RU2207732C2 - Procedure of reception of parallel multifrequency compound signal and facility for its implementation - Google Patents

Abstract

FIELD: transmission of digital information, realization of multichannel modems with parallel multifrequency compound orthogonal signals. SUBSTANCE: technical result of invention is realized due to preliminary memorization of signals corresponding to rated level of each of i-th subcarriers U_0i, to computation for each subcarrier at moment of termination of elements of signal evaluating level U_i corresponding to i-th subcarrier, to averaging of computed evaluations of level U_i for each i-th subcarrier in series of information symbols received in sequence to change amplitude of cophased and quadrature components of reference signals corresponding to each subcarrier utilized in reception of next elements of signal. Each of N units processing received signal in facility for implementation of procedure is supplemented with two squarers, first computer, averager, second computer, first and second storages and two multipliers. EFFECT: reduced degree of influence of selective noise on noise immunity of reception of digital information in modems with parallel multifrequency compound orthogonal signals. 1 cl, 2 dwg

Description

 The invention relates to the field of digital information transmission and can be used to implement multi-channel modems with parallel multi-frequency composite orthogonal signals.

A known method of receiving a parallel multi-frequency composite signal, which is the sum of N mutually orthogonal harmonic subcarriers, the information on each of which is synchronously transmitted using the relative phase modulation method, which consists in the formation of N pairs (by the number of subcarriers in the parallel multi-frequency composite signal) in-phase and quadrature components reference channel mutually orthogonal signals with frequencies equal to the frequencies of the respective subcarriers of parallel nogochastotnogo composite signal in determining the expectation of the boundaries of elements of the signals transmitted on subcarriers in the computation within those limits on the duration of the interval of orthogonality of subcarriers T (T is not more than the elements of the signal duration) N pairs of correlation functions _{X i (t), Y i} (t ) of the received parallel multifrequency composite signal to said N pairs of in-phase and quadrature components of the reference channel are mutually orthogonal signals, using the values X _i, Y _i of each of the instructions x pairs of correlation functions received at the end of the signal elements corresponding to each subcarrier, together with the values of these pairs of correlation functions obtained at the end of a series of previous signal elements, on the same subcarrier to decide on the information symbol transmitted on this subcarrier, information symbols received on each of the subcarriers into one common stream and the issuance of this information stream to the recipient.

 Closest to the claimed device (prototype) is a device for receiving a parallel multi-frequency composite signal, which is the sum of N mutually orthogonal harmonic subcarriers, the transmission of information on each of which is carried out synchronously by the method of relative phase modulation [1], containing N processing blocks of the received signal (one per subcarrier as part of a parallel multi-frequency composite signal), code conversion unit, synchronization unit, and information inputs N N received signal processing blocks are connected together and serve as the receiver input, N outputs of the received signal processing blocks are connected to the corresponding information inputs of the code conversion block, the output of which serves as the output of the device, the input of the synchronization block is connected to the input of the device, and the output of the synchronization block is connected to connected the clock inputs of N received signal processing units and code conversion unit, each of the N received signal processing units consists of an in-phase generator and the quadrature components of the reference channel signal with a frequency corresponding to the frequency of the subcarrier, for receiving which this processing unit of the received signal, two identical correlators, a solving device, which decides on the information symbol adopted on this subcarrier, is intended, and in each of the N processing blocks of the received signal, the first the information inputs of the correlators are connected together and serve as the information input of the received signal processing unit, the second information input the first correlator is connected to the output of the in-phase component of the generator of the in-phase and quadrature components of the reference channel signal, the second information input of the second correlator is connected to the output of the quadrature component of the generator of the in-phase and quadrature components of the reference channel signal, the outputs of the correlators are connected to the corresponding information inputs of the resolver, the reset inputs of both correlators and the clock input of the solver is connected together and connected to the clock input of the processing unit Since the signal is received, the output of the deciding device serves as the output of the block for processing the received signal.

 A known device for receiving a parallel multi-frequency composite signal [1] works as follows.

где N - количество ортогональных поднесущих, составляющих параллельный многочастотный составной сигнал;
U_0i - амплитуда i-й поднесущей;
ω_i - частота i-й поднесущей;
φ_i - начальная фаза i-й поднесущей.A parallel multi-frequency composite signal S (t), which is the sum of N mutually orthogonal harmonic subcarriers, is transmitted to the input of the device from the communication channel, the information is transmitted on each of them synchronously by the method of relative phase modulation,

where N is the number of orthogonal subcarriers constituting a parallel multi-frequency composite signal;
U _0i is the amplitude of the i-th subcarrier;
ω _i is the frequency of the i-th subcarrier;
φ _i is the initial phase of the i-th subcarrier.

где j и k - номера поднесущих.The subcarriers constituting the parallel multi-frequency composite signal are mutually orthogonal on a time interval T whose duration does not exceed the duration of the signal elements transmitted on the subcarriers; equality is true for them

where j and k are the numbers of subcarriers.

The amplitudes of each of the subcarriers (their nominal level) U _{0i are} set on the transmitting side, based on the condition for ensuring the required noise immunity of information reception [2].

 In the synchronization unit, the mathematical expectation of the position of the boundaries of the elements of the signals transmitted on subcarriers is determined. The corresponding signals are generated at the output of the synchronization block, the temporary position of which coincides with the mathematical expectation of the position of the boundaries of the signal elements transmitted on the subcarriers. The corresponding output signals of the synchronization block are supplied to the clock inputs of the N processing blocks of the received signal and the code conversion block.

A parallel multi-frequency composite signal (1) is supplied to the information inputs of N processing units of the received signal connected together, in each of which, in the first and second correlators, a pair of correlation functions X _i (t), Y _i (t) of the input parallel multi-frequency composite signal with in-phase u _c (t) = Acosω _i t and quadrature u _s (t) = Asinω _i t components of the reference channel signals, the frequency of which ω _j corresponds to the frequency of that subcarrier, for the reception of which this processing unit of the received signal is designed a.

At the moment of termination of the signal elements, the values of X _i , Y _{i of the} indicated correlation functions are supplied to the corresponding information inputs of the solver.

В силу ортогональности поднесущих [1]

В решающем устройстве значения X_i, Y_i указанных корреляционных функций вместе с соответствующими значениями этих корреляционных функций, вычисленными на предыдущих элементах сигнала, используются для принятия по одному из известных методов, например по методу сравнения фаз, решения о переданном на данной поднесущей информационном символе, который поступает на выход блока обработки сигнала и далее - на соответствующий информационный вход преобразователя кода. Принятые решения о переданных на поднесущих информационных символах, поступившие на соответствующие информационные входы преобразователя кода, по сигналу от блока синхронизации, поступившему на тактовый вход преобразователя кода, преобразуются в один общий поток и выдаются с выхода устройства приема получателю.

Due to the orthogonality of the subcarriers [1]

In the solver, the values X _i , Y _{i of the} indicated correlation functions, together with the corresponding values of these correlation functions calculated on the previous signal elements, are used to make a decision on the information symbol transmitted on this subcarrier using one of the known methods, for example, by the phase comparison method, which goes to the output of the signal processing unit and then to the corresponding information input of the code converter. The decisions made on the information symbols transmitted on the subcarriers received at the corresponding information inputs of the code converter, are converted into one common stream by the signal from the synchronization block received at the clock input of the code converter, and are issued from the output of the receiving device to the receiver.

 The disadvantage of the prototype method and prototype device is the limited functionality associated with insufficient noise immunity of receiving information, which is due to the impact on the parallel multi-frequency composite signal in the communication channel of selective fading [2]. As a result of their action, the level of individual subcarriers of a parallel multi-frequency composite signal supplied to the input of the receiver decreases and, as a result, the signal-to-noise ratio on the corresponding subcarriers decreases, which leads to a decrease in the noise immunity of receiving information on these subcarriers.

Предположим также, что в канале на сигнал помимо мультипликативной помехи действует аддитивная помеха типа "белого" шума со спектральной плотностью N₀ [2]. Тогда отношение сигнал/шум h_i в полосе частот Δω_i, занимаемой i-й ортогональной поднесущей, оценивается величиной

Согласно [2] средняя вероятность ошибки Р_ош при передаче двоичных сигналов методом относительной фазовой модуляции приближенно равна

где Ф(t) - функция Крампа (интеграл вероятности) [2].Indeed, if a parallel multi-frequency composite signal S (t) (1) is supplied to the input of the communication channel, and in the communication channel it is affected by the multiplicative interference K (ω _i ), which leads to selective fading of the signal, then the channel signal is received at the input of the receiving device z (t)

Suppose also that in the channel, in addition to the multiplicative noise, an additive interference of the type of “white” noise with a spectral density of N ₀ [2] acts. Then the signal-to-noise ratio h _i in the frequency band Δω _i occupied by the ith orthogonal subcarrier is estimated as

According to [2], the average probability of an error R _OSH for transmitting binary signals by the method of relative phase modulation is approximately equal to

where Φ (t) is the Crump function (probability integral) [2].

A decrease in the signal-to-noise ratio h _i on the ith subcarrier as a result of the effect of selective fading leads to an increase in the probability of errors in the transmission of discrete information.

 The aim of the invention is to reduce the degree of influence of selective interference on the noise immunity of receiving digital information in modems with parallel multi-frequency composite orthogonal signals.

соответствующей i-й поднесущей, усредняют вычисленные оценки уровня U_i для каждой i-й поднесущей на ряде последовательно полученных информационных символов, применяют полученные усредненные оценки уровня

для изменения в

раз амплитуд синфазной и квадратурной составляющих опорных сигналов, соответствующих каждой из i-х поднесущих, используют новые указанные значения амплитуд синфазной и квадратурной составляющих опорных сигналов, соответствующих каждой из i-х поднесущих, для приема следующих элементов сигнала.This goal is achieved by the fact that in the method of receiving a parallel multi-frequency composite signal, which is the sum of N mutually orthogonal harmonic subcarriers, information is transmitted on each of them synchronously by the method of relative phase modulation, which consists in the formation of N pairs (by the number of subcarriers in the composition of the parallel multi-frequency composite signal) in-phase and quadrature components of the reference channel mutually orthogonal signals with frequencies equal to the frequencies corresponding subcarriers of a parallel multi-frequency composite signal, in determining the mathematical expectation of the position of the boundaries of the elements of the signals transmitted on the subcarriers, in calculating inside these boundaries on the duration of the orthogonality interval of the subcarriers T (T does not exceed the duration of the signal elements) N pairs of correlation functions X _i (t), Y _i (t) received parallel multifrequency composite signal to said N pairs of in-phase and quadrature components of the reference channel are mutually orthogonal signals, the use of Achen X _i, Y _i of each of said pairs of correlation functions obtained at the moment of closure element signals corresponding to each subcarrier, together with the values of said pairs of correlation functions obtained at the time of closure of a number of previous elements of the signal on the same subcarrier for deciding the transmitted on this subcarrier information symbol, in combining information symbols received on each of the subcarriers into one common stream and issuing this information stream to the recipient, previously storing m signals corresponding to the nominal level of each subcarrier i-x U _0i, calculated at the time of closure elements using said signal values X _i, Y _i of each of said pairs of correlation functions level evaluation

corresponding i-th subcarrier, average the calculated level estimates U _i for each i-th subcarrier on a series of information symbols successively obtained, apply the obtained average level estimates

for change in

times the amplitudes of the in-phase and quadrature components of the reference signals corresponding to each of the i-subcarriers, use the new indicated amplitudes of the in-phase and quadrature components of the reference signals corresponding to each of the i-subcarriers to receive the following signal elements.

 Moreover, in the device for receiving a parallel multi-frequency composite signal, which is a sum of N mutually orthogonal harmonic subcarriers, the information on each of them is synchronously transmitted by the method of relative phase modulation containing N processing units of the received signal (one for each subcarrier in the composition of the parallel multi-frequency composite signal ), a code conversion unit, a synchronization unit, and the information inputs of N received signal processing units are connected together they serve as the input of the receiver, the outputs of the N processing units of the received signal are connected to the corresponding information inputs of the code conversion unit, the output of which serves as the output of the device, the input of the synchronization unit is connected to the input of the device, and the output of the synchronization unit is connected to the clock inputs of the N processing units of the received signal connected together and a code conversion unit, each of the N received signal processing units consists of an in-phase and quadrature component of the reference channel signal with the frequency corresponding to the subcarrier frequency, for reception of which the given processing unit of the received signal, two identical correlators, is designed, a solver that provides a decision on the information symbol received on this subcarrier, and in each of the N processing blocks of the received signal, the first information inputs of the correlators are connected together and are the information input of the processing unit of the received signal, the outputs of the correlators are connected to the corresponding information inputs of the decisive devices, the reset inputs of both correlators and the clock input of the resolver are connected together and connected to the clock input of the received signal processing unit, the output of the resolver serves as the output of the received signal processing unit, two squaring units are introduced into each of the N received signal processing units, in series connected to the first calculator, the averaging block, the second calculator, the first memory block, as well as two multiplication blocks, the second memory block; moreover, the clock inputs of the squaring blocks of the first and second calculators, the averaging block and the first memory block are connected together and connected to the clock input of the received signal processing block, the first inputs of the multiplication blocks are connected together and connected to the output of the first memory block, the second input of the first multiplication block is connected with the output of the in-phase component of the generator of the in-phase and quadrature components of the reference channel signal, the output of the first multiplication unit is connected to the second information input of the first the correlator, the second input of the second multiplication unit is connected to the output of the quadrature component of the generator of the in-phase and quadrature components of the reference channel signal, the output of the second multiplication unit is connected to the second information input of the second correlator, the output of the second memory unit is connected to the second information input of the calculator, the information input of the first erection unit the square is connected to the output of the first correlator, the information input of the second squaring unit is connected to the output of the second correlator, the first and second information inputs of the first calculator are connected respectively to the outputs of the first and second squaring units.

где u_c(t) = Acosω_it и u_s(t) = Asinω_it - соответственно синфазная и квадратурная составляющие опорного сигнала, соответствующего i-й поднесущей.So, after determining the mathematical expectation of the position of the boundaries of the elements of the signals transmitted on the subcarriers, inside these boundaries on the duration of the interval of the orthogonality of the subcarriers T (T does not exceed the duration of the signal elements), N pairs of correlation functions X _i (t), Y _i (t) of the received parallel multi-frequency composite signal z (f) with the above N pairs of in-phase and quadrature components of the reference channel mutually orthogonal signals. At the end of the signal elements, the values X _i , Y _{i of} each of the indicated pairs of correlation functions are read

where u _c (t) = Acosω _i t and u _s (t) = Asinω _i t are the in-phase and quadrature components of the reference signal corresponding to the ith subcarrier, respectively.

В решающем устройстве значения X_i, Y_i указанных корреляционных функций вместе с соответствующими значениями этих корреляционных функций, вычисленных на предыдущих элементах сигнала, используются для принятия решения по одному из известных методов, например по методу сравнения полярностей, о переданном на данной поднесущей информационном символе, который поступает на выход блока обработки сигнала, затем - на соответствующий информационный вход преобразователя кода. Одновременно получают оценку уровня U_i, соответствующей i-й поднесущей, поступившей из канала на вход приемного устройства.Due to the orthogonality of the subcarriers [1]

In the solver, the values X _i , Y _{i of the} indicated correlation functions, together with the corresponding values of these correlation functions calculated on the previous signal elements, are used to make a decision using one of the known methods, for example, by the method of comparing polarities, about the information symbol transmitted on this subcarrier, which goes to the output of the signal processing unit, then to the corresponding information input of the code converter. At the same time, an estimate of the level of U _i corresponding to the ith subcarrier received from the channel at the input of the receiving device is obtained.

Осуществляют усреднение вычисленных в соответствии с (10) оценок уровня U_i для каждой i-й поднесущей на ряде последовательно полученных информационных символов, используют полученные усредненные оценки уровня

для изменения в

раз амплитуд синфазной и квадратурной составляющих опорных сигналов, соответствующих каждой из i-х поднесущих, используют новые указанные значения амплитуд синфазной и квадратурной составляющих опорных сигналов, соответствующих каждой из i-х поднесущих, для приема следующих элементов сигнала. Параметры усреднения оценок уровня U_i поднесущих определяется длительностью элементов сигнала, передаваемых на поднесущих, и скоростью изменения параметров канала при селективных замираниях; соответствующие рекомендации по их выбору приведены в [2].

Averaging the estimates of the level of U _i calculated in accordance with (10) is carried out for each ith subcarrier on a series of successively obtained information symbols, using the obtained average level estimates

for change in

times the amplitudes of the in-phase and quadrature components of the reference signals corresponding to each of the i-subcarriers, use the new indicated amplitudes of the in-phase and quadrature components of the reference signals corresponding to each of the i-subcarriers to receive the following signal elements. The parameters of averaging the estimates of the level U _{i of the} subcarriers are determined by the duration of the signal elements transmitted on the subcarriers and the rate of change of the channel parameters during selective fading; relevant recommendations for their selection are given in [2].

, равную

Указанная усредненная оценка уровня i-й поднесущей

используется для изменения амплитуд синфазной и квадратурной составляющих опорных сигналов, соответствующих данной i-й поднесущей в

раз

При последующем приеме элементов сигнала используют новые, измененные в

раз значения амплитуд синфазной и квадратурной составляющих опорных сигналов, соответствующих каждой из i-х поднесущих. При подстановке соответствующих значений амплитуд опорных сигналов в выражения (8а, 8б) получаем:

следовательно, происходит компенсация действия селективной помехи, при этом значения X_i, Y_i каждой из указанных N пар корреляционных функций принимаемого параллельного многочастотного составного сигнала z(t) с упомянутыми N парами синфазных и квадратурных составляющих опорных канальных взаимно ортогональных сигналов, полученные в момент окончания элементов сигнала, не зависят от коэффициента передачи канала K(ω_i); следовательно, повышается помехоустойчивость приема параллельного многочастотного составного сигнала в условиях действия селективных помех.So, suppose that due to selective fading of the ith subcarrier of a parallel multi-frequency composite signal in a series of successively obtained signal elements, the level of this subcarrier remains unchanged and is estimated by the value calculated by formula (10). As a result of averaging these estimates, we obtain

equal to

The indicated average estimate of the level of the i-th subcarrier

used to change the amplitudes of the in-phase and quadrature components of the reference signals corresponding to a given i-th subcarrier in

time

With the subsequent reception of signal elements, new ones are used, modified in

times the amplitudes of the in-phase and quadrature components of the reference signals corresponding to each of the i-subcarriers. When substituting the corresponding values of the amplitudes of the reference signals in the expression (8a, 8b) we get:

consequently, the effect of selective interference is compensated, and the values of X _i , Y _{i of} each of these N pairs of correlation functions of the received parallel multi-frequency composite signal z (t) with the mentioned N pairs of in-phase and quadrature components of the reference channel mutually orthogonal signals obtained at the time of termination signal elements are independent of the transmission coefficient of the channel K (ω _i ); therefore, the noise immunity of receiving a parallel multi-frequency composite signal increases under conditions of selective interference.

 It is advisable to change the amplitudes of the in-phase and quadrature components of the reference channel mutually orthogonal signals at time points corresponding to the mathematical expectation of the position of the boundaries of the signal elements transmitted on the subcarriers.

 Thus, the claimed technical solution has the following distinctive features.

соответствующей i-й поднесущей. Этот признак позволяет выявить отличие уровней принимаемых сигналов от номинального значения.1. Preliminarily store the signals corresponding to the nominal level of each of the i-subcarriers U _0i , calculate for each of the subcarriers at the time of the end of the signal elements, using the specified values X _i , Y _{i of} each of the mentioned pairs of correlation functions, the level estimate

corresponding i-th subcarrier. This feature allows you to identify the difference between the levels of the received signals from the nominal value.

для изменения в

раз амплитуды синфазной и квадратурной составляющих опорных сигналов, соответствующих каждой из поднесущих, используют новые указанные значения амплитуд синфазной и квадратурной составляющих опорных сигналов, соответствующих каждой из i-х поднесущих, для приема следующих элементов сигнала. Этот признак выявляет устойчивую тенденцию отличия уровня принимаемой поднесущей от номинального, которое считается следствием действия селективной помехи; позволяет осуществлять изменение амплитуд опорных сигналов таким образом, чтобы при приеме следующих элементов сигнала происходила компенсация действия селективной помехи, что повышает помехоустойчивость приема информации в условиях действия селективных помех.2. The calculated estimates of the level of U _i for each i-th subcarrier are averaged over a series of information symbols obtained successively; the obtained average level estimates are used

for change in

times the amplitudes of the in-phase and quadrature components of the reference signals corresponding to each of the subcarriers, use the new indicated values of the amplitudes of the in-phase and quadrature components of the reference signals corresponding to each of the i-subcarriers to receive the following signal elements. This feature reveals a steady tendency to distinguish the level of the received subcarrier from the nominal, which is considered to be a consequence of the action of selective interference; allows you to change the amplitudes of the reference signals so that when the following signal elements are received, the effect of selective interference is compensated, which increases the noise immunity of receiving information under conditions of selective interference.

 3. The composition of each of the N received signal processing units that are part of the parallel multi-frequency composite signal receiving device includes two squaring units connected in series to the first computer, the averaging unit, the second computer, the first memory unit, and two multiplication units, the second memory unit, which in the above combination and interconnection allows to compensate for the effect of selective interference and increases the noise immunity of receiving information under conditions of selective interference.

 Based on the foregoing, it is seen that the claimed technical solution has significant differences.

 Figure 1 shows a diagram of a device for receiving a parallel multi-frequency composite signal, consisting of N processing units of the received signal 1.1. . . 1.N (one for each subcarrier in the composition of the signal 1.1 ... 1.N (one for each subcarrier in the parallel multi-frequency composite signal)), code conversion unit 2, synchronization unit 3, and the information inputs of N processing units the signal 1.1 ... 1.N are connected together and serve as the input of the receiver 4, the outputs N of the processing units of the received signal 1.1. . .1.N are connected to the corresponding information inputs of the code conversion unit 2, the output of which serves as the output of the device 5, the input of the synchronization unit 3 is connected to the input of the device 4, and the output of the synchronization unit 3 is connected to the clock inputs N of the received signal processing units 1.1 connected together .. .1.N and code conversion unit 2. In FIG. 2 is a diagram of the i-th block of the received signal processing, intended for receiving the i-th subcarrier, consisting of an in-phase and quadrature components of the reference channel signal i.6, two identical correlators i.7, i.8, resolver i.9, two blocks of squaring i.10, i.11, connected in series to the first calculator i. 12, averaging block i.13, second calculator i.14, first memory block i. 15, as well as two blocks of multiplication i.16, i.17 of the second memory block i. 18, and the first information inputs of the correlators i.7, i.8 are connected together and serve as the information input of the received signal processing unit, the output of the correlator i.7 is connected to the first information input of the resolving device i.9 and the input of the first squaring unit i . 10, the output of the correlator i.8 is connected to the second information input of the resolver i.9 connected together and the input of the second squaring i. 11, the reset inputs of both correlators i.7, i.8, clock inputs of the resolver i. 9, the first squaring block i.10, the second squaring block i.11, the first calculator i.12, the averaging block i. 13, the second calculator i.14 and the first memory block i.15 are connected together and connected to the clock input of the received signal processing unit, the output of the resolver i.9 serves as the output of the received signal processing unit, the first inputs of both multiplication units i.16 and i. 17 are connected together and connected to the output of the first memory block i.15, the second input of the first multiplication block i. 16 is connected to the output of the in-phase component of the generator of the in-phase and quadrature components of the reference channel signal i.6, the output of the first multiplication block i.16 is connected to the second information input of the first correlator i. 7, the second input of the second multiplication block i.17 is connected to the output of the quadrature component of the in-phase and quadrature components of the reference channel signal i.6, the output of the second multiplication block i.17 is connected to the second information input of the second correlator i.8, the output of the second memory block i .18 is connected to the second information input of the second calculator i.14. The device of the remaining (N-1) blocks of the processing of the received signal included in the device for receiving a parallel multi-frequency composite signal is similar.

The work of the proposed method consists in the sequential implementation of the claimed device of the following operations:
1. Previously, based on the required noise immunity of the information transmission, the signal-to-noise ratio value necessary for ensuring such noise immunity is determined and, accordingly, the nominal values U _0i of the subcarrier levels constituting the parallel multi-frequency composite signal. An appropriate technique for determining the necessary signal-to-noise ratios at the receiving point and the nominal values U _0i of the subcarrier levels is given in [2].

The values U _{0i of the} nominal subcarrier levels in the form of corresponding signals are recorded and stored in the second memory blocks i.18 of the respective signal processing units, the numbers of which coincide with the numbers of the corresponding subcarriers in the parallel composite signal.

 2. N pairs are formed (by the number of subcarriers in the parallel multi-frequency composite signal) in-phase and quadrature components of the reference channel mutually orthogonal signals with frequencies equal to the frequencies of the corresponding sub-carriers of the parallel multi-frequency composite signal.

These operations are performed in each of the signal processing units using an in-phase and quadrature component of the reference channel signal i.6. The generators i.6 at their outputs form in-phase u _c (t) = Acosω _i t and quadrature u _s (t) = Asinω _i t components of the reference channel signal with a frequency ω _i, respectively. The frequency ω _{i of the} in-phase and quadrature components of the reference channel signal generated by the generator i. 6 corresponds to the subcarrier frequency for which this i-th signal processing unit is intended.

  3. Determine the mathematical expectation of the position of the boundaries of the elements of the signals transmitted on subcarriers.

 This operation is performed in the synchronization unit 3, the output of which is formed by a sequence of corresponding signals that ensure the functioning of the components of the device.

4. Inside these boundaries, on the duration of the orthogonality interval of the subcarriers T (T does not exceed the duration of the signal elements) N pairs of correlation functions X _i (t), Y _i (t) of the received parallel multi-frequency composite signal with the mentioned N pairs of in-phase and quadrature reference channel components are calculated mutually orthogonal signals.

 These operations are performed in each of the signal processing units, respectively, by the first i.7 and second i.8 correlators.

5. Use the values of X _i , Y _{i of} each of these pairs of correlation functions obtained at the end of the signal elements corresponding to each subcarrier, together with the values of each of these pairs of correlation functions obtained on the same subcarrier at the time of the end of a number of previous signal elements, to decide on the information symbol transmitted on this subcarrier.

These operations are performed in each of the signal processing blocks by the deciding device i.9, the first i.7 and the second i.8 correlators. According to the corresponding signal arriving at the clock input of the resolver i.9 from the synchronization unit 3, in the resolver i.9 a decision is made about the information symbol transmitted on this subcarrier by jointly processing the indicated values X _i , Y _{i of the} correlation functions received at the first and second information inputs of the resolver i.9 from the first i.7 and second i.8 correlators; and the corresponding first i.7 and second i.8 correlators; and the corresponding values of the correlation functions calculated on the previous elements of the signal. The decision is made by one of the known methods, for example, by the method of comparing the phases or the method of comparing the polarities [2]. The adopted information symbol from the output of the resolver i.9 goes to the output of the corresponding i-th signal processing unit and then to the corresponding information input of the code conversion unit 2. After the triggering of the resolver 1.9 by the corresponding signal from the synchronization unit 3, which is input to the reset input of the first i .7 and second i.8 correlators of each of the signal processing units, these correlators are reset. Then the correlators i.7 and i.8 are ready to process the next signal element.

 6. Combine the information symbols received on each of the subcarriers into one common stream and issue this information stream to the recipient.

 This operation is carried out in the code conversion unit 2 by the corresponding signal received at its clock input from the synchronization unit 3. Information symbols from the outputs of all N signal processing units are sent in parallel to the corresponding information inputs of the code conversion unit 2, converted into a serial form and fed to the output of the device 5.

соответствующей i-й поднесущей, усредняют вычисленные оценки уровня U_i для каждой i-й поднесущей на ряде последовательно полученных информационных символов, используют полученные усредненные оценки уровня

для изменения в

раз амплитуды синфазной и квадратурной составляющих опорных сигналов, соответствующих каждой i-й поднесущей, используют новые указанные значения амплитуд синфазной и квадратурной составляющих опорных сигналов, соответствующих каждой i-й поднесущей, для приема следующих элементов сигнала.7. Calculate at the end of the signal elements using the specified values X _i , Y _{i of} each of the mentioned pairs of correlation functions, an estimate of the level

corresponding i-th subcarrier, average the calculated estimates of the level U _i for each i-th subcarrier on a number of successively obtained information symbols are averaged, the obtained average level estimates are used

for change in

times the amplitudes of the in-phase and quadrature components of the reference signals corresponding to each i-th subcarrier, use the new indicated values of the amplitudes of the in-phase and quadrature components of the reference signals corresponding to each i-th subcarrier to receive the following signal elements.

i-й поднесущей. Сформированные в первом вычислителе i.12 на ряде последовательно полученных информационных символах оценки уровня U_i i-й поднесущей усредняются в блоке усреднения i.13. Длительность интервала, на котором производится усреднение оценок уровня, определяется длительностью элементов сигнала, передаваемых на поднесущих, и скоростью изменения параметров канала при селективных замираниях; соответствующие рекомендации по их выбору приведены в [2]. Результат усреднения оценок уровня

с выхода блока усреднения i.13 подается на первый информационный вход второго вычислителя i. 14, на второй информационный вход второго вычислителя i. 14 из второго блока памяти i.18 подается сигналом, соответствующим номинальному уровню U_0i, из i-й поднесущей. Во втором вычислителе i. 14 в соответствии с формулой (12) вычисляется корректирующий коэффициент для изменения в

раз амплитуды синфазной и квадратурной составляющих опорных сигналов соответствующих i-х поднесущих. Значения корректирующего коэффициента

с выхода второго вычислителя i.14 записываются в первый блок памяти i.15, с выхода которого значения корректирующего коэффициента

подаются на соединенные вместе вторые входы первого i.16 и второго i.17 блоков умножения. На первый вход первого блока умножения i.16 с выхода генератора i. 6 синфазной и квадратурной составляющих опорного канального сигнала подаются синфазная u_c(t) = Acosω_it составляющая опорного канального сигнала с частотой ω_i. На первый вход второго блока умножения i.17 с выхода генератора i. 6 синфазной и квадратурной составляющих опорного канального сигнала подается квадратурная u_s(t) = Asinω_it составляющая опорного канального сигнала с частотой ω_i. Частота ω_i синфазной и квадратурной составляющих опорного канального сигнала, формируемого генератором i.6, соответствует частоте поднесущей, для приема которой предназначен данный i-й блок обработки сигнала. В результате перемножения на выходах первого i.16 и второго i. 17 блоков умножения формируются синфазная и квадратурная составляющие опорного канального сигнала, амплитуды которых равны

. Синфазная составляющая опорного канального сигнала с выхода первого блока умножения i.16 подается на второй информационный вход первого коррелятора i. 7; a квадратурная составляющая опорного канального сигнала с выхода второго блока умножения i.17 подается на второй информационный вход второго коррелятора i. 8 и используются при обработке следующих элементов сигнала. Если при этом, вследствие действия селективных замираний, происходит изменение уровня соответствующей поднесущей, то осуществляется его компенсация в результате выполнения последовательности операций, изложенных выше. При этом коррекцию амплитуды указанных синфазной и квадратурной составляющих опорного канального сигнала целесообразно осуществлять в моменты времени, совпадающие с математическим ожиданием положения границ элементов принимаемого сигнала.These operations are performed in each of the signal processing channels using two squaring blocks i.10, i.11, the first calculator i.12, the averaging block i.13, the second calculator i.14, the first memory block i.15, two multiplication blocks i.16, i.17, the second memory block i.18. By the corresponding signal from the synchronization unit 3 to the clock input of the signal processing unit and from it to the clock inputs of the two squaring i blocks connected together. 10, i.11, the first calculator i.12, the averaging block, the second calculator i.14, the first memory block i.15, simultaneously with the decision on the information symbol transmitted on this subcarrier in the first and second blocks of squaring i.10 , i.11 calculate the squares X _i ² , Y _i ^{2 of the} indicated values X _i , Y _{i of} each of the mentioned pairs of correlation functions, from which a level estimate is formed in the first calculator i.12

i-th subcarrier. The estimates of the level U _{i of the} i-th subcarrier generated in the first calculator i.12 on a series of information symbols sequentially obtained are averaged in the averaging block i.13. The duration of the interval over which the level estimates are averaged is determined by the duration of the signal elements transmitted on the subcarriers and the rate of change of the channel parameters during selective fading; relevant recommendations for their selection are given in [2]. Level Averaging Result

from the output of the averaging block i.13 is fed to the first information input of the second calculator i. 14, to the second information input of the second calculator i. 14 from the second memory block i.18 is supplied by a signal corresponding to the nominal level U _0i from the i-th subcarrier. In the second calculator i. 14, in accordance with formula (12), a correction coefficient is calculated for the change in

times the amplitude of the in-phase and quadrature components of the reference signals of the corresponding i-subcarriers. Correction Factor Values

from the output of the second calculator i.14 are recorded in the first memory block i.15, from the output of which the values of the correction coefficient

served on the second inputs of the first i.16 and second i.17 multiplication blocks connected together. At the first input of the first block of multiplication i.16 from the output of generator i. In-phase and quadrature components of the reference channel signal are fed in-phase u _c (t) = Acosω _i t component of the reference channel signal with a frequency ω _i . At the first input of the second block of multiplication i.17 from the output of generator i. 6 in-phase and quadrature components of the reference channel signal, the quadrature u _s (t) = Asinω _i t component of the reference channel signal with a frequency ω _i is supplied. The frequency ω _{i of the} in-phase and quadrature components of the reference channel signal generated by the i.6 generator corresponds to the subcarrier frequency for which this i-th signal processing unit is intended. As a result of multiplication at the outputs of the first i.16 and second i. 17 multiplication blocks are formed in-phase and quadrature components of the reference channel signal, the amplitudes of which are equal

. The in-phase component of the reference channel signal from the output of the first multiplication block i.16 is fed to the second information input of the first correlator i. 7; a quadrature component of the reference channel signal from the output of the second multiplication block i.17 is supplied to the second information input of the second correlator i. 8 and are used in processing the following signal elements. If, due to selective fading, a change in the level of the corresponding subcarrier occurs, then it is compensated as a result of the sequence of operations described above. At the same time, it is advisable to correct the amplitudes of the indicated in-phase and quadrature components of the reference channel signal at time points that coincide with the mathematical expectation of the position of the boundaries of the elements of the received signal.

 Similarly, signal processing is carried out in the remaining (N-1) blocks of the received signal processing, which are part of the device for receiving a parallel multi-frequency composite signal.

 The blocks that make up the inventive device are known in the art. For its implementation, both the corresponding blocks from the prototype device and the blocks described in the literature can be used.

 The squaring blocks i.10, i.11, the first calculator i.12, the averaging block i.13, the second calculator i.14 can be performed on the basis of arithmetic-logic devices (ALU). Examples of constructing these blocks based on ALU are given in [3]. The first i.15 memory block can be implemented as a parallel register, examples of parallel registers implementation are given in [3].

 To implement the multiplication blocks i.16, i.17, you can use multiplying digital-to-analog converters. Examples of multiplying digital-to-analog converters and implementations of multiplying blocks based on them are given in [3].

 The second i.18 memory block can be made on the basis of read-only memory, examples of constructing devices of this type are described in [3].

 Other executions of these blocks are possible. If the signal processing in the device for receiving a parallel multi-frequency composite signal is carried out in analog form, then with examples of execution of the squaring blocks i.10, i.11, the first calculator i.12, the averaging block i.13, the second calculator i.14, the first memory block i.15, multiplication blocks i.16, i.17, as well as the second memory block i.18 based on analog elements can be found in [3].

Sources of information
1. Equipment for the transmission of discrete information MS-5. Ed. A.M. Zaezdnogo, Yu.B. Okuneva. - M.: Communication, 1970.

 2. Theory of electrical communication: Textbook for high schools / A.G. Zyuko, D.D. Klovsky, V.I. Korzhik, M.V. Nazarov. Ed. D.D. Klovsky.-M.: Radio and Communications, 1998.

 3. Titz U., Schenk K. Semiconductor circuitry. Reference guide. / Per. with him. - M.: Mir, 1982.

Claims (3)

1. The method of receiving a parallel multi-frequency composite signal, which is the sum of N mutually orthogonal harmonic subcarriers, the information transmission on each of which is carried out synchronously by the method of relative phase modulation, which consists in the formation of N pairs (by the number of subcarriers in the composition of the parallel multi-frequency composite signal) in-phase and quadrature components of the reference channel mutually orthogonal signals with frequencies equal to the frequencies of the respective subcarriers of the parallel multichannel -frequency composite signal in determining the expectation of the boundaries of elements of the signals transmitted on subcarriers in the computation within those limits on the duration of the interval of orthogonality of subcarriers T (T is not more than the elements of the signal duration) N pairs of correlation functions X _{i (t), Y i (} t ) received parallel multi-frequency composite signal with the mentioned N pairs of in-phase and quadrature components of the reference channel mutually orthogonal signals, using the values of X _i , Y _i , each of these pairs correlation functions received at the end of the signal elements corresponding to each subcarrier, together with the values of the specified pairs of correlation functions obtained at the end of a series of previous signal elements, on the same subcarrier to decide on the information symbol transmitted on this subcarrier, in the combination of information symbols received on each of the subcarriers into one common stream and the issuance of this information stream to the recipient, characterized in that the signals are previously stored, respectively corresponding to the nominal level of each of the i-subcarriers U _0i , at the moment of the end of the signal elements are calculated using the specified values of X _i , Y _i , each of the mentioned pairs of correlation functions, the level estimate

corresponding i-th subcarrier, average the calculated estimates of the level U _i for each i-th subcarrier on a number of successively obtained information symbols are averaged, the obtained average level estimates are used

for change in

times the amplitudes of the in-phase and quadrature components of the reference signals corresponding to each i-th subcarrier, use the new indicated values of the amplitudes of the in-phase and quadrature components of the reference signals corresponding to each i-th subcarrier to receive the following signal elements.  2. The method of receiving a parallel multi-frequency composite signal according to claim 1, characterized in that the amplitudes of the in-phase and quadrature components of the reference signals are changed at time points corresponding to the mathematical expectation of the position of the boundaries of the signal elements transmitted on the subcarriers.  3. A device for receiving a parallel multi-frequency composite signal, which is the sum of N mutually orthogonal harmonic subcarriers, the information on each of which is synchronously transmitted by the method of relative phase modulation, containing N processing units of the received signal (one for each subcarrier in the composition of the parallel multi-frequency composite signal) , a code conversion unit, a synchronization unit, wherein the information inputs of N received signal processing units are connected together and At the input of the receiver, the outputs of the N processing units of the received signal are connected to the corresponding information inputs of the code conversion unit, the output of which serves as the output of the device, the input of the synchronization unit is connected to the input of the device, and the output of the synchronization unit is connected to the clock inputs of the N processing units of the received signal connected together and a code conversion unit, each of the N received signal processing units consists of an in-phase and quadrature component of the reference channel signal with a frequency d corresponding to the frequency of the subcarrier for receiving which the given processing unit of the received signal is intended, two identical correlators, a solver that provides a decision on the information symbol received on this subcarrier, and in each of the N processing blocks of the received signal, the first information inputs of the correlators are connected together and serve as the information input of the processing unit of the received signal, the outputs of the correlators are connected to the corresponding information inputs of the solver , the reset inputs of both correlators and the clock input of the resolver are connected together and connected to the clock input of the received signal processing unit, the output of the resolver serves as the output of the received signal processing unit, characterized in that two construction blocks are introduced into each of the N received signal processing units square, connected in series to the first calculator, the averaging block, the second calculator, the first memory block, as well as two multiplication blocks, the second memory block, and the clock inputs are squaring the first and second calculators, the averaging block and the first memory block are connected together and connected to the clock input of the received signal processing block, the first inputs of both multiplication blocks are connected together and connected to the output of the first memory block, the second input of the first multiplication block is connected to the output the in-phase component of the generator of the in-phase and quadrature components of the reference channel signal, the output of the first multiplication unit is connected to the second information input of the first correlator, the second input d of the second multiplication block is connected to the output of the quadrature component of the in-phase and quadrature components of the reference channel signal, the output of the second multiplication block is connected to the second information input of the second correlator, the output of the second memory block is connected to the second information input of the second calculator, the information input of the first squaring block is connected to the output of the first correlator, the information input of the second squaring unit is connected to the output of the second correlator, the first and second oh information inputs of the first calculator are connected respectively to the outputs of the first and second blocks of squaring.

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