KR100252490B1 - Radio communications system using satellite compensating for relay delay of satellite - Google Patents

Abstract

PURPOSE: A wireless communication system using satellite compensating repeating delay is provided to compensate a repeating delay of satellite so as to execute traffic carrying successfully all the time. CONSTITUTION: A satellite repeating signals located above a service area. A repeater amplifies and transmits signals in service frequency band transmitted from each terminal and transmits a received signal after amplification. A repeater base station for multiple satellites converts and transmits the signals from the repeater into frequency for the satellite. The repeater base station for multiple satellites has up down converter for terminals which changes signals transmitted from the satellite into signals in service frequency band. A down converter used for the repeater base station for multiple satellites. A time delay compensating unit compensates a time delay in accordance with a satellite delay coefficient set up for compensating the repeating delay of the satellite after inputting the signals from the down converter. The first pseudo noise offset converter converts a pseudo noise offset in accordance with the output of the time delay-compensating unit. An intermediate frequency process block processes the output of the first pseudo noise offset converter. The second pseudo noise offset converter converts the pseudo noise offset in advance in accordance with the satellite delay coefficient set by the inputting the intermediate frequency process block.

Description

Wireless communication system using satellite to compensate for relay delay of satellite

The present invention relates to a wireless communication system, and more particularly, to a wireless communication system using a satellite capable of compensating a relay delay of a satellite and always completing a call communication in a wireless communication system using a satellite as a relay device.

Conventional radiotelephone and mobile communication is divided into TRS and CT-2 services in 800 MHz band, advanced mobile phone service (AMPS) in 800-900 MHz band, time division multiple access (TDMA), and code division. Cellular using code division multiple access (CDMA), personal communication services (PCS) in the 1.8GHz band, and GMPCS using satellites such as iridium and ICO. They form a transmission path between the subscriber and the switching center using radio technology in a designated frequency band. That is, a terminal is required at the subscriber side and a remote base station is provided at the switching station side for the radio transmission path configuration. These terminals and base stations are capable of modulating and amplifying the necessary information into radio frequency signals and transmitting them to free space, and receiving and demodulating the signals damaged by free space loss and radio section fading, and providing demodulated signals as necessary information. Has

Therefore, the transmission distance between the base station and the terminal is limited by the size of the output between each other, and the transmission distance limited by the propagation loss of the radio section leads to the limitation of the service area. In order to overcome the propagation limitation of the base station, a frequency reuse scheme and a CDMA code reuse scheme may be applied, and a cellular scheme that uses a cell repeatedly by limiting a cell radius, which is a coverage of a base station, may be used.

This cellular method can secure a large number of communication channels and can reduce the output of the terminal and improve the call quality due to the small coverage. On the other hand, a large number of base stations are needed to cover a specific area. Since the higher the frequency, the higher the transmission loss of the wireless section, the PCS in the 1.8 GHz band needs a larger number of base stations than the cellular mobile communication in the low frequency 800 MHz band, for example, to obtain the same coverage.

Currently, services in the 1 GHz band are depleted by the allocation of existing frequencies, and new service frequencies are gradually designated as high frequency bands according to ITU-R's frequency allocation and national frequency policies. Therefore, a larger number of base stations are required than existing base stations, and in particular, in a mountainous terrain, the base station coverage is smaller than the open area, and thus a larger number of base stations are required for perfect service coverage. Such a large number of base stations lead to an increase in investment costs, and there is a problem that leads to a huge financial burden when a mobile operator wants to expand coverage or when a new operator establishes a wireless network.

In addition, since all base stations must be connected to a base station controller and a switch with a dedicated line for communication, network construction costs are increased, and in particular, the installation of such a dedicated line in a remote area such as a mountainous terrain has become a difficult factor for network construction. .

In order to solve the problems of the conventional wireless communication system as described above, a block diagram of a wireless communication system using a satellite of the applicant No. 97-82059 filed December 31, 1997 is shown in FIG.

The wireless communication system using the satellite shown in FIG. 1 includes a satellite 14 for relaying a signal located in a service area, and amplifies a signal of a service frequency band transmitted from each subscriber station 20. Outputs the signal received from the repeater 18 and the repeater 18 for outputting and amplifying the signal received from the repeater 18 and the repeater 18 by converting the signal output from the satellite 14 and the satellite 14 And a plurality of satellite relay base stations each having an up-down converter 16 for a terminal for receiving and converting the signal into a signal of a service frequency band.

In addition, the wireless communication system using the satellite, a plurality of base stations for receiving a signal transmitted from the satellite 14, converts it into a signal of the service frequency band and outputs it, and converts the received signal into a satellite up-frequency signal for transmission And a central station connected to the up-down converter 10 and the base station controller / switch 13 and having a plurality of base stations 12 for inputting and processing signals output from the up-down converter 10 for the base station.

Referring to FIG. 1, a signal transmitted from a subscriber station 20 in a specific region is received and amplified by the corresponding repeater 18, and then an uplink frequency signal for a satellite (eg, 14 GHz) is applied to the up-down converter 16 for the corresponding terminal. Large signal) and is sent out.

The satellite 14 receives this, converts it into a satellite down frequency signal (for example, a 12 GHz band signal), and transmits the converted signal. The up-down converter 10 for the base station in the central station receives this and converts the received signal into a signal of a general service frequency band (a signal of 1.7 GHz), and the corresponding base station 12 in the central station is connected to an E1 dedicated line. After processing the signal using the base station controller / switch 13, the base station 12 outputs a signal of the service frequency band (1.8 GHz band signal). This signal is converted into a satellite uplink frequency signal (for example, 14 GHz band signal) and transmitted by the up-down converter 10 for a base station in the central station, and the satellite 14 receives the satellite downlink frequency signal (for example, 12 GHz band) and transmits the signals to the satellite relay base stations 16 and 18. The up-down converter 16 for the terminal in the satellite relay base station receives this signal and converts it into a signal of a service frequency band (for example, a 1.8 GHz band signal), which is amplified by the corresponding repeater 18, and then the coverage. It is transmitted to the prospective subscriber station 20 via an antenna (not shown).

In the wireless communication system using the above-mentioned satellites, only the satellite relay base stations 16 and 18 need to be installed in the service need area. It is possible to easily establish a nationwide wireless communication network without a region, to reduce the number of base stations required and to reduce the cost of the wireless communication network.

However, in the wireless communication system using the satellite of FIG. 1, since the satellite is used as a relay, a relay delay occurs due to the satellite.

In other words, in order to relay mobile communication using geostationary satellites, time delay between satellite and terrestrial base station must be overcome. This time delay is about 125ms, which is 250ms when considering uplink and downlink, and when the base station or subscriber station requests confirmation of receiving a message, the total time delay reaches about 500ms. Therefore, when the base station or the subscriber station checks the confirmation request signal using the internal timer, call setup may fail due to time delay due to satellite relay.

In addition, satellites above 36,000 kilometers of geostationary trajectory include inclination distances in areas other than the equator, and the delay according to this distance is twice the distance from the ground to the satellites. Due to this delay, the CDMA pseudo noise code (hereinafter referred to as PN code) transmitted by the base station and the subscriber station is recognized as a completely different PN code. Due to such a change in the PN code, the call setup attempt in the terminal or the base station may fail.

The technical problem to be achieved by the present invention is to provide a wireless communication system using a satellite that can always complete the communication by compensating the relay delay of the satellite in a wireless communication system using the satellite as a relay equipment.

1 is a block diagram of a wireless communication system using a general satellite.

2 is a block diagram of a wireless communication system using a satellite to compensate for relay delay of a satellite according to a first embodiment of the present invention.

3 is a block diagram of a wireless communication system using a satellite to compensate for relay delay of a satellite according to a second embodiment of the present invention.

4 is a block diagram of a wireless communication system using a satellite to compensate for relay delay of a satellite according to a third embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

22 ... satellite, 24 ... up-down converter for repeater,

26 repeaters, 28 subscriber terminals,

29 ... satellite relay station, 30 ... up converter for base station,

32 ... down converter for base station, 34 ... base station,

36 ... second PN offset transducer, 38 ... time delay compensator,

40 ... first PN offset converter, 42 ... intermediate frequency processing block.

In the wireless communication system using a satellite to compensate for the relay delay of the satellite according to the present invention for achieving the above object, in the wireless communication system for processing the communication to the terminal in each cell by dividing the service area into a cell, the service area A satellite located above the satellite for relaying signals; Amplifying and outputting a signal of a service frequency band transmitted from each terminal, amplifying and receiving a signal received from each terminal, and converting the signal output from the repeater into an uplink frequency signal for satellite and transmitting the signal; A plurality of satellite relay base stations each having an up-down converter for a terminal for receiving the transmitted signal and converting the signal into a signal of a service frequency band; And a plurality of base station down converters for receiving the signal transmitted from the satellite, converting the signal into a signal of the service frequency band, and outputting the signal, and a plurality of base station up-converters for converting the received signal into an uplink frequency signal for satellite transmission. A time delay compensator that compensates for the time delay according to a satellite delay constant set to compensate for the relay delay caused by the satellite by inputting a signal output from the downconverter for converting a pseudo noise offset according to the output of the time delay compensator. Inputs an intermediate frequency processing block for processing the output signal of the first pseudo noise offset converter and the first pseudo noise offset converter and a signal output from the intermediate frequency processing block, and converts the pseudo noise offset in advance according to the set satellite delay constant. A second output to the upconverter for the base station And a central station having a plurality of base stations having a pseudo-noise converter.

The satellite relay base station may further include a pilot signal generator for transmitting a set pilot signal, and the central station detects the pilot signal input through the satellite to calculate a delay due to drift of the satellite and then delays the delay constant. Preferably, the apparatus further includes a satellite drift delay compensator that compensates for the delay caused by the satellite drift by correcting the value.

In addition, the wireless communication system using a satellite to compensate for the relay delay of the satellite, after detecting the pseudo noise code in the signal output from the down converter for the base station to calculate the delay due to the drift of the satellite, the delay constant value It is preferable to further include a pseudo-noise code recognition device that compensates for the delay caused by the satellite's trip by correcting.

In addition, the radio signal of the service band is preferably a radio signal of the personal communication service band.

In addition, the radio signal of the service band is preferably a radio signal of the cellular phone service band.

In addition, the radio signal of the service band is preferably a radio signal of the IMT-2000 communication service band.

In addition, the radio signal of the service band is preferably a radio signal of a radio calling communication service band.

Hereinafter, exemplary embodiments of a wireless communication system using a satellite to compensate for relay delay of a satellite according to the present invention will be described with reference to the accompanying drawings.

2 is a block diagram of a wireless communication system using a satellite to compensate for relay delay of a satellite according to a first embodiment of the present invention. In a wireless communication system using a satellite that compensates for relay delay of a satellite shown in FIG. 2, a wireless communication system that divides a service area into cells and processes communication for subscriber terminals in each cell, wherein A satellite 22 for locating and relaying a signal, and a repeater 26 for amplifying and outputting a signal of a service frequency band transmitted from the subscriber terminal 28 and amplifying the received signal to the subscriber terminal 28; And an up-down converter 24 for a terminal for converting and outputting a signal output from the repeater 26 into a satellite uplink frequency signal, receiving a signal transmitted from the satellite 22, and converting the signal into a signal of a service frequency band. A plurality of satellite relay base stations 29 are provided.

In addition, the wireless communication system using a satellite to compensate for the relay delay of the satellite shown in Figure 2, the plurality of base station down-converter (10) for receiving a signal transmitted from the satellite 22, converts it into a signal of the service frequency band ( 32) and a signal output from the plurality of base station up-converters 30 and the base station down-converter 32, which converts the received signal into a satellite up-frequency signal and transmits the same, to relay relay delay caused by the satellite 22. Converting PN Offset to Pseudo Noise Offset (PN Offset) According to Outputs of Time Delay Compensator 38 and Time Delay Compensator 38 Compensating Time Delay According to Set Satellite Delay Constant Input signals output from the intermediate frequency processing block 42 and the intermediate frequency processing block 42 for processing the output signals of the first PN offset converter 40 and the first PN offset converter 40 And a plurality of base stations 34 including a second PN offset converter 36 for converting the PN offset according to the set satellite delay constant and outputting the converted PN offset to the upconverter 30 for the base station.

In the wireless communication system using a satellite that compensates for the relay delay of the satellite according to the present invention configured as described above, the base station 34 processes the relay delay caused by the satellite 22 to a predetermined constant value so that the second PN offset converter 36 is processed. By converting the PN offset by the &lt; RTI ID = 0.0 &gt;), CDMA &lt; / RTI &gt; When the signal is received at the subscriber station 28 via the satellite 22, the subscriber station 28 matches the information obtained from the pilot signal with the information obtained from the sync channel so that the traffic channel is established through the paging channel. You can be assigned and talk.

In addition, since the relay delay caused by the satellite 22 described above occurs when the signal transmitted from the subscriber station 28 is received by the base station 34 through the satellite 22, the base station 34 is connected to the satellite 22. Compensating the relay delay caused by satellite 22 by converting the PN offset of the received signal into a PN offset that takes into account the time delay constant rather than the received state using the time delay compensator 38 and the first PN offset converter 38. do.

The first PN offset converter 40 and the second PN offset converter 36 convert the CDMA long code and the short code and expand the search window to convert the PN code. That is, the long code is adjusted in units of 80 ms, and the delay is adjusted in units of 1 chip / 8 register by short code conversion, and the slight change extends the search window to transmit and receive the PN code.

On the other hand, as described in the first embodiment, to compensate for the relay delay caused by the satellite 22 on the stationary orbit by constant processing, the relay delay can be accurately compensated only if the stationary satellite is stopped. However, the satellite 22 continuously changes its position and angle due to perturbation and attitude control between the moon and the earth. Since even a slight change in the angle of the satellite causes significant delay, it is desirable to compensate for the delay due to the drift of the satellite 22 in addition to compensating the relay delay with a constant.

3 shows a second embodiment of the present invention that compensates for delays due to satellite drift. In the wireless communication system using a satellite to compensate for the relay delay of the satellite according to the second embodiment of the present invention shown in Figure 3, the satellite 50 for relaying a signal located over the service area, and the subscriber terminal ( Amplifying and outputting a signal of a service frequency band transmitted from 56), amplifying the received signal, and transmitting the signal to the subscriber station 56 and generating a predetermined pilot signal and outputting the signal output from the repeater 54 and repeater 54. A plurality of satellite relay base stations (57) including a terminal up-down converter (52) for converting and transmitting a satellite uplink frequency signal and receiving a signal transmitted from the satellite (50) and converting the signal into a signal of a service frequency band; Equipped.

In addition, the wireless communication system using a satellite to compensate for the relay delay of the satellite according to the second embodiment of the present invention shown in Figure 3, receives the signal transmitted from the satellite 50 and converts it into a signal of the service frequency band A plurality of base station up-down converters 58 for outputting and converting the received signals into satellite up-frequency signals, and signals output from the base station up-down converters 58, and the pilot signals inserted by the repeater 54 are inputted. According to the satellite drift delay compensator 62 to compensate for the delay due to the drift of the satellite 50 and the time constant value set to compensate for the relay delay of the satellite 50 and the output signal of the satellite drift delay compensator 62. A plurality of base stations 60 including a PN offset converter 64 for converting PN offsets are provided.

In a wireless communication system using a satellite that compensates for relay delay of a satellite according to the second embodiment of the present invention configured as described above, the base station 60 compensates the relay delay of the satellite 50 according to a set constant value, and the satellite By detecting the pilot signal inserted in the repeater 54 by the drift delay compensator 62 and further compensating for the delay due to the drift of the satellite 50, even if the position of the satellite 50 changes, regardless of the amount of drift variation. Accurate appeal can be completed.

4 shows a third embodiment of the present invention. A wireless communication system using satellites that compensate for relay delay of a satellite according to a third embodiment of the present invention shown in FIG. 4 includes a satellite 70 for relaying a signal located in a service area and a subscriber terminal ( Amplifying and outputting a signal of a service frequency band transmitted from 76), amplifying the received signal and converting the signal output from the repeater 74 and the repeater 74 to the subscriber terminal 76 into a satellite up frequency signal A plurality of satellite relay base stations 77 including a terminal up-down converter 72 for transmitting and receiving a signal transmitted from the satellite 70, converting the signal into a signal of a service frequency band, and outputting the signal are provided. Although a plurality of components other than the satellite 70 should be illustrated in FIG. 4, only one component is illustrated for convenience of description.

In addition, the wireless communication system using a satellite to compensate for the relay delay of the satellite according to the third embodiment of the present invention shown in Figure 4, receives the signal transmitted from the satellite 70 and converts it into a signal of the service frequency band A plurality of base station up-down converters 78 outputting and converting the received signals into satellite up-frequency signals and the signals output from the base station up-down converters 78 detect the PN codes to drift of the satellites 50. PN offset converter for converting the PN offset according to the time constant value set in order to compensate for the delay delay of the PN code recognition device 80 and satellite 70 and the signal output from the PN code recognition device 80 to compensate for the delay caused by A plurality of base stations 82 including 84 are included.

In a wireless communication system using a satellite that compensates for relay delay of a satellite according to the third embodiment of the present invention configured as described above, the base station 82 compensates the relay delay of the satellite 70 according to a set constant value, and PN By detecting the PN code by the code recognition device 80 to further compensate for the delay due to the drift of the satellite 70, even if the position of the satellite 70 changes, accurate call communication can always be completed regardless of the amount of drift change. have.

The above embodiments can be easily applied to a personal communication service, a cellular phone service, an IMT-2000 communication service, and a wireless paging communication service in the 1.8 GHz band.

As described above, a wireless communication system using a satellite compensating a relay delay of a satellite according to the present invention has the advantage of always completing a communication between a terminal and a base station by compensating a delay caused by a satellite relay delay and a drift of the satellite. There is this.

Claims (7)

A wireless communication system for processing a communication for a terminal in each cell by dividing a service area into cells, A satellite for relaying a signal located above the service area; Amplifying and outputting a signal of a service frequency band transmitted from each terminal, amplifying and receiving a signal received from each terminal, and converting the signal output from the repeater into an uplink frequency signal for satellite and transmitting the signal; A plurality of satellite relay base stations each having an up-down converter for a terminal for receiving the transmitted signal and converting the signal into a signal of a service frequency band; And A plurality of base station down-converters for receiving the signal transmitted from the satellite and converting the signal into a signal of the service frequency band and outputting the plurality of base station up-converters for converting the received signal into an uplink frequency signal for satellite and transmitting the signal; A time delay compensator for compensating time delay according to a satellite delay constant set to compensate for a relay delay due to the satellite by inputting a signal output from a downconverter and a pseudo noise offset for converting a pseudo noise offset according to the output of the time delay compensator 1 Inputs an intermediate frequency processing block for processing the output signal of the pseudo noise offset converter and the first pseudo noise offset converter and a signal output from the intermediate frequency processing block, and converts the pseudo noise offset in advance according to the set satellite delay constant. A second output to the upconverter for the base station Wireless communication system using a satellite to compensate for the transit delay of the satellite, characterized in that it comprises a central station having a plurality of base stations comprising the four noise converter. The satellite station of claim 1, further comprising a pilot signal generator for transmitting a set pilot signal, wherein the center station detects the pilot signal input through the satellite and calculates a delay due to drift of the satellite. And a satellite drift delay compensator for compensating a delay due to the trip of the satellite by correcting the delay constant value. The method of claim 1, wherein the delay due to the satellite constant is corrected by calculating a delay caused by the drift of the satellite by detecting a pseudo noise code from the signal output from the down converter for the base station. A wireless communication system using a satellite to compensate for the relay delay of the satellite, characterized in that it further comprises a pseudo-noise code recognition device for compensating. The wireless communication system of claim 1, wherein the wireless signal of the service band is a wireless signal of a personal communication service band. The wireless communication system of claim 1, wherein the wireless signal of the service band is a wireless signal of a cellular phone service band. The radio communication system of claim 1, wherein the radio signal of the service band is a radio signal of an IMT-2000 communication service band. The wireless communication system of claim 1, wherein the radio signal of the service band is a radio signal of a radio call communication service band.