JP2013046096A - Wireless communication system and method for proving communication service from base station to wireless terminal according to plan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless communication system and method capable of compensating a cover area of a base station under operation suspension, of providing communication opportunities to a wireless terminal, of relaxing congestion of the base station caused by concentration of communication requests, and of suppressing run-out of batteries of the wireless terminal.SOLUTION: A base station produces schedule information prescribing a startup time timing of a wireless communication part in a wireless terminal, and broadcasts a broadcast message including the schedule information to a wireless terminal. The base station radiates a radiowave at a timing depending on the schedule information while changing a radiation direction and/or a radiation angle. The wireless terminal on-off controls power supply to the wireless communication part depending on the startup time timing of the schedule information in the broadcast message. Thereby, a timing when the radiation direction and/or the radiation angle of the radiowave of the base station directs to the wireless terminal and a timing when the power supply to the wireless communication part of the wireless terminal is turned on are synchronized with each other.

Description

  The present invention relates to a technique applied to a radio communication system having a base station and a radio terminal when a base station fails.

  FIG. 1 is a system configuration diagram in a wireless communication network in which a plurality of base stations and a plurality of wireless terminals are distributed.

  According to FIG. 1, three base stations 1a to 1c arranged in a distributed manner cover a wide area where a large number of wireless terminals 2a to 2e are located. A radio wave radiated from the base station 1 having a plurality of antennas is generally omnidirectional (for example, MIMO (Multiple Input Multiple Output)) and reaches the radio terminal 2 located in all directions.

  FIG. 2 is a system configuration diagram of a wireless communication network when a failure occurs in some base stations.

  According to FIG. 2, a failure has occurred in the two base stations 1b and 1c. Wireless terminals located only within the communication area of the base stations 1b and 1c cannot communicate. Base station failures are not limited to small-scale failures such as failures, but also include large-scale failures such as disasters. In particular, a base station stoppage during a major disaster leads to a stoppage of communication infrastructure, which causes an increase in damage to the entire society.

When a failure occurs in some base stations, the following four problems occur in other base stations and wireless terminals.
[Problem 1] A wireless terminal that is out of communication range cannot communicate.
According to FIG. 2, when the base stations 1b and 1c fail, the wireless terminals d and e cannot communicate.
[Problem 2] A wireless terminal that is out of communication range repeats base station acquisition processing (search processing). Therefore, the power consumption of the wireless terminal outside the communication range becomes larger than the power consumption of the wireless terminal in the communication range, and the battery is likely to run out.
According to FIG. 2, the wireless terminals d and e are liable to run out of batteries.
[Problem 3] A base station in operation tends to be congested because communication requests from a large number of wireless terminals are concentrated.
According to FIG. 2, the base station 1a is likely to fall into a congestion state due to concentration of communication requests.
[Problem 4] In the event of a disaster, a user uses a wireless terminal to make a call in order to communicate with another person. However, the call destination base station is in a congested state or the call is restricted. Thus, the connection with the base station cannot be established, for example, when the number of receivables is limited, and as a result, the user repeats the call (connection retry). The wireless terminal repeats outgoing calls to a base station that is in a congested state and is subject to outgoing restrictions, thereby increasing the power consumption of the wireless terminal and facilitating battery exhaustion. The call rate of the entire system at the time of disaster increases more rapidly than usual.
According to FIG. 2, when the users of the wireless terminals 2a, b, and c repeat the call operation many times, the power of the wireless terminals 2a, b, and c is wasted and the battery is likely to run out. .

  According to the prior art, when a radio communication unit of a part of sectors is a base station composed of a plurality of sectors, the antenna directivity of the radio communication unit in other non-failed sectors is controlled. There is a technology (see, for example, Patent Document 1). According to this technique, the sector which the faulty radio communication unit is carrying can be covered by the sector of another radio communication unit without using the adjacent base station.

  Also, there is a technique for a mobile communication system (wireless LAN system) composed of a plurality of base stations (access points) so that when a base station fails, another base station adjacent to the base station controls antenna directivity. (For example, refer to Patent Documents 2 and 3). According to this technique, an area covered by a failed base station is covered by another base station adjacent thereto.

JP 2007-228481 A JP 2008-31815 A JP 2003-264866 A

"Active antenna system", [online], [Search August 6, 2011], Internet <URL: http://wirelesswire.jp/NSN_in_WWN/201105181206.html>

  According to the techniques described in Patent Documents 1 to 3, it is possible to solve [Problem 1] and [Problem 2] described above. In other words, this is because the other base stations that are operating can cover the coverage area of the base stations that are not operating.

  However, according to the techniques described in Patent Documents 1 to 3, [Problem 3] and [Problem 4] described above cannot be solved. Rather, communication requests can be concentrated by making more radio terminals repeat calls in the operating base station, so that it is more likely to fall into a congestion state, and [Problem 3] and [Problem 4] The degree of assignment will increase.

  Therefore, the present invention compensates for the coverage area of a base station that is out of service, provides a communication opportunity for the wireless terminal, relieves congestion of the base station due to concentration of communication requests, and reduces battery exhaustion of the wireless terminal. It is an object of the present invention to provide a wireless communication system and method that can be used.

According to the present invention, in a radio communication system having a base station having an antenna capable of variably controlling the radiation direction and / or radiation angle of a radio wave, and a radio terminal having a radio communication unit communicating with the base station,
The base station
Schedule information creating means for creating schedule information defining the start time timing of the wireless communication unit in the wireless terminal;
Broadcast message creation means for creating a broadcast message including schedule information and broadcasting to a wireless terminal via an antenna;
Radio wave radiation control means for controlling the antenna so as to radiate radio waves while changing the radiation direction and / or radiation angle at the timing according to the schedule information,
Wireless terminal
Broadcast message control means for controlling based on broadcast message schedule information;
According to the start time timing of the schedule information, it has energization control means for on / off control of power supply to the wireless communication unit,
The timing at which the radiation direction and / or the radiation angle of the radio wave of the base station is directed to the wireless terminal is synchronized with the timing at which power supply is turned on to the wireless communication unit of the wireless terminal.

  According to another embodiment of the wireless communication system of the present invention, the energization control means of the wireless terminal is after a predetermined time has elapsed or a predetermined number of base station searches have elapsed after turning on the power supply to the wireless communication means. However, when the base station cannot be found, it is also preferable to turn off the power supply again and continue the off state until the next turn-on timing.

  According to another embodiment of the radio communication system of the present invention, the radio wave radiation direction in the radio wave radiation control means of the base station is preferably controlled in a horizontal direction and / or a vertical direction with respect to the ground surface.

  According to another embodiment of the wireless communication system of the present invention, the schedule information creation means of the base station is included in an area of the radio wave radiation direction and / or radiation angle for each radio wave radiation direction and / or radiation angle. It is also preferable to define different radiation directions and / or radiation angles in the schedule information depending on the number of wireless terminals to be used and / or the traffic.

According to another embodiment of the wireless communication system of the present invention,
The base station has a normal mode and a failure mode,
The schedule information creation means, broadcast message creation means and radio wave emission control means are executed only in the failure mode,
The broadcast message creation means preferably transmits a broadcast message including a normal mode or a failure mode using BC-SMS (BroadCast-Short Message Service).

According to another embodiment of the wireless communication system of the present invention,
The system further comprises a controller that controls the mode of the base station;
The control device
From each base station, collect base station operation information indicating the presence or absence of failure,
Instruct the base station adjacent to the base station where the fault occurred to the fault mode,
It is also preferable to instruct the normal mode to the base station that has instructed the failure mode after recovery from the failure.

According to another embodiment of the wireless communication system of the present invention,
The broadcast message creation means of the base station further includes text related to the schedule information to be notified to the user operating the wireless terminal in the broadcast message,
The broadcast message receiving means of the wireless terminal preferably instructs the text included in the broadcast message to be displayed on the display unit of the wireless terminal.

  According to another embodiment of the wireless communication system of the present invention, when the power supply control unit of the wireless terminal turns on the power supply to the wireless communication unit, it has fluctuations for a time based on a random number within a predetermined time range. It is also preferable to delay.

According to the present invention, in a wireless communication method in a system including a base station having an antenna that can variably control the radiation direction and / or radiation angle of a radio wave, and a wireless terminal having a wireless communication unit that communicates with the base station,
A first step in which the base station creates schedule information that defines the activation time timing of the wireless communication unit in the wireless terminal;
A second step of creating a broadcast message including schedule information and broadcasting to a wireless terminal via an antenna;
A third step in which the wireless terminal receives the broadcast message and obtains schedule information;
A fourth step in which the wireless terminal performs on / off control of power supply to the wireless communication unit in accordance with the startup time timing of the schedule information;
A fifth step of controlling the antenna to emit radio waves while changing the radiation direction and / or the radiation angle at a timing according to the schedule information,
The timing at which the radiation direction and / or the radiation angle of the radio wave of the base station is directed to the wireless terminal is synchronized with the timing at which power supply is turned on to the wireless communication unit of the wireless terminal.

  According to the wireless communication system and method of the present invention, the coverage area of a base station that is out of service is compensated, a communication opportunity is provided to the wireless terminal, congestion of the base station due to concentration of communication requests is alleviated, and the wireless terminal The battery can run out less. In particular, all the [Problems 1 to 4] described above can be solved.

1 is a system configuration diagram in a wireless communication network in which a plurality of base stations and a plurality of wireless terminals are arranged in a distributed manner. It is a system configuration | structure figure of a radio | wireless communication network when a failure generate | occur | produces in some base stations. It is explanatory drawing by which the radiation direction of the electromagnetic wave from a base station is controlled to a horizontal direction with respect to the ground surface. It is explanatory drawing by which the radiation direction of the electromagnetic wave from a base station is controlled by the orthogonal | vertical direction with respect to the ground surface. It is a functional block diagram of the base station and radio | wireless terminal in this invention. It is a flowchart of the base station and radio | wireless terminal in this invention. It is explanatory drawing showing the radiation direction of the electromagnetic wave for transmitting a broadcast message. It is explanatory drawing showing the 1st radiation | emission direction in the electromagnetic wave radiated | emitted from a base station. It is explanatory drawing showing the 2nd radiation | emission direction in the electromagnetic wave radiated | emitted from a base station. It is explanatory drawing showing the 3rd radiation | emission direction in the electromagnetic wave radiated | emitted from a base station. It is explanatory drawing showing the radiation range from which an electromagnetic wave differs according to the number of the radio | wireless terminals located in the area of a radiation direction.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  According to the present invention, even when a base station fails due to, for example, a power failure or a disaster, a neighboring base station that is in operation can systematically provide a communication service to a wireless terminal (SCoP (Scheduled Coverage Provision)). The base station operates in “normal mode” or “failure mode”. The “failure mode” means that a failure has occurred in an adjacent base station for the base station.

The base station has an antenna that can control the directivity of radio wave radiation, and switches the directivity according to the mode.
Normal mode: No directivity (omnidirectional)
Failure mode: Directivity The base station in the “failure mode” extends the distance of radio wave radiation as much as possible by narrowing down the radio wave directivity. As a result, radio waves can be radiated to the area covered by the base station where the failure has occurred.

  FIG. 3 is an explanatory diagram in which the radiation direction of radio waves from the base station is controlled in the horizontal direction with respect to the ground surface.

  According to FIG. 3, the radio wave from the base station 1a is divided into six radiation directions in the horizontal direction with respect to the ground surface. Then, the base station 1a switches the directional radio wave so as to rotate every predetermined time (for example, 20 minutes) or at a predetermined angular velocity. As a result, the communication service is provided for a predetermined time only to the wireless terminal 2 located in a specific area (radiation direction). At this time, since a communication opportunity can be physically given only to a specific area in the radial direction, the number of terminals performing connection attempts at the same time can be reduced (solution to [Problems 3 and 4]).

  Further, according to FIG. 3, there are a large number of wireless terminals 2a to 2e communicating with the base station around the base station 1a. Here, when the base station 1a is in the “normal mode”, the wireless terminals 2a to 2c are located in an area where the omnidirectional radio wave can be received. On the other hand, the wireless terminals 2d and 2e are not located in an area where radio waves can be received in the “normal mode” of the base station 1a. Of course, the wireless terminals 2d and 2e cannot communicate with the base stations 1d and 1e that have failed.

  Here, when the base station 1a is in the “failure mode”, radio waves having directivity are radiated while switching directions. That is, according to FIG. 3, when the radiation direction of the base station 1a is directed to the position of the wireless terminal 2d, the wireless terminal 2d can communicate with the base station 1a. Thereafter, when the radiation direction of the base station 1a is directed to the position of the wireless terminal 2e, the wireless terminal 2e can communicate with the base station 1a. On the other hand, the radio terminals 2a to 2c cannot communicate with the base station 1a unless the radiation direction of the base station 1a is directed to the positions of the radio terminals 2a to 2c.

  According to FIG. 3, it has further the control apparatus 3 connected with all the base stations 1 via the communication carrier network. The control device 3 collects base station operation information indicating whether or not a failure has occurred from all the base stations 1. Then, SCoP information (mode shift command and transmission output value) based on the base station operation information is transmitted to each base station 1. The mode transition command represents “normal mode / failure mode”. The transmission output value represents a level that can cover the communication incapable area (cover area of the base station that has failed).

  The control device 3 transmits SCoP information (failure mode and transmission output value) to a base station adjacent to the base station where the failure has occurred. Then, after recovery from the failure, SCoP information (normal mode) is transmitted to the base station instructing the failure mode.

  FIG. 4 is an explanatory diagram in which the radiation direction of radio waves from the base station is controlled in a direction perpendicular to the ground surface.

  According to FIG. 3 described above, the base station controls the radiation direction of radio waves in the horizontal direction using, for example, an array antenna. On the other hand, according to FIG. 4, the radiation direction of the radio wave is controlled in the vertical direction by using, for example, a sector antenna having an electric tilt. An example of such an antenna is an active antenna system (see, for example, Non-Patent Document 1). Of course, according to the present invention, the horizontal direction and the vertical direction may be changed simultaneously. According to the present invention, it is important to systematically create a communication area with a limited area.

  FIG. 5 is a functional configuration diagram of the base station and the wireless terminal in the present invention.

  According to FIG. 5, the base station 1 includes an antenna communication unit 101, a communication carrier network interface unit 102, an encoding / decoding unit 11, a schedule information creation unit 12, a broadcast message creation unit 13, and radio waves. And a radiation control unit 14.

  The antenna communication unit 101 is an antenna that radiates radio waves having directivity, and has a large number of antenna elements in order to change the radiation direction. The antenna communication unit 101 includes a plurality of antenna elements arranged in a plane, a phase level adjustment unit for each antenna, and one distribution unit. The distribution unit distributes the transmission signal to each antenna element and integrates the reception signal from each antenna element. The phase level adjustment unit for each antenna adjusts the amplitude and phase of the radio wave (controls the transmission array weight vector) in accordance with an instruction from the radio wave radiation control unit 14. Thereby, the radiation direction and / or radiation angle of the radio wave is variably controlled. Even if the output of each antenna element is weak, a large output is obtained as a result of combining the outputs from a plurality of antenna elements.

  Regarding the transmission of radio waves, the combined wave radiated simultaneously from each antenna travels in a direction perpendicular to the antenna surface. Here, the composite wave is radiated in an oblique direction from the antenna surface by shifting the phase of the radio wave for each antenna. On the other hand, regarding the reception of radio waves, the incident direction of radio waves can be detected by detecting the phase difference of each antenna.

  The encoding / decoding unit 11 encodes data received from the communication carrier network interface unit 102 and outputs the data to the antenna communication unit 101. Also, the data received from the antenna communication unit 101 is decoded and output to the communication carrier network interface unit 102.

The schedule information creation unit 12 generates schedule information that defines the activation time timing of the wireless communication unit of the wireless terminal. The schedule information creation unit 12 receives the SCoP information from the control device 3, and creates schedule information for each radiation direction based on the SCoP information. The created schedule information is output to the broadcast message creation unit 13.
SCoP information: "Mode at failure" + "Transmission output value"
Schedule information: Start-up timing of the wireless communication unit of the wireless terminal (for example, every 20 minutes)
(Start time-end time and time interval, or start time and time interval)
Text message to be notified to user Further, the schedule information creation unit 12 outputs the schedule information and the transmission output value to the radio wave radiation control unit 14.

  The broadcast message creation unit 13 creates a broadcast message including schedule information. The broadcast message is created as, for example, BC-SMS (BroadCast-Short Message Service). BC-SMS is a short message service capable of broadcast transmission, for example, which is currently used for earthquake early warning, and can also transmit a short text. The broadcast message output from the broadcast message creation unit 13 is output to the encoding / coding unit 11.

  The BC-SMS format complies with, for example, the specifications of TIA / EIA (The US Telecommunications Industry Association / Electronic Industries Alliance) IS-637. This message format includes a broadcast address and can be received by all wireless terminals. According to the present invention, the failure mode start / end flag, failure mode start time, activation time timing, and flight mode release time are included as user data parameters in the BC-SMS data burst message.

  The radio wave radiation control unit 14 controls the antenna communication unit 101 to radiate radio waves while changing the radiation direction and / or the radiation angle at a timing according to the schedule information. The radio wave radiation control unit 14 controls the transmission array weight vector of the antenna communication unit 101. The radio wave radiation control unit 14 controls transmission output power from the antenna communication unit 101 according to the transmission output value input from the schedule information creation unit 12. For the base station of the sector antenna, it is also preferable to control the position of the reflector when changing the beam in the horizontal direction within the sector. It is also preferable to control the tilt angle when changing the beam in the vertical direction.

  For the base station 1, the schedule information creation unit 12, the broadcast message creation unit 13, and the radio wave emission control unit 14 described above are executed only in the “failure mode”.

  The wireless terminal 2 includes a wireless communication unit 201, a display unit 202, a battery 200, a broadcast message control unit 21, and an energization control unit 22.

  The wireless communication unit 201 can transmit and receive radio waves to and from the base station 1 upon receiving power supply from the battery 200. The wireless communication unit 201 does not waste power by cutting off the power supply from the battery 200. The state in which the wireless communication unit 201 is cut off from the power supply from the battery 200 may be referred to as “flight mode”.

  The broadcast message control unit 21 receives a broadcast message from the base station 1 via the wireless communication unit 201. The broadcast message includes schedule information for the wireless terminal 2 to energize the wireless communication unit 201. Then, the broadcast message control unit 21 outputs the activation time timing included in the schedule information to the energization control unit 22. In addition, the broadcast message control unit 21 outputs the “text message to be notified to the user” included in the schedule information to the display unit 202 and clearly indicates to the user who operates the wireless terminal 2.

  The energization control unit 22 turns on / off the power supply to the wireless communication unit 201 according to the activation time timing input from the broadcast message control unit 21. Thereby, the timing at which the base station 1 changes the radiation direction and / or the radiation angle can be synchronized with the timing at which the wireless communication unit 201 of the wireless terminal 2 is turned on. That is, the power supply to the wireless communication unit 201 is turned on only at a timing when the area of the radiated radio wave from the base station 1 may be directed to the position of the wireless terminal 2, otherwise, the wireless terminal 2 wirelessly The power supply to the communication unit 201 is turned off.

  Further, it is preferable that the energization control unit 22 delays with “fluctuation” by a time based on a random number within a predetermined time range when turning on the power supply to the wireless communication unit 201. Immediately after the base station 1 switches the radiation direction, the wireless terminals 2 located in the area included in the switched radiation direction transmit a communication request to the base station 1 all at once. Such a situation leads the base station 1 to an instantaneous congestion state. Therefore, according to the present invention, communication requests from a large number of wireless terminals 2 included in the radiation direction immediately after switching are made to arrive at the base station 1 with variations. In addition, when the wireless terminal 2 cannot find the base station 1 within a predetermined time, or when the wireless terminal 2 cannot find the base station 1 even after executing the base station search a predetermined number of times, The supply is turned off, and the off state (flight mode state) is continued until the next on timing.

  FIG. 6 is a flowchart of the base station and the wireless terminal in the present invention.

(S110) First, the base station 1 receives the SCoP information from the control device 3, and shifts to the failure mode. And the base station 1 produces | generates the schedule information which prescribed | regulated the starting time timing of the radio | wireless communication part of a radio | wireless terminal (refer the schedule information production | generation part 12 of FIG. 5).

(S120) Next, the base station 1 creates a broadcast message including schedule information, and broadcasts it to the wireless terminal 2 via the antenna (see the broadcast message creation unit 13 in FIG. 5).
(S121) When receiving the broadcast message in the failure mode, the wireless terminal 2 shifts to the “failure mode”.

  FIG. 7 is an explanatory diagram showing the radiation direction of radio waves for transmitting a broadcast message.

  The base station 1 broadcasts a broadcast message to all wireless terminals 2 by radiating radio waves while changing the radiation direction and / or radiation angle. The broadcast message includes “activation time timing” and “text message to be notified to the user” in the radiation direction.

According to FIG. 7, the broadcast message received by the wireless terminal 2e includes the following activation time timing, for example.
“Search for base stations every 20 minutes from 9:00 (after 5 minutes)”
“If you do not find a base station after searching for 10 seconds, switch to flight mode.”
“If you ca n’t find a base station after 10 searches, go to flight mode.”

  Here, the “flight mode” (in-flight mode) is generally a mode in an airplane and is a mode in which the wireless terminal does not emit or receive any radio waves. Of course, it is not limited to the existing flight mode, and any mode that does not emit or receive radio waves may be used. As a result, the wireless terminal that is out of the communication range does not repeat the base station acquisition process (search process), and [Problem 2] is solved.

The broadcast message includes, for example, the following text message.
"[Notice from company a] Shifts to disaster mode. Please check the screen every 20 minutes. Communication will be possible within 2 hours. When communication is possible, we will notify you again on the screen. Until then, it will be in flight mode, but this is not a malfunction. "

(S122) The wireless terminal 2 displays the text message included in the broadcast message on the display of the wireless terminal 2 and clearly indicates it to the user.

(S123) The wireless terminal 2e shifts to the flight mode and turns off the energization of the energization control unit 22 until the activation time of the wireless terminal 2e.

(S130) The base station 1 radiates radio waves while changing the radiation direction and / or the radiation angle at a timing according to the schedule information. On the other hand, the wireless terminal 2 performs on / off control of power supply to the wireless communication unit according to the start time timing of the schedule information.

  FIG. 8 is an explanatory diagram showing a first radiation direction in the radio wave radiated from the base station.

  According to FIG. 8, even if the wireless terminal 2d cannot communicate with the base station 1a in the normal mode, it can communicate with the base station 1a in the failure mode. As a result, the wireless terminal 2d out of the communication range can also communicate, and [Problem 1] is solved.

  On the other hand, the radio terminals 2a to 2c that can communicate with the base station 1a even in the normal mode cannot communicate with the base station 1a. In the failure mode, the wireless terminals 2a to 2c cannot communicate unless the radiation direction and / or radiation angle of the radio wave radiated from the base station 1a includes its own position.

  For example, the wireless terminal 2a cannot communicate with the base station 1a because the wireless terminal 2a is outside the communication range in the radiation direction of the radio wave radiated from the base station 1a. The wireless terminal 2a energizes the wireless communication unit from the battery at the timing when the base station 1a changes the radiation direction of the radio wave to the first radiation direction. However, even if the base station 1a is searched for 10 seconds, the base station 1a cannot be found. Move to “Flight Mode”. When outside the communication range, the user who operates the wireless terminal 2a can also reserve data transmission for the application of the wireless terminal 2a. For example, it may be a mail transmission reservation.

  FIG. 9 is an explanatory diagram showing a second radiation direction in the radio wave radiated from the base station.

  FIG. 9 shows the radio wave emission control of the base station 20 minutes after FIG. The radio wave emission direction of FIG. 9 is rotated from the radio wave emission direction of FIG. As a result, the wireless terminals 2a and 2e, which are out of range in FIG. 8, are within the range of the base station 1a in FIG. On the other hand, the wireless terminal 2d that was in the area in FIG. 8 is outside the area of the base station 1a in FIG. When the wireless terminal 2a is reserved for data transmission when out of service area, the data is automatically transmitted at this timing.

  As a result, since the operating base station communicates only in a specific radiation direction, the number of wireless terminals to communicate with does not increase. That is, communication requests from a large number of wireless terminals are not concentrated, and the congestion state is eased, and [Problem 3] and [Problem 4] are solved.

(S131) The wireless terminals 2a and 2e release the flight mode by energizing the wireless communication unit from the battery. Here, the radio terminals 2a and 2e can find a pilot signal from the base station 1a by searching the base station.

(S132) The wireless terminals 2a and 2e are provided with a communication service from the base station 1a during the activation time timing (activation time interval).

  At this time, it is also preferable that the base station 1a notifies the duration in the radiation direction by BC-SMS or a control message. Thereby, after the continuation time elapses, the wireless terminals 2a and 2e can automatically shift to the flight mode again. In addition, this BC-SMS or control message is alert | reported only within the range of the said radiation direction, and is not alert | reported to another radiation direction.

(S133) Thereafter, after the activation time timing has elapsed, the wireless terminals 2a and 2e turn off the energization control unit 22 again and shift to the flight mode.

  FIG. 10 is an explanatory diagram showing a third radiation direction in the radio wave radiated from the base station.

  FIG. 10 shows the radio wave emission control of the base station 20 minutes after FIG. The radio wave radiation direction of FIG. 10 is rotated from the radio wave radiation direction of FIG. As a result, the wireless terminal 2b, which is out of range in FIGS. 8 and 9, is within the range of the base station 1a in FIG. On the other hand, the wireless terminals 2a and 2e that are within the range in FIG. 9 are out of the range of the base station 1a in FIG.

(S140) The base station 1a determines whether or not the “failure mode” is still maintained after making a round of all the radiation directions (for example, rotating 360 degrees).

(S150) When “failure mode” is maintained, the schedule information is updated. Here, the schedule information includes, for each radiation direction and / or radiation angle, the activation time timing and / or the radiation direction and / or the radiation angle depending on the number of wireless terminals included in the area and / or the communication amount. , Will be defined again.

  FIG. 11 is an explanatory diagram showing different radiation ranges of radio waves according to the number of wireless terminals located in the area in the radiation direction.

  According to FIG. 11, the width of the beam from the antenna is narrowed down for an area where the number of wireless terminals or the amount of communication is large. On the other hand, the beam width is widened in an area where the number of wireless terminals or the communication amount is small. For example, if the number of wireless terminals located in the first radiation direction area is twice the number of wireless terminals located in the second radiation direction area, the beam angle in the first radiation direction is , Set to ½ of the beam angle in the second radiation direction. For example, the beam angle in the first radiation direction is set to 15 degrees, and the beam angle in the second radiation direction is set to 30 degrees.

  As another embodiment, even if the beam angles are the same, the allocation time in the first radiation direction may be set to twice the allocation time in the second radiation direction. For example, the allocation time in the first radiation direction is set to 40 minutes, and the allocation time in the second radiation direction is set to 20 minutes.

(S160) When the “normal mode” is set, the base station 1 is notified of the broadcast message (normal mode) while changing the radiation direction and / or the radiation angle.

(S161) The wireless terminal 2 shifts to the normal mode by receiving the broadcast message (normal mode).

(S170) The base station 2 shifts to the normal mode and radiates radio waves in a non-directional manner.

  As described above in detail, according to the radio communication system and method of the present invention, the coverage area of a base station that is out of service is compensated, communication opportunities are provided to radio terminals, and base stations due to concentration of communication requests are provided. And the battery of the wireless terminal can be reduced. In particular, all the [Problems 1 to 4] described above can be solved.

  Various changes, modifications, and omissions of the above-described various embodiments of the present invention can be easily made by those skilled in the art. The above description is merely an example, and is not intended to be restrictive. The invention is limited only as defined in the following claims and the equivalents thereto.

DESCRIPTION OF SYMBOLS 1 Base station 101 Antenna communication part 102 Communication carrier network interface part 11 Encoding / decoding part 12 Schedule information preparation part 13 Broadcast message preparation part 14 Radio wave emission control part 2 Radio | wireless terminal 200 Battery 201 Wireless communication part 202 Display part 21 Same Information message control unit 22 Energization control unit

Claims (9)

In a radio communication system having a base station having an antenna capable of variably controlling the radiation direction and / or radiation angle of a radio wave, and a radio terminal having a radio communication unit communicating with the base station,
The base station
Schedule information creating means for creating schedule information defining the activation time timing of the wireless communication unit in the wireless terminal;
Creating a broadcast message including the schedule information, and sending a broadcast message to a wireless terminal via an antenna; and
Radio wave radiation control means for controlling the antenna to radiate radio waves while changing the radiation direction and / or radiation angle at the timing according to the schedule information,
The wireless terminal is
Broadcast message control means for controlling based on schedule information of the broadcast message;
Energization control means for controlling on / off of power supply to the wireless communication unit according to the start time timing of the schedule information,
A wireless communication system characterized by synchronizing a timing at which a radio wave radiation direction and / or radiation angle of a base station is directed to the wireless terminal and a timing at which power supply is turned on to a wireless communication unit of the wireless terminal.   The energization control means of the wireless terminal turns on the power supply to the wireless communication means, and if the base station cannot be found even after a lapse of a predetermined time or a predetermined number of base station searches, the power supply is again supplied. 2. The wireless communication system according to claim 1, wherein the wireless communication system is turned off until the next turn-on timing.   The radio communication system according to claim 1 or 2, wherein a radio wave radiation direction in the radio wave radiation control means of the base station is controlled in a horizontal direction and / or a vertical direction with respect to a ground surface.   The schedule information creating means of the base station is provided for each radio wave radiation direction and / or radiation angle according to the number of radio terminals and / or the amount of communication included in the radio wave radiation direction and / or radiation angle area. 4. The wireless communication system according to claim 1, wherein different radiation directions and / or radiation angles are defined in the schedule information. 5. The base station has a normal mode and a failure mode,
The schedule information creation means, the broadcast message creation means and the radio wave emission control means are executed only in the failure mode,
5. The broadcast message creating means transmits the broadcast message including the normal mode or the failure mode using BC-SMS (BroadCast-Short Message Service). The wireless communication system according to any one of the above. The system further comprises a control device for controlling the mode of the base station,
The controller is
From each base station, collect base station operation information indicating the presence or absence of failure,
Instructing the failure mode to the base station adjacent to the failed base station,
6. The wireless communication system according to claim 1, wherein after the failure is restored, the normal mode is instructed to the base station that has instructed the failure mode. The broadcast message creation means of the base station further includes text related to the schedule information to be notified to the user operating the wireless terminal in the broadcast message,
7. The broadcast message receiving means of the wireless terminal instructs to display the text included in the broadcast message on a display unit of the wireless terminal. The wireless communication system described.   The power supply control unit of the wireless terminal delays with fluctuations by a time based on a random number within a predetermined time range when turning on the power supply to the wireless communication unit. The wireless communication system according to any one of the above. In a wireless communication method in a system having a base station having an antenna capable of variably controlling the radiation direction and / or radiation angle of a radio wave, and a wireless terminal having a wireless communication unit communicating with the base station,
A first step in which the base station creates schedule information that defines a startup time timing of a wireless communication unit in the wireless terminal;
A second step of creating a broadcast message including the schedule information and broadcasting to the wireless terminal via an antenna;
A third step in which the wireless terminal receives the broadcast message and acquires the schedule information;
A fourth step in which the wireless terminal performs on / off control of power supply to the wireless communication unit according to a start time timing of the schedule information;
A fifth step of controlling the antenna to emit radio waves while changing the radiation direction and / or radiation angle at a timing according to the schedule information,
A wireless communication method characterized by synchronizing a timing at which a radiation direction and / or radiation angle of radio waves of the base station is directed to the wireless terminal and a timing at which power supply is turned on to a wireless communication unit of the wireless terminal.

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