JPH02174321A - Transmitter-receiver using polarized wave in common for mobile station of mobile body satellite communication - Google Patents

Abstract

PURPOSE:To attain effective utilization of a frequency by receiving and comparing an incoming call of a zone in which a mobile station is possibly resident and other control channel signal to specify the resident zone, and setting a transmission-reception polarized wave to a designated polarized wave of the zone. CONSTITUTION:The transmitter-receiver is provided with a circularly polarized wave radiation element 12 and a feeding switch 17 to switch the relative phase between two feeding points, or a paralyzer to be used as the circularly polarized wave radiation element 12 and a linearly polarized wave primary radiation element capable of radiating both horizontal and vertical polarized waves selectively to be used as the feeding switch 17. Then the right rotatory and left rotatory circularly polarized waves are selected, and an incoming call signal of one and plural zones and other control channel signal in which the mobile station is possibly resident are received by an antenna circuit and a reception circuit 15, respectively, and the reception intensity is compared with a reception intensity comparator circuit 18 to specify the resident zone and the transmission reception polarized wave is set to the designated polarized wave of the zone. Thus, the frequency is effectively utilized.

Description

[Detailed Description of the Invention] "Industrial Application Field" This invention uses shared polarized waves for communication between mobile stations on the ground or between fixed stations on mobile stations via a 16 ml repeater installed on a geostationary satellite. The present invention relates to a polarization sharing transmitter/receiver for a mobile station in a multi-beam mobile satellite communication system.

[Prior Art J] Figure 6 shows the zone of a link (mobile link) between a mobile station and a geostationary satellite in a conventional multi-beam mobile satellite communication system. The service area is divided into a plurality of zones 10, and a mobile station 11 moves between these zones 10. The numbers in zone 10 are the numbers assigned to each zone, such as assigned frequencies, and the polarization uses right-handed or left-handed circularly polarized waves.

The configuration of the transmitter/receiver of the mobile station 11 is shown in FIG.

The circularly polarized wave radiating element 12 is connected to a diplexer 13, and a transmitting circuit 14 and a receiving circuit 15 are connected to the diplexer 13.

Conventionally, mobile links for this type of satellite communication system include:
A portion of UHF, L band, and S band frequencies i;) is allocated. These banded bandwidths are not wide enough to meet expected future demand, so we aim to increase the number of accommodated channels by forming regional zones as shown in Figure 6 and reusing frequencies. A multi-beam system has been considered and is being put into practical use in many countries.

Regarding polarization, in order to reduce deterioration in line quality due to rotation of polarization due to surrounding embedding on the propagation path or receiving side,
It is a circularly polarized wave, and only one polarized wave is used. Therefore, even if the mobile station moves to a zone irradiated with another beam, there is no need to switch the polarized wave used. Therefore, the transmitter/receiver 3 of the mobile station is not configured to automatically switch the polarization used as the mobile station moves between zones, as shown in FIG.

At this time, in order to suppress the amount of interference between beams using the same frequency, Iπ before the frequency allocation for each beam is set at approximately the same interval between two beams, taking into account the radiation pattern of the antenna onboard the satellite. It is common practice to allocate frequencies.

``Problem to be solved by the invention'' If demand increases further in the future, in order to make even more effective use of limited frequency resources, the repetition of the same frequency will be changed from the conventional 2-beam spacing to 1-beam spacing. A request to change arises. One effective way to achieve this without increasing the amount of inter-beam interference is to use mutually different polarizations between beams that are closest to each other among beams that use the same frequency. At this time, since either right-handed or left-handed polarization is assigned to each zone, the mobile object must select the polarization assigned to the destination zone when moving to another zone. Furthermore, this selection function needs to be automated in preparation for receiving and responding to incoming call signals that occur irregularly.

As described above, when sharing polarized waves, an automatic polarization selection function is required, which is inconvenient with conventional mobile station transmitter/receiver technology that transmits and receives only one polarized wave.

This invention was made to solve the above-mentioned problems, and in a multi-beam mobile satellite communication system that shares polarization, it is possible to specify either right-handed or left-handed polarization for each wireless zone of the mobile link. One object of the present invention is to provide a dual polarization transmitter/receiver for a mobile station that can automatically detect and select the designated polarization of the zone in which the mobile station is located.

"Means for Solving Problems" The dual polarization transmitter/receiver for a mobile station in mobile satellite communication according to the present invention includes a circularly polarized wave radiating element capable of selectively receiving both circularly polarized waves in the mobile station; It is equipped with a radio equipment Djh consisting of an antenna system consisting of a power supply switching circuit for switching polarization, a reception strength comparison circuit, and other transmitting/receiving circuits, and by these, one or more zones where a mobile station may be located. The system receives and compares incoming calls and other control channel signals, identifies the zone in which it is located, and sets the transmitting and receiving polarization to the designated polarization for that zone.

"Function" The polarization shared transmitter/receiver for a mobile station for mobile satellite communication according to the present invention is provided with a circularly polarized wave radiating element and a feed switching device for switching the relative phase between two feed points of the radiating element. Alternatively, by arranging a polarizer as a circularly polarized wave radiating element and providing a linearly polarized primary radiating element that can selectively radiate horizontal and vertical circularly polarized waves as a feeding switch, it is possible to select between right-handed and left-handed circularly polarized waves. The antenna circuit and the receiving circuit respectively receive incoming calls and other control channel signals of 1 or 1M zones in which the mobile station may be located, and the receiving strength is compared by the receiving strength comparison circuit. This method specifies the existing zone and sets the transmission and reception polarization to the designated polarization of that zone.

"Embodiment" FIG. 1 shows an embodiment of the present invention, and parts corresponding to those in FIG. 7 are given the same reference numerals.
0° hybrid 16 is connected, 90' hybrid 1
゛16 and diplexer! A power supply cutoff unit 17 is connected between the receiving circuit 15 and the receiving circuit 15, and a receiving strength comparing circuit 18 is connected to the receiving circuit 15.

When the right-handed circularly polarized wave (RIICP) is incident on the circularly polarized wave radiating element 12, its output appears on the R side of the output end of the 90@hybrid 16, and when the left-handed circularly polarized wave (LHCI') is incident,
Its output appears on the L side of the 90° hybrid 16.

The 90° hybrid 1G is for feeding power to the feeding points of the circularly polarized wave radiating element 12 with a phase of 90° above each other.

The power supply switch 17 connects either the 1z or L power supply end of the 90" hybrid 16 to the transmission/reception system using the polarization selection control signal from the reception strength comparison circuit 18. Transmission/reception is performed by selecting R or L. The polarization can be determined.The diplexer 13 is for sharing one antenna for transmission and reception.The transmission 3 circuit 14
Performs modulation, frequency conversion, and amplification.

The receiving circuit 15 demodulates each carrier frequency and outputs the signal strength thereof. The reception strength comparison circuit 18 is connected to the power supply switch 1
It outputs a polarization switching control signal for operating the receiver circuit 7, and monitors and compares the reception strength signal output from the receiver circuit 15.

The operation of the embodiment shown in FIG. 1 when a mobile station moves from a - zone to an adjacent zone in the zone configuration example shown in FIG. 5 will be described. In addition, in FIG. 5, R and L mean the designated polarization of the zone.

When the mobile station 11 moves beyond the boundary area with the adjacent zone, the reception strength of the mobile station 11 decreases below the reference level, and the reception strength comparison circuit 1 determines that the mobile station 11 is moving between zones.
Detected at 8. Note that the received waves at this time can be radio waves of incoming calls and other control channel signals emitted from satellites for each zone. In order to identify which of the multiple zones adjacent to the zone in which it was previously located, i.e. the frequency band and polarization assigned to that zone, Radio waves of incoming calls and other control channel signals are sequentially received by combining their assigned frequencies and polarizations. At this time, the polarization is determined by switching the polarization of the circularly polarized wave radiating element 12 by the operation of the feeding switch 17 using the polarization switching control signal of the reception intensity ratio rotation r31B, and the frequency is determined by the local oscillation frequency of the receiving circuit 15. They are switched by changing, etc. As a result, the reception strength comparison circuit 18 detects the combination of frequency and polarization when the reception strength is the strongest, specifies the location zone, and selects the specified polarization.

In the above embodiment, the negative circularly polarized wave radiating element is shared for transmission and reception, but as shown in Fig. 2, the negative circularly polarized wave radiating element is used exclusively for reception, and the other circularly polarized wave radiating elements are also used for reception. By using it only for transmission, the diplexer 13 is unnecessary and the power supply switching 2
A similar effect can be obtained by arranging 317 in both transmission and reception systems.

Moreover, as shown in the embodiment of FIG.
A polarizer 19 and a linearly polarized radiation element 21 are used instead of the 0' hybrid, and a power supply switch is also used! A similar effect can be obtained by configuring that the feeding end of the linearly polarized wave radiating element 21 is switched by 7 to switch the polarization of the linearly polarized wave radiating element 21. As specific examples of the polarizer 19 shown in FIG. 3, FIG. 4 shows examples of a mean line polarizer 19a and a cross dipole polarizer 19b. , a conductor pattern formed on a dielectric substrate, which is designed so that when radio waves pass through it, there is a phase difference of 906 between the two components E // and E. Therefore, it works as a converter between circularly polarized waves and linearly polarized waves. In other words, a linearly polarized wave with a plane of polarization at an angle of 45° with respect to the direction along the crank-shaped conductor line is a right-handed polarized wave, while a 135° polarized wave is a right-handed polarized wave.
Each linearly polarized wave with a plane of polarization forming an angle of is converted to a left-handed polarized wave. In Fig. 3, ■ means the former linearly polarized wave and its feeding end, H means the latter linearly polarized wave and its feeding end, R means right-handed circularly polarized wave, and L means left-handed circularly polarized wave. means. Further, the cross dipole polarizer 19b is a fourth
As shown in FIG. 3(b), a phase difference of 90° is provided between one dipole and the other dipole, and it has the same effect as the mean line polarizer.

"Effects of the Invention" As described above, according to the present invention, a mobile station automatically selects either right-handed or left-handed polarized waves assigned to the zone in which it is located. Even when a mobile station moves between zones in a shared multi-beam mobile satellite communication system, it automatically continues to be able to transmit and receive data, contributing to smooth communication. This has the great effect of facilitating the introduction of a multi-beam mobile satellite communication system that shares polarized waves and is superior in effective frequency use compared to the previously used mobile satellite communication system.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one embodiment of this invention, Fig. 2 is a block diagram showing another embodiment of this invention, and Fig. 3 is a circularly polarized wave radiating element in this invention and its radiating element. 4 is a diagram showing a specific example of the polarizer in FIG. 3, and FIG. 5 is a diagram showing a zone configuration of a mobile satellite communication system when polarized waves are shared. 6 is a diagram showing a zone configuration of a conventional mobile satellite communication system, and the seventh leap is a diagram showing a conventional mobile station transmitting/receiving device.

Claims (4)

[Claims] (1) A receiving circuit that demodulates each carrier frequency and outputs the signal strength corresponding to the radio frequency band assigned to each zone of the mobile link, and converts and amplifies the modulated wave of voice or data to the carrier frequency. A transmitter/receiver for a mobile station for mobile satellite communications, which is equipped with a transmitting circuit for transmitting a signal, a circularly polarized wave radiating element that selectively radiates both right-handed and left-handed polarized waves, and two power feeds for the circularly polarized wave radiating element. a power supply switching device disposed between the circularly polarized wave radiating element and the receiving circuit and the transmitting circuit so as to switch the relative phase between points; and a receiving strength comparison circuit that compares each receiving strength output of the receiving circuit. These are used to receive and compare incoming calls and other control channel signals in one or more zones in which the mobile station may be located, identify the zone in which the mobile station is located, and change the transmitting and receiving polarization to the designated polarization of that zone. A polarization shared transmitting/receiving device for a mobile station for mobile satellite communication, characterized in that it is set to a polarized wave. (2) The polarization shared transmitting/receiving device for a mobile station for mobile satellite communication according to claim 1, wherein the feed switching device is disposed between a circularly polarized wave radiating element used for both transmission and reception and a diplexer. . (3) The circularly polarized wave radiating element is provided for transmitting and for receiving, and the first feeding switch is provided between the circularly polarized wave radiating element for transmitting and the transmitting circuit, 2. The polarization shared transmitting/receiving device for a mobile station for mobile satellite communication according to claim 1, wherein the second feed switching device is provided between the polarization radiating element and the receiving circuit. (4) A polarizer is provided as the circularly polarized wave radiating element, and a linearly polarized primary radiator that selectively radiates both horizontal and vertically polarized waves is provided as the feeding switch. 4. A shared polarization transmitter/receiver for a mobile station for mobile satellite communication according to 2 or 3.