RU2356142C1 - Transmitting-receiving antenna device for multichannel system of cellular communication - Google Patents

Abstract

FIELD: physics, radio.

SUBSTANCE: invention is related to the field of radio engineering and may be used in multichannel systems of cellular communication. Antenna device comprises transmitting antenna array from N radiators, N¹ - channel power divider, inlet of which is inlet of device, receiving antenna array from M radiators and power divider, M inlets of which are connected accordingly to M radiators of receiving antenna array, and M¹ outlets of power divider are accordingly device outlets. In order to achieve technical result, the first diagram-forming circuit is introduced, which forms N distributions at the outlet, which are own vectors of channel power matrix, N inlets of which are connected accordingly with outlets of N¹ - channel power divider, which is arranged with controlled coefficient of division, N outlets of the first diagram-forming circuit are connected accordingly to N radiators of transmitting antenna array, power divider with M inlets and M¹ outlets is arranged in the form of the second diagram-forming circuit, which transforms system of M¹ own vectors of channel power matrix at the inlet from M radiators in system of M¹ independent outlets.

EFFECT: increased safety of processed items with simultaneous simplification of design and reduction of power inputs.

5 cl, 10 dwg

Description

The invention relates to radio engineering and can be used to implement the reception and transmission of information in multi-channel cellular communication systems.

To organize a multi-channel (Multiple-Input-Multiple-Output (MIMO) cellular communication system (CCC) and to increase its efficiency, it is necessary to fulfill at least two conditions: the presence of a multi-channel (multi-beam) radio path and multi-channel radio transmitting and receiving antennas.

The known [1] diagram of the antenna device (AU) MIMO CCC (Fig. 1), consisting of N transmitting and M receiving emitters separated by a multi-channel (multipath) space and connected to the output of the transmitting device and the input of the receiving device by respective power dividers. Multichannel mode is provided either by code or frequency division multiplexing. In this case, each of the channels forms any of the pairs of transmitting and receiving emitters.

There is also a known AU CCC scheme, in which the power divider of the transmitting antenna array (AR) has N 'inputs, and the power divider of the receiving AR is M' outputs (figure 2), i.e. power dividers are diagram-forming circuits (DOS) [3, 4].

In the circuit of FIG. 3, in addition to code and frequency, spatial separation of signals is also possible due to the formation of different radiation patterns (ND) for each of 1 ... N 'and 1 ... M' inputs.

In well-known DOS devices in receiving and transmitting ARs, they are selected from the condition of sufficient isolation between the radiation patterns of various beams in free space and do not take into account the features of the radio path ([4], p. 217, [5], p. 474, 482). Therefore, such multi-beam ARs are ineffective for MIMO CCC and are used to increase the signal-to-noise ratio at the input of single-channel CCC, as well as to organize and optimize the multi-sector mode of base stations in single-channel communication systems.

Known devices do not provide the ability to achieve maximum spectral efficiency for a number of reasons, the main of which are the inability to increase the number of independent channels M ', the maximum value of which is determined by the property of the radio path, and the inability to ensure equal channel gain in different channels.

An object of the invention is the creation of a transceiver antenna device that provides efficient operation in multi-channel communication systems with maximum spectral efficiency, as well as providing equal gain in the channels of a multi-channel communication system.

The problem is achieved in a transceiver antenna device for a multi-channel cellular communication system containing a transmitting antenna array of N emitters, N ¹ is a channel power divider, the input of which is the input of the device, a receiving antenna array of M emitters and a power divider, M inputs of which are connected respectively to M emitters of the receiving antenna array, and M ¹ outputs of the power divider are respectively the outputs of the device into which, according to the invention, the first diagram-shaped the output circuit N forming the eigenvectors of the channel energy matrix, N ¹ inputs of which are connected respectively to the outputs of N ¹ - channel power divider, which is made with an adjustable division ratio, N outputs of the first diagram-forming circuit are connected respectively to N emitters of the transmitting antenna lattice, a power divider with M inputs and M ¹ outputs is made in the form of a second diagram-forming circuit that converts the system M 'of eigenvectors of channel energy matrix at the input from M emitters to the system M ¹ independent outputs.

At the same time, channel gain equalizers are placed between the transmitting and receiving antenna arrays, consisting of the receiving and transmitting antennas with controlled radiation patterns, between which a controlled power amplifier is connected.

In addition, channel reflectors are installed in each radio channel, each of which consists of a re-reflecting antenna array loaded onto a controllable reactive multipole, while the re-reflecting reflector arrays of the reflectors are multi-beam with switchable radiation patterns, and the controllable reactive multipole is made in the form of an adjustable power amplifier.

The invention is illustrated by drawings. Figure 1, 2 and 3 shows the structural electrical circuits of analogues; figure 4 shows the dependence of spectral efficiency on the number of channels of the communication system; 5 is a structural electrical diagram of a transceiver antenna device for a multi-channel cellular communication system; 6 is an embodiment of a divider 2 with an adjustable division ratio; figure 7 presents a view of the radiation pattern of the transmitting emitters 1; on Fig - structural electrical diagram of a device with re-reflectors on the track; figure 9 - antenna array with switchable radiation patterns; figure 10 is a structural electrical diagram of a device with equalizers of channels.

The transceiver antenna device for a multi-channel cellular communication system (Fig. 5) comprises a transmitting antenna array 1 of N emitters, N ¹ a channel power divider 2, the input of which is the input of the device, a receiving antenna array 3 of M emitters and a power divider 4, M inputs which are connected respectively to M emitters of the receiving antenna array 1, and M ¹ outputs of the power divider 4 are respectively the outputs of the device, the first diagram-forming circuit 5, forming at the output of N distributions, which are with the natural vectors of the channel energy matrix, N ¹ inputs of which are connected respectively to the outputs of N ¹ - channel power divider 2, which is made with an adjustable division ratio, N outputs of the first diagram-forming circuit 5 are connected respectively to N emitters of the transmitting antenna array 1, the power divider 4 with M M inputs and ^one output is formed as a second beamforming circuit transforming system M 'eigenvectors of the channel matrix at the input of energy from the emitters in the M ¹ M independent s outputs.

Between the transmitting and receiving antenna arrays 1, 3 (Fig. 10) are placed channel gain equalizers 6, consisting of series-connected receiving and transmitting antennas 7 and 8 with controlled radiation patterns, between which a controlled power amplifier 9 is connected.

Q channel reflectors 10 are installed in the radio channel, each of which consists of a re-reflecting antenna array 11 loaded on a controllable reactive multipole 12, while the re-reflecting antenna arrays 11 of the reflectors are multipath with switchable radiation patterns, and the controllable reactive multipole 12 is made in the form of an adjustable power amplifier .

Spectral efficiency (SE) With _{M '} is the most important parameter of the CCC. When organizing M 'independent and identical (in terms of channel amplifications | µ _i | ² (| µ _i | ² = | µ ₁ | ² , i = 1 ... N)) channels, the SC SCC reaches a maximum equal to

where ρ = Pc (A) / Psh (B) is the signal-to-noise ratio at the input of the m-th receiving antenna located at point B with the radiation power of the transmitting antenna Pc (A) (A is the location point of the transmitting antenna).

The greatest potential gain of MIMO systems γ in the presence of M 'is equivalent in magnitude | µ _i | ² (| µ _i | ² = | µ ₁ | ² , i = 1 ... N) channels compared to a single-channel path is determined by the ratio

The dependence of γ _max on the number of channels M 'is shown in Fig. 4 for various values of ρ | μ ₁ | ² . As can be seen, γ _max grows both with an increase in the number of channels M 'and with an increase in ρ | μ ₁ | ² . For unequal channels, it can be shown that the maximum SC is determined by the relation

, поступающей от передатчика на вход m канала в соответствии с закономand achieved by providing power

coming from the transmitter to the input of the channel m in accordance with the law

Numerical modeling of relations (3) - (4) shows that if the channels are not equivalent in magnitude | µ _i | ² , then the gain in the solar cell γ decreases rapidly and tends to unity as the difference between the values of | μ _i | ² .

From the relations (1) - (3) it follows that the main directions of increasing the SS of the SS are:

- ensuring optimal multi-channel operation on the CCM multi-path radio path;

- an increase in the number of independent channels of the radio path;

- equalization of channel gain in multi-channel radio paths;

- increase in energy (values ρ | µ _i | ² ) of each i-th channel.

To implement the above conditions for increasing SE, the following is proposed.

In the presence of a multichannel (multipath) radio path, it is necessary to create independent amplitude-phase distributions in N-transmitting emitters N ¹ , each of which corresponds to the structure of the eigenvector T _{m '} 〉 of the energy channel matrix W, defined by the relations

where T is the matrix of orthonormal vectors of the matrix W.

Accordingly, the energy channel matrix W is determined by the expression W = H * _t H, where H is the field channel matrix, determined taking into account the characteristics of the radio path, type of AR, and the interaction of emitters in the AR.

To create N ¹ own distributions at the input of the transmitting AR into the path of the transmitting AR, use a controlled power divider 2 and a diagram-forming circuit (DOS) 5 (Fig. 4), N outputs of which are connected respectively to N transmitting emitters 1, and to N ^{1 of} its inputs from the transmitter through a controlled power divider 2, a signal is supplied, the power of which is determined by the ratio (4).

The division power in divider 2 must be controlled for the following reason. As the analysis of the properties of multi-channel radio paths shows, the channel amplification values | µ _i | ^{2 of} many channels substantially depend on the relative positions of points A and B, i.e. coordinates of the transmitter and receiver (subscriber). Therefore, when working with various subscribers and when moving one of the subscribers, the value | µ _i | ² can change rapidly, and in accordance with expression (4), it is necessary to change the optimal distribution of power transmitted to each channel.

DOS 5 of the transmission path differs from the widely used DOS in multipath ARs, as the structure of the excitation vectors at the input of the emitters in the MIMO CCC must satisfy relation (4), which takes into account the properties of radio paths, while for “ordinary” multipath ARs, the parameters of the radio path are not taken into account in the formation of multipath radiation paths.

To separate the channels in the receiving path is a diagram-forming circuit (DOS) 4 of the receiving antenna (figure 4), which converts each m = 1 ... M 'of the eigenvector of the incident field to one of the M outputs of this DOS. Similarly, as for DOS 5 of the transmitting antenna, the receiving DOS 4 differs from the widely used DOS in multipath ARs, because the structure of the excitation vectors on the emitters of the receiving AR must satisfy relation (4), taking into account the properties of the radio path.

So, for example, for MIMO CCCs with a two-beam path formed due to diffraction by buildings, and with two transmitting (N = 2) and two receiving (M = 2) emitters, the self-excitations at the inputs of the transmitting and receiving emitters are proportional to in-phase (1, 1) _t and antiphase (1, -1) _t vectors. DOS 4 and 5 of the receiving and transmitting AR looks like a sum-difference divider from the inputs. Figure 6 shows one of the options for such a divider, consisting of 3 dB directional coupler and a fixed phase shifter 90 °. The two-beam beam of the transmitting and receiving antennas is described in this case by the relations

respectively for in-phase and antiphase channels.

The view of these DNs is shown in Fig.7. When such MDs are formed for transmission and reception by SC, the CCC increases in accordance with relations (1) - (2) to almost 3 dB at ρ | µ ₁ | ² ≥30 dB compared to single path. Note that the option of a two-beam AR in free space and its DNs are shown in [5, Fig. 19.11] and fundamentally differ from DOS and DNs shown in Fig. 5 and Fig. 6.

For homogeneous (few-beam) or low-channel paths, an increase in SE can be achieved by artificially increasing multichannel (multipath) by setting additional re-reflectors 10 on the path Q (Fig. 8). Each reflector 10 represents a system of emitters 11 loaded on a reactive controlled multipole 12. In the particular case, the antennas of the reflectors are multipath ARs with switched DNs (Fig. 9). The use of controlled multipoles makes it possible to form two beams for reception and transmission with different directions of maximums of the beam.

To align the channel gain at the receiving points in multi-channel paths, channel equalizers are installed on the path, consisting of a receiving and transmitting antenna 7, 8 connected by a feeder path and a power amplifier 9 in this path with an adjustable gain (Fig. 10). Power amplifiers can also be located in reactive multipoles of additional reflectors.

When using M 'equalizers 6 (according to the number of independent channels) with adjustable gain and controlled gain, it is possible to completely equalize the channel gain and gain in the SC in accordance with expression (2). The use of power amplifiers 9 in channel equalizers can also increase the value of ρ | µ _i | ² , which, in accordance with (2), also leads to an increase in the SC of the CCC without increasing the power of the main transmitting device. The latter circumstance has a positive effect on environmental safety and reducing the level of mutual interference.

When choosing a beam in channel reflectors and equalizers from the condition of maximum isolation with the field of the signal transmitted through other channels, the maximum efficiency of equalizers is achieved, namely, with a given upper limit of the gain of the amplifier located in the equalizer, the maximum equal channel gain on all channels is ensured, and therefore, the maximum SC of the CCC.

Information sources

1. David Gesbert, Mansoor Shaft; Da-shau Shiu, Peter J. Shith, Ayman Naguib. From Theory to Practice: An Overview of MIMO Space-Time Coded Wireless System, IEEE Journal on selected areas in communications, vol. 21, no. 3, April 2003, p. 281-302.

2. Wei Zhang, Xiang-Gen Xia, Khaled Ben Letaief. Space-Time / Frequency Coding for MIMO-OFDM in Next Generation Broadband, IEEE Wireless Communications Magazine, June, 2007.

3. V. Zaharov, F. Casco, O. Amine. Smart antenna base station beamformer for mobile communications, journal of radioelectronics, No. 11, 2000.

4. Yu.A. Gromakov, O. O. Vasilenko. Digital and antenna arrays for cellular mobile communication systems. Pages 132-219 in the book "Active phased antenna arrays", ed. D.I. Voskresensky, A.I. Kanaschenkova. M .: Radio engineering, 2004, 488 p.

5. Voskresensky D. I., Gostyukhin V. L., Maksimov V. M., Ponomarev L. I. Microwave antennas and devices, M .: MAI, 1999, 527 p.

Claims (5)

1. Transceiver antenna device for a multi-channel cellular communication system, comprising a transmitting antenna array of N emitters, N ¹ is a channel power divider, the input of which is the input of the device, a receiving antenna array of M emitters and a power divider, M inputs of which are connected respectively to M emitters receiving antenna array, and M ^{1 the} outputs of the power divider are respectively the outputs of the device, characterized in that the first diagram-forming circuit is introduced, forming at the output of the N distribution lines, which are eigenvectors of the channel energy matrix, N ¹ inputs of which are connected respectively to the outputs of the N ^1- channel power divider, which is made with an adjustable division factor, N outputs of the first diagram-forming circuit are connected respectively to N emitters of the transmitting antenna array, the power divider with M inputs and M ¹ outputs made in the form of a second diagram-forming circuit, converting a system of M ¹ eigenvectors of the channel energy matrix at the input from M emitters to Stem M ¹ independent outputs. 2. The transceiver antenna device according to claim 1, characterized in that between the transmitting and receiving antenna arrays are placed channel gain equalizers, consisting of a receiving and transmitting antenna with controlled radiation patterns, between which a controlled power amplifier is connected. 3. The transceiver antenna device according to claim 1, characterized in that channel reflectors are installed in each radio channel, each of which consists of a re-reflecting antenna array loaded onto a controllable reactive multipole. 4. The transceiver antenna device according to claim 3, characterized in that the reflective antenna arrays are multi-beam with switchable radiation patterns. 5. The transceiver antenna device according to claim 3, characterized in that the controllable reactive multipole is made in the form of an adjustable power amplifier.

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