JP2012205176A - Radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication system capable of suppressing the power consumption of a battery in an out-of-zone state and suppressing the delay of time of returning to an in-zone state.SOLUTION: A radio communication system includes a mobile station, a normal transmission base station for normally periodically and wirelessly transmitting downlink transmission signals to the mobile station, and an emergency transmission base station for wirelessly transmitting a downlink signal when there is information to be transmitted to the mobile station. When transitioning from the state of in-zone of the normal transmission base station to that of an out-of-zone thereof, the mobile station performs the steps of: performing channel scans for intermittently searching for a base station in first intervals; measuring a reception signal level of a downlink transmission signal from the emergency transmission base station upon receiving the signal; and performing channel scans by making the reception interval of the signals from the emergency transmission base station shorter than the first interval if the reception signal level is equal to or higher than a predetermined value.

Description

  The present invention relates to a wireless device that is required to reduce power consumption, such as a wireless device that is powered by a battery, and a wireless communication system that uses the wireless device. The present invention relates to a wireless device and a wireless communication system that reduce power consumption.

  First, a description will be given of an intermittent reception control method during standby in a conventional wireless communication system. Conventionally, in a mobile communication wireless communication system represented by, for example, a mobile phone or a commercial wireless system, when a mobile station apparatus is located within a service area (in a coverage area) covered by a base station, the base station periodically Receive control information. The transmission period of the control information from the base station is defined in advance by the system, and is transmitted at a constant period mainly synchronized with the frame timing of base station transmission called a super frame. The mobile station apparatus determines whether the incoming call is for the mobile station apparatus by receiving the control information. If the incoming call is not for the mobile station apparatus, the mobile station apparatus has a timing other than the control information reception section. And power down control of each processor including a CPU (Central Processing Unit) to suppress power consumption of the battery.

  On the other hand, when the mobile station apparatus moves and becomes out of the service area (out of service area) of the base station, control information cannot be received from the base station, and is stored in the frequency table of the mobile station apparatus. Measure periodically the received electric field strength or signal-to-interference wave level at each frequency transmitted by multiple base stations, and access to the base station again when returning to the service area of any base station Control to resume.

  In the prior art, in order to extend the usage time of a mobile station device driven by a battery, a time interval for performing a search for base station control information (hereinafter referred to as channel scan) performed when the mobile station device is out of service is By setting it longer than the intermittent reception operation to be performed, control for suppressing the power consumption of the battery when out of service is performed.

  However, in the out-of-service state as described above, when the intermittent reception cycle longer than the in-service state is set, it is possible to suppress the power consumption of the battery compared to the in-service state, but when the cycle is simply increased, There is a trade-off relationship between the time interval and the time until return to the service area due to movement, and there is a high possibility that the mobile station apparatus remains in the out-of-service state even in an environment where the mobile station apparatus can be used (an environment in which the mobile station apparatus can enter the service area).

  Also, in mobile communications, the radio propagation path situation is unstable, and not only the simple horizontal plane area of the base station, but also the influence of terrain buildings, so the transition to the in-range or out-of-range state is unstable, In systems where frequent transitions to in-range or out-of-range conditions occur, simply increasing the intermittent reception interval when out-of-range cannot be set to a sufficient length, reducing battery power consumption Is not sufficiently obtained.

Further, in a radio communication system, as a signal transmission / reception method between a base station and a mobile station apparatus, in addition to the above-mentioned regular transmission system that constantly transmits a downlink transmission signal from the base station, it transmits to the mobile station apparatus. There is an emergency transmission system including an emergency transmission base station from which a base station outputs a transmission signal when there is a message to be transmitted, specifically, user information such as control information for a mobile station device, voice or text message.
Patent Document 1 below discloses a control method for a mobile station radio in an industrial digital radio system having an emergency transmission base station that transmits a downstream wave from a base station when necessary.

JP 2003-199156 A

As described above, in the conventional wireless communication system, in the out-of-service state, simply setting an intermittent reception period longer than the in-service state does not sufficiently suppress the power consumption of the battery, or the time until returning to the service area There was a problem of slowing down.
The present invention has been made to solve such a conventional problem, and even in an emergency transmission system, the power consumption of the battery can be suppressed in an out-of-service state, and the time until return to the service area is delayed. An object of the present invention is to provide a wireless communication system capable of suppressing the above.

A typical configuration of the present invention for solving the above problems is as follows. That is,
A mobile station,
A regular transmission base station that periodically and periodically transmits a downlink transmission signal to a mobile station;
An emergency transmission base station that wirelessly transmits a downlink transmission signal when there is information to be transmitted to the mobile station,
When the mobile station transitions from the in-range state of the regular transmission base station to the out-of-range state, it performs a channel scan that intermittently searches for a base station at a first interval, and receives a downlink transmission signal from the emergency transmission base station. Measure the received signal level of the signal, and when the received signal level is equal to or higher than a predetermined value, perform a channel scan with a signal reception interval from the emergency transmission base station shorter than the first interval. A wireless communication system.

  According to the present invention, it is possible to suppress the power consumption of the battery in the out-of-service state, and it is possible to suppress the time until the service area is restored.

It is a figure which shows the structure of the mobile station apparatus which concerns on embodiment of this invention. It is a figure which shows the frame structure which concerns on embodiment of this invention, and the state of a mobile station apparatus. It is a flowchart explaining the process of 1st Example. It is a flowchart explaining the process of 2nd Example. It is a flowchart explaining the process of 4th Example.

  In the present embodiment, when the mobile station device driven by a battery is located outside the base station coverage area, the standby reception is repeated in a cycle longer than the intermittent reception time interval in the coverage area, The continuation time that is located outside the service area is measured, and when the time that the mobile station is located outside the service area reaches a predetermined time or longer, adaptive control is performed to increase the intermittent reception time when the service area is out of service area.

  In addition, in the control of the intermittent reception time when outside the service area, the reception signal level from the base station is periodically measured when the service area is outside the service area, and the intermittent reception interval when the service is outside the service area is controlled according to the measured amount of change in the reception signal level. Specifically, when the amount of change in the received signal level exceeds a predetermined level, adaptive control is performed to shorten the intermittent reception time when out of service.

  Furthermore, the mobile station apparatus includes a means for acquiring position information such as GPS (Global Positioning System) as an externally connected device or as a built-in functional unit, holds changes in the position information, and moves the mobile station apparatus The intermittent reception interval at the time of out-of-service is controlled according to the state. Specifically, when the amount of movement of the mobile station apparatus exceeds a predetermined amount of movement, the intermittent reception interval at the time of out-of-service is adaptively controlled to shorten the time.

  In addition, the wireless communication system to which the mobile station device belongs is a regular transmission base station in which the base station device constantly transmits control information periodically, and an emergency transmission in which the base station device transmits control information when there is information to be transmitted. If the emergency transmission system has both base stations, the transmission status of the destination base station (regular transmission / emergency transmission) when moving to another base station area within the service area of the base station. ) To automatically change the control of the standby reception interval. Specifically, for example, when the destination base station is a regular transmission base station, the above-mentioned mobile station out-of-service stay time or reception signal Controls the intermittent reception interval when out of service according to the amount of change in level and the amount of movement of the mobile station device, and when the destination base station is an emergency transmission base station, the received signal level is greater than or equal to a predetermined value Can always receive transmission signal from base station To control.

  According to the above-described embodiment, the intermittent reception interval is controlled while monitoring the status of the mobile station device when it is out of service, such as the out-of-service time, position, and received signal level. You can recognize the increase. Therefore, it is possible to reset the time interval of intermittent reception when out of service area before moving to the service area position, and it is possible to suppress delay in the service area transition time due to intermittent reception and to reduce battery power consumption. It becomes.

  FIG. 1 shows the configuration of a mobile station apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 101 denotes an antenna unit that includes an antenna that receives a radio frequency band signal from the air during a reception operation and transmits a radio frequency band signal from the radio unit 102 during a transmission operation. is there. Reference numeral 102 denotes a radio unit that performs frequency conversion of a high-frequency band signal received by the antenna unit 101 into a baseband signal and performs reverse frequency conversion at the time of transmission. Reference numeral 103 denotes a DA converter (digital analog converter) that converts a baseband output of a digital signal to be transmitted into an analog signal and outputs the analog signal to the wireless unit 102. A modulation unit 104 performs data modulation processing on a signal to be transmitted and outputs a modulated signal to the DA converter 103. Reference numeral 105 denotes a channel encoder that performs encoding for error correction of a signal to be transmitted and framing processing corresponding to a radio frame defined in the radio communication system.

  Reference numeral 106 denotes an AD converter (analog / digital converter) that converts an analog signal from the wireless unit 102 that has received user data such as a control signal from a base station, an audio signal, and a non-audio digital signal into a digital signal. Reference numeral 108 denotes a demodulator that demodulates the signal modulated by the base station and performs data demodulation of the baseband signal that is the output of the AD converter 106. Reference numeral 109 denotes a synchronization unit that extracts the synchronization timing of a radio frame signal from the base station by detecting the coincidence of a specific known pattern based on the received data, and manages the radio frame timing synchronization with the base station. . Reference numeral 110 denotes a channel decoder unit that performs error correction processing on the demodulated signal from the demodulation unit 108 and extracts data. A reception level measurement unit 112 measures the reception signal level and reports the channel quality of the connected base station and the reception levels of the neighboring base stations to the 111 control unit.

  Reference numeral 113 denotes a display unit as a user interface for displaying a clock, mail, and the like. Reference numeral 114 denotes an input unit as a user interface for inputting characters, telephone numbers, and the like. Reference numeral 107 denotes a saving timer that controls a time interval when performing intermittent reception operation within or outside of the service area. When the reception operation is performed again after each function unit is powered down, the timer 111 wakes up the control unit 111 due to the timeout of this timer. Input an up interrupt signal. Reference numeral 115 denotes a GPS receiving unit for acquiring the movement state of the mobile station apparatus using the position information.

  111 includes a CPU, performs wireless protocol processing such as line connection and disconnection with the base station, and controls each component of the mobile station apparatus including processing of user interfaces such as the display unit 113 and the operation unit 114 It is a control part which performs. In addition, the control unit 111 controls the intermittent reception interval of the mobile station device and the intermittent operation of each component unit such as the radio unit 102 based on the measurement result of the reception level measurement unit 112, the measurement result of the GPS reception unit 115, and the like. Also performs power-down control during reception.

Next, the intermittent reception operation of this embodiment will be described.
First, a description will be given of the intermittent reception operation in the standby state in the area. When the mobile station apparatus is located in the base station area, the mobile station apparatus is in a standby state except communication of user data including voice and communication of control information within the wireless communication system. In the standby state, the base station periodically transmits control information at a predetermined timing, and the mobile station apparatus periodically receives the control information.
In the radio communication system of this embodiment, a communication unit between a mobile station apparatus and a base station is a radio frame, a super frame is composed of a plurality of radio frames, and the position of control information in the super frame is defined in advance. Thus, periodic transmission of control information is realized. FIG. 2 shows a frame configuration example and the state of the mobile station apparatus. In the example of FIG. 2, the length of one frame is 40 ms, the superframe is 18 frames (720 ms) from frame 0 to frame 17, and the mobile station apparatus receives the control information in frame 0 and frame 1, for example, When it is determined by the control information that the transmission is not addressed to the own station, that is, when it is determined that the state should be continuously waited for, the reception timing of frame 0 of the next superframe to be received and the movement after the power-down is canceled Timing in consideration of the time required for starting the station apparatus is set in the saving timer 107, and a transition is made to the power-down state. The time required for starting the mobile station apparatus depends on the mobile station apparatus.

  In the power-down state, the wireless unit 102, DA converter 103, modulation unit 104, channel encoder 105, AD converter 106, demodulation unit 108, synchronization unit 109, channel decoder 110, and reception level measurement unit 112 are powered on. Although the power is not supplied, the control unit 111, the saving timer 107, the GPS receiving unit 115, the display unit 113, and the operation unit 114 are continuously supplied with power.

  At the power-down release timing, an interrupt signal is input to the control unit 111 due to a timeout of the saving timer 107, the power-down of the mobile station device is released, and the mobile station apparatus shifts to the reception state again. By repeating this operation, the standby state in the area is continued.

Next, the operation when out of service will be described.
When out of service area, control information of the base station cannot be received, and radio frame and superframe synchronization is not established, so the channel scan timing is arbitrary, and operates based on the timing of the mobile station device .

  The channel scan is performed as follows. That is, the mobile station apparatus holds a plurality of frequency information for performing communication with a plurality of base stations in advance as a table, and sequentially selects a frequency from among the plurality of candidate frequencies. The frequency is set as the reception frequency of mobile station apparatus radio section 102, and the level of the received signal at that frequency is measured. The reception level is usually measured by the electric field strength. When the reception level is equal to or higher than a preset threshold value, demodulation processing is performed to establish synchronization, and control information is received.

(First embodiment: Control by reception level measurement variation)
As a result of the channel scan, if it is determined that there is no channel whose reception level is equal to or higher than the threshold value and it is continuously in the out-of-service state, the power-down state is entered again, and the next is performed by the saving timer 107 as in the in-service area Is set to the channel scanning timing (power down time: T). At this time, the timing of transition from the in-range to the out-of-range is stored in the storage unit of the mobile station device. Specifically, in order to simplify the determination process in the control unit 111, the number of times that a series of periodic processing of power down / channel scan is continued is monitored, and the number of continuations (n) is a predetermined number ( N) If it is above, the power down time is changed longer. _Assuming that the first stage power-down time is T _out1 and the second stage power-down time is T _out2 ,
n (T _out1 )> N then T = T _out2 (T _out2 > T _out1 )
If the power down time is extended step by step as described above and the device is stably in the out-of-service state, the number of channel scans per unit time can be reduced to reduce battery power consumption when out of service. Realize.

However, if the above-mentioned stepwise extension of the channel scan cycle when out of service area is simply performed, the mobile station device stays in the out-of-service environment for a long time and then returns to the service area due to movement, etc. As compared with the case where the channel scan interval extension is not performed, there is a problem that the time until the area is restored is delayed by the extension of the channel scan interval.
In this embodiment, in order to avoid this problem, if it is determined that there is a high possibility of returning to the service area based on the received signal level measurement information at the time of channel scanning outside the service area, the time interval is gradually increased. The extended saving timer value is returned to the initial short channel scan period.

  As described above, during the channel scan, the reception signal level of the candidate channel (frequency) is measured. If the reception signal level is equal to or higher than the threshold value, synchronization is established and reception of the control signal is performed step by step. Do. Here, in synchronization establishment, a unique bit string used for synchronization between a base station and a mobile station apparatus is generally defined, and the detection is used for synchronization determination. For control signal reception, the control signal transmitted on the base station side is encoded with an error detection code such as encoding and CRC (Cyclic Redundancy Check) according to certain rules. It is possible to determine whether the station information has been received.

  The determination result of the amount of change in the received signal level is used to determine whether or not to return the channel scan period to the initial stage, that is, whether or not there is a high possibility of returning to the range. The reception signal level is measured based on the received electric field strength for each set frequency. In this case, the determination is made based on the relative change amount for each frequency. For example, as a typical example, the results of periodic channel scans at a certain frequency are all at a stable and low level, whereas the results of the most recent measurement are sufficiently higher than the previous measured values. This is the case when the level is large and fluctuates. Also in this determination, a predetermined threshold value (ΔR) is set in advance for the amount of fluctuation of the received signal level, and when the fluctuation amount exceeds the threshold value (ΔR), the channel scan cycle is set to the initial stage. return.

An example of the operation outside the above range will be described with reference to FIG. FIG. 3 is a flowchart for explaining the processing of the first embodiment. In the example of FIG. 3, received signal strength indication (RSSI) is used as the received signal level.
In FIG. 3, when a transition is made to the out-of-service state, first, the timer value of the saving timer 107 is set (step S1), and the mobile station apparatus is powered down (step S2). An interrupt signal is input to the control unit 111 due to timeout of the saving timer 107, and the control unit 111 cancels the power down and performs a channel scan (step S4).
As a result of the channel scan, if there is a channel whose received electric field strength is equal to or greater than the threshold value (Yes in step S5), synchronization is established in that channel and the area transition is performed (step S6).
As a result of the channel scan, if there is no channel whose received electric field strength is equal to or higher than the threshold value (No in step S5), if there is a channel whose variation in received electric field strength exceeds a predetermined threshold value (ΔR) ( In step S7, the number (n) of the series of power-down / channel scan cycle processing is cleared to zero, the timer value of the saving timer 107 is initialized (step S8), and the channel scan cycle is returned to the initial stage. .

  When there is no channel in which the variation amount of the received electric field intensity exceeds the predetermined threshold value (ΔR) (No in step S7), the number (n) of performing a series of periodic processing of power down / channel scan is predetermined. (N in step S10), the number (n) is cleared to zero (step S11), the timer value of the saving timer 107 is changed (step S12), and the power down time is lengthened. In step S11, the predetermined number (N) may be updated to a different number, for example, a larger number or a smaller number.

  As described above, in the example of FIG. 3, when there is no channel in which the fluctuation amount of the received electric field intensity exceeds the predetermined threshold value (ΔR), the power down time becomes gradually longer. Can be reduced. In addition, when there is a channel whose received electric field strength fluctuation amount exceeds a predetermined threshold value (ΔR), the power down time is returned to the initial short value, so that the time to return to the service area is delayed. Can be suppressed.

(Second embodiment: control based on position information change amount)
A case where the GPS receiver 115 is used in the control of the power-down period when out of service will be described.
The GPS receiving unit 115 can provide the control unit 111 with 1 PPS (Pulse Per Second) signal, 10 MHz reference signal, and coordinate data as position information by receiving a GPS signal from the satellite. Depending on the wireless communication system, it is possible to know the position of the mobile station, the distance from the base station, etc. by notifying the coordinate data to the upper network side, but in this embodiment, the cooperation with the upper network system is Control is performed by simply grasping the change in relative position. That is, similar to the calculation of the amount of change in the received signal level when out of service described above, the relative position change in the position information acquired by the GPS receiver 115 is detected, and the amount of change in the position, that is, power down If the amount of movement of the mobile station device is large, it is determined that there is a high possibility of moving into the service area provided by the base station, and the power-down cycle is extended to a short cycle, which is the initial state, and extended in stages. Reduce the effect of the power-down cycle.

In the case of the present embodiment as well, as a result of measuring the reception signal of each frequency at the time of channel scanning, the measurement result of the reception signal level is stable and stable as in the case of changing the setting value of the saving timer value due to the level fluctuation described above. In the out-of-service state, a change in the amount of movement exceeding the predetermined threshold (ΔP) is recognized by the simple comparison of the position information acquired by the GPS receiver 115 with the position information acquired during the previous channel scan. If it is determined, it is determined that there is a high possibility of transition to a state in which communication with the base station is possible thereafter, and processing for returning to the short-cycle channel scan, that is, the setting value of the saving timer is initialized.
If no change in the amount of movement exceeding the predetermined threshold value (ΔP) is recognized, the power down time is increased stepwise as in the first embodiment when the channel scan exceeds the predetermined number of times. By performing the process, the power consumption of the battery can be reduced.

A second embodiment will be described with reference to FIG. FIG. 4 is a flowchart for explaining the processing of the second embodiment. 4 differs from FIG. 3 in that step S7 in FIG. 3 is changed to step S27 in FIG. The other points are the same as in FIG.
In step S27 of FIG. 4, if there is no channel whose received signal level is equal to or higher than the threshold value as a result of the channel scan (step S24) (No in step S25), the amount of change in position is a predetermined threshold value (ΔP). If exceeded (Yes in step S27), the number (n) of the series of power-down / channel scan cycle processing is cleared to zero and the timer value of the saving timer 107 is initialized (step S28). Return the cycle to the initial stage.

When the amount of change in the position does not exceed the predetermined threshold value (ΔP) (No in step S27), the number (n) of the series of power down / channel scan periodic processing is the predetermined number (N). (Yes in step S30), the number of times (n) is cleared to zero (step S31), the timer value of the saving timer 107 is changed (step S32), and the power down time is lengthened.
As described above, in the example of FIG. 4, when the amount of change in position does not exceed the predetermined threshold value (ΔP), the power-down time becomes gradually longer step by step, so that the reduction of the power consumption of the battery is promoted. be able to. Further, when the amount of change in position exceeds a predetermined threshold value (ΔP), the power down time is returned to the initial short value, so that it is possible to suppress the problem that the time until return to the area is delayed.

(Third embodiment: operation at the time of automatic switching of normal transmission and emergency transmission)
In the wireless communication systems shown in the first and second embodiments described above, even when there is no message addressed to the mobile station device, a downlink transmission signal with empty transmission data is always periodically transmitted from the base station. Transmitted as a reference signal, the mobile station apparatus periodically captures a control signal from the base station within the area of the base station even in a situation where message communication such as user information does not occur with the base station. It is possible to determine whether or not the communication area with the base station can be determined by the channel scan operation.

  On the other hand, in the case of an emergency transmission system including an emergency transmission base station from which a base station outputs a transmission signal when there is user data such as control information, voice or text message for the mobile station device, a downlink signal from the base station Even if an attempt is made to measure the received signal level by channel scanning using the frequency information to be used, there is a state in which the base station is not transmitting anything, so it cannot be determined whether it is in or out of range. In other words, in the emergency transmission system including the emergency transmission base station, in addition to the switching of the basic communication operation between the base stations at the time of out-of-service and out-of-service as described above, each component of the mobile station apparatus outside the communication section It is also necessary to switch the saving operation for performing power down and the like by performing power supply control.

  In the third embodiment, the mobile station apparatus stores in advance in the channel information (frequency table) information on whether the base station apparatus of that frequency takes the normal transmission mode or the emergency transmission operation mode. When the mobile station is located in the base station area, the above-mentioned in-range / out-of-range saving operation is performed, and when the mobile station moves to the emergency transmission base station area, the saving operation at the time of regular transmission is automatically switched.

  Specifically, for example, in the operation in the out-of-service area of the first and second embodiments described above, the periodic channel scan using the saving timer 107 is executed, and the result of the channel scan in a state where this operation is continued. , Detecting the frequency of the base station taking the emergency transmission mode, and if the signal level of the downlink transmission from the base station of the frequency is equal to or higher than a predetermined value, the operation by the saving timer 107 is interrupted, The operation mode corresponding to the emergency transmission base station, which is different from the operation mode for standby within and outside the service area in the second embodiment, that is, a state in which a signal from the base station can always be received is entered. When the signal level of the downlink transmission from the emergency transmission base station is smaller than a predetermined value, the operation by the saving timer 107 is continued.

  When an emergency transmission base station generates a user message such as control information or voice information from the base station to the mobile station apparatus, a downlink signal is immediately transmitted. At this time, when the mobile station apparatus performs an intermittent reception operation by power-down, it is easily conceived that the reception signal cannot be normally received. That is, in the emergency transmission system, since the intermittent reception operation by periodically capturing the base station downlink signal cannot be performed, it is preferable that the mobile station apparatus maintain the radio unit 102 in a state in which the signal from the base station can always be received. .

  In this embodiment, the mobile station apparatus recognizes whether the operation state of the base station is a normal transmission or an emergency transmission, and when the operation state of the base station is an emergency transmission, the mobile station device downloads from the emergency transmission base station. When the signal level of transmission is greater than or equal to a predetermined value, the user automatically switches to a state where the signal from the base station can always be received, so that the user performs a mode switching operation or the like depending on the communication state or movement with the base station. Even without this, it is possible to appropriately suppress the power consumption of the mobile station apparatus using a battery, and it is possible to suppress the problem that the time to return to the service area is delayed.

(Fourth embodiment: operation during emergency transmission)
In the third embodiment described above, when the mobile station apparatus moves to the area of the emergency transmission base station, the mobile station apparatus shifts to a state in which a signal from the base station can be received at all times. Continuous operation time is shortened.
Therefore, in the fourth embodiment, when the mobile station devices directly communicate with each other between the mobile station devices, the control unit 11 reduces the output power at the time of transmission of the radio unit 12. When communication is performed within a range that is not so far away, such as direct communication between mobile station apparatuses, there is no problem even if the output power during transmission is reduced. Receiving is possible if a signal having a reception sensitivity level or higher is input to the radio unit 102 of the mobile station apparatus.
Lowering the output power at the time of transmission is one of the FDMA (Frequency Division Multiple Access) systems, and since there is no concept of time division, the SCPC always keeps transmitting at the time of transmission. In the wireless communication system of the (Single Channel Per Carrier) method, the transmission time is longer than the TDMA (Time Division Multiple Access) method in which the transmission time and the reception time are divided in time, This is effective for reducing power consumption.

  In the fourth embodiment, even during emergency transmission, reception during standby is intermittent reception. When communicating with the emergency transmission base station, since the wireless communication start time is not known, unless the mobile station device receiving unit is always turned on, the reception data is cut off and the first sound cannot be received. If it is acceptable to have some time (several hundreds of milliseconds) to cut off the head, for example, if it is only necessary to listen again, the mobile station apparatus can be set to intermittent reception. For example, if the power of the receiving unit is turned ON / OFF every 80 msec when one frame is 40 ms, the power consumption of the receiving unit during standby is halved.

  At this time, on the transmission side, it is desirable to provide a call prohibition time for a predetermined time from the start of transmission. By providing the call prohibition time, it is possible to cover the head cut time on the receiving side, and reception is possible without feeling the head cut. On the transmission side, the call is made after waiting for a while during the call prohibition time. It would be more convenient if there was a function to notify the user with a sound such as “beep” when a call became possible.

FIG. 5 is a flowchart showing the processing operation of the fourth embodiment. Normally, the user does not select the low power consumption mode (OFF in step S41) and operates in the normal mode (step S42), but when the user wants to extend the battery life, the user selects the low power consumption mode. (ON in step S41) and operate in the low power consumption mode (step S43).
In the low power consumption mode, when the transmission mode is set (Yes in step S44), the output power during transmission is lowered (step S45). When the standby mode is set (Yes in step S46), intermittent reception is performed (step S47), and a call prohibition time is provided (step S48).

  As described above, in the fourth embodiment, there is a limit to the functions that can be used, such as a decrease in transmission power, a break in the head, a call prohibition time, etc., but the power consumption is reduced and the operation time is reduced as much as possible. It is effective when you want to make it longer.

  The first to fourth embodiments can be used in combination as appropriate. For example, the first embodiment and the second embodiment may be combined. Specifically, for example, when there is no channel in which the amount of fluctuation of the received electric field intensity exceeds a predetermined threshold (ΔR) in step S7 of FIG. 3 of the first embodiment, the diagram of the second embodiment. In step S27 of FIG. 4, it is determined whether or not the position change amount exceeds a predetermined threshold value (ΔP). If it exceeds, the process proceeds to step S8 of FIG. What is necessary is just to make it progress to step S9.

The present invention is not limited to a TDMA or FDMA wireless communication system, but can be applied to a mobile communication system having a wireless base station.
In addition, the present invention is understood not only as a system for executing processing according to the present invention, but also as an apparatus and method, a program for realizing such a method and system, and a recording medium for recording the program. can do.
Further, the present invention may be configured such that the CPU performs control by executing a control program stored in a memory, or may be configured as a hardware circuit.

The present specification includes at least the following inventions.
The first invention is
A mobile station,
A regular transmission base station that periodically and periodically transmits a downlink transmission signal to a mobile station;
An emergency transmission base station that wirelessly transmits a downlink transmission signal when there is information to be transmitted to the mobile station,
When the mobile station shifts from the in-range state of the regular transmission base station to the out-of-range state, the mobile station performs a channel scan to search for the base station intermittently at a first interval, and receives a downlink transmission signal from the emergency transmission base station. Measure the received signal level of the signal, and when the received signal level is equal to or higher than a predetermined value, perform a channel scan with a signal reception interval from the emergency transmission base station shorter than the first interval. A wireless communication system.
If comprised in this way, while reducing the power consumption of a battery in an out-of-service state, it can control that the time to return to the service area becomes late.

The second invention is
The wireless communication system according to the first invention,
The mobile communication system, wherein the mobile station can always receive a signal from an emergency transmission base station when the received signal level is a predetermined value or more.
If comprised in this way, it can further suppress that time to area return is delayed.

  101 .. Antenna unit, 102 .. Radio unit, 103 .. DA converter, 104 .. Modulation unit, 105 .. Channel encoder, 106 .. AD converter, 107 .. Saving timer, 108 .. Demodulation unit, 109. Synchronizing unit, 110, channel decoder, 111, control unit, 112, reception level measuring unit, 113, display unit, 114, operation unit, 115, GPS receiving unit

Claims (1)

A mobile station,
A regular transmission base station that periodically and periodically transmits a downlink transmission signal to a mobile station;
An emergency transmission base station that wirelessly transmits a downlink transmission signal when there is information to be transmitted to the mobile station,
When the mobile station shifts from the in-range state of the regular transmission base station to the out-of-range state, the mobile station performs a channel scan to search for the base station intermittently at a first interval, and receives a downlink transmission signal from the emergency transmission base station. Measure the received signal level of the signal, and when the received signal level is equal to or higher than a predetermined value, perform a channel scan with a signal reception interval from the emergency transmission base station shorter than the first interval. A wireless communication system.

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