JP2836000B2 - Mobile terminal location detection and registration method for orbiting satellite communication systems - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an orbiting satellite communication system, and more particularly to a system for detecting and registering the position of a mobile terminal used in the orbiting satellite communication system.

[0002]

2. Description of the Related Art As one of next-generation mobile satellite communication systems, a mobile satellite communication system using a multi-spot beam orbiting communication satellite (hereinafter, a communication satellite is simply referred to as a satellite) has been proposed. This communication system has an orbital altitude lower than that of a geostationary satellite conventionally used in a satellite communication system, that is, a low orbit (altitude of 500 to 2,000).
Kilometers) or medium altitude orbits (altitudes between 10,000 and 3)
(6,000 km), and communication between the orbiting satellite and the mobile terminal must be performed via a multi-spot beam. The multi-spot beam orbiting satellite communication system has a small propagation loss and propagation delay, a simple satellite configuration, and requires a smaller number of beams per satellite than a multi-spot beam geostationary satellite. Has advantages.

FIG. 5 shows a conceptual diagram of communication between a mobile terminal and a land earth station in a multi-spot beam satellite communication system. In the figure, 1 is a mobile terminal, 2 is a land earth station, 3
0 is a multi-spot beam satellite capable of communicating with the mobile terminal 1 and the land earth station 2, and 30-1 to 30-7 are those in which the area communicable with the mobile terminal 1 is divided into small areas, each of which is irradiated with a spot beam. This is the irradiation area of each spot beam. When a call is generated to a mobile terminal in such a mobile satellite communication system, a call is made to connect the call to a desired terminal. However, it is desirable to set the area used for calling as small as possible because the number of lines used for calling is made as small as possible.

[0004]

SUMMARY OF THE INVENTION Inmarsat Standard A
In the system, a method is adopted in which a caller designates a sea area where a mobile terminal is located at the time of dialing operation. However, if the area used for calling is large, the number of areas that must be selected by the caller decreases, but the number of lines required for calling increases, and if the area is small, the number of calling lines decreases, but the number of calling lines decreases. Due to the increased burden, it is not practical to apply this method, especially to communication systems with many subscribers. Therefore, the communication system accurately grasps information on the locations of all mobile terminals that can be called, such as a land-based cellular system, for example, by managing a database or the like on a land network. A method of calling a desired mobile terminal simply by dialing a number given to a terminal user is desired. When using a geosynchronous satellite that adopts the multi-spot beam method, a location detection / registration similar to a terrestrial cellular system is performed by using the irradiation area of the spot beam including the mobile terminal as it is as the location information of the mobile terminal. It is possible to do. However, when using an orbiting satellite, since the satellite 30 revolves around the earth,
The area where the satellite 30 can communicate with the mobile terminal 1 and the spot beam irradiation areas 30-1 to 30-7 move so as to sequentially scan the earth's surface. When used as location information, location information is updated very frequently, and registration and updating of location information of a mobile terminal requires many lines, which is not practical.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and is an orbiting satellite communication system capable of detecting and registering the current position of a mobile terminal independently of the orbiting of orbiting satellites. It is intended to provide a location detection / registration method for a mobile terminal.

[0006]

In order to achieve this object, a position detection / registration method for a mobile terminal for an orbiting satellite communication system according to the present invention is provided by each of a plurality of spot beams of a plurality of satellites orbiting the earth. Transmits the identification information of each spot beam, and when the mobile terminal desires position registration, receives the spot beam identification information at predetermined time intervals, and receives the spot beam identification information and each. A time and predetermined unique information of the mobile terminal are transmitted as the location information of the mobile terminal via the orbiting satellite, and a plurality of spot beams corresponding to the identification information included in the location information are respectively assigned to the location registration request. It is configured to register an area where the area irradiated at the time received by the mobile terminal overlaps as the position information of the mobile terminal desired to be registered. .

[0007]

According to the present invention, as described above, the latest position information of the mobile terminal is registered in the data storage device attached to the terrestrial earth station. Only the required terrestrial earth station, satellite and spot beam need to be selected and called for only the area where the call is made.
Therefore, the number of lines required for calling is reduced.

[0008]

An embodiment of the present invention will be described with reference to the drawings.
In this embodiment, a satellite uses a multi-spot beam orbiting satellite, and one or more satellites can always communicate with the mobile terminal and the land earth station. Also, a unique identification number is assigned to each of the spot beams of the orbiting satellites, and the mobile terminal can identify these mutually. The orbiting satellite always transmits the corresponding spot beam identification number via each spot beam. When the mobile terminal desires location registration, communication is performed with the desired time and three times of (desired time + predetermined time interval Δt) and {desired time + 2 × (predetermined time interval Δt)}. It receives the identification numbers of the possible spot beams and transmits these to the terrestrial network together with the time at which they were received and the identification number of the mobile terminal. FIG. 1 is a conceptual diagram showing a positional relationship between a mobile terminal, a satellite, and a land earth station at a certain time in the position detection / registration method using the present invention. In the figure, 1 is a mobile terminal, 30 and 31 are orbiting satellites, 30-7 and 3
0-7 'is an area irradiated by the same spot beam of the orbiting satellite 30 at time T and T + Δt, 31-3 ″ is an area irradiated by the spot beam of the orbiting satellite 31 at time T + 2Δt, and 4 is the position of the mobile terminal 1. A data storage device for managing information, 5 is an arithmetic device for providing orbit information of all orbiting satellites, 6 is a land network of a mobile satellite communication system using orbiting satellites, and 10 is a mobile terminal 1 estimated by the land network. An example of a method for obtaining the orbital information of an artificial satellite is described in the Radio Research Institute Quarterly Report (published in July, 1972, p.
345-353, "Orbits of artificial satellites and missions suitable for them"), and satellite orbit information can be calculated instantly if the date and time are known. The mobile terminal 1 is at time T
At the spot beam irradiation area 30-7, time T + Δ
At t, the spot beam irradiation area 30-7 'and at time T + 2Δt, the spot beam irradiation area 31-3 "
Located within.

When the mobile terminal 1 desires position registration at time T, it receives the spot beam identification number received at time T, T + Δt and T + 2Δt. That is, at time T, the spot beam identification number BID307,
At time T + Δt, the spot beam identification number BID30
7, and at time T + 2Δt, spot beam identification number B
The ID 313 is received. The mobile terminal 1 transmits the spot beam identification number received at each reception time and each with the terminal identification number (unique information) TID1 via the orbiting satellite. These information are received by the land earth station 2, for example. The terrestrial earth station 2 sends these information to the arithmetic unit 5
Transfer to

FIG. 2 shows how the position of the mobile terminal 1 is estimated in the arithmetic unit 5 based on the information. The arithmetic unit 5 identifies the identification number BI based on the orbit information of all the satellites.
Area 30-7 where the spot beam corresponding to D307 irradiates at reception time T, area 30-7 'where the spot beam corresponding to identification number BID307 irradiates at reception time T + Δt, spot corresponding to identification number BID313 Region 31 where the beam was radiated at reception time T + 2Δt
Further, the arithmetic unit 5 calculates an area (indicated by hatching) where the spot beam irradiation areas 30-7, 30-7 'and 31-3 "overlap each other, and calculates the movement of the mobile terminal and the orbiting satellite. In consideration of the deviation from the trajectory, a range 10 slightly wider than the overlapping area is estimated as the position of the mobile terminal 1. The estimated area 10 is transferred to the data storage device 4 as position information of the mobile terminal 1 at time T together with the terminal identification number (unique information) TID1 of the mobile terminal 1 and registered.

After registration, a call is made to the mobile terminal 1,
FIG. 4 shows a conceptual diagram when the mobile terminal 1 is called. In the figure, 32 and 33 are orbiting satellites, and 32-6 and 32-
7 and 33-1, 33-3, 33-4 and 33-5 are spot beams of the orbiting satellites 32 and 33, respectively. Reference numeral 7 denotes an exchange, 8 denotes a public network, and 9 denotes a general subscriber's telephone. When a call is made to the mobile terminal 1, the location information 10 of the mobile terminal 1 registered in the data storage device 4 is stored.
Is the terminal information (unique information) TID1 of the mobile terminal 1.
Is referred to as a search key. This area 10 is transferred to the arithmetic unit 5, where the spot beam of the satellite illuminating the area 10 at the time of the call occurrence is selected. Further, an appropriate land earth station is selected to make a call using the selected spot beam. In the case of the positional relationship shown in FIG. 3, the spot beams 32-6, 32-
7, 33-1, 33-3, 33-4 and 33-6, land earth stations 2 and 2 'are selected, and a call message is transmitted to the area 10 registered as the position of the mobile terminal 1. .

[0012]

According to the present invention, the position estimated on the basis of the satellite spot beam with which the mobile terminal can communicate is registered in the land system. Can select an appropriate land-based earth station, satellite, and spot beam based on the registered position, and make a call to a limited small area.
Therefore, the number of lines required for calling can be reduced.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing how a position is detected and registered according to the present invention.

FIG. 2 is a conceptual diagram showing how a position information of a mobile terminal is estimated as a certain area based on information transmitted from the mobile terminal in the method of the present invention.

FIG. 3 is a conceptual diagram showing a state in which a mobile terminal is called based on position information in the method of the present invention.

FIG. 4 is a conceptual diagram of a conventional mobile satellite communication system.

[Explanation of symbols]

Reference Signs List 1 mobile terminal 2, 2 'land earth station 30, 31, 32, 33 orbiting satellite 30-7, 30-7' spot beam irradiation area of orbiting satellite 30 31-3 "spot beam irradiation area of orbiting satellite 31 32-6 , 32-7 Spot beam irradiation area of orbiting satellite 32 33-1, 33-3, 33-4, 33-5 Orbiting satellite 3
3 spot beam irradiation area 4 data storage device 5 arithmetic device 6 land network in mobile satellite communication system using orbiting satellite 7 exchange 8 public network 9 general subscriber telephone 10 location of mobile terminal estimated and registered by land system

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-27887 (JP, A) JP-A-4-354216 (JP, A) JP-A-9-93681 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) H04B 7/14-7/26 H04Q 7/00-7/38

Claims (1)

(57) [Claims] 1. A terrestrial network configured on earth such that each mobile terminal located within a desired service area on earth communicates via any of a plurality of orbiting satellites. Having each of the plurality of mobile terminals located in the desired service area so as to be able to communicate with at least one of the land earth stations via at least one of the plurality of orbiting satellites. Orbiting satellites are arranged, and each of the plurality of orbiting satellites is divided into a plurality of small regions by dividing a region that can communicate with the orbiting satellite at each time into a plurality of small regions. Communicates with a mobile terminal located within the mobile terminal, and when a plurality of spot beams of each of the orbiting satellites transmits identification information unique to each spot beam, the mobile terminal desires location registration. , The received plurality of times at predetermined time intervals the identification information of the communication possible spot beam of the plurality of spot beams of orbiting satellites, a plurality of spot beams identification information thus received,
Transmitting, via the orbiting satellite, information about the time at which each of the plurality of received spot beam identification information is received and predetermined unique information of the mobile terminal as position information of the mobile terminal; At least one of the stations receives the position information, and an area where the area irradiated at the time when the spot beams corresponding to the plurality of spot beam identification information transmitted from the mobile terminal desiring registration are respectively received overlaps with each other. A mobile terminal position detection / registration method for an orbiting satellite communication system configured to register as a position of the mobile terminal based on the above.