUBSTANCE: suggested algorithm for quasi-coherent receipt of multi-beam signal with continuous pilot signal is based on algorithm, adaptive to freeze frequencies, for estimation of complex skirting curve, which uses both pilot and information signal. Use of information symbols for estimation of complex skirting curve allows, with weak pilot signal, to substantially increase precision of estimation of said curve and, as a result, significantly decrease possible error of information parameters estimation.

EFFECT: higher interference resistance.

2 cl, 10 dwg

 

The invention relates to the field of radio engineering, in particular to methods quasicoherent signal in communication systems with code division multiplexing, and can be used in the receiving device base and mobile (subscription) stations.

The received signal is an MPSK or MQAM signal with expanding pseudo-random code sequence (SRP), passed through a multipath channel and the observed against the background noise. Signals rays (multipath component of the signal) is exposed in the General case of independent fading (fading). Frequency fading determined by the carrier frequency and the speed of the mobile station, can be significant. The transmitted message is a sequence of information symbols and pilot symbols (see figure 1). The pilot and information signals are orthogonal. This type of pilot signal is called a continuous pilot signal. The pilot signal is designed to assess the complex envelope of the received useful signal required for quasicoherent reception. With a relatively weak continuous pilot signal quality estimate of the complex envelope of the pilot-signal, and hence the quality quasicoherent reception becomes poor.

The known method quasicoherent reception in which the assessment included the red envelope is carried out on the pilot symbols, included in the time interval “sliding window”described in article Gorazza G. E., de Gaudenzi, R. Pilot-Aided Coherent Uplink for Mobile Satellite CDMA Networks // IEEE Trans. Commun. - May 1999. - Vol.47. No.5. - R-784. In accordance with the described method the evaluation of the complex envelope information symbol represents the sum of the estimates of the complex envelope of the pilot symbols of the window, the center of which is in the range of the estimated information symbol (see figure 2). The resulting evaluation of the complex envelope is used for the assessment of the information symbol.

This algorithm estimates the complex envelope suggests that the interval sliding window of the complex envelope of the received signal varies weakly and uses a powerful pilot signal. When fast fading condition of constancy of the complex envelope on the interval sliding window is not performed, and the accuracy of the estimation of the complex envelope falls. When reducing the length of the moving window estimation accuracy of the complex envelope falls, if the power of the pilot signal is small.

The known method quasicoherent the technique described in S. Abeta, M. Sawahashi, and F. Adachi, " Performance comparison between time-multiplexed pilot channel and parallel pilot channel for coherent rake combining is DS-CDMA mobile radio// IEICE Trans. Commun. - July 1998. - vol.E81-B, no.7. - P.1417-1425. In accordance with the described method quasicoherent receiving the evaluation of the complex envelope information of the character done by who is using linear filtering estimates the complex envelope of the pilot symbols (see 3). The paper proposes several variants of the impulse response of the filter, which differ in length and shape. The shape of the impulse response of the filter optimize under a certain average rate of fading of the input signal.

Recording the impulse response of the filter simplifies the implementation of the algorithm, however, the refusal to adapt to the frequency of the fading leads to poor noise immunity. With the rapid fading of the signal bandwidth of the filter is less than the width of the spectrum of the input signal, which leads to suppression of the high-frequency part of the spectrum of the useful signal. In the slow fading of the signal bandwidth of the filter is substantially greater than the width of the spectrum of the useful input signal, which leads to deterioration of the quality evaluation of the integrated signal envelope.

Closest to the proposed solution method is quasicoherent multibeam reception and device for its implementation with the processing unit, see S. Abeta, M. Sawahashi, and F. Adachi Adaptive channel estimation for coherent DS-CDMA mobile radio using time-multiplexed pilot and parallel pilot structures // IEICE Trans. Commun. - Sept. 1999. - Vol.E82-B No.9. - P.1505-1513. Here multibeam receiver consists of several single-beam receivers that produce soft decision information symbols. Combining soft decisions to produce in choosing the accordance with the criterion of maximizing the signal-to-noise ratio at the receiver output.

The described method is as follows.

for each multipath components of the signal form the sequence of correlation responses of the pilot and information symbols, determining the correlation of the input signal with a known SRP at intervals the duration of each symbol,

- remember the correlation responses of the pilot and information symbols

for each multipath components of the signal form evaluation of the complex envelope of information symbols based on the pilot signal, filtering the correlation responses of the pilot symbols,

for each multipath components of the signal are soft decision information symbols using correlation feedback information symbols and evaluation of complex envelope of these characters,

- form a combined soft-decision information symbols by summing the soft decision information symbols of all multipath component of the signal.

Correlation responses of the pilot symbols is filtered, forming a weighted sum of the correlation responses of the pilot symbols.

The weighting coefficients of the filter determined using the estimate of the autocorrelation function of the in-phase and quadrature components of the complex envelope of characters.

Formation evaluation of the autocorrelation function of the in-phase and quadrature components of the complex is the envelope of the characters produced by the correlation responses of the pilot symbols.

Soft decision information symbols is formed by multiplying the complex correlation responses of information symbols by a complex conjugate of the estimate of the complex envelope of information symbols.

For realization of this method is presented in figure 4, where indicated:

1 - single beam quasicoherent receivers,

2 - block correlation,

3 - unit delay

4 - generator SRP,

5 - demodulator of the information channel

6 - demodulator pilot channel

7 - handling block,

8, 9, the first and second adders,

10 - control,

The device comprises N single-beam quasicoherent receiver 1-1 to 1-N, the control unit 10, the first 8 and second 9 adders. Each receiver includes a demodulator information 5 and the pilot channel 6 and the processing unit 7. Each demodulator 5 and 6 contains a block correlation 2, the delay unit 3, the generator 4 SRP. The first and second input blocks of correlation 2 (first and second inputs of the demodulators 5 and 6) are integrated and are used as inputs in-phase and quadrature components of the input beam signal and the first and second inputs of each single-beam quasicoherent receiver 1-1 to 1-N. Third and fourth inputs of the block correlation 2 are connected to the outputs of the generator SRP 4, which are the outputs of the SRP, the respective in-phase kVA and the temperature signal components. The generator input SRP 4 and the third input of the delay unit 3 demodulators 5 and 6 single-beam quasicoherent receivers 1-1 to 1-N are combined, are the third (combined) input of each single-beam quasicoherent receiver 1-1 to 1-N, which is connected to the output values of the temporary provisions of the signal beams in the received multipath signal control unit 10. The first and second outputs of the block correlation 2, which are the outputs of the correlation responses of the characters are connected with the inputs of the delay unit 3, the outputs of which are the outputs of the corresponding demodulator 5 and 6. The first and second outputs of the demodulator news channel 5, which are the outputs of the correlation responses of information symbols, connected with the first and second inputs of the processing unit 7. The first and second outputs of the demodulator pilot channel 6, which are the outputs of the correlation responses of the pilot symbols, connected with the third and fourth inputs of the processing unit 7. The outputs of the processing unit 7, which are both outputs of the corresponding single-beam quasicoherent receiver 1-1 to 1-N and outputs the soft decision information symbols, connected to respective inputs of the first 8 and second 9 adders. The outputs of the adders 8 and 9 are outputs estimates of information symbols, and outputs of the device.

Works eliminate the STV prototype as follows.

In-phase and quadrature components of the input signal received at the single-beam receivers 1-1 to 1-N, namely, the first and second inputs of the demodulator news channel 5 and the demodulator pilot channel 6, which are both the first and second input blocks of correlation 2. On the third and fourth inputs of the blocks of correlation 2 with the output of the generator 4 SRP act known SRP, the corresponding in-phase and quadrature components of the signal. State generator SRP 4 by the control unit 10 in accordance with the values of the temporary provisions of the signal beams in the received multipath signal. With outputs blocks of 2 correlation signals representing the correlation responses of characters transmitted through the delay unit 3 outputs of the demodulator 5 or 6. With the first and second outputs of the demodulator news channel 5 correlation responses of information symbols received at the first and second inputs of the processing unit 7. With the first and second outputs of the demodulator pilot channel 6 correlation responses of the pilot symbols received on the third and fourth inputs of the processing unit 7. The delay time of the signal delay unit 3 by the control unit 10 in accordance with the values of the temporary provisions of the signal beams in the received multipath signal so that the correlation responses of relevant symb is the catch all rays coming into the processing units 7 single-beam quasicoherent receivers simultaneously. The output signals of the processing unit 7 are simultaneously output signals of the corresponding single-beam quasicoherent receiver 1-1 to 1-N and represent the soft decision information symbols. With the first and second output of the processing unit 7 of each single-beam quasicoherent receiver 1-I,in-phase and quadrature components of the soft decision information symbols are received at the I-th inputs of the first and second, respectively, adders 8, 9. In the adders 8 and 9 soft solutions all single-beam receivers are combined, namely, cumulative. Output signals multibeam quasicoherent device, proceed with the outputs of the adders 8, 9, and represent estimates of information symbols. The control unit 10 allows simultaneous operation blocks of the receiver.

A processing unit for a device prototype, see S. Abeta, M. Sawahashi, and F. Adachi Adaptive channel estimation for coherent DS-CDMA mobile radio using time-multiplexed pilot and parallel pilot structures // IEICE Trans. Commun. - Sept. 1999. - Vol.E82-B No.9. - P.1505-1513 presented on figure 5, where indicated:

11-I, 11-Q - nodes filter /(in-phase) and Q (quadrature) channels

12 - unit delay,

13 is a crucial node.

The processing unit 7 contains the node filtering in-phase channel 11-I, the node filtering the I and q channel 11-Q, the node delays 12 and the node 13. The first and second the first inputs of the processing unit 7 are first and second inputs of the node delays 12 and inputs the correlation response information symbols. The third and fourth inputs of the processing unit 7 are inputs respectively of filtering the in-phase channel 11-I and node filtering the I and q channels 11-Q and are the inputs of the correlation responses of the pilot symbols.

The first and the second output node of the delay 12 is connected to the third and fourth inputs of the decision making node 13, the first and second inputs of the decision making node 13 are connected respectively to the outputs of the filtering unit of the first channel 11-I and node filter Q channel 11. the First and second outputs of the decision making node 13 are outputs soft decisions and outputs of the processing unit 7.

Does the processing unit 7 in the device prototype as follows.

To the input of the processing unit 7 receives the discrete complex signal representing the correlation feedback information and pilot symbols. The evaluation of the complex envelope is produced at the nodes of the filter 11-I, 11-Q for the correlation responses of the pilot symbols. Nodes filter 11-I, 11-Q treated respectively in-phase and quadrature components of the correlation responses of the pilot symbols. Evaluation of the complex envelope of information symbols from the outputs of the filter units 11-I, 11-Q act on the first and second inputs of the decision making node 13, the third and fourth inputs of which receive in-phase and quadrature components of the complex correlation responses of information symbols detained in the unit delay 12. The delay of the complex correlation responses of information symbols necessary to compensate for the time delay in the evaluation of the complex envelope of the signal at the nodes of the filter 11-I, 11-Q. In the final node 13 are formed of soft decision information symbols by multiplying the complex correlation responses of information symbols on the complex conjugate values of the estimates of the complex envelope.

The filtering is presented on Fig.6.

The filtering device prototype works as follows.

From the output of the demodulator pilot channel 6 in-phase (quadrature) component of the feedback from the pilot symbols received at the input of delay line 14. Evaluation of the in-phase (quadrature) component of the complex envelope are the result of a weighted summation of detainees in delay line 14 in-phase (quadrature) component of the complex correlation responses of the pilot symbols. The weighting of the correlation responses of the pilot symbols is performed in the multiplier products 15-1 to 15-N. the Calculation of the values of weight coefficients occurs in the host adaptation 17 with the use of delayed correlation responses of the pilot symbols and evaluation of complex envelope.

The disadvantages of this method and device quasicoherent multibeam reception should be attributed to the rejection of the use of information the traditional correlation responses for assessing the complex envelope. This disadvantage leads to lack of accuracy of demodulation, especially in the conditions of the pilot signal with a low power level. A register of this information in the estimation algorithm of the complex envelope will increase its effectiveness.

The objective of the present invention, the increased robustness of reception signals with continuous relatively weak pilot signal in arbitrary channels, including fast fading.

To solve this problem in a way quasicoherent reception of multipath signal containing information and pilot components, namely, that for each multipath components of the signal form the sequence of correlation responses of the pilot and information symbols, determining the correlation of the input signal with a known SRP at intervals the duration of each symbol, remember correlation responses of the pilot and data symbols for each multipath components of the signal form evaluation of the complex envelope of information symbols based on the pilot channel, filtering the correlation responses of the pilot symbols for each multipath components of the signal are soft decision information symbols using correlation feedback information symbols and evaluation the complex envelope of these characters, formirovanie soft decision information symbols, summing the soft decision information symbols of all multipath component of the signal, characterized in that

- remember assess the complex envelope of information symbols based on the pilot channel.

- the formation of the combined soft decision information symbols is carried out in M stages;

thus

- at the first stage take tough decisions in the first stage of the information symbols in the combined soft decision information symbols, in the subsequent steps take tough decisions in the current stage of information symbols in the combined soft decisions of the previous stage;

- at each stage:

for each multipath components of the signal are compared, the correlation module feedback information symbols with a given threshold, if the threshold is exceeded, the corresponding information symbols form of assessing the complex envelope of these characters;

for each multipath components of the signal form evaluation of the complex envelope of information symbols on the information channel, filtering the generated estimate of the complex envelope of information symbols multipath components of the signal;

for each multipath components of the signal to form a combined assessment of the complex envelope of information symbols according to estimates complex bending the processes of information symbols based on the pilot channel and estimates the complex envelope of information symbols on the information channel;

for each multipath components of the signal are soft decisions of the current stage of information symbols using the correlation responses of information symbols and the joint evaluation of the complex envelope of these characters;

- form a combined soft decision in the current stage of information symbols by summing the soft decision in the current stage of information symbols of all multipath component of the signal.

For the final soft decision information symbols take the combined soft-decision information symbols of the last M-th stage.

Correlation responses of the pilot symbols is filtered, for example, by forming a weighted sum of the correlation responses of the pilot symbols.

The weighting coefficients of the filter determine, for example, using the estimate of the autocorrelation function of the in-phase and quadrature components of the complex envelope of characters.

Soft decision information symbols to form, for example, multiplying the complex correlation responses of information symbols by a complex conjugate of the estimate of the complex envelope of information symbols.

Evaluation of the complex envelope of information symbols to form, for example, multiplying the correlation feedback information symbols on the complex conjugate tough decisions about matched the existing information symbols.

Joint evaluation of the complex envelope of information symbols to form, for example, by summing the appropriate assessment of the complex envelope of information symbols based on the pilot channel and the evaluation of complex envelope information symbols on the information channel.

The threshold is chosen, for example, equal to 0.2 the value of the average correlation module feedback information symbols.

Evaluation of the complex envelope of information symbols is filtered, for example, by forming a weighted sum of the estimates of the complex envelope of information symbols.

Soft decision in the current stage of information symbols to form, for example, multiplying the complex correlation responses of information symbols by a complex conjugate of the joint evaluation of the complex envelope of information symbols.

To solve the same problem in the device quasicoherent reception of multipath signal containing N single-beam quasicoherent receivers, the control unit, the first and second adders, each adsolutely quasicoherent the receiver includes a demodulator of the information channel and the demodulator pilot channel processing unit, and first and second inputs of the demodulators of the information channel and demodulators pilot channel interconnected and are the first and the second inputs of each single beam is vascularizing receiver and inputs the in-phase and quadrature components of the input beam signal, the third inputs of the demodulators of the information channel and demodulators pilot channel combined are the third input of each single-beam quasicoherent receiver and connected with the corresponding output of the control unit, which is the output of the temporary provisions of signal beams, each single-beam quasicoherent the receiver of the first and second outputs of the demodulator of the information channel, which are the outputs of the correlation responses of information symbols, connected with the first and second inputs of the processing unit, the first and second outputs of the demodulator pilot channel, which are the outputs of the correlation responses of the pilot symbols, connected with the third and fourth inputs of the processing unit, the outputs of the processing unit, which are both outputs the corresponding single-beam quasicoherent receiver and outputs the soft decision information symbols, connected to respective inputs of the first and second adders,

added synchronization unit, the first and second switches, the first and second computing units, and the output of the first and second adders outputs are combined soft decision information symbols and respectively connected with the first inputs of the first and second switches, the second inputs of the first and second switches ablauts the managers and is connected to the second output of the synchronization unit, the fifth and sixth inputs of the processing unit of each single-beam quasicoherent receiver input hard decision information symbols and are connected to the outputs of the first and second computing units, the seventh input of the processing unit of each single-beam receiver is a synchronization input connected to the first output of the synchronization unit, the first outputs of the first and second switches are connected respectively to the inputs of the first and second computing units, which are used as inputs combined soft decision, the second outputs of the first and second switches are the final outputs soft decision information symbols and outputs of the device quasicoherent reception of multipath signal.

In the processing unit of the single-beam quasicoherent receiver containing the first nodes of the filtered in-phase and quadrature channels, the first unit delay, a crucial node, and first and second inputs of the first node delays are the inputs of the correlation responses of information symbols and first and second inputs of the processing unit, the inputs of the first node filtering in-phase and quadrature channels are used as inputs of the correlation responses of the pilot symbols and the third and fourth inputs of the processing unit, the first and second outputs of the decision making node are outputs soft decisions about the information the x symbols and outputs of the processing unit,

added the second node filtering in-phase and quadrature channels, the first and second memory nodes, the first and second adders, the second node of the delay, the node comparison with a threshold, the node information retrieval, and the first and the second output of the first unit delay is connected with the first and second inputs of the first memory node, a third input which is a control input, the outputs of the first node filtering in-phase and quadrature channels, which are the outputs of the evaluation of complex envelope information symbols on the pilot channel is connected with the first and second inputs of the second memory node, a third input which is managing, the third inputs of the first and second memory nodes are combined in the seventh input of the processing unit, which is managing the outputs of the evaluation of complex envelope information symbols on the pilot channel of the second memory node connected to the first inputs of the first and second adders, the second inputs of the first and second adders are connected with the first and second outputs of the second unit delay, which are the outputs of the evaluation of complex envelope on the information channel, the outputs of the first and second adders are outputs in-phase and quadrature components of the combined assessments of the complex envelope of information symbols and connected with the first and second inputs of casting the evil, the first and second outputs of the first memory node outputs are in-phase and quadrature components of the complex correlation responses of information symbols and connected with the third and fourth inputs of the decision making node and the first and the second input node of the comparison with the threshold, the output node of the comparison with the threshold outputs are in-phase and quadrature components of the corresponding complex correlation responses of information symbols and connected with the third and fourth inputs of the node, removing information, the first and second inputs of which are the inputs of the hard decision information symbols and the fifth and sixth inputs of the processing unit, the first and second outputs node information retrieval are the outputs of the evaluation phase and quadrature components of the complex envelope information symbols and are connected with the inputs of the second node filtering in-phase and quadrature components, the outputs of which are connected to first and second inputs of the second unit delay.

Graphic materials presented in the application materials:

Figure 1 - example of a sequence of information symbols and the pilot symbols.

Figure 2 - evaluation of the complex envelope of the information symbol.

Figure 3 - the evaluation of the complex envelope of the pilot symbols.

4 is a block diagram of the device quasicoherent reception of multipath signals is a (prototype).

5 is a block diagram of the processing unit single-beam quasicoherent receiver (prototype).

6 is an example of executing nodes filtering processing unit.

7 is a block diagram of the proposed device quasicoherent reception of multipath signal.

Fig - structural diagram of the proposed single-beam processing unit quasicoherent receiver.

Fig.9 is an example of execution of the node memory of the processing unit.

Figure 10 - the dependence of the probability of bit error on the signal/noise ratio per bit.

This invention is a method quasicoherent reception of multipath signal with a continuous pilot signal, a device for its implementation and the processing unit for this device.

The proposed method quasicoherent reception of multipath signal having information and pilot components, is as follows:

for each multipath components of the signal form the sequence of correlation responses of the pilot and information symbols, determining the correlation of the input signal with a known SRP at intervals the duration of each symbol;

- remember the correlation responses of the pilot and information symbols;

for each multipath components of the signal form evaluation of the complex envelope of information symbols based on the pilot channel, filtering the corre is azione responses of pilot symbols, and remember;

for each multipath components of the signal are soft decision information symbols using correlation feedback information symbols and evaluation of complex envelope of these symbols on the pilot channel.

- form a combined soft-decision information symbols by summing the soft decision information symbols of all multipath component signal;

- form the final combined soft decision information symbols in M stages, performing at each step the following operations:

- at the first stage take tough decisions in the first stage of the information symbols in the combined soft decision information symbols, in the subsequent steps take tough decisions in the current stage of information symbols in the combined soft decisions of the previous stage;

for each multipath components of the signal are compared, the correlation module feedback information symbols with a given threshold, if the threshold is exceeded, the corresponding information symbols form of assessing the complex envelope of these characters;

for each multipath components of the signal form evaluation of the complex envelope of information symbols on the information channel, filtering the generated estimate of the complex envelope information shall include characters multipath components of a signal;

for each multipath components of the signal to form a combined assessment of the complex envelope of information symbols according to the estimates of the complex envelope of information symbols based on the pilot channel and estimates the complex envelope of information symbols on the information channel;

for each multipath components of the signal are soft decisions of the current stage of information symbols using the correlation responses of information symbols and the joint evaluation of the complex envelope of these characters;

- form a combined soft decision in the current stage of information symbols by summing the soft decision in the current stage of information symbols of all multipath component of the signal.

For the final soft decision information symbols take the combined soft-decision information symbols of the last M-th stage.

Correlation responses of the pilot symbols is filtered, for example, by forming a weighted sum of the correlation responses of the pilot symbols.

The weighting coefficients of the filter determine, for example, using the estimate of the autocorrelation function of the in-phase and quadrature components of the complex envelope of characters.

Soft decision information symbols to form, for example, multiplying the complex correlation responses of information the traditional symbols on the complex conjugate of the estimate of the complex envelope of information symbols.

Evaluation of the complex envelope of information symbols to form, for example, multiplying the correlation feedback information symbols by a complex conjugate of the hard decisions on respective information symbols.

Joint evaluation of the complex envelope of information symbols to form, for example, by summing the appropriate assessment of the complex envelope of information symbols based on the pilot channel and the evaluation of complex envelope information symbols on the information channel.

The threshold is chosen, for example, equal to 0.2 the value of the average correlation module feedback information symbols.

Evaluation of the complex envelope of information symbols is filtered, for example, by forming a weighted sum of the estimates of the complex envelope of information symbols.

Soft decision in the current stage of information symbols to form, for example, multiplying the complex correlation responses of information symbols by a complex conjugate of the joint evaluation of the complex envelope of information symbols.

For realization of this method is presented on Fig.7, where indicated:

1 - single beam quasicoherent receivers,

5 - demodulator of the information channel

6 - demodulator pilot channel

7 - handling block,

8, 9, the first and second adders

10 - control,

18 - unit synchronization

19, 21, the first and second switches,

20, 22, the first and second computing units.

The device comprises N single-beam quasicoherent receivers 1-1 to 1-N, the control unit 10, the synchronization unit 18, the first 8 and second 9 adders, the first 19 and second 21 switches, the first 20 and second 22 critical blocks. The composition of each receiver 1-1 to 1-N includes demodulators information 5 and the pilot channel 6 and the processing unit 7. The first and second inputs of the demodulators information 5 and the pilot channel 6 connected together and are used as inputs in-phase and quadrature components of the input beam signal and the first and second inputs of each single-beam quasicoherent receiver 1-1 to 1-N. Third input of the demodulator information 5 and the pilot channel 6 is the third input of each single-beam quasicoherent receiver 1-1 to 1-N and connected with the corresponding output of the control unit 10, which is the value of the temporary provisions of the signal beams in the received multipath signal. The first and second outputs of the demodulator news channel 5, which are the outputs of the correlation responses of information symbols, connected with the first and second inputs of the processing unit 7. The first and second outputs of the demodulator pilot channel 6, which are the outputs of the correlation from the faces of pilot symbols, connected to the third and fourth inputs of the processing unit 7. The outputs of the processing unit 7, which are both outputs of the corresponding single-beam quasicoherent receiver 1-1 to 1-N and outputs the soft decision information symbols, connected to respective inputs of the first 8 and second 9 adders. The outputs of the adders 8 and 9 are United outputs soft decision information symbols and respectively connected with the first inputs of the first 19 and second 21 switches. The second inputs of the switches 19 and 21 are control and is connected to the second output of the synchronization unit 18. The fifth and sixth inputs of the processing unit 7 of each single-beam quasicoherent receiver 1-1 to 1-N are input hard decision information symbols and are connected to the outputs of the first and second computing units 20 and 22. The seventh input of the processing unit 7 of each single-beam receiver is a synchronization input connected to the first output of the synchronization unit 18. The first outputs of the switches 19 and 21 are connected with the inputs of the combined soft decision corresponding computing units 20 and 22. The second outputs of the switches 19, 21 are the final outputs soft decision information symbols and outputs of the device quasicoherent reception of multipath signal.

The proposed device operates after the existing image.

In-phase and quadrature components of the input signal received at the single-beam receivers 1-1 to 1-N, namely, the first and second inputs of the demodulators information 5 and the pilot channel 6. The operation of the demodulators 5, 6 by the control unit 10 in accordance with the values of the temporary provisions of the signal beams in the received multipath signal. With the first and second outputs of the demodulator news channel 5 correlation responses of information symbols received at the first and second inputs of the processing unit 7. With the first and second outputs of the demodulator pilot channel 6 correlation responses of the pilot symbols received third and fourth inputs of the processing unit 7.

On the fifth and sixth inputs of the processing unit 7 receives the hard decision information symbols from outputs of crucial blocks 20 and 22. The output signals of the processing unit 7 are simultaneously output signals of the corresponding single-beam receiver 1-1 to 1-N and represent the soft decision information symbols of the signal beam. With the first and second outputs of the processing unit 7 of each single-beam quasicoherent receiver 1-I,in-phase and quadrature components of the soft decision information symbols are received at the I-th inputs respectively of the first and second adders 8, 9. In the adders 8 and 9 in-phase and RMS the structural components of the soft decisions of all single-beam receivers are combined, namely, are summarized. The results of combining soft decisions from the outputs of the adders 8, 9 are received at the inputs of the switches 19 and 20, respectively. The switches 19, 21 according to the control signal fed to the control inputs of the synchronization unit 18 serves the combined soft-decision information symbols on the first or second outputs. From the first outputs of the switches 19 and 21 combined soft decision received on the respective computing units 20, 22, which made the hard decision information symbols by comparing the combined soft decision thresholds determined by the type of modulation. Hard decision information symbols are received at the inputs of the processing unit 7 of each single-beam quasicoherent receiver 1-I,where used to obtain soft decisions about other information symbols. Output signals multibeam quasicoherent device receives from the second outputs of the switches 19, 21 and represent the final soft decision information symbols.

The control unit 10 and the synchronization unit 18 provide synchronisation blocks of the receiver and can be implemented on modern microprocessors digital signal processing (DSP), for example, TMS 320Cxx, Motorola 56xxx, Intel, etc.

The processing unit 7 single-beam is vesicularity receivers 1-1 - 1-N can be completely implemented on a digital processor, a structural diagram of this block is presented on Fig where indicated:

11-I, 11-Q - the first nodes of the filtered in-phase and quadrature channels

12, 27, the first and second nodes of the delay,

13 is a crucial node

23, 24, the first and second memory nodes,

25, 26, the first and second adders,

28 site compare with the threshold,

29-I 29-Q - second nodes filter the in-phase and quadrature channels

30 - node information retrieval.

The first and second inputs of the processing unit 7 are first and second inputs of the first unit delay 12 and inputs the correlation response information symbols. The third and fourth inputs of the processing unit 7 are inputs of the first node filtering in-phase and quadrature channels 11-I - 11-Q and the inputs of the correlation responses of the pilot symbols. The first and the second output of the first unit delay 12 is connected to the first and second inputs of the first memory node 23, the third input is a control input. The outputs of the first node filtering in-phase and quadrature channels 11-I - 11-Q, which are the outputs of the evaluation of complex envelope information symbols on the pilot channel, is connected with the first and second inputs of the second memory node 24, the third input of which is managing. The control inputs of the first memory node 23, the second memory node 24 unite the ENES and are the seventh input of the processing unit 7. The outputs of the evaluation of complex envelope information symbols on the pilot channel memory node 24 is connected with the first inputs of the adders 25 and 26, the second inputs of the adders 25 and 26 are connected to the outputs of the second unit delay 27, which are the output signals of the zero level and estimates the complex envelope of information symbols on the information channel. The outputs of the adders 25 and 26 are outputs in-phase and quadrature components of the estimated complex envelope information symbols and connected with the first and second inputs of the decision making node 13. The first and second outputs of the first memory node 23 outputs are in-phase and quadrature components of the complex correlation responses of information symbols and connected with the third and fourth inputs of the decision making node 13 and the first and the second input node of the comparison with the threshold 28. The output node of the comparison with the threshold 28 outputs are in-phase and quadrature components of the corresponding complex correlation responses of information symbols and connected with the third and fourth inputs of node removal information 30, the first and second inputs of node removal information 30 are the fifth and sixth inputs of the processing unit 7, and inputs the hard decisions on the information symbols. The first and second outputs node information retrieval 30 are the outputs of the evaluation phase and quadrature with the bringing of the complex envelope of information symbols and are connected with the inputs of the second node filtering in-phase and quadrature components 29-I, 29. the Outputs of the second node filtering in-phase and quadrature channels 29-I 29-Q connected with the first and second inputs of the second unit delay 27. The first and second outputs of the decision making node 13 are outputs soft decision information symbols and outputs of the processing unit 7.

Does the processing unit 7 as follows.

To the input of the processing unit 7 receives the sequence of complex correlation responses of information and pilot symbols. Correlation responses of the pilot symbols received at the inputs of filter units 11-I, 11-Q. Nodes filter 11-I, 11-Q treated respectively in-phase and quadrature components of the input pilot signal. Nodes filter 11-I, 11-Q correlation responses of the pilot symbols are weight summation. The weighting coefficients of the filter element depends on the statistics of the channel. With the outputs of the filter units 11-I, 11-Q evaluation of the complex envelope of information symbols based on the pilot channel received by the first and second inputs of the memory node 24, where they are stored for a specified period of time. The host memory 24 consists of two parallel standard memory element. From the outputs of the memory node 24 evaluation of the complex envelope of information symbols based on the pilot channel received at the first inputs of the adders 25 and 26, the second inputs of the adders 25 and 26 from the unit delay 27 is transported is t: to M-step procedure the signal zero level during the M-step procedures - evaluation of the complex envelope of information symbols on the information channel. From the outputs of the adders 25 and 26 in-phase and quadrature components of the estimated complex envelope of information symbols received at the first and second inputs of the decision making node 13, the third and fourth inputs of which receive in-phase and quadrature components of the complex correlation responses of information symbols from the memory node 23.

Node memory 23 stores the in-phase and quadrature components of the complex correlation responses of information symbols received at its input through the unit delay 12. The delay of the complex correlation responses of the characters in the unit delay 12 necessary to compensate for the time delay in the evaluation of the complex envelope of the signal at the nodes of the filter 11-I, 11-Q. Nodes delay 12 and 27 represent two standard parallel device delay.

In the final node 13 are formed of soft decision information symbols by multiplying the complex correlation responses of information symbols on the normalized complex conjugate values of the estimates of the complex envelope of these characters. These soft decisions after combining all rays are used to produce hard decisions about the information the x symbols. Hard decision information symbols received in the key blocks 20, 22 (see Fig.7), goes to first and second inputs of node removal information 30.

From the outputs of the memory node 23 in-phase and quadrature components of the complex correlation responses of information symbols received on the crucial site 13 and site compare with the threshold 28. In site compare with the threshold 28 form the modules of the complex correlation responses of information symbols and comparing it with a given threshold. In case of exceeding the threshold with the output node of the comparison with the threshold 28 in-phase and quadrature components of the corresponding complex correlation responses of information symbols received on the third and fourth inputs of node removal information 30. Otherwise, third and fourth inputs of the node information retrieval 30 receives a null value.

Removing information in the node information retrieval 30 is made by multiplying the correlation response information symbols (or zero) on the normalized complex conjugate of the hard decision information symbols. Obtained after removal of information evaluation phase and quadrature components of the complex envelope of information symbols from the first and second outputs node information retrieval 30 arrive at the inputs of filter units 29-I 29-Q. In the line is Noah filtering nodes filter 29-I, 29-Q are formed of assessing the complex envelope of information symbols on the information channel, which Svichado filter units 29-I 29-Q go through the unit delay 27 on the second inputs of the adders 25 and 26 are used to obtain joint estimates of the complex envelope. Delay refined estimates of the complex envelope of the characters in the unit delay 27 necessary to synchronize the operation of the adders 25 and 26. Memory nodes 23, 24, depending on the stage of operation of the device function (remember, store, provide information and zero content) in accordance with the control signal from the synchronization unit 18.

The process of obtaining estimates of the information symbols in the key blocks 20, 22 comparison with a threshold at the node 28 to generate estimates of the complex envelope in the node information retrieval 30, filtering nodes filter 29-I 29-Q, obtain joint estimates of the complex envelope of the adders 25, 26 and soft solutions in node 13, combining them all single-beam receivers in the adders 8, 9, repeat M times.

An example implementation of the memory node 23 presented on Fig.9.

Node memory 23 contains the first 31 and second 32 switching elements, the first 33 and second 34, third 35 and 36 fourth memory elements.

At the input of the memory node 23 a sequence of complex correlation responses of information si the oxen is divided into equal blocks. In-phase components of the complex correlation responses of information symbols blocks sequentially written in the memory elements 33 and 34, the quadrature components in the memory elements 35 and 36. During iterative processing of the previous block in-phase and quadrature components of the complex correlation responses of information symbols stored, for example, in the memory elements 33, 35 at the input node of the memory 23 in-phase and quadrature components of the complex correlation responses of characters stored in the memory elements 34, 36, and Vice versa. Switching the input of the correlation responses of characters to corresponding inputs of the memory elements perform the switching elements 31, 32 in accordance with the control signals from the synchronization unit 18.

Figure 10 shows curves of probability of bit error on the signal to noise ratio (total useful signal to the spectral power density of the noise at the bit for the proposed method and the method prototype, obtained through computer simulation.

The received signal was represented by a sequence of information and pilot symbols with a duration of 62.5 μs. Fading of the signal corresponded to the Jakes model. The product of the frequency of fading on the duration of the symbol was chosen 0,014 that when the frequency was carrying the soup 2 GHz corresponds to the speed of the subscriber 120 km/H. The power ratio of the information signal to the pilot signal was taken equal to 10.

As can be seen from figure 10, the application of the proposed method can significantly improve the characteristics of the reception.

Thus, the application of the proposed method helps to ensure the robustness and capacity of the communication system which is unattainable using known algorithms.

1. The way quasicoherent reception of multipath signal containing information and pilot components, namely, that for each multipath components of the signal form the sequence of correlation responses of the pilot and information symbols, determining the correlation of the input signal with a known pseudo-random sequence at intervals the duration of each symbol, remember correlation responses of the pilot and data symbols for each multipath components of the signal form evaluation of the complex envelope of information symbols based on the pilot channel, filtering the correlation responses of the pilot symbols for each multipath components of the signal are soft decision information symbols using correlation feedback information symbols and evaluation of complex envelope these characters form a combined soft-decision information symbols, summarizing aggie decisions about the information symbols of all multipath component signal, characterized in that the evaluation of the complex envelope of information symbols based on the pilot channel remember, the final combined soft decision information symbols is carried out in M stages, the first stage taking tough decisions in the first stage of the information symbols in the combined soft decision information symbols, in the subsequent steps take tough decisions in the current stage of information symbols in the combined soft decisions of the previous stage, at each stage for each multipath components of the signal are compared, the correlation module feedback information symbols with a given threshold, if the threshold is exceeded, the corresponding information symbols form of assessing the complex envelope of these characters, for each multipath components of the signal form evaluation of the complex envelope of information symbols on the information channel, filtering the generated estimate of the complex envelope of information symbols multipath components of the signal for each multipath components of the signal to form a combined assessment of the complex envelope of information symbols according to the estimates of the complex envelope of information symbols based on the pilot channel and estimates the complex envelope of information symbols according to the information the th channel, for each multipath components of the signal are soft decisions of the current stage of information symbols using the correlation responses of information symbols and the joint evaluation of the complex envelope of these characters form a combined soft decision in the current stage of information symbols by summing the soft decision in the current stage of information symbols of all multipath component of the signal for the final soft decision information symbols take the combined soft-decision information symbols of the last M-th stage.

2. The method according to claim 1, characterized in that the correlation responses of the pilot symbols is filtered by forming weighted sums of the correlation responses of the pilot symbols.

3. The method according to claim 1, characterized in that the weighting coefficients of the filter determined using the estimate of the autocorrelation function of the in-phase and quadrature components of the complex envelope of characters.

4. The method according to claim 1, wherein the soft decision information symbols is formed by multiplying the complex correlation responses of information symbols by a complex conjugate of the estimate of the complex envelope of information symbols.

5. The method according to claim 1, characterized in that the evaluation of the complex envelope of information symbols is formed by multiplying the CDF is elezione feedback information symbols by a complex conjugate of the hard decisions on respective information symbols.

6. The method according to claim 1, characterized in that the joint estimation of the complex envelope of information symbols is formed by summing the appropriate assessment of the complex envelope of information symbols based on the pilot channel and the evaluation of complex envelope information symbols on the information channel.

7. The method according to claim 1, characterized in that the evaluation of the complex envelope of information symbols is filtered, forming a weighted sum of the estimates of the complex envelope of information symbols.

8. The method according to claim 1, wherein said soft decision in the current stage of information symbols is formed by multiplying the complex correlation responses of information symbols by a complex conjugate of the joint evaluation of the complex envelope of information symbols.

9. The device quasicoherent reception of multipath signal containing N single-beam quasicoherent receivers, the control unit, the first and second adders, each adsolutely quasicoherent the receiver includes a demodulator of the information channel and the demodulator pilot channel processing unit containing the first nodes of the filtered in-phase and quadrature channels, the first unit delay, a crucial node, and first and second inputs of the first node delays are the inputs of the correlation responses of information symbols and first and second the m inputs of the processing unit, the inputs of the first node filtering in-phase and quadrature channels are used as inputs of the correlation responses of the pilot symbols and the third and fourth inputs of the processing unit, the first and second outputs of the decision making node are outputs soft decision information symbols and outputs of the processing unit, and first and second inputs of the demodulators of the information channel and demodulators pilot channel interconnected and are the first and the second inputs of each single-beam quasicoherent receiver and inputs the in-phase and quadrature components of the input beam signal, the third inputs of the demodulators of the information channel and demodulators pilot channel combined are the third input of each single-beam quasicoherent receiver and connected with the corresponding the output of the control unit, which is the output of the temporary provisions of signal beams, each single-beam quasicoherent the receiver of the first and second outputs of the demodulator of the information channel, which are the outputs of the correlation responses of information symbols, connected with the first and second inputs of the processing unit, the first and second outputs of the demodulator pilot channel, which are the outputs of the correlation responses of the pilot symbols, connected with the third and fourth inputs of the processing unit, the outputs of block education is otki, which are both outputs of the corresponding single-beam quasicoherent receiver and outputs the soft decision information symbols, connected to respective inputs of the first and second adders, characterized in that the synchronization unit, the first and second switches, the first and second computing units in the processing unit further introduced the second node filtering in-phase and quadrature channels, the first and second memory nodes, the first and second adders, the second node of the delay, the node comparison with a threshold, the node information retrieval, and output the first and second adders outputs are combined soft decision information symbols and are connected respectively with the first the inputs of the first and second switches, the second inputs of the first and second switches are control and is connected to the second output of the synchronizer, fifth and sixth inputs of the processing unit of each single-beam quasicoherent receiver input hard decision information symbols and are connected to the outputs of the first and second computing units, the seventh input of the processing unit of each single-beam receiver is a synchronization input connected to the first output of the synchronization unit, the first outputs of the first and second switches are connected respectively to the inputs of p is pout and second computing units, which inputs are combined soft decision, the second outputs of the first and second switches are the final outputs soft decision information symbols and outputs of the device quasicoherent reception of multipath signal, the processing unit of the first and second outputs of the first unit delay is connected with the first and second inputs of the first memory node, a third input which is a control input, the outputs of the first node filtering in-phase and quadrature channels, which are the outputs of the evaluation of complex envelope information symbols on the pilot channel, is connected with the first and second inputs of the second memory node, a third input which is managing, the third inputs of the first and second nodes memory combined in the seventh input of the processing unit, which is managing the outputs of the evaluation of complex envelope information symbols on the pilot channel of the second memory node connected to the first inputs of the first and second adders, the second inputs of the first and second adders are connected with the first and second outputs of the second unit delay, which are the outputs of the evaluation of complex envelope on the information channel, the outputs of the first and second adders are outputs in-phase and quadrature components of the combined assessments of the complex envelope of the information symbol is connected with the first and second inputs of the decision making node, the first and second outputs of the first memory node outputs are in-phase and quadrature components of the complex correlation responses of information symbols and connected with the third and fourth inputs of the decision making node and the first and the second input node of the comparison with the threshold, the output node of the comparison with the threshold outputs are in-phase and quadrature components of the corresponding complex correlation responses of information symbols and connected with the third and fourth inputs of the node, removing information, the first and second inputs of which are the inputs of the hard decision information symbols and the fifth and sixth inputs of the processing unit, the first and second outputs node information retrieval are the outputs of the evaluation phase and quadrature components of the complex envelope information symbols and are connected with the inputs of the second node filtering in-phase and quadrature components, the outputs of which are connected to first and second inputs of the second unit delay.



 

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