JP2010119052A - Mobile communication system, mobile terminal, base station, synchronization control method, program and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce interference with another station between mobile stations by reducing a time difference between symbol synchronization timing set at a base station and symbol arrival timing of a transmission signal from a mobile station even while the mobile station moves in mobile communication. <P>SOLUTION: The present invention relates to a mobile communication system comprising a base station, that covers cells within a predetermined range, and a mobile terminal. The base station includes a control information management means for managing control information including cell position information and timing information and for transmitting the control information to the mobile terminal when starting communication with the mobile terminal. The mobile terminal includes: a control information holding means for holding control information transmitted from the base station; a current position acquiring means for acquiring positional information about a current position of the terminal itself; and a transmission timing control means for controlling transmission timing when transmitting a signal to the base station while using timing information corresponding to the positional information of the current position acquired by the current position acquiring means, of the control information held by the control information holding means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mobile communication system, a mobile terminal, a base station, a synchronization control method, a program, and a recording medium, and in particular, a signal from a mobile station to a base station in a multiple access environment of mobile communication using a CDMA system. The present invention relates to a technique that is preferably applied to suppress interference between other stations that occurs during transmission.

  In recent years, the number of mobile phone users has increased rapidly with the increase in speed and functionality of mobile phones. Although the number of users is saturated, future mobile communications are expected to achieve higher speeds and higher quality, and various communication methods and technologies have been studied to make effective use of limited frequency resources. Has been done.

  For example, in code division multiple access (CDMA) mobile communication, a plurality of mobile stations in a communication area of a base station communicate with each other using orthogonal orthogonal codes. Unlike the (Access) method and FDMA (Frequency Division Multiple Access) method, a plurality of mobile stations (mobile terminals, hereinafter the same) can use the same frequency at the same time. On the other hand, in the case of signal transmission from the mobile station to the base station, that is, in the uplink, when complete synchronization cannot be established between the mobile stations, signals of other mobile stations cause interference between other stations.

As a technique for reducing such interference between other stations, for example, there is a wireless communication system disclosed in Patent Document 1. In the wireless communication system, when a signal from each mobile station is received at the base station, the time difference between the symbol arrival timing of the transmission signal from the mobile station and the symbol synchronization timing set by the base station is measured and notified to the mobile station . Each mobile station that has received the notification controls the signal transmission time based on the notified time so as to align the signal arrival timings at the base station.
JP 2005-269061 A

  FIG. 10 shows a time chart in the case where there is one mobile station in the wireless communication system of Patent Document 1. In the base station, the symbol synchronization timing St is engraved every predetermined time, and is notified to the mobile station by a reference synchronization signal. Here, the symbol synchronization timing St is a timing at which the arrival timing of the received signal from the mobile station is aligned in symbol units.

  At time A1, the base station transmits a reference signal A10 to the mobile station. The mobile station determines the symbol synchronization timing Sr based on this signal. Sr is the symbol synchronization timing of the transmission signal of the mobile station, and is engraved every predetermined time. At time A2, the mobile station transmits a signal A11 (arbitrary transmission signal) to the base station. At time A3, the base station measures a time difference T1 between the symbol arrival timing of the received signal A11 and the symbol synchronization timing St set by the base station.

  Then, at time A4, the base station notifies the measured time T1 to the mobile station. The signal A12 is a signal including information on the measured time T1. At time A5, the mobile station adjusts the symbol synchronization timing of the signal by S1 from Sr to Srm. At time A6, the mobile station transmits a signal A13 (arbitrary transmission signal) at symbol synchronization timing Srm. At time A7, the base station receives a signal synchronized with the symbol synchronization timing St.

  As described above, in the invention of Patent Document 1, the time difference between the symbol arrival timing of the signal received at the base station and the symbol synchronization timing set at the base station is calculated and notified to the mobile station (see FIG. 10). If the mobile station moves during the period Td), the symbol synchronization timing at the base station may not be aligned. That is, the system requires a calculation time of the timing time difference and a processing time for notification, and if the mobile station moves during this time, the synchronization shift increases accordingly. If the symbol arrival timings from the mobile stations are not aligned, the orthogonality of the spread codes is lost, and interference between other stations increases, resulting in a problem that the bandwidth capacity decreases in the system.

  Therefore, the present invention reduces the time difference between the symbol synchronization timing set at the base station and the symbol arrival timing of the transmission signal from the mobile station even when the mobile station is moving in mobile communication, and The purpose is to reduce interference between other stations.

  In order to achieve the above object, a first mobile communication system of the present invention is a mobile communication system including a base station that covers a predetermined range of cells and a mobile terminal. Has control information management means for managing control information including cell position information and timing information, and transmitting control information to the mobile terminal at the start of communication with the mobile terminal. Control information holding means for holding control information transmitted from the station, current position acquisition means for acquiring position information of the current position of the terminal, and current position acquisition means among the control information held by the control information holding means Transmission timing control means for controlling the transmission timing when transmitting a signal to the base station using the timing information corresponding to the position information of the current position acquired by.

  The first mobile terminal of the present invention is a mobile terminal that constitutes a mobile communication system together with a base station covering a predetermined range of cells, and manages control information including cell position information and timing information. Control information holding means for holding control information from the base station that transmits control information to the mobile terminal when communication with the mobile terminal is started, and current position acquisition for acquiring position information of the current position of the own terminal Among the control information held by the control information holding means and the timing information corresponding to the position information of the current position acquired by the current position acquisition means, Transmission timing control means for performing control.

  The first base station of the present invention constitutes a mobile communication system together with a mobile terminal, covers a predetermined range of cells, and manages control information including cell position information and timing information. In addition, when starting communication with a mobile terminal for a mobile terminal that controls transmission timing when transmitting a signal to the base station using timing information corresponding to position information of the current position of the terminal itself Control information management means for transmitting control information to the mobile terminal.

  A first synchronization control method of the present invention is a synchronization control method in a mobile communication system including a base station that covers a predetermined range of cells and a mobile terminal. Control information including cell location information and timing information is managed, and has a control information management step of transmitting control information to the mobile terminal at the start of communication with the mobile terminal. Acquired by the current position acquisition step among the control information holding step for holding the transmitted control information, the current position acquisition step for acquiring the position information of the current position of the terminal itself, and the control information held by the control information holding step A transmission timing control step for controlling the transmission timing when transmitting a signal to the base station using timing information corresponding to the position information of the current position A.

  A first program of the present invention is a program used in a mobile communication system including a base station that covers a predetermined range of cells and a mobile terminal, and the base station and the mobile terminal are Control information including a computer and storage means, managing control information including cell position information and timing information in a base station computer, and transmitting control information to the mobile terminal when communication with the mobile terminal is started A control information storage step for executing the management step and storing the control information transmitted from the base station in the storage means of the mobile terminal in the computer of the mobile terminal, and the current position for acquiring the position information of the current position of the own terminal Of the control information stored in the acquisition step and the control information storage step, the type corresponding to the position information of the current position acquired in the current position acquisition step. With ring information, and transmission timing control step for controlling the transmission timing when a signal is transmitted to the base station, is executed.

  The first recording medium of the present invention is a computer-readable recording medium on which the above program is recorded.

  According to the present invention, even when the mobile station is moving in mobile communication, the time difference between the symbol synchronization timing set in the base station and the symbol arrival timing of the transmission signal from the mobile station is reduced, Inter-station interference can be reduced.

  The present invention relates to quasi-synchronization control between mobile stations in a multiple access environment of mobile communication using the CDMA system. In quasi-synchronization control, when transmitting a signal from the mobile station to the base station, the symbol synchronization timing of each mobile station is provided by the reference signal transmitted from the base station. The arrival timing is controlled to be sufficiently small for one symbol. In the present invention, even when the mobile station is moving, it is possible to reduce the time lag of the symbol arrival timing of the transmission signal of the mobile station with respect to the symbol synchronization timing provided in the base station. Further, it is possible to flexibly change the accuracy of the synchronization control in accordance with a request to the system.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are preferred embodiments of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. Unless otherwise stated, the present invention is not limited to these embodiments.

[First Embodiment]
In the first embodiment of the present invention, cells covered by a base station at the time of system design are divided into several areas, position information (latitude, longitude) and signal arrival time to the base station are measured, Information is prepared as a set value. The data is transmitted from the base station to the mobile station when communication is started, and the mobile station stores the data in a storage area after reception. When the mobile station transmits a signal to the base station, the base station confirms the position information of the local station and the above data from the local station GPS, and the base station has a reception timing within a certain range. Transmission timing control is performed so as to be within the range.

  The configurations of the base station and mobile station in this embodiment will be described. First, the base station is described. FIG. 1 is a functional block diagram showing a configuration of a base station according to this embodiment, and FIG. 11 is a functional block diagram showing a configuration of a conventional base station.

  The base station of the present embodiment adds one control signal to be handled by the processing unit 115 of the conventional base station, adds a new process, and a storage area to which a new storage area is added to the storage area 116. 16 is different from the conventional configuration. By having these configurations, the base station uplink processing (uplink function) is realized. Other configurations (wireless signal receiving unit, spreading code generating unit, demodulating unit, wired signal receiving unit, transmitting unit) are the same as those in the prior art.

  The radio signal receiving unit 11 is connected to a receiving antenna and receives a modulated signal from a mobile station. The spreading code generation unit 12 generates a spreading code used as secondary modulation in each mobile station. The demodulator 13 demodulates the modulated signal received by the radio signal receiver 11 using the spread code generated by the spread code generator 12.

  The wired signal receiving unit 14 receives a signal transmitted from the host. The processing unit 15 performs processing according to the signal received by the wired signal receiving unit 14. The storage area 16 holds data processed by the processing unit 15 and data such as position information and transmission timing information for each area. The transmission unit 17 transmits the data processed by the processing unit 15 and data such as position information and transmission timing information to the mobile station.

  The uplink operation (uplink function) of the base station of this embodiment will be described. Since operations other than the processing unit 15 and the storage area 16 are the same as those of the conventional base station, description thereof is omitted here. In the present embodiment, the wired signal reception unit 14 to the transmission unit 17 that are conventionally used as the downlink function are also used as the uplink function.

  The processing unit 15 performs processing according to the signal received by the wired signal receiving unit 14. In this embodiment, the reference time (ST) at the base station as shown in FIGS. 3A and 3B, the symbol transmission interval (Ti), and the location information for each area obtained by dividing the cell covered by the base station ( A control signal 1516 including information on latitude, longitude) and transmission timing time (Si) is prepared. The control signal 1516 is stored in the storage area 16 and is rewritten as needed when there is a change in information.

  As shown in FIG. 3A, the management information (1) regarding the base station 10 has information on the base station ID, the reference time (ST) of symbol synchronization timing, and the symbol transmission interval (Ti). As shown in FIG. 3B, the management information (2) regarding the base station 10 includes the area name (A to BH) of the area obtained by dividing the cell covered by the base station, and the area position information (latitude, Longitude), route time, and transmission timing delay time information.

  These pieces of information are examined in advance at the time of system design, and are expanded from the upper level to the base station when the system operation is started. The transmission timing delay time is a transmission timing delay time for the signal of the mobile station in each area to reach the reference time of the base station. That is, the transmission timing delay time is set larger as the position is closer to the base station, and the transmission timing delay time is set smaller as the position is farther from the base station. Then, the transmission unit 17 transmits information such as the control signal 1516 stored in the storage area 16 to the mobile station.

  Next, the mobile station will be described. FIG. 2 is a functional block diagram showing the configuration of the mobile station according to this embodiment, and FIG. 12 is a functional block diagram showing the configuration of a conventional mobile station.

  The mobile station according to the present embodiment inputs the storage area 24 in which a new storage area is added to the storage area 124 of the conventional mobile station, and the GPS position information from the position information calculation unit 22, and inputs to the conventional processing unit 125. The processing unit 25 to which a new function is added and the transmission timing control unit 29 that controls the transmission timing of the transmission signal to the mobile station are different from the conventional configuration. With these configurations, uplink processing (uplink function) of the mobile station is realized. Other configurations (GPS signal receiving unit, position information calculating unit, information modulating unit, spreading code generating unit, spreading signal generating unit, and radio signal receiving unit) are the same as those in the prior art.

  The GPS signal receiving unit 21 is connected to a receiving antenna and receives radio waves from a plurality of GPS satellites. The position information calculation unit 22 calculates the position information (latitude and longitude) of the own station from the signal received by the GPS signal reception unit 21.

  The radio signal receiving unit 23 receives the signal transmitted from the transmitting unit 17 of the base station and sends it to the control unit 15. The control unit 25 processes the signal received by the wireless signal receiving unit 23 and stores it in the storage area 24. Further, the control unit 25 sends transmission timing information used for timing control to the transmission timing control unit 29. The storage area 24 holds data processed by the control unit 25 and position information and transmission timing information for each area received from the mobile station.

  The information modulator 26 performs primary modulation on the uplink data sequence to be transmitted to the base station. The spreading code generation unit 27 generates a spreading code assigned to the own mobile station. The spread signal generator 28 uses the spread code generated by the spread code generator 27 to secondary-modulate the data that has been primarily modulated by the information modulator 26. The transmission timing control unit 29 performs transmission control of data secondarily modulated by the spread signal generation unit 28 using the transmission timing information from the control unit 25.

  The uplink operation (uplink function) of the mobile station of this embodiment will be described. Since operations other than the storage area 24, the control unit 25, and the transmission timing control unit 29 are the same as those of the conventional mobile station, description thereof is omitted here. In the present embodiment, the wireless signal receiving unit 23 to the control unit 25 that are conventionally used as the downlink function are also used as the uplink function.

  In addition to the conventional function, the control unit 25 acquires control information 2425 similar to the control signal 1516 from the signal received by the wireless signal receiving unit 23 and stores it in the storage area 24. The control information is transmitted from the base station to the mobile station when the mobile station starts communication with the base station. Also, the position information 2225 from the position information calculation unit 22 is acquired.

  At this time, the position information 2225 includes longitude and latitude information, and the control unit 25 searches the area belonging to the management information of the area stored in the mechanism area 24, and the transmission timing information corresponding thereto. 2529 is selected. The transmission timing control is performed by inputting the transmission timing information 2529 (symbol transmission time) to the block of the transmission timing control unit 29.

  In the storage area 24, a storage area for storing information 2425 and the like is further added to the conventional area. Based on the time of the transmission timing information 2529 input from the control unit 25, the transmission timing control unit 29 controls the timing for transmitting the signal secondarily modulated by the spread signal generation unit 28 and transmits it to the base station.

The transmission timing control operation in this embodiment will be specifically described assuming the following conditions.
・ The cell radius of the base station is 1 km.
-The spreading band is 5 MHz, and the radio wave wavelength is 100 m.
The chip transmission rate is 3.84 Mcps (chip / s).
The allowable chip deviation (τ) for quasi-synchronous control is within 4 chips (2.08 μs). FIG. 4 shows the allowable timing deviation in this embodiment.
・ GPS positioning accuracy is about several tens of meters.

  FIG. 5 shows an assumed environment. In FIG. 5, a mobile station 20a and a mobile station 20b exist in a cell 50 (cell radius 1 km) covered by the base station 10. The area to be covered is divided into about 60 areas A to BH (250 m * 250 m square), and position information (latitude, longitude) and signal arrival time to the base station are measured in advance. When a signal is transmitted from the end of the cell (linear distance: 1 km), it takes 2 μs at the shortest. For this reason, it is necessary to examine the cell range, the diffusion band, and the allowable chip deviation according to the environment such as an obstacle or a shield during actual design.

  Assume that the mobile station 20a is located in the area N (straight line distance 500 m, path time 1 μs), and the mobile station 20 b is located in the area Z (straight line distance 1 km, path time 2 μs). The mobile station 20a and the mobile station 20b extract the transmission timing time (Si) from the management information (2) shown in FIG. Here, the transmission timing time S0 of the mobile station 20a is 0.4 μs, and the transmission timing time S1 of the mobile station 20b is 3.0 μs. The mobile station 20a transmits a signal at a timing when 4.0 μs has elapsed with respect to the symbol synchronization timing St, and the mobile station 20b transmits a signal at a timing when 3.0 μs has elapsed with respect to the symbol synchronization timing St. The base station 10 receives a signal whose timing is controlled at the symbol synchronization timing St.

  FIG. 6 shows a time chart. In the base station 10, the time is recorded at a constant interval Ti (5 μs) from a predetermined time St at the symbol synchronization timing notified from the host and stored in the storage area 16. This symbol synchronization timing St is a timing at which the arrival timing of the transmission signal from the mobile station is aligned in symbol units.

  At time B1, the base station transmits the control information shown in FIG. 3 to the mobile stations 20a and 20b. The received mobile stations 20 a and 20 b store these pieces of information in the storage area 24. At time B2 (B2 ′), the mobile station 20a (20b) determines the symbol transmission timing S0 (S1) from the position information (latitude, longitude) from the position information calculation unit 22 and the symbol transmission timing time for each area stored in the storage area 24. ) B20 and B21 indicate input signals from the position information calculation unit 22 and the storage area 24, respectively.

  Then, at time B3 (B3 '), the mobile station 20a (20b) transmits a signal at a timing when S0 (S1) has elapsed from the symbol synchronization timing St. At time B4, the base station 20a receives a signal controlled to arrive at the symbol synchronization timing St.

[Second Embodiment]
In the second embodiment of the present invention, position information prepared as a set value at the time of system design and signal arrival time to the base station are set to uniform values within the cell without dividing each area. The second embodiment is the same as the first embodiment except that the position information and the transmission timing information prepared in the base station and transmitted to the mobile station are different. For this reason, the description regarding the configuration of the base station and the mobile station is omitted, and the control operation of the transmission timing is described.

When the present invention is applied, the smaller the cell, the smaller the arrival time lag to the base station, so that timing control can be easily performed. In the second embodiment of the present invention, the case of Femto BTS (cell radius of about 10 m) is examined under the following conditions, and the transmission timing control operation will be specifically described.
-The cell radius of the base station is 10 m.
・ The spread band is 5 MHz and the radio wave wavelength is 100 m.
The chip transmission rate is 3.84 Mcps (chip / s).
The allowable chip deviation (τ) for quasi-synchronous control is within 1 chip (0.52 μs). FIG. 7 shows the allowable timing deviation in this system.
・ GPS positioning accuracy is about several tens of meters.

  In the case of a Femto cell, since the distance between the cell edge and the base station is short, the cell is not divided into areas, and the transmission timing is uniform within the cell. When a signal is transmitted from the end of the cell (straight line distance: 10 m), the signal arrives at a minimum of 0.02 μs. In actual design, it is necessary to consider the cell range, spreading bandwidth, and allowable chip deviation according to the environment of obstacles and shielding.

  Figure 8 shows the assumed environment. In FIG. 8, a mobile station 40a and a mobile station 40b exist in a cell 60 (cell radius 10 m) covered by the base station 30. It is assumed that the mobile station 40a is at a linear distance of 5 m and a path time of 0.01 μs, and the mobile station 40b is at a linear distance of 10 m and a path time of 0.02 μs with respect to the base station 30. Here, the transmission timing time of the mobile station 40a and the mobile station 40b is a timing when 4.98 μs has elapsed with respect to the symbol synchronization timing St. The base station 30 receives a signal having a timing deviation within 0.02 μs with respect to the symbol synchronization timing St. This is within an allowable chip deviation of 1 chip.

  FIG. 9 shows a time chart. In the base station 30, the time is recorded from the predetermined time St at a constant interval Ti (5 μs) at the symbol synchronization timing notified from the host and stored in the storage area 16. This symbol synchronization timing St is a timing at which the arrival timing of the transmission signal from the mobile station is aligned in symbol units.

  At time E1, the base station transmits control information (here, information on the base station 30) shown in FIG. 3A to the mobile stations 40a and 40b. The received mobile stations 40 a and 40 b store these pieces of information in the storage area 24. At time E2, the mobile stations 40a and 40b transmit signals at a timing when 4.98 μs has elapsed from the symbol synchronization timing St. At time E3, the base station 30 receives a signal controlled to arrive at the symbol synchronization timing St. That is, the base station 30 receives a signal from the mobile station 40a at time E2 'and receives a signal from the mobile station 40b at time E3. Thus, the arrival timing of the signal falls within 0.02 μs with respect to the symbol synchronization timing St.

  As described above, in the embodiment, the transmission timing control of the mobile station that is performed based on the information calculated by the base station is performed using information that can be acquired on the mobile station side. In the conventional method, timing measurement is performed at the base station based on a signal received from the mobile station, and the result is transmitted to the mobile station. In this method, first, the transmission / reception process reduces the time by half (comparison between FIG. 10 and FIG. 6). This reduces the time required for timing measurement and the path time between the base station and the mobile station. Thus, according to the present embodiment, the transmission timing control time of the mobile station can be shortened, and the time lag of the symbol arrival timing of the transmission signal can be reduced even when the mobile station is moving. As a result, interference between other stations can be kept small, and accordingly, the system can increase the bandwidth capacity.

  Further, according to the embodiment described above, it is possible to ensure the synchronization accuracy that meets the requirements for the system. The synchronization accuracy can be changed according to the number of divided areas in the cell to be covered. In cells where the number of users is large and interference is expected to increase, the number of divisions can be increased to improve synchronization accuracy in exchange for the amount of work, and conversely, the number of users can be reduced and interference can be reduced. In the assumed area, a flexible design is possible such as reducing the number of divisions (or without dividing) and reducing the amount of work in exchange for synchronization accuracy.

  The above-described embodiment is a preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiment alone, and various modifications are made without departing from the gist of the present invention. Implementation is possible.

  That is, the program executed in the mobile communication system in this embodiment has a module configuration including the above-described units (processing unit, control unit, transmission timing control unit, etc.), and uses actual hardware. To realize concrete means. That is, when the computer (CPU) reads a program from a predetermined recording medium and executes it, the above-mentioned means are loaded onto the main storage device, and a processing unit, a control unit, a transmission timing control unit, etc. are generated on the main storage device. Is done.

  The program executed in the mobile communication system in the present embodiment may be configured to be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Further, the program may be provided or distributed via a network such as the Internet.

  The program is a file in an installable or executable format, such as a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, DVD, nonvolatile memory card, or the like. It may be configured to be provided by being recorded on a computer-readable recording medium. Further, the program may be provided by being incorporated in advance in a ROM or the like.

  In this case, the program code itself read from the recording medium or loaded and executed through the communication line realizes the functions of the above-described embodiments. And the recording medium which recorded the program code comprises this invention.

It is the functional block diagram which showed the structure of the base station which concerns on embodiment of this invention. It is the functional block diagram which showed the structure of the mobile station which concerns on embodiment of this invention. It is a figure for demonstrating the control information used for the timing control of the signal transmission in embodiment of this invention. It is a figure for demonstrating the allowable timing shift | offset | difference in the signal transmission timing control in embodiment of this invention. It is a figure for demonstrating the environment where the timing control of the signal transmission in embodiment of this invention is performed. It is the figure which showed the time chart at the time of performing the timing control of the signal transmission in embodiment of this invention. It is a figure for demonstrating the allowable timing shift | offset | difference in the signal transmission timing control in embodiment of this invention. It is a figure for demonstrating the environment where the timing control of the signal transmission in embodiment of this invention is performed. It is the figure which showed the time chart at the time of performing the timing control of the signal transmission in embodiment of this invention. It is the figure which showed the time chart at the time of performing the timing control of the signal transmission by the conventional system. It is the functional block diagram which showed the structure of the conventional base station. It is the functional block diagram which showed the structure of the conventional mobile station.

Explanation of symbols

11, 111 Radio signal receiver 12, 27, 112, 127 Spreading code generator 13, 113 Demodulator 14, 114 Wired signal receiver 15, 115 Processor 16, 24, 116, 124 Storage area 17, 117 Transmitter 21 , 121 GPS signal receiver 22, 122 Position information calculator 23, 123 Radio signal receiver 25, 125 Controller 26, 126 Information modulator 28, 128 Spread signal generator 29, 129 Transmission timing controller 1516, 2425 Control information 2225 Position information 2529 Transmission timing information

Claims (19)

A mobile communication system including a base station that covers a predetermined range of cells and a mobile terminal,
The base station
Control information including position information and timing information of the cell, and control information management means for transmitting the control information to the mobile terminal at the start of communication with the mobile terminal,
The mobile terminal is
Control information holding means for holding the control information transmitted from the base station;
Current position acquisition means for acquiring position information of the current position of the terminal;
Of the control information held by the control information holding unit, transmitted when transmitting a signal to the base station using the timing information corresponding to the position information of the current position acquired by the current position acquisition unit A transmission timing control means for controlling timing;
A mobile communication system comprising:   Using the position information of the current position acquired by the current position acquisition means, the timing information corresponding to the position information of the current position is retrieved from the control information held by the control information holding means, and the timing information The mobile communication system according to claim 1, further comprising a control unit that transmits a transmission timing to the transmission timing control unit. The timing information represents a delay time from the synchronization timing in the base station,
2. The transmission timing control unit performs control so that a signal is transmitted to the base station at a timing obtained by adding the delay time to a synchronization timing after receiving a signal from the base station. Or a mobile communication system according to 2; The timing information represents a delay time from the synchronization timing in the base station, and for each area that is a divided region of the cell, an area close to the base station is set to a large value and a remote area is set to a small value,
2. The transmission timing control unit performs control so that a signal is transmitted to the base station at a timing obtained by adding the delay time to a synchronization timing after receiving a signal from the base station. 4. The mobile communication system according to any one of items 1 to 3. The timing information represents a delay time from the synchronization timing in the base station, the value is uniformly set in the cell,
The transmission timing control means performs control so that a signal is transmitted to the base station at a timing obtained by adding the delay time to a synchronization timing after receiving a signal from the base station. 5. The mobile communication system according to any one of 1 to 4.   The mobile communication system according to any one of claims 1 to 5, wherein the control information management unit rewrites data when a change occurs in the content of the control information. A mobile terminal that constitutes a mobile communication system together with a base station that covers a predetermined range of cells,
Control that manages the control information including the location information and timing information of the cell, and holds the control information from the base station that transmits the control information to the mobile terminal when communication with the mobile terminal starts Information holding means;
Current position acquisition means for acquiring position information of the current position of the terminal;
Of the control information held by the control information holding unit, transmitted when transmitting a signal to the base station using the timing information corresponding to the position information of the current position acquired by the current position acquisition unit A transmission timing control means for controlling timing;
A mobile terminal characterized by comprising:   Using the position information of the current position acquired by the current position acquisition means, the timing information corresponding to the position information of the current position is retrieved from the control information held by the control information holding means, and the timing information The mobile terminal according to claim 7, further comprising: a control unit that transmits a message to the transmission timing control unit. The timing information represents a delay time from the synchronization timing in the base station,
8. The transmission timing control means performs control so as to transmit a signal to the base station at a timing obtained by adding the delay time to a synchronization timing after receiving a signal from the base station. Or the mobile terminal according to 8; The timing information represents a delay time from the synchronization timing in the base station, and for each area that is a divided region of the cell, an area close to the base station is set to a large value and a remote area is set to a small value,
8. The transmission timing control means performs control so as to transmit a signal to the base station at a timing obtained by adding the delay time to a synchronization timing after receiving a signal from the base station. The mobile terminal according to any one of 1 to 9. The timing information represents a delay time from the synchronization timing in the base station, the value is uniformly set in the cell,
The transmission timing control means performs control so that a signal is transmitted to the base station at a timing obtained by adding the delay time to a synchronization timing after receiving a signal from the base station. The mobile terminal according to any one of 7 to 10. A base station that constitutes a mobile communication system together with a mobile terminal and covers a predetermined range of cells,
Controls control information including the location information and timing information of the cell, and controls transmission timing at the time of signal transmission to the base station using the timing information corresponding to the location information of the current location of the terminal itself A base station comprising control information management means for transmitting the control information to the mobile terminal when communication with the mobile terminal is started. A synchronization control method in a mobile communication system including a base station that covers a predetermined range of cells and a mobile terminal,
In the base station,
Control information including the location information and timing information of the cell, and a control information management step of transmitting the control information to the mobile terminal at the start of communication with the mobile terminal,
In the mobile terminal,
A control information holding step for holding the control information transmitted from the base station;
A current position acquisition step for acquiring position information of the current position of the terminal;
Of the control information held by the control information holding step, transmitted when transmitting a signal to the base station using the timing information corresponding to the position information of the current position acquired by the current position acquisition step. A transmission timing control step for controlling timing;
A synchronization control method characterized by comprising:   Timing to retrieve and acquire the timing information corresponding to the position information of the current position from the control information held by the control information holding step using the position information of the current position acquired by the current position acquisition step 14. The synchronization control method according to claim 13, further comprising an information acquisition step. The timing information represents a delay time from the synchronization timing in the base station,
14. The transmission timing control step performs control so that a signal is transmitted to the base station at a timing obtained by adding the delay time to a synchronization timing after receiving a signal from the base station. Or the synchronous control method of 14. A program used in a mobile communication system including a base station that covers a predetermined range of cells and a mobile terminal,
The base station and the mobile terminal comprise a computer and storage means,
In the base station computer,
Managing control information including the location information and timing information of the cell, and executing a control information management step of transmitting the control information to the mobile terminal at the start of communication with the mobile terminal;
In the computer of the mobile terminal,
A control information storage step of storing the control information transmitted from the base station in a storage means of the mobile terminal;
A current position acquisition step for acquiring position information of the current position of the terminal;
Of the control information stored in the control information storage step, transmitted when transmitting a signal to the base station using the timing information corresponding to the position information of the current position acquired in the current position acquisition step A transmission timing control step for controlling timing;
A program characterized by having executed.   Timing to retrieve and acquire the timing information corresponding to the position information of the current position from the control information stored in the control information storage step using the position information of the current position acquired in the current position acquisition step The program according to claim 16, wherein the information acquisition step is executed by a computer of the mobile terminal. The timing information represents a delay time from the synchronization timing in the base station,
17. The transmission timing control step performs control so that a signal is transmitted to the base station at a timing obtained by adding the delay time to a synchronization timing after receiving a signal from the base station. Or the program of 17.   A recording medium which records the program according to any one of claims 16 to 18 and is readable by a computer.

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