RU2114510C1 - Multichannel frequency-reuse radio communication system - Google Patents

Abstract

FIELD: radio communications; space and ground radio communication links. SUBSTANCE: system has on sending end phase-modulated signal generator, two amplitude modulators whose inputs are connected to outputs of phase-modulated signal generator and outputs, two transmitting antennas; on receiving end, it has two receiving antennas connected to adder inputs and demodulator. Newly introduced in system on its sending end are frequency standard, encoder, third amplitude modulator, and third transmitting antenna; newly introduced on receiving end are third receiving antenna, reference-signal shaper, and three synchronous detectors. EFFECT: enlarged functional capabilities, increased number of data signals transmitted (up to three). 5 dwg

Description

 The invention relates to radio communication systems and can be used in radio links with frequency reuse (PMP).

 Known radio frequency reuse (PICH) radio communication systems in which the PICH is achieved by ensuring polarization orthogonality of two simultaneously transmitted signals with circular or linear polarization.

 However, with this method of radio communication with the PMP, the use of a pilot signal is required to ensure high requirements for orthogonality in the polarization of the transmitted signals.

 The use of a pilot signal requires the allocation of an additional frequency channel that does not coincide with the frequency spectrum of the transmitted signal, which reduces the noise immunity of this method of radio communication with a PICH.

 The closest in technical essence to the claimed object is [1] adopted as a prototype.

In FIG. 1 is a functional diagram of a prototype device, where 1 is an FM signal generator, 2 is a power splitter, 3, 4 are amplitude modulators, 5 is an out-of-phase amplifier, 6, 7 are transmit antennas, 8, 9 are receive antennas, 10 is an adder 11 - a subtractor, 12 - 90 ^o phase shifter, 13 - multiplier, 14 - main message demodulator, 15 - low-pass filter (LPF).

The prototype device contains on the transmitting side a signal generator 1, modulated by the main message, the output of which is connected to the input of the power splitter 2, the first and second outputs of which are connected through the first and second amplitude modulators 3, 4 to the first and second transmitting antennas 6, 7, the first and second outputs of the out-of-phase amplifier 5 are connected to the control inputs of the amplitude modulators 3, 4, respectively, and the input is the input of an additional message of the device, on the receiving side, the first and second receiving antennas 8, 9, the outputs of which are connected respectively to the first and second inputs of the adder 10 and the subtractor 11, the output of which through the multiplier 13 is connected to the input of the PLL 15, the output of which is an additional output of the device, and the output of the adder 10 through the phase shifter is 90 ^° connected to the other input of the multiplier 13 and with the input of the demodulator of the main message 14, the output of which is the main output of the device.

 The prototype device operates as follows.

The signal generator 1, modulated in phase or frequency by the main message, generates a signal of the form
U _s (t) = v _c cosψ (t) (1)
where U _with - the amplitude of the signal;
ψ (t) = ω (t) + φ (t);
ω is the angular frequency;
φ (t) - is the function of changing the phase of the signal corresponding to the phase or frequency modulation of the main message.

где U - амплитуда;
f(t) - функция изменения амплитуды сигнала, соответствующая дополнительному сообщению.The signal (1) is fed to the input of a power splitter 2, from the output of which the signal branches into two channels in which amplitude modulators 3, 4 are installed, made in the form of controlled high-frequency amplifiers. In them, the amplitude of the transmitted signals changes out of phase according to the law of the additional message using the voltages taken from the out-of-phase amplifier 5. Moreover, the signals at the outputs of modulators 3, 4 have the form

where U is the amplitude;
f (t) is the signal amplitude change function corresponding to the additional message.

 Signals (2) and (3) are emitted into space by transmitting antennas 6, 7.

 In FIG. 2 shows the location in space of transmitting 6, 7 and receiving 8, 9 antennas.

Transmitting and receiving antennas are located symmetrically about the axis O ^- O ¹ connecting the middle without antennas d _T , d _R. The case is considered when there is no isolation between the transmitting and receiving antennas, which takes place at Z _T <<d _T , Z _T <<d _R , where Z _T and Z _{R are the} aperture sizes of the transmitting and receiving antennas. In this case, the antenna patterns almost completely overlap.

где U_п - амплитуда сигнала в месте приема, обусловленная излучением одной из передающих антенн;
Δφ - разность фаз, возникающая от разности хода лучей, которая определяется как

где Δt - время, необходимое для преодоления радиоволной расстояния Δl (разности хода лучей);
C - скорость света.At the outputs of the receiving antennas 8, 9 we get a signal

where U _p - the amplitude of the signal at the receiving location, due to the radiation of one of the transmitting antennas;
Δφ is the phase difference arising from the difference in the path of the rays, which is defined as

where Δt is the time required to overcome the radio wave distance Δl (the difference in the path of the rays);
C is the speed of light.

, то

Из геометрических построений на фиг. 2 следует, что

Подставив (7) в (6), получим

где λ - длина волны;
D - расстояние между передающей и приемной сторонами.Because

then

From the geometric constructions in FIG. 2 it follows that

Substituting (7) into (6), we obtain

where λ is the wavelength;
D is the distance between the transmitting and receiving sides.

После преобразования получим

Из выражений (11) и (12) видно, что сигнал с выхода сумматора 10 имеет только угловую модуляцию функцией φ(t) [поскольку ψ(t) = ω(t) + φ(t)] ], а сигнал с выхода вычитателя 11 имеет как угловую, так и амплитудную модуляцию функцией f(t).The outputs of the adder 10 from the subtractor 11 will act signals

After the conversion, we get

It can be seen from expressions (11) and (12) that the signal from the output of adder 10 has only angular modulation by the function φ (t) [since ψ (t) = ω (t) + φ (t)]], and the signal from the output of the subtractor 11 has both angular and amplitude modulation by the function f (t).

 It should be noted that this amplitude modulation is the result of spatial modulation of the signal emitted by transmitting antennas.

эти коэффициенты передачи равны, при этом

Амплитудно-модулированный сигнал (12) с выхода вычитателя 11 поступает на вход цепочки последовательно включенных перемножителя 13 и ФНЧ 15. Эта цепочка играет роль синхронного демодулятора (см. Андреев В.С. Теория нелинейный электрических цепей. - М., "P и C", 1982, с. 100), на выходе которого выделяется дополнительное сообщение, передававшееся по каналу пространственной модуляции.A radio link with additional spatial modulation of the signal can be considered as two-channel. Obviously, the transmission coefficients of the signals in the channels of angular and spatial modulation are periodic functions of the phase shift Δφ, which is a function of the distance between the antennas on the transmitting and receiving sides d _T and d _R , the communication range D and the wavelength λ. At

these transmission coefficients are equal, while

The amplitude-modulated signal (12) from the output of the subtractor 11 is fed to the input of the chain of series-connected multipliers 13 and the low-pass filter 15. This chain plays the role of a synchronous demodulator (see Andreev VS Theory of nonlinear electric circuits. - M., "P and C ", 1982, p. 100), the output of which is allocated an additional message transmitted on the channel of spatial modulation.

To use the output signal of the adder 10 as a reference for the synchronous demodulator, it must be phased with the input signal of this demodulator, for which the phase shifter is 90 ^o 12.

 The output signal of the phase shifter 12 is modulated only in angle. Therefore, it arrives for demodulation by angle on the demodulator of the main message 14, the output of which is allocated the main message transmitted through the channel of angular modulation.

 The disadvantage of this prototype device is the insufficient amount of transmitted information, because currently increasing the amount of transmitted information every day is becoming more and more necessary.

 To increase the amount of information transmitted to the prototype device, containing on the transmitting side the FM signal generator, the first and second amplitude modulators, the outputs of which are connected to the first and second transmitting antennas, respectively; on the receiving side, the first and second receiving antennas, which are connected respectively to the first and second inputs of the adder, and a main message demodulator are introduced: on the transmitting side, a reference generator whose output is connected to one of the inputs of the FM signal generator, a third amplitude modulator, one of the inputs which is connected to the third output of the FM signal generator, an encoder whose input is connected to the output of the reference generator, and the first output is connected to the second input of the FM signal generator, the second, third and fourth the first outputs of the encoder are connected respectively to the second inputs of the first, second and third amplitude modulators, and the output of the third amplitude modulator is connected to a third transmitting antenna; on the receiving side, the third receiving antenna, which is connected to the third input of the adder, a reference signal shaper, the input of which is connected to the demodulator output and the decoder input, the output of which is the main message signal, the output of the reference signal shaper is connected by the first inputs of the first, second and third synchronous detectors, the second inputs of which are connected respectively to the first, second and third receiving antennas. INF2, INF3 and INF4 are removed from the outputs of the first, second and third synchronous detectors.

 In FIG. 3 shows a functional diagram of the proposed device, where 1 is a reference generator, 2 is an FM signal generator, 3, 4, 5 are amplitude modulators, 6 is an encoding device, 7, 8, 9 are transmit antennas, 10, 11, 12 are receive antennas, 13 - adder, 14 - demodulator, 15 - driver of the reference signal, 16 - decoding device, 17, 18, 19 - synchronous detectors.

 The composition of the encoding device includes (see FIG. 5): 61 — a clock shaper, 62 — a synchronization circuit made according to a trigger circuit; 63 - shift register; 64, 65, 66 - pulse counters, 67.68, 69 - synchronization blocks made according to the trigger scheme.

 The proposed device has the following functional relationships: reference generator 1, the output of which is connected to the inputs of the encoder 6 and the FM signal generator 2, the three outputs of which are connected to the first inputs of the first 3, second 4 and third 5 amplitude modulators, respectively, the encoder 6, the first the output of which is connected to the second input of the FM signal generator 2, and the second, third and fourth outputs of this encoder are connected to the second inputs of the first 3, second 4 and third 5 amplitude modulators co Accordingly, the outputs of which are connected respectively to the first 7, second 8, and third 9 transmit antennas, the first 10, second 11, and third 12 receive antennas are connected to the three inputs of the adder 13, respectively, the output of which through the demodulator 14 to the input of the decoding device 16, from the output of which basic information is also taken to the input of the driver of the reference signal 15, the output of which is connected to the first inputs of the first 17, second 18 and third 19 synchronous detectors, the second inputs of which are connected respectively to the first 10, second 11 and third 12 pr with first-order antennas, with the output of the first 17, second 18 and third 19 synchronous detectors, the first, second and third additional information are removed, respectively.

 The proposed device operates as follows.

 The reference generator generates harmonic oscillations, which are fed to the first input of the phase manipulator 2, to the second input of which the signal of the basic information INF 1 from the encoder 6 is supplied.

 In FIG. 5 is a diagram of one embodiment of this encoding device, where oscillations from the reference oscillator 1 are applied to the input of the clock pulse generator 61. The clock pulses generated by the block 61 are fed to one of the inputs of the synchronization block 62, to the second input of which the main information signal INF 1, and the output of this synchronization block is removed INF 1, which is fed to the second input of the phase manipulator 2 (see Fig. 3). From the output of the phase manipulator 2 through three outputs, the phase-manipulated signal according to the law of the basic information signal INF 1 is supplied to the first inputs of the first 3, second 4 and third 5 amplitude modulators, respectively. The second inputs of these modulators receive signals INF 2, INF 3 and INF 4 from the second, third and fourth outputs of the encoder 6, respectively.

 In FIG. 5 shows a functional diagram of the formation of INF 2, INF 3 and INF 4.

 The clock pulses generated by the shaper 61 are fed to the shift register 63. Pulses with different temporal positions are taken from the three outputs of this register, which are respectively fed to the inputs of the first 64, second 65 and third 66 counters.

 The output pulses from these counters are respectively supplied to the inputs of the first 67, second 68, and third 69 synchronization blocks made according to the trigger circuit, the second inputs of which are supplied with INF 2, INF 3 and INF 4, respectively, and INF 2 is removed from the outputs of these synchronization blocks, INF 3 and INF 4, tied to clock pulses.

 In FIG. 4 shows the temporary position of the generated information signals associated with clock pulses.

 From the outputs of the first 3, second 4 and third 5 amplitude modulators, the signal enters the first 7, second 8 and third 9 transmit antennas that emit these signals into space.

 The signals received by the first 10, second 11, and third 12 receiving antennas are supplied respectively to the three inputs of the adder 13, from the output of which the total signal is fed to demodulator 14, where INF 1 is extracted, which is then decoded in decoding device 16 and supplied to the consumer. At the same time, the signal from the output of the demodulator 14 is supplied to form the reference signal in the shaper 15. From the output of the shaper 15, the reference signal is supplied to the first inputs of the synchronous detectors 17, 18 and 19, the second inputs of which are fed from the first 10, second 11, and third 12, respectively receiving antennas.

 INF 2 is removed from the output of the first synchronous detector 17, INF 3 is removed from the output of the second synchronous detector 18, and INF 4 is removed from the output of the third synchronous detector 19.

 The introduction of a reference generator, an encoder, and a third transmitting antenna on the transmitting side, a third receiving antenna, a reference signal shaper, and three synchronous detectors on the receiving side made it possible to transmit four information signals instead of two information signals in the prototype device, which is naturally an advantage over the proposed device prototype device.

 In FIG. 5 is a functional diagram of one of the embodiments of the encoder 6. The implementation of the remaining blocks and nodes does not cause any difficulties, because they are widely covered in technical literature.

Claims (1)

 A multi-channel frequency reuse radio communication system comprising, on the transmitting side, a phase-shifted signal generator, first and second amplitude modulators, the outputs of which are connected to the first and second transmitting antennas, on the receiving side containing the first and second receiving antennas, the outputs of which are connected to the first and second input the adder, and the main message demodulator, characterized in that a reference generator, a third amplitude modulator, the output of which is connected to the input of the third transmitting antenna, an encoding device, wherein the output of the reference generator is connected to the first input of the phase-manipulated signal generator, the three outputs of which are connected to the first inputs of the first, second and third amplitude modulators, and to the first input of the encoder, the three outputs of which are connected to the second inputs of the first , the second, third amplitude modulators, the second, third, fourth, fifth inputs of the encoder are respectively the first, second, third, fourth information system inputs, on the receiving side a third receiving antenna is introduced, the output of which is connected to the third input of the adder, a reference signal shaper, a decoding device, first, second, third synchronous detectors, and the outputs of the first, second and third antennas are connected respectively to the first inputs of the first, second and the third synchronous detectors, the second inputs of which are connected to the output of the driver of the reference signals, the output of the adder is connected to the input of the demodulator of the main message, the output of which is connected to the input the driver of the reference signals and with the input of the detecting device, the output of which is the first information output, the outputs of the first, second, third synchronous detectors are respectively the second, third and fourth information outputs of the system.

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