RU2297713C2 - Method and device for receiving multibeam signal - Google Patents

Abstract

FIELD: receiving and decoding data from different users in code-division multiple access communication systems.

SUBSTANCE: using autoregressive smoothing of relaxed solutions concerning reliability of receiving code characters by multiple-user detector, their next joint iterative decoding involving recovery of whole code word, autoregressive smoothing of recovered relaxed solutions followed by relaxed limiting of hyperbolic tangent functions, as well as evaluation of complex envelope at each iteration make it possible to enhance quality of reception in code-division multiple access channel, that is to enhance noise immunity of receiver and capacity of communication system, as well as to reduce cost of base station in CDMA channel.

EFFECT: enhanced noise immunity of communication system signal receiver.

4 cl, 7 dwg

Description

The invention relates to the field of radio engineering, in particular to a method and device for receiving a multipath signal, and can be used in communication systems with moving objects.

In communication systems with moving objects, the signal propagation channels between the receiver and the data transmitter are multipath and non-stationary. Typically, the multipath of the propagation channel in mobile communication systems is taken into account by summing the energy of the components of the multipath signal in a Rake receiver. The signal of each beam is received by a separate single-beam receiver, including, inter alia, a time synchronization block. This approach is effective in the presence of several well-resolved multipath components, i.e. spaced apart by time on several chips. The PSP chip is the duration of one elementary time interval of a pseudo-random sequence. However, often the frequency-selective fading is of such a nature that the components of the multipath signal are unresolvable (the difference in the temporal positions of the signals of adjacent rays is smaller than the PSP chip).

Due to an incorrect estimate of the number of components of the multipath signal, there are energy losses and a deterioration in the quality of demodulation both in the absence and in the presence of fading. These losses are due to non-optimal processing of a signal containing unresolved beams. Obviously, the work of an effective tracking and demodulation system in the conditions of unresolvable multipath should differ from the work of known devices.

During the operation of the tracking system of the receiving device, it is possible to detect signals of several beams. Due to the influence of the beam signals on each other, the data streams are distorted, according to which the complex envelope (carrier recovery) of the signals of each beam is estimated. This should be taken into account when receiving data.

The effectiveness of a communication system is largely determined by the ability of time synchronization algorithms to provide the necessary accuracy in estimating the number and time positions of multipath signal components in multipath non-stationary channels, and carrier recovery algorithms to provide high accuracy in evaluating the complex envelope of signals of found multipath signal components.

The problem of synthesis and analysis of algorithms for tracking the time delay of a single-beam signal (an independent component of a multipath signal) has been solved over the past few decades by many authors (see, for example, Riccardo De Gaudenzi "Direct-Sequence Spread-Spectrum Chip Tracking in the Presence, of Unresolvable Multipath Components ”, IEEE Trans. Veh. Tech., Vol. 48, pp. 1573-1583, Sept. 1999 [1] and G.Proakis“ Digital Communications ”, McGraw-Hill, 3rd Edition, 1995 [2]). Algorithms developed as a result of these studies that monitor the time delay of a single-beam signal in systems include procedures for generating an estimate of the timing synchronization error and its subsequent correction. As a rule, these procedures are implemented in analog or digital form based on automatic control systems in which time synchronization is carried out using control feedback or without it.

One of the incoherent tracking systems for one code signal implemented in practice is described in the article by M.K.Simon, J.K. Omura, RAScholtz, and V.K. Levitt "Spread Spectrum Communications", Electrical Engineering Communications and Signal Processing, volume III, 1985 [3]. The tracking system includes a discriminator, a controlled reference signal generator (PSP generator) and data demodulation branches. The discriminator includes two quadrature correlators, two quadrators, and a difference calculation circuit. Each of the quadrature correlators consists of a channel quadrature multiplier and a filter. The data extraction branch includes a correlator and a data detector. A device made in this way corrects the tracking error of the time shift between the received and reference signal and is not sensitive to a random initial phase of the input signal. To generate a tracking error signal, a reference signal is applied to the multiplier of the first discriminator correlator ahead of a certain time interval Δ relative to the current time position, and the second signal is delayed by a time interval Δ. As a result, an error signal is generated at the output of the difference calculation circuit, corresponding to a time mismatch between the input and reference signal, which is used to correct the time delays of the SRP generator.

There are various modifications of the described device and its implementation algorithm. For example, Richard A. Yost and Robert W. Boyd in his report “A modified pn code tracking loop: Its performance analysis and comparative evaluation”, IEEE Transactions on Communications, COM-30 (5): 1027-36, May 1982 [4 ] proposed a modified algorithm for tracking a single code signal. The advantage of this algorithm is that its implementation requires fewer standard blocks. On the other hand, such a technical solution is very sensitive to the estimation of the phase of the input signal, which leads to a decrease in the stability of the work.

A disadvantage of the known signal delay tracking systems is that when individual receivers monitor closely located components of a multipath signal, both receivers are likely to capture one component, while the other (weaker) component is no longer monitored. This leads to energy loss. In addition, in the case of unresolvable multipath, a large tracking error signal jigger occurs, which reduces the stability of the tracking system and also causes energy loss.

A known approach aimed at overcoming the disadvantages of the above tracking methods. It consists in the fact that the receivers track the components of the multipath signal in such a way as to prevent their approaching by a distance shorter than some minimum acceptable (see, for example, published international application WO 97/28608 “Method and Arrangement of Signal Tracking and a Rake- receiver Utilizing Said Arrangement ”, 08/07/97 [5] and US patent No. 6345078 B1, Feb.5, 2002,“ Finger assignment system for a multiple finger receiver and method therefore ”[6]).

In [5], a method for receiving a multipath signal with unresolvable components is described. A system that implements the proposed method consists of a search receiver, a tracking system for the components of the detected signal, a control processor, and a RAKE receiver. The algorithm used in the tracking procedure is as follows. If the components are not resolved, and the decision function has a unimodal shape, then to perform the tracking and demodulation procedures, a separate signal delay tracking scheme is used that corresponds to the time position of the maximum of the decision function.

If the decisive function of the total unresolved signal has a multimodal shape, then the adjustment procedure begins with the receiver tracking system demodulating the maximum component of the multipath signal. For other components, this procedure is performed so that the time shift between the reference signals of any two demodulators is not less than some predetermined value T _min . In [5], three different strategies for implementing this condition were proposed.

A method for tracking a multipath signal, prohibiting the approximation of the temporal positions of adjacent receivers, does not solve the main problem of tracking in conditions of unresolved multipath, which consists in determining the number of components of a multipath signal. Actually, the distance between the signals of neighboring rays can be less than a given minimum distance between the receivers. An error in determining the number of unresolvable components can lead to significant energy losses.

Another well-known method for tracking a signal with unresolvable multipath (see Volker Aue and Gerhard P. Fettweis "A Noncoherent Tracking Scheme for the RAKE Receiver That Can Cope With Unresolvable Multipath", ICC '99, Vancouver, Canada, June, 1999 [7] and US patent No. 6, 381, 264 B1, Apr.30, 2002 "Efficient multipath centroid tracking circuit for a code division multiple access (CDMA) system" [8]) is the synchronous control of all single-beam receivers installed in the field of multipath. The method is based on the formation of a total tracking error for all single-beam receivers. The resulting total tracking error is used for unidirectional adjustment of the time positions of all single-beam receivers.

In [7], an incoherent tracking scheme for the RAKE receiver for unresolved components of a multipath signal was proposed and its analysis was performed. The described system for tracking time delays contains several receivers, each of which contains a correlator and a unit for estimating errors of time tracking. If the distance between the components of the multipath signal is large compared to the duration of the chip, then the receivers track the components of the multipath signal independently.

If the distance between the components of the multipath signal is approximately equal to the duration of the chip or less than it, then for these rays a group of equally spaced receivers is allocated, spaced relative to each other by some fixed distance. Tracking for each group of receivers is carried out while maintaining the relative time interval between the receivers.

The disadvantage of jointly adjusting the set of receivers is that they do not know the number of components of the multipath signal (this problem cannot be solved as part of the tracking procedure). In the case of frequent (closer than 1 chip) arrangement of receivers in the multipath domain, a large number of receivers are required. And in the case of a rare arrangement, energy losses occur, which are mentioned above. In addition, the beam signals can drift in different directions, which cannot be tracked with joint tuning.

The closest technical solution to the claimed method of quasicoherent reception of multipath signals and a device for its implementation are the method and device for its implementation, described in Gunnar Fock, Jens Baltersee, Peter Schulz-Rittich, and Heinrich Meyr "Channel Tracking for Rake Receivers in Closely Spaced Multipath Environments ”, IEEE Journal, On Selected Areas hi Communications, Vol., 19, No. 12, December 2001 [9].

The prototype method is as follows:

they search for the components of the multipath signal and determine the initial estimate of their temporal positions.

interpolating the input signal, resulting in an increase in the sampling frequency of the input signal;

for each component:

delay the input signal in accordance with the evaluation of the time position of the component,

form complex correlation responses of signal symbols, as well as delayed and leading complex correlation responses of symbols,

form the difference between lagging and leading complex correlation responses of the signal symbols,

form a component tracking error by multiplying the generated difference by a complex conjugate estimate of the complex envelope of the component symbol and a complex conjugate estimate of the symbol information parameter,

correct the component tracking error by subtracting from the resulting product the interfering influence of other components,

filter the correct component tracking error for several characters,

adjust the estimate of the signal delay of the component according to the filtered adjusted tracking error,

complex correlation responses of signal symbols are delayed and multiplied by a complex conjugate estimate of the complex envelope of the symbols, obtaining soft solutions of the information symbols of the component;

form soft decisions of information symbols, summing up soft decisions of information symbols of all components;

form estimates of information symbols by soft decisions of information symbols;

multiply the complex correlation responses of the signal symbols of all components to a complex conjugate estimate of the information parameter of the symbol;

Correct the received works;

form estimates of the complex envelopes of component symbols by filtering the corrected works;

for each component, an interfering effect of other components in the tracking error of the components is formed according to the estimates of the complex envelope of the component symbols, as well as from the adjusted estimates of the component signal delays.

The device with which the prototype method is implemented (FIG. 1) comprises a search receiver 1, a control unit 2, a pseudo-random sequence generator (PSP) 3, L single-beam receivers 4 ₁ -4 _L signals, a first correction unit 5, a second correction unit 6 , block 7 complex conjugation, the decision block 8 and the adder 9, with each single-beam receiver 4 ₁ -4 _L signal contains a block 10 for determining the delay, a complex interpolator-decimator 11, a complex register 12, a complex switch 13, the first 14, the second 15 and third 16 complex correlators, to complex subtractor 17, complex delay line 18, component tracking error generating unit 19, loop filter 20, subtractor 21, complex conjugation block 22, filter 23, first 24 and second 25 complex multipliers, the first inputs of the search receiver 1 and complex interpolator-decimator 11 in each single-beam receiver 4 ₁ -4 _{L of the} signal are combined, forming the input of the device, which is the input of a complex discrete signal, the output of the search receiver 1 is connected to the input of the control unit 2, the first output of which is connected to the second the input of the search receiver 1, the second output of the control unit 2 is connected to the first input of the delay determination unit 10 in each single-beam signal receiver 4 ₁ -4 _L , the third output of the control unit 2 is connected to the input of the SRP generator 3, the output of which is connected to the first inputs of the first 14 , the second 15 and third 16 complex correlators in each single-beam receiver 4 ₁ -4 _L signal, the fourth output of the control unit 2 is connected to the second inputs of the first 14, second 15 and third 16 complex correlators in each single-beam receiver 4 ₁ -4 _L output _{One of the} delay determination unit 10 in each single-beam receiver 4 ₁ -4 _{L of the} signal is connected to the second input of the complex interpolator - decimator 11 and the corresponding first inputs of the first 5 and second 6 correction units, the input of the delay determination unit 10 is connected to the output of the loop filter 20, output complex register 12 is connected to the third input of the first complex correlator 14, the output of which is connected to the first input of the complex subtractor 17, the second input of which is connected to the output of the second complex correlator 15, the output of the complex of the second subtractor 17 is connected to the first input of the component tracking error generating unit 19, the third input of the second complex correlator 15 and the input of the complex register 12 are combined and connected to the first output of the complex switch 13, the input of which is connected to the output of the complex interpolator - correlator 11, the second output of the complex switch 13 is connected to the third input of the third complex correlator 16, the output of which is connected to the first input of the first complex multiplier 24 and the input of the complex delay line 18, the output which is connected to the first input of the second complex multiplier 25, the second input of the complex multiplier 25 and the second input of the component tracking error generating unit 19 are combined and connected to the output of the complex conjugation unit 22, the third input of the component tracking error generating unit 19 and the second input of the first complex multiplier 24 v each single-beam receiver 4 ₁ -4 _{L of the} signal are combined and connected to the output of the complex conjugation unit 7, the output of the component tracking error generation unit 19 is connected to the first input m of the subtractor 21, the output of which is connected to the input of the loop filter 20, the second input of the subtractor 21 in each single-beam receiver 4 ₁ -4 _{L of the} signal is connected to the corresponding output of the first block 5 correction, the output of the filter 23 in each single-beam receiver 4 ₁ -4 _{L of the} signal connected to the input unit 22, a complex conjugate and its corresponding correction input of the first unit 5, the second inputs of the second correction unit 6 connected to the outputs of complex multiplier 24 of each single beam receiver April ₁ -4 _L signal, outputs the second correction unit 6 is connected from each single beam receiver filter input 23 January ₄ -4 _L signal complex conjugation block input 7 connected to an output deciding unit 8 having an input connected to the output of the adder 9, which is an output device, the inputs of the adder connected to the outputs of complex multiplier 25 of each single beam receiver 4 ₁ -4 _L , signal.

The prototype device operates as follows (see Figure 1). The complex input discrete signal is fed to the first input of the search receiver 1 and to the inputs L of single-beam receivers 4 ₁ -4 _{L of the} signal, namely, to the first inputs of complex interpolators - decimators 11. The signal from the control unit 2 in the search receiver 1 searches for components of the input multipath signal and form an initial estimate of their temporary positions relative to the temporary position of the reference signal of the generator 3 SRP. An initial estimate of the time positions of the detected components of the multipath input signal is fed through the control unit 2 to the first inputs of the delay determination units 10 of the corresponding single-beam receivers 4 ₁ -4 _L. On the control signal from the third output of the control unit 2, the SRP generator 3 at the output generates in-phase and quadrature components of the reference signal, which are fed to the first inputs of the first 14, second 15 and third 16 complex correlators of single-beam receivers 4 ₁ -4 _L. The second inputs of the first 14, second 15 and third 16 complex correlators of single-beam receivers 4 ₁ -4 _L provide a reset signal from the control unit 2. For each component in the corresponding single-beam receiver 4 ₁ -4 _{L, the} necessary input signal delay arrives at the second input of the complex interpolator - decimator 11 from the output of the delay determination unit 10. Initially, it is equal to the initial estimate of the temporal position of the component relative to the temporal position of the reference signal coming from the control unit 2, and subsequently, the sum of the current estimate of the temporal position of the component and the filtered corrected tracking error from the output of the loop filter 20.

In the complex interpolator-decimator 11, the input complex discrete signal is interpolated, as a result of increasing its sampling frequency, and the input signal is delayed in accordance with the estimate of the time position of the component and the delay signal is decimated. From the output of the complex interpolator - decimator 11, the samples of the delayed discrete complex signal through the complex switch 13 are supplied alternately (through 0.5 chips) to the third input of the third complex correlator 16, to the third input of the second complex correlator 15 and through the complex register 12 to the third input of the first complex correlator 14. The complex register 12 carries out a delay on one chip.

The first 14 and second 15 complex correlators are used to generate delayed and leading complex correlation responses of signal symbols, which respectively arrive at the first and second input of complex subtractor 17. From the output of complex subtractor 17, the difference between delayed and leading complex correlation responses of signal symbols is sent to the first input of the block 19 forming component tracking errors.

In block 19, a component tracking error is generated by multiplying the generated difference sequentially by the complex conjugate estimate of the complex envelope of the symbol of the component and the complex conjugate estimate of the symbol information parameter, which are received at the second and third inputs of block 19 from the outputs of the complex conjugation blocks 22 and 7, respectively. Additionally, a complex conjugate estimate of the information parameter of the symbol is fed to the second input of the first complex multiplier 24.

The generated tracking error of the components is fed to the first input of the subtractor 21, in which it is corrected by subtracting from it the interfering effect of the other components, which comes from the correction unit 5. Interfering influences for all components are formed in block 5 according to estimates of the complex envelope of the symbol and the temporal positions of the components. The corrected tracking error of the components is filtered by several characters in the loop filter 20 and fed to the second input of the delay determination unit 10.

The third complex correlators of 16 single-beam receivers 4 ₁ -4 _L are used to receive information symbols. The complex correlation responses of the signal symbols from the output of the third complex correlator 16 are input to the complex delay line 18 and to the first input of the first complex multiplier 24. In the complex delay line 18, the complex correlation responses of the signal symbols are delayed by the time interval necessary to estimate the complex envelope of the component symbols, and multiplied in the second complex multiplier 25 by a complex conjugate estimate of the complex envelope of the symbols, obtaining soft solutions of information character components.

Soft decisions of information symbols of all components are summarized in adder 9, resulting in soft decisions of information symbols that are output to the device and decision block 8. In block 8, soft decisions of information symbols form estimates of information symbols that enter block 7 of complex conjugation . From block 7, complex conjugate estimates of information symbols are supplied to the third inputs of blocks 19 and second inputs of the first complex multipliers 24 of single-beam signal receivers 4 ₁ -4 _L.

In the first complex multipliers, 24 single-beam signal receivers 4 ₁ -4 _L multiply the complex correlation responses of the signal symbols to the complex conjugate estimate of the symbol information parameter, and the multiplication results are supplied to the second inputs of the second correction block 6. The first inputs of the first 5 and second 6 correction blocks from the outputs of the delay determination unit 10 of the single-beam receivers 4 ₁ -4 _L receive delay component of the input signal. In the second block 6 corrections correct the resulting product, eliminating the mutual influence of the beam signals on each other. The corrected products of the components from the outputs of the second correction unit 6 are sent to the corresponding filters 23 of single-beam receivers 4 ₁ -4 _L , in which they are filtered over the interval of several symbols, thus forming estimates of the complex envelopes of the component symbols. The generated estimates of the complex envelopes of the component symbols are fed to the inputs of the blocks 22 of the complex pairing of single-beam receivers 4 ₁ -4 _L and to the second inputs of the first block 5 of the correction. In the first block 5, the corrections according to the estimates of the complex envelope of the symbol of the components and the delays of the components of the input signal from block 10 form for each component an interfering effect of the other components on the tracking error.

The main disadvantage of the prototype method is the lack of an effective solution to the problem of determining the number of components of a multipath signal in conditions of unresolved multipath. An error in determining the number of unresolvable components can lead to significant energy losses.

The task of the claimed invention is to increase the noise immunity of signal reception in the conditions of unresolvable multipath, reducing the required processing resource.

The technical result is achieved due to the fact that in the method of receiving a multipath signal, in which for tracking and evaluating the propagation channel, the number of simultaneously analyzed time positions of the signal is limited to N, which consists in the fact that:

- periodically with a period of T _s in the field of multipath, search for components of the multipath signal and determine the assessment of the search for their temporary positions,

- periodically with a step of duration T _t determine the temporary position of the components of the multipath signal,

- form in-phase and quadrature components of the complex correlation responses of the pilot signal in the interval of the tracking step,

- find an estimate of the temporary positions of the components,

- find soft solutions for information symbols using the generated estimate of the time positions of the multipath signal component, for which:

- form estimates of the complex envelope of the pilot symbols corresponding to the estimates of the time positions of the components of the multipath signal, as the weighted sum of the complex correlation responses of the pilot symbols of the components,

- form estimates of the complex envelope of the information symbols of the component, filtering the corresponding estimates of the complex envelope of the pilot symbols,

- form in-phase and quadrature components of the complex correlation responses of information symbols corresponding to estimates of the time positions of the components of the multipath signal,

- form soft decisions of the components about information symbols, multiplying the corresponding complex correlation responses of information symbols by a complex conjugate estimate of the complex envelope of the information symbols of the component,

- form soft decisions about information symbols, summing up soft decisions of components about information symbols,

according to the invention, the following sequence of actions is introduced:

- carry out the ranking in decreasing order of the power of temporary positions found in the search procedure,

- periodically with a step of duration T _t determine the number of components of the multipath signal, for which at each step:

- carry out the ranking of temporary positions that are 1/2 chip ahead and behind the temporal positions of the components of the previous tracking step, in decreasing order of the power of the generating component, and for the first tracking step, the components found during the search are used as components of the previous tracking step,

- carry out the ranking in decreasing order of the power of temporary positions that were investigated at the previous tracking step, with the exception of the first tracking step,

- form an array of temporary positions to be analyzed at each tracking step, while the array is filled with temporary positions in the following sequence:

a) temporary positions of the components of the previous tracking step,

b) ranked temporary positions that are 1/2 chip ahead and behind the temporal positions of the components of the previous tracking step, and, starting from this group of temporary positions and further on, the temporary position is added to the generated array only if the distance between this temporary position and temporary positions already in the array, not less than 1/2 of the chip,

c) the ranked temporary positions of the components found in the last search procedure,

d) the ranked temporary positions that were examined in the previous tracking step,

the formation of the array is stopped upon reaching the number of temporary positions of the array of magnitude N,

- in-phase and quadrature components of the complex correlation responses of the pilot signal at the interval of the tracking step, as well as the sum of their squares, are formed simultaneously for all temporary positions of the generated array,

- find the maximum sum of the squares of the in-phase and quadrature components of the complex correlation responses of the pilot signal in the interval of the tracking step,

- the temporary positions of the formed array are grouped into temporary areas in such a way that if the temporary distance between the temporary positions of the array is less than the chip, then they enter the same area, otherwise the temporary positions enter the different areas,

- for each time domain, simultaneously with finding an estimate of the time positions of the components, an estimate is found corresponding to the number of components, for which:

- discard the temporary positions of the region for which the sum of the squares of the in-phase and quadrature components of the complex correlation responses of the pilot signal in the interval of the tracking step is less than a predetermined threshold, the value of which is proportional to the maximum sum of the squares of the in-phase and quadrature components of the complex correlation responses of the pilot signal in the interval of the tracking step,

- from all kinds of sets of the remaining temporary positions of the region, the number of possible temporary positions of the set is from 1 to m, the time distance between the temporary positions of the set is at least 1/2 of the chip, a set of temporary positions of the region is found for which the decisive function, which is the sum of the quadratic form of the in-phase components complex correlation responses of the pilot signal at the interval of the tracking step for the time positions of the set, quadratic form of quadrature components of the complex correlation responses of the pilot signal to int the interval of the tracking step for the temporary positions of the set and the term linearly decreasing with increasing the number of temporary positions of the set and proportional to the maximum sum of squares of the in-phase and quadrature components of the complex correlation responses of the pilot signal in the interval of the tracking step of the temporary positions of the formed array is the maximum; temporary positions of the found set are taken as an estimate of the temporary positions of the components, and the number of temporary positions of the set is taken as an estimate of the number of components in the study area,

- if the sum of the estimates of the number of components of all regions does not exceed the maximum value of the monitored components of P, then the final estimate of the number of components of the multipath signal is equal to the sum of the estimates of the number of components of all regions, and the estimate of their temporal positions corresponds to the estimates of the temporal positions of the regions, otherwise from the set of estimates of the temporary positions the component of all regions selects the P component with maximum power values, and the estimate of the time positions of the multipath signal component corresponds to the time positions m of the most powerful component

- soft decisions about information symbols are found using the generated estimate of the number of components.

The problem is also solved due to the fact that in the device for receiving multipath signals containing a search receiver, a control unit, a pseudo-random sequence generator (PSP), L single-beam signal receivers, a correction unit and an adder, each single-beam signal receiver contains the first and second complex correlators , a complex delay line, a complex conjugation unit, a filter and a complex multiplier, and the first input of the search receiver is the input of the device, the input of the complex discrete signal, the output the search receiver is connected to the first input of the control unit, the first output of which is connected to the second input of the search receiver, the second output of the control unit is connected to the input of the SRP generator, the first output of which is connected to the first input of the first complex correlator in each single-beam signal receiver, the third output of the control unit is connected with the second input of the first and first input of the second complex correlators in each single-beam signal receiver, the output of the second complex correlator is connected to the input of the complex line and a delay whose output is connected to the first input of the complex multiplier, the second input of which is connected to the output of the complex conjugation block, the input of which is connected to the filter output, the filter input of each single-beam signal receiver is connected to the corresponding output of the correction block, the outputs of the complex multiplier of each single-beam signal receiver connected to their respective inputs of the adder, the output of which is the output of the device,

according to the invention introduced:

M delay blocks,

M complex correlators,

multi-channel block for calculating the sum of squares,

first, second and third ranking blocks,

maximum search block,

block for forming an array of temporary positions,

key,

a unit for generating estimates of temporary positions of regions,

block limiting the number of components

a delay node is introduced into each single-beam signal receiver,

wherein the first inputs M of the delay units and the first input of the delay unit in each single-beam signal receiver are connected to the input of the device,

the second inputs of the M delay blocks, the first inputs of the M blocks of complex correlators, the second inputs of the delay nodes of each single-beam signal receiver, the first inputs of the correction block, the first inputs of the third ranking block and the block for generating estimates of the temporal positions of the regions are connected to the third output of the control unit,

the second inputs M of the complex correlators are connected to the first output of the PSP generator,

the second output of the SRP generator is connected to the second inputs of the second complex correlators of each single-beam signal receiver,

the third inputs of the first and second complex correlators are connected to the output of the delay node in each single-beam signal receiver,

the third inputs of the M complex correlators are connected to the outputs of the M delay units,

the outputs of the M complex correlators are connected to their respective M inputs of a multi-channel unit for calculating the sum of squares,

L inputs of a multi-channel sum-square calculation unit are combined with L second inputs of the correction unit and connected to the outputs of the corresponding first complex correlators of each single-beam signal receiver,

moreover, the M and L inputs of the multi-channel unit of calculating the sum of squares are combined with the second inputs of the unit for forming estimates of temporary positions,

the outputs of the multi-channel block for calculating the sum of squares are connected to the input of the first ranking block, the input of the maximum search block, the first input of the component number limiting block and the third input of the block for generating estimates of the temporal positions of the regions

the fourth input of the unit for estimating the temporary positions of the regions is connected to the output of the maximum search unit,

the output of the unit for estimating the temporal positions of the regions is connected to the second input of the component number limiting unit,

the third input of the block limiting the number of components, the second input of the third ranking block and the first input of the block forming the array of temporary positions are connected to the output of the key,

the fourth input of the block limiting the number of components and the first input of the key are combined and connected to the fourth output of the control unit,

the output of the block limiting the number of components is connected to the second inputs of the key and the control unit,

the fifth output of the control unit is connected to the input of the second ranking unit, the output of which is connected to the third input of the key and the second input of the block for forming an array of temporary positions, the third input of which is connected to the output of the third ranking unit,

the fourth input of the block forming the array of temporary positions is connected to the output of the first ranking block,

the output of the block forming the array of temporary positions is connected to the third input of the control unit.

The introduction of new distinctive features in the method and device according to the described invention allows to obtain a new technical result - to increase the noise immunity of signal reception in the conditions of unresolved multipath and reduce the necessary processing resource.

The inventive method of receiving a multipath signal and a device for its implementation, in contrast to the known technical solutions, specify in the tracking process not only the temporary positions of the components of the multipath signal, but also their number. The algorithm for receiving a multipath signal when evaluating the complex envelope compensates for the mutual influence of the signals of different rays on each other, which makes it possible to obtain a significant energy gain in conditions of insoluble multipath in comparison with the best known algorithms. In this case, the noise immunity of the proposed method is practically not inferior to the potential one (when the temporal positions of the components of the multipath signal are a priori known). Moreover, the inventive method allows to reduce the required processing resource (the number of correlators).

The invention is illustrated by examples and drawings:

Figure 1 shows the structural diagram of the device of the prototype.

Figure 2 is a structural diagram of the inventive device.

Figure 3 is a structural diagram of a correction unit 6, shown as an example of implementation.

Figure 4 - algorithm of block 33 forming an array of temporary positions.

Figure 5 - algorithm of block 35 for the formation of estimates of the temporary positions of the regions.

6 and 7 show the results of comparing the noise immunity of the claimed invention and known algorithms obtained by computer simulation.

The inventive device for receiving a multipath signal (Fig. 2) comprises a search receiver 1, a control unit 2, a pseudo-random sequence generator (PSP) 3, L single-beam receivers 4 ₁ -4 _{L of the} signal, a correction unit 6, and an adder 9, wherein each single-beam receiver 4 _The 1-4 _L signal contains the first 16 ₁ and second 16 ₂ complex correlators, a complex delay line 18, a complex pairing unit 22, a filter 23 and a complex multiplier 25, the first input of the search receiver 1 being the input of the device, the output of the search receiver 1 being connected to the first in the control unit 2, the first output of which is connected to the second input of the search receiver 1, the second output of the control unit 2 is connected to the input of the SRP generator 3, the first output of which is connected to the first input of the first 16 ₁ complex correlator in each single-beam receiver 4 ₁ -4 _L signal The third output of the control unit 2 is connected to the second input of the first 16 ₁ and the first input of the second February ₁₆ complex correlators in each receiver single-beam April ₁ -4 _L signal output of the second complex correlator February ₁₆ connected to the input line 18 integrated setbacks , The output of which is connected to a first input of complex multiplier 25, a second input coupled to an output of the complex conjugate unit 22, whose input is connected to the output of the filter 23, the filter entrance 23 of each single beam receiver April ₁ -4 _L signal coupled to its corresponding output of the correction 6 , the outputs of the complex multiplier 25 of each single-beam receiver 4 ₁ -4 _L signal are connected to the corresponding inputs of the adder 9, the output of which is the output of the device, according to the invention further comprises: M blocks 26 ₁ -2 6 _M delays, M complex correlators 27 ₁ -27 _M , multi-channel block 28 for calculating the sum of squares, first 29, second 30 and third 31 ranking blocks, maximum search block 32, array of temporary positions block 33, key 34, estimator 35 the time positions of the regions, the unit 36 for limiting the number of components, a delay unit 37 is introduced into each single-beam receiver 4 ₁ -4 _{L of the} signal, while the first inputs of the M units 26 ₁ -26 _{M of the} delay and the first input of the unit of the delay 37 in each single-beam receiver 4 ₁ - 4 _L signals are connected to the input of the device, the second the inputs of the M blocks 26 ₁ -26 _M delay, the first inputs of the M blocks 27 ₁ -27 _M complex correlators, the second inputs of the nodes 37 delay each single-beam receiver 4 ₁ -4 _L signal, the first inputs of the block 6 correction, the first inputs of the third block 31 ranking and forming unit 35 estimates the time position regions are connected to third output control unit 2, the second inputs of M complex correlators January ₂₇ -27 _M are connected to the first output of generator 3 SAPs second generator output SRP 3 is connected to second inputs of the second complex correlators February ₁₆ each odnoluche January ₄ th receiver -4 _L signal third inputs of first 16 ₁ and second 16 ₂ set of correlators are connected to the output of delay unit 37 in each single-beam receiver April ₁ -4 _L signal third inputs of M complex correlators January ₂₇ -27 _M are connected to the outputs M delay blocks 26 ₁ -26 _M , the outputs of M complex correlators 27 ₁ -27 _{M are} connected to the corresponding M inputs of the multi-channel sum of squares calculator 28, L inputs of the multi-channel sum of squares calculator 28 are combined with L second inputs of the correction block 6 and connected to outputs corresponding uyuschih them first complex correlator ₁₆ January each single beam receiver April ₁ -4 _L signal, the M and L multichannel input unit 28 calculating the sum of squares are combined to second inputs 35 time slots form a block count, the outputs of the multichannel unit 28 calculating the sum of the squares connected to the input of the first block 29 ranking, the input of the maximum search block 32, the first input of the block 36 limiting the number of components and the third input of the block 35 forming estimates of the temporary positions of the regions, the fourth input of the block 35 forming the sc the area temporal position knob is connected to the output of the maximum search unit 32, the output of the area temporal position estimator 35 is connected to the second input of the component number limiting unit 36, the third input of the component number limiting unit 36, the second input of the third ranking unit 31 and the first input of the forming unit 33 an array of temporary positions are connected to the output of the key 34, the fourth input of the component limiting unit 36 and the first input of the key are combined and connected to the fourth output of the control unit 2, the output of the limiting unit 36 h If the component is connected to the second inputs of the key 34 and the control unit 2, the fifth output of the control unit 2 is connected to the input of the second ranking unit 30, the output of which is connected to the third input of the key 34 and the second input of the array position block 33, the third input of which is connected to the output the third ranking unit 31, the fourth input of the temporary position array forming unit 33 is connected to the output of the first ranking unit 29, the output of the temporary position array forming unit 33 is connected to the third input of the control unit 2 .

Correction block 6, an example of the execution of which for processing one area is shown in Fig. 3, contains Q correction elements 38 ₁ -38 _Q , matrix generation element 41 B ^-1 , each correction element contains Q complex multipliers 39 ₁ -39 _Q and a complex adder 40.

In figures 1, 2 and 3, arrows (connections) are made of various thicknesses, while thin arrows show the connection of blocks through direct connections, and thicker arrows show the connection of blocks and structural elements on the bus (many connections).

The inventive method of receiving a multipath signal, in which for tracking and evaluating the propagation channel, the number of simultaneously analyzed temporal positions of the signal is limited to N, as follows:

- periodically with a period of T _s in the multipath domain, search for the components of the multipath signal and determine the search estimate of their number and time positions;

- carry out the ranking in decreasing order of the power of temporary positions found in the search procedure;

- periodically with a step of duration T _t determine the number and time positions of the components of the multipath signal, for which at each step the following operations are performed:

- carry out the ranking of temporary positions that are 1/2 chip ahead and behind the temporal positions of the components of the previous tracking step, in decreasing order of the power of the generating component, and for the first tracking step, the components found during the search are used as components of the previous tracking step;

- carry out the ranking in decreasing order of the power of temporary positions that were investigated at the previous tracking step, with the exception of the first tracking step;

- form an array of temporary positions to be analyzed at each tracking step, while the array is filled with temporary positions in the following sequence:

a) temporary positions of the components of the previous tracking step,

b) ranked temporary positions that are 1/2 chip ahead and behind the temporal positions of the components of the previous tracking step, and, starting from this group of temporary positions and further on, the temporary position is added to the generated array only if the distance between this temporary position and temporary positions already in the array, not less than 1/2 of the chip,

c) the ranked temporary positions of the components found in the last search procedure,

d) ranked temporary positions that were investigated in the previous tracking step;

array formation is stopped when the number of temporary array positions of value N is reached;

- form in-phase and quadrature components of the complex correlation responses of the pilot signal at the interval of the tracking step for all temporary positions of the formed array, as well as the sum of their squares;

- find the maximum sum of the squares of the in-phase and quadrature components of the complex correlation responses of the pilot signal in the interval of the tracking step;

- the temporary positions of the formed array are grouped into temporary areas in such a way that if the temporary distance between the temporary positions of the array is less than the chip, then they enter the same area, otherwise the temporary positions enter the different areas;

- for each time domain, an estimate of the number and time positions of the components is found, for which:

- discard the temporary positions of the region for which the sum of the squares of the in-phase and quadrature components of the complex correlation responses of the pilot signal in the interval of the tracking step is less than a predetermined threshold, the value of which is proportional to the maximum sum of the squares of the in-phase and quadrature components of the complex correlation responses of the pilot signal in the interval of the tracking step;

- from all kinds of sets of the remaining temporary positions of the region, the number of possible temporary positions of the set is from 1 to m, the time distance between the temporary positions of the set is at least 1/2 of the chip, a set of temporary positions of the region is found for which the decisive function, which is the sum of the quadratic form of the in-phase components complex correlation responses of the pilot signal at the interval of the tracking step for the time positions of the set, the quadratic form of quadrature components of the complex correlation responses of the pilot signal to int the interval of the tracking step for the temporary positions of the set and the term linearly decreasing with increasing the number of temporary positions of the set and proportional to the maximum sum of squares of the in-phase and quadrature components of the complex correlation responses of the pilot signal in the interval of the tracking step of the temporary positions of the formed array is the maximum; the temporary positions of the found set are taken as an estimate of the temporary positions of the components, and the number of temporary positions of the set is taken as an estimate of the number of components in the study area,

- the proportionality coefficient for the third term of the decisive function is, for example, 0.1 ÷ 0.2,

- the matrix of quadratic forms for the decisive function is the matrix inverse to the normalized correlation matrix corresponding to the temporal positions of the set;

- if the sum of the estimates of the number of components of all regions does not exceed the maximum value of the monitored components of P, then the final estimate of the number of components of the multipath signal is equal to the sum of the estimates of the number of components of all regions, and the estimate of their temporal positions corresponds to the estimates of the temporal positions of the regions, otherwise from the set of estimates of the temporary positions the component of all regions selects the P component with maximum power values, and the estimate of the time positions of the multipath signal component corresponds to the time positions m of the most powerful component;

- find soft solutions for information symbols using the generated estimate of the number and time positions of the components of the multipath signal, for which:

- form estimates of the complex envelope of the pilot symbols corresponding to the estimates of the time positions of the components of the multipath signal, as the weighted sum of the complex correlation responses of the pilot symbols of the components;

- form estimates of the complex envelope of the information symbol of the component, filtering the corresponding estimates of the complex envelope of the pilot symbol of the component;

- form in-phase and quadrature components of the complex correlation responses of information symbols corresponding to estimates of the time positions of the components of the multipath signal;

- form soft decisions of the components about information symbols, multiplying the corresponding complex correlation responses of information symbols by a complex conjugate estimate of the complex envelope of the information symbols of the component;

- form soft decisions about information symbols, summing up soft decisions of components about information symbols.

The inventive method is carried out on a device for receiving a multipath signal, the structural diagram of which is made in figure 2.

The input complex discrete signal is supplied to the first input of the search receiver 1, to the first inputs of the M blocks 26 ₁ -26 _M delay and to the first inputs of the L nodes 37 ₁ -37 _L delay single-beam receivers 4 ₁ -4 _L signal. By the control signal from the first output control unit 2 in the receiver 1 search periodically with a period T _s in multipath is searched component multipath signal and determining an estimate of the search of the number and temporal position relative to the temporal position of the generator 3 SRP reference signal, which together with the corresponding values of power arrives at the first input of control unit 2. The power and temporary positions of the components found in the search procedure come from the fifth output of the control unit 2 to the input of the second ranking unit 30. In the second ranking unit 30, a ranking is performed in decreasing order of the power of the temporary positions found in the search procedure. Ranked in decreasing order of power, temporary positions from block 30 go to the second input of block 33 for forming an array of temporary positions, and ranking in decreasing order of power, temporary positions and powers of the components found go to the third input of key 34. To the second input of key 34 and to the second input of control unit 2 temporary positions and powers of the components of the previous tracking step are received from the output of the component number limiting unit 36. Periodically with a step of duration T _t , the number and time positions of the components of the multipath signal are determined.

In this case, from the fourth output of the control unit 2, a control signal is supplied to the first controlled input of the key 34 and to the fourth input of the unit 36 for limiting the number of components. For the first step after the search for the tracking step, it is equal, for example, to a logical unit, for subsequent steps, to logical zero. According to this control signal, to the first input of block 33 for forming an array of temporary positions, to the second input of third block 31 of ranking and to the third input of block 36 for limiting the number of components at the first step from the output of key 34, the temporal positions and powers found in the procedure search, and in the next steps - temporary positions and powers of the components of the previous tracking step.

Temporary positions and powers of the components of the previous tracking step from the output of the block 36 for limiting the number of components are also sent to the second input of the control unit 2. The third input of the control unit 2 from the block 33 of the formation of an array of temporary positions receives temporary positions to be analyzed at the current tracking step. Further, from the third output of the control unit 2, the temporary positions of the components are supplied to the second inputs of the L nodes 37 ₁ -37 _{L of the} delay of the single-beam receivers 4 ₁ -4 _{L of the} signal, and the remaining temporary positions to be analyzed are sent to the second inputs of the M blocks 26 ₁ -26 _M delays. In addition, the temporary positions and powers of the components of the previous tracking step from the third output of the control unit 2 are supplied to the first input of the third ranking unit 31 and to the first input of the unit 35 for generating estimates of the temporal positions of the regions.

The control signal from the second output of the control unit 2 at the second and first outputs of the SRP generator 3 generates in-phase and quadrature components of the reference signal, respectively, for information and pilot symbols. The in-phase and quadrature components of the reference signal of the pilot symbols are supplied to the second inputs M of the complex correlators 27 ₁ -27 _M and the first inputs of the first complex correlators 16 ₁₁ -16 _1L single-beam receivers 4 ₁ -4 _L signal. The in-phase and quadrature components of the reference signal of information symbols are fed to the second inputs of the complex correlators 16 ₂₁ -16 _2L single-beam receivers 4 ₁ -4 _L.

The third inputs of the M complex correlators 27 ₁ -27 _M from the outputs of the M blocks 26 ₁ -26 _M delay receive samples of the delayed input complex signal. The third inputs of the first complex correlators 16 ₁₁ -16 _1L and second complex correlators 16 ₂₁ -16 _2L single-beam receivers 4 ₁ -4 _L signals from the outputs of their respective nodes 37 ₁ -37 _L delay receive samples of the delayed input complex signal, and the delay corresponds to the estimates time positions of a multipath component. The number of single-beam signal receivers is determined by estimating the number of multipath signal components. To the first inputs of the M complex correlators 27 ₁ -27 _M , as well as to the second inputs of the first complex correlators 16 ₁₁ -16 _1L and the first inputs of the second complex correlators 16 ₂₁ -16 _2L single-beam receivers 4 ₁ -4 _{L of the} signal from the third output of control unit 2 a reset signal is received.

The complex correlation responses of the pilot symbols from the outputs of the M complex correlators 27 ₁ -27 _M and the first complex correlators 16 ₁₁ -16 _1L single-beam receivers 4 ₁ -4 _L signals corresponding to the time positions to be analyzed at the current tracking step are fed to the inputs of the multi-channel block 28 calculating the sum of squares and to the second input of block 35 forming estimates of the temporary positions of the regions.

From the outputs of block 28, the sum of the squares of the in-phase and quadrature components of the correlation responses of the pilot signal are input to the first block 29 and the input of the maximum search block 32, to the third input 35 of the block for estimating the temporal positions of regions and to the first input of the block 36 for limiting the number of components.

In block 32 search maximum determine the maximum value of the sum of the squares of the in-phase and quadrature components of the correlation response of the pilot signal, which is fed to the fourth input of block 35 of the formation of estimates of the temporary positions of the regions. Block 35 generates an estimate of the number and time positions of the component regions, which is fed to the second input of the block 36 for limiting the number of components. If the sum of the estimates of the number of components of all regions does not exceed the maximum value of the monitored components of P, then the final estimate of the number of components of the multipath signal is equal to the sum of the estimates of the number of components of all regions, and the estimate of their temporal positions corresponds to the estimates of the temporal positions of the regions; otherwise, from the set of estimates of the temporary positions of the components of all areas, the P component with the maximum power values is selected, and the estimate of the time positions of the multipath component corresponds to the time position these most potent component.

In the first block 29 ranking carry out the ranking in decreasing order of the analyzed time positions. The ranking result is fed to the fourth input of block 33 forming an array of temporary positions.

In the third ranking unit 31, the ranking of temporary positions is carried out 1/2 of the chip ahead of and lagging behind the temporary positions of the components of the previous tracking step, in decreasing order of the power of the generating component, and for the first tracking step, the components found at search. Generating for 1/2 shifted chips ahead and behind, we call the component relative to which the shift is carried out. The ranking result from block 31 goes to the third input of block 33 forming an array of temporary positions. In block 33, an array of temporary positions to be analyzed at the current tracking step is formed.

The complex correlation responses of the pilot symbols from the outputs of the first complex correlators 16 ₁₁ -16 _1L , single-beam receivers 4 ₁ -4 _L are fed to the second inputs of the correction unit 6, the first inputs of which receive temporary positions corresponding to these responses. In the correction block 6, estimates of the complex envelope of the pilot symbols corresponding to the estimates of the time positions of the components of the multipath signal are generated as a weighted sum of the complex correlation responses of the pilot symbols of the components, eliminating the mutual influence of the beam signals on each other.

The generated estimates of the complex envelope of the pilot symbols from the outputs of the correction unit 6 are supplied to the filters 23 ₁ -23 _L corresponding to the single-beam receivers 4 ₁ -4 _{L of the} signal. As a result of filtration, estimates of the complex envelope of the information symbols of the components are generated, which are supplied from the filters 23 ₁ -23 _L to the complex conjugation blocks 22 ₁ -22 _L and then to the second input of the complex multipliers 25.

The complex correlation responses of the information symbols of the signal from the outputs of the second complex correlators 16 ₂₁ -16 _2L single-beam receivers 4 ₁ -4 _L are received at the inputs of the corresponding complex delay lines 18 ₁ -18 _L. In complex 18 ₁ -18 _L delay lines, the complex correlation responses of information symbols are delayed by the time interval necessary for estimating the complex envelope of the information symbols of the components and multiplied in the corresponding complex multipliers 25 ₁ -25 _L by the complex conjugate estimate of the complex envelope of the information symbols of the components, obtaining soft solutions of information symbols components.

Soft solutions of information symbols of all components are summed in the adder 9, as a result of which soft solutions of information symbols are formed, which are output to the device.

Consider the implementation of the block 6 correction on the example of processing one area (see figure 3).

Тогда оценка А комплексной огибающей пилот-символов компонент многолучевого сигнала области может быть реализована посредством преобразованияSuppose that the algorithm for estimating the number and time position of the components of a multipath signal (included in the tracking system for the temporary position of the signal) made a decision that in the region p of the components whose temporal positions are τ _i ,

Then, the estimate A of the complex envelope of the pilot symbols of the component of the multipath signal of the region can be realized by transforming

- нормированная корреляционная матрица, соответствующая временным позициям компонент многолучевого сигнала области.where X is the vector of the complex correlation responses of the pilot symbols of the component of the multipath signal of the region, B = {B _nm },

- normalized correlation matrix corresponding to the time positions of the components of the multipath signal of the region.

For a band-limited signal, approximate equality

T _c - the duration of the chip PSP.

Expression (2) determines the necessary operations with the complex correlation responses of the pilot symbols of the components of the multipath signal of the region, which must be performed to compensate for the mutual influence of the signals of different beams on each other. This procedure is a weighted summation of the complex correlation responses of the pilot symbols of the signals of the components of the multipath signal with the weights determined by the elements of the matrix B and serves to correctly evaluate the complex envelope of the signals of the components of the multipath signal. Block 6 correction (figure 3) works as follows.

The input of the correction unit 6, namely, the inputs of the correction elements 38 ₁ -38 _Q , receives complex correlation responses of the pilot symbols of the multipath component. The other inputs of the correction elements 38 ₁ -38 _Q receive the corresponding weight coefficients calculated in the matrix forming element 41 of the matrix B ^-1 in accordance with the evaluation of the time positions of the multipath component. This estimate comes from control unit 2. The element 41 of the formation of the matrix In ^-1 can be performed, for example, on a microprocessor. The correction element 38 carries out a weighted summation of the complex correlation responses of the pilot symbols of the multipath signal components in the complex adder 40. The estimates of the complex envelope of the pilot symbols of the multipath signal components from the outputs of the complex adders 40 represent the output signals of the correction elements 38 and are also outputs of the correction block 6.

Let us consider in more detail the operation of block 33 forming an array of temporary positions, the algorithm of which is illustrated in Fig. 4.

The inputs of block 33 of the formation of an array of temporary positions to be analyzed receive the following signals.

с выхода ключа 34, N_A - число компонент предыдущего шага слежения.At the first input - temporary position of the components of the previous tracking step And _i ,

from the output of the key 34, N _A is the number of components of the previous tracking step.

с выхода второго блока 30 ранжирования, N_c - число компонент поиска.To the second input - the ranked temporary positions of the components found in the last search procedure, C _i ,

output from the second unit 30 ranking, N _c - number of the search component.

с выхода третьего блока 31 ранжирования, N_B - число компонент, отстоящих на 1/2 чипа с опережением и отставанием от временных позиций компонент предыдущего шага слежения.To the third input - ranked temporary positions, spaced 1/2 of the chip ahead of and lagged behind the temporary positions of the components of the previous tracking step B _i ,

output from the third unit 31 ranking, N _B - number of components spaced at 1/2 chip ahead and behind by previous temporal position tracking pitch component.

с выхода первого блока 29 ранжирования, N_D - число временных позиций, которые исследовались на предыдущем шаге слежения.On the fourth input - sorted temporary positions that were studied on the preceding tracking step D _i,

from the output of the first ranking block 29, N _D is the number of temporary positions that were studied in the previous tracking step.

последовательно добавляя элемент за элементом, начиная с первого. Для чего сначала в формируемый массив добавляют временные позиции компонент предыдущего шага слежения R_j=A_j,

Затем анализируют ранжированные временные позиции, отстоящие на 1/2 чипа с опережением и отставанием от временных позиций компонент предыдущего шага слежения, для чего последовательно, начиная с первой временной позиции, сравнивают расстояние между этой временной позицией и временными позициями, уже находящимися в массиве. Если это расстояние хотя бы для одной временной позиции, уже находящейся в массиве, меньше 1/2 чипа, то переходят к анализу следующей временной позиции, в противном случае анализируемую временную позицию добавляют в формируемый массив. Причем после добавления каждой временной позиции анализируют объем массива. Если объем массива оказывается равным заданному числу N, то формирование массива заканчивают.In block 33 form an array of temporary positions R _j

sequentially adding item by item, starting from the first. Why first add to the formed array the temporary positions of the components of the previous tracking step R _j = A _j ,

Then, the ranked temporary positions are analyzed, which are 1/2 chip ahead and behind the temporal positions of the components of the previous tracking step, for which the distance between this temporary position and the temporary positions already in the array is compared sequentially from the first temporary position. If this distance for at least one temporary position already in the array is less than 1/2 of the chip, then they proceed to the analysis of the next temporary position, otherwise the analyzed temporary position is added to the generated array. Moreover, after adding each time position, the volume of the array is analyzed. If the volume of the array is equal to a given number N, then the formation of the array is completed.

и ранжированные временные позиции, которые исследовались на предыдущем шаге слежения D_i,

.In a similar way, the ranked temporary positions found in the last search procedure C _i are added to the formed array,

and the ranked temporary positions that were investigated in the previous tracking step D _i ,

.

, подлежащих анализу, поступает на третий вход блока 2 управления.The array of temporary positions R _j formed in block 33

to be analyzed, is fed to the third input of control unit 2.

Let us consider in more detail the operation of block 35 for forming estimates of the temporal positions of regions, the algorithm of which is illustrated in FIG.

The inputs of the block 35 forming estimates of the temporary positions of the regions receive the following signals.

с третьего выхода блока 2 управления.The first input is an array of temporary positions to be analyzed R _i ,

from the third output of control unit 2.

с выходов комплексных корреляторов 27₁-27_М и 16₁₁-16_1L The second input contains in-phase and quadrature components of the complex correlation responses of the pilot signal Xc _i , Xs _i

from the outputs of complex correlators 27 ₁ -27 _M and 16 ₁₁ -16 _1L

с выходов многоканального блока 28 вычисления суммы квадратов.The third input is the sum of the squares of the in-phase and quadrature components of the complex correlation responses of the pilot signal M _j ,

from the outputs of the multi-channel block 28 calculating the sum of squares.

The fourth input is the maximum sum of the squares of the in-phase and quadrature components of the complex correlation responses of the pilot signal M1 from the output of the maximum search block 32.

начиная с первого элемента, группируя временные позиции массива во временные области таким образом, что, если временное расстояние между временными позициями массива меньше, чем чип, то они входят в одну область, в противном случае временные позиции входят в разные области. Определяя первую область, формируют массив временных позиций области τ_j

и соответствующий массив синфазной и квадратурной составляющих комплексных корреляционных откликов пилот-сигнала области Yc_j, Ys_j

, причем в эти массивы включают только те временные позиции, для которых сумма квадратов синфазной и квадратурной составляющих комплексных корреляционных откликов пилот-сигнала на интервале шага слежения не меньше заданного порога. Величина порога равна, например, произведению постоянного множителя (h=0.1÷0.2) на максимальную сумму М1 квадратов синфазной и квадратурной составляющих комплексного корреляционного отклика пилот-сигнала на интервале шага слежения.In block 35 of the formation of estimates of the temporary positions of the regions sequentially analyze the elements of the array of temporary positions to be analyzed R _i ,

starting from the first element, grouping the temporary positions of the array into temporary areas so that if the temporary distance between the temporary positions of the array is less than the chip, then they enter the same area, otherwise the temporary positions enter the different areas. Defining the first region, form an array of temporary positions of the region τ _j

and the corresponding array of in-phase and quadrature components of the complex correlation responses of the pilot signal of the region Yc _j , Ys _j

moreover, these arrays include only those temporary positions for which the sum of the squares of the in-phase and quadrature components of the complex correlation responses of the pilot signal at the interval of the tracking step is not less than a given threshold. The threshold value is, for example, the product of a constant factor (h = 0.1 ÷ 0.2) by the maximum sum M1 of the squares of the in-phase and quadrature components of the complex correlation response of the pilot signal over the interval of the tracking step.

, находят такой набор временных позиций из всевозможных наборов временных позиций

, входящих в этот массив, причем временное расстояние между временными позициями набора должно быть не менее 1/2 чипа, р - максимальное число компонент одной области, для которого решающая функция (3) максимальна.Defining the array τ _j

find such a set of temporary positions from various sets of temporary positions

included in this array, and the time distance between the temporary positions of the set should be at least 1/2 of the chip, p is the maximum number of components of one region for which the decisive function (3) is maximum.

Figure 5 shows an embodiment of the algorithm when p = 2.

Temporary positions of this set are taken as an estimate of the temporary positions of the components, and the number of temporary positions of the set is taken as an estimate of the number of components in the studied region p.

Having determined the assessment of the time positions of the components of the first area, we proceed to the analysis of the next area. The time positions of the components of subsequent regions are estimated in a similar way.

с выхода блока 35 формирования оценок временных позиций областей поступает на второй вход блока 36 ограничения числа компонент.The sum of the estimates of the number of components of all regions Z _i

from the output of block 35 forming estimates of the temporary positions of the regions, it enters the second input of block 36 for limiting the number of components.

The control unit 2 operates in such a way that at the output it generates five control signals:

the control signal from the first output of the control unit 2 in the search receiver 1 periodically with a period Ts in the multipath region searches for the components of the multipath signal and determines the search estimate of their number and time positions relative to the temporary position of the reference signal of the SRP generator 3, which is fed to the first input of block 2 management;

on the control signal from the second output of the control unit 2 at the second and first outputs, the SRP generator 3 generates in-phase and quadrature components of the reference signal, respectively, for information and pilot symbols;

according to the control signal from the third output of the control unit 2, the temporary positions of the components are supplied to the second inputs of the L nodes 37 ₁ -37 _{L of the} delay of the single-beam receivers 4 ₁ -4 _{L of the} signal, and the remaining temporary positions to be analyzed are sent to the second inputs of the M blocks 26 ₁ - 26 _M delay; in addition, the temporary positions and powers of the components of the previous tracking step from the third output of the control unit 2 are supplied to the first input of the third ranking unit 31 and to the first input of the unit 35 for generating estimates of the temporary positions of the regions;

the control signal from the fourth output of the control unit 2 to the first controlled input of the key 34 and the fourth input of the block 36 to limit the number of components receives a control signal; for the first step after the search for the tracking step, it is equal, for example, to a logical unit, for subsequent steps to logical zero. According to this control signal, to the first input of block 33 for forming an array of temporary positions, to the second input of third block 31 of ranking and to the third input of block 36 for limiting the number of components at the first step from the output of key 34, the temporal positions and powers found in the procedure search, and in the next steps - temporary positions and powers of the components of the previous tracking step;

from the fifth output of the control unit 2, the power and time positions found in the component search procedure are input to the second ranking unit 30.

The control unit 2 can be implemented on modern microprocessors.

Analysis of the claimed invention was carried out by computer simulation. 6 and 7 depicts the bit error ratio BER of a binary symbol energy to noise power spectral density E _b / N0 of the algorithm (curve - «Original») for different distribution channels and reception conditions (6 - 2 counts per input signal chip, speed 10 km / h, character duration - 4 chips, information power and pilot component ratio 4; Fig. 7 - 4 counts per input signal chip, speed 120 km / h, character duration - 4 chips, power ratio information and pilot component 4). In addition, FIGS. 6 and 7 show curves for alternative algorithms for tracking a multipath signal. The curve “Alternative 1” corresponds to the first alternative tracking algorithm [1], the curve “Alternative 2” corresponds to the second alternative tracking algorithm [5], the curve “Alternative 3” corresponds to the third alternative tracking algorithm [7], the curve “Potential” corresponds to the ideal algorithm . An ideal algorithm is an algorithm for which the time positions of the components of a multipath signal are known. It is obvious from the simulation results that the developed algorithm in multipath channels provides a significant gain in the accuracy of data reception.

Thus, the introduction of new distinguishing features in the method and device according to the described invention allows to obtain a new technical result - to increase the noise immunity of signal reception in conditions of unresolved multipath and reduce the necessary processing resource.

The inventive method of receiving a multipath signal and a device for its implementation, in contrast to the known technical solutions, specify in the tracking process not only the temporary positions of the components of the multipath signal, but also their number. The algorithm for receiving a multipath signal when evaluating the complex envelope compensates for the mutual influence of the signals of different rays on each other, which makes it possible to obtain a significant energy gain in conditions of insoluble multipath in comparison with the best known algorithms. In this case, the noise immunity of the proposed method is practically not inferior to the potential one (when the temporal positions of the components of the multipath signal are a priori known). Moreover, the inventive method allows to reduce the required processing resource (the number of correlators).

Claims (4)

1. A method of receiving a multipath signal, in which for tracking and evaluating the propagation channel, the number of simultaneously analyzed temporal positions of the signal is limited to N, which periodically with a period T _s in the multipath domain searches for components of the multipath signal and determines the search estimate of their temporal positions periodically increments the duration _{T t} is determined temporary position of the multipath signal components, form-phase and quadrature components of the complex correlation none of the pilot signal at the interval of the tracking step, find an estimate of the temporal positions of the components, find soft solutions for information symbols using the generated estimate of the temporal positions of the components of the multipath signal, which form estimates of the complex envelope of the pilot symbols corresponding to estimates of the temporal positions of the components of the multipath signal, as the weighted sum of the complex correlation responses of the component pilot symbols, form estimates of the complex envelope of the component information symbols, filtering the The corresponding estimates of the complex envelope of the pilot symbols form the in-phase and quadrature components of the complex correlation responses of information symbols corresponding to the estimates of the time positions of the components of the multipath signal, form soft decisions of the components about information symbols, multiplying the corresponding complex correlation responses of information symbols by the complex conjugate estimate of the complex envelope of information symbols components form soft decisions about information symbol x, summing the soft decision component of the information symbols, characterized in that the performed ranging descending power time slots found in the search procedure periodically increments the duration _{T t} determine the number of components of the multipath signal to which each step is performed ranking time slots, spaced 1/2 chip ahead of and lagging behind the time positions of the components of the previous tracking step, in decreasing order of the power of the generating component, and for the first tracking step as components of the previous tracking step, use the components found during the search, perform a ranking in decreasing order of the power of the temporary positions that were studied in the previous tracking step, except for the first tracking step, form an array of temporary positions to be analyzed at each tracking step, while the array is filled with temporary positions in the following sequence: temporary positions of the components of the previous tracking step, ranked temporary positions separated by 1/2 of the chip ahead and behind the time positions of the components of the previous tracking step, in this case, starting from this group of temporary positions and further, the temporary position is added to the formed array only if the distance between this temporary position and the temporary positions already in the array is not less than 1/2 of the chip , the ranked temporary positions of the components found in the last search procedure, the ranked temporary positions that were examined in the previous tracking step, the formation of the array is stopped when the number of temporary positions of the array is reached Ichina N; the in-phase and quadrature components of the complex correlation responses of the pilot signal at the interval of the tracking step, as well as the sum of their squares are formed simultaneously for all time positions of the formed array, find the maximum sum of the squares of the in-phase and quadrature components of the complex correlation responses of the pilot signal at the interval of the tracking step, time positions the formed array is grouped into temporary areas so that if the temporary distance between the temporary positions of the array is less, If we eat a chip, then they enter one area, otherwise, temporary positions enter different areas, for each time area, at the same time finding an estimate of the time positions of the components, they find an estimate of the corresponding number of components, for which they’ll discard the temporary positions of the area for which the sum of the common-mode squares and the quadrature components of the complex correlation responses of the pilot signal at the interval of the tracking step is less than a predetermined threshold, the value of which is proportional to the maximum sum of squares of the in-phase and quad of the components of the complex correlation responses of the pilot signal at the interval of the tracking step, from all kinds of sets of the remaining temporary positions of the area, the number of possible temporary positions of the set is from 1 to t, the time distance between the temporary positions of the set is at least 1/2 of the chip, find a set of temporary positions of the area, for which the decisive function, which is the sum of the quadratic form of the in-phase components of the complex correlation responses of the pilot signal in the interval of the tracking step for the temporary positions of the set, kva of the quadratic form of the quadrature components of the complex correlation responses of the pilot signal at the interval of the tracking step for the time positions of the set and the term linearly decreasing with increasing the number of temporary positions of the set and proportional to the maximum sum of squares of the in-phase and quadrature components of the complex correlation responses of the pilot signal at the interval of the tracking step of the time positions formed array - maximum; the temporary positions of the found set are taken as an estimate of the temporary positions of the components, and the number of temporary positions of the set is taken as an estimate of the number of components in the study area, if the sum of the estimates of the number of components of all areas does not exceed the maximum value of the monitored components P, then the final estimate of the number of components of the multipath signal is equal to the sum of the estimates the number of components of all regions, and the assessment of their temporary positions corresponds to the estimates of the temporary positions of the regions, otherwise from the set of estimates of the temporary positions of the components nt all areas of the P-component is selected from the maximum values of power, time and position estimation of a multipath signal component corresponds to the temporal position of the most powerful component of the soft decisions about information symbols found using the generated estimate of the component. 2. The method according to claim 1, characterized in that the proportionality coefficient for the third term of the decisive function is 0.1-0.2. 3. The method according to claim 1, characterized in that the matrix of quadratic forms for the decisive function is the matrix inverse to the normalized correlation matrix corresponding to the temporal positions of the set. 4. A device for receiving multipath signals, containing a search receiver, a control unit, a pseudo-random sequence generator PSP, L single-beam signal receivers, a correction unit and an adder, wherein each single-beam signal receiver contains a first and second complex correlators, a complex delay line, a complex pairing unit, a filter and a complex multiplier, and the first input of the search receiver is the input of the device, the input of a complex discrete signal, the output of the search receiver is connected to the first input ohm of the control unit, which is the input of search evaluation signals for temporary positions and their powers, the first output of the control unit, which generates a search control signal at this output, is connected to the second input of the search receiver, the second output of the control unit, which generates a position control signal at this output by pseudo-random sequences connected to the input of the PSP generator, the first output of which is connected to the first input of the first complex correlator in each single-beam signal receiver, the third output of the control unit of the line forming the reset signal at the third output is connected to the second input of the first and first input of the second complex correlators in each single-beam signal receiver, the output of the second complex correlator is connected to the input of the complex delay line, the output of which is connected to the first input of the complex multiplier, the second input of which is connected with the output of the complex conjugation unit, the input of which is connected to the output of the filter, the filter input of each single-beam signal receiver is connected to the corresponding output unit corrections, the outputs of the complex multiplier of each single-beam signal receiver are connected to the corresponding inputs of the adder, the output of which is the output of the device, characterized in that M delay units, M complex correlators, a multi-channel unit for calculating the sum of squares, the first, second and third ranking units, block maximum search, block for generating an array of temporary positions, a key, a block for generating estimates of the temporary positions of regions, a block for limiting the number of components, in each single-beam receiver a delay node is introduced to the signal, while the first inputs of the M delay blocks and the first input of the delay node in each single-beam signal receiver are connected to the input of the device, the second inputs of M delay blocks, the first inputs of M blocks of complex correlators, the second inputs of the delay nodes of each single-beam signal receiver, the first inputs of the correction unit, the first inputs of the third ranking unit and the unit for generating estimates of the temporal positions of the regions are connected to the third output of the control unit, the second inputs of the complex correlators with the first output of the SRP generator, the second output of the SRP generator is connected to the second inputs of the second complex correlators of each single-beam signal receiver, the third inputs of the first and second complex correlators are connected to the output of the delay node in each single-beam signal receiver, the third inputs of the complex correlators are connected to the outputs M delay units, the outputs of the M complex correlators are connected to their respective M inputs of a multi-channel unit for calculating the sum of squares, L inputs of a multi-channel unit for computing The sums of squares are combined with the L second inputs of the correction unit and connected to the outputs of the corresponding first complex correlators of each single-beam signal receiver, the M and L inputs of the multi-channel unit for calculating the sum of squares combined with the second inputs of the unit for generating estimates of temporary positions, the outputs of the multi-channel unit for calculating the sum of squares connected to the input of the first ranking block, the input of the maximum search block, the first input of the component number limiting block and the third input of the form block of estimating the temporal positions of the regions, the fourth input of the block for estimating the temporary positions of the regions is connected to the output of the maximum search block, the output of the block for estimating the temporary positions of the regions is connected to the second input of the block for limiting the number of components, the third input of the block for limiting the number of components, the second input of the third ranking block and the first input of the block forming the array of temporary positions connected to the output of the key, the fourth input of the block limiting the number of components and the first input of the key are combined and connected s with the fourth output of the control unit, which generates a switching signal at the fourth output, the output of the unit for limiting the number of components that generates the temporary positions and power of the components of the previous tracking step, is connected to the second inputs of the key and the control unit, the fifth output of the control unit that forms at this output the power and temporary positions found in the search procedure are connected to the input of the second ranking block, the output of which is connected to the third input of the key and the second input of the block forming the array of temporary positions, the third input of which is connected to the output of the third ranking block, the fourth input of the block of forming an array of temporary positions is connected to the output of the first block of ranking, the output of the block of forming an array of temporary positions is connected to the third input of the control unit, which is the input of the signal of temporary positions and powers of the components of the previous step .

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