JP2003134027A - Radio equipment, method and program for updating threshold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide radio equipment, a method and a program for updating threshold in which a threshold to be compared with a received electric field strength (RSSI) can be updated optimal corresponding to an environment. SOLUTION: This equipment is provided with a radio part 103 for outputting a baseband signal from a received signal, a decoding part 105 for decoding the baseband signal, an RSSI detecting part 107 for detecting the RSSI of the baseband signal, a signal class judging part 109 for discriminating whether the received signal is full burst or half burst by comparing the RSSI in the first half of a previously assigned slot with the RSSI in the latter half, an RSSI comparing part 111 for comparing the RSSI in the first half of the correspondent slot with a threshold predetermined by an RSSI threshold setting part 113, and a control part 115 for detecting a synchronous word from decoded data or instructing the update of the threshold to the RSSI threshold setting part 113 on the basis of the RSSI discriminated from the possibility of synchronous word detection or decoded data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless device, a threshold value updating method and a threshold value updating program for executing the method, and more particularly to updating a threshold value used for reception judgment according to environment. Wireless device, threshold updating method, and threshold updating program.

[0002]

2. Description of the Related Art A conventional wireless device enters a saving mode in which power is not supplied to a component such as a DSP that consumes a relatively large amount of power when communication is not being performed, thereby reducing current consumption of the wireless device. Is suppressed. On the other hand, in the modes other than the saving mode, the normal reception mode in which electric power is supplied to the components necessary for performing communication and other adjustments. Therefore, the conventional wireless device shifts from the saving mode to the normal reception mode at the start of communication and shifts from the normal reception mode to the saving mode at the end of communication.

For example, when a conventional wireless device used in a communication system of a system in which a multiplexing system is TDMA (Time Division Multiplexing System) and a slot for communication is preallocated by a base station, the wireless device is in a saving mode. Monitors only the received electric field strength (hereinafter, referred to as RSSI) of a slot assigned in advance. And R
SSI is a predetermined threshold value (hereinafter simply referred to as threshold value)
When the value exceeds the limit, the wireless device releases the saving mode and shifts to the normal reception mode. However, in the wireless device, the threshold value is fixedly set.

[0004]

The wireless device is often carried and used, and the environment around the device changes in various ways. When the environment changes, the ambient noise also changes, but as described above, the threshold value compared with the RSSI is set to a fixed value in the above-described conventional wireless device. May not perform the desired operation. That is, when the ambient noise of the wireless device is higher than the threshold value, the wireless device in the saving mode frequently shifts to the normal reception mode even if the transmission signal is not transmitted from the base station. In this case, there is a problem in that the power saving effect of the saving mode cannot be expected so much. On the other hand, when the threshold value is too high, even if the wireless device in the saving mode receives the transmission signal from the base station, the device does not shift to the normal reception mode, which causes a problem in communication. was there.

The present invention has been made in view of the above-mentioned conventional problems, and a wireless device that can be updated so that a threshold value to be compared with RSSI (received electric field strength) becomes optimum according to the environment, It is intended to provide a threshold updating method and a threshold updating program.

[0006]

In order to solve the above problems, a radio apparatus according to the present invention is a radio apparatus which receives a signal multiplexed by a time division multiplexing system and is assigned to the radio apparatus. R for detecting the received electric field strength (hereinafter referred to as RSSI) of the received signal in the predetermined slot
SSI detection means and RS in the first half of the slot of the received signal
Signal type determining means for comparing the SI and RSSI in the latter half of the slot and determining the type of the received signal based on the level difference, and R detected by the RSSI detecting means.
After the RSSI comparing means for comparing the SSI and the threshold value and the threshold value updating means for updating the threshold value, the received signal of the predetermined slot is judged to be a full burst signal by the signal type judging means. If the RSSI of the received signal in the predetermined slot is less than the threshold continuously for a predetermined number of frames or more, the threshold updating means updates the threshold downward.

As described above, the threshold value compared with the RSSI of a predetermined slot is not fixed, but conditions can be set and appropriately updated. Therefore, an optimum threshold value setting that is adapted to environmental changes should be performed. You can Therefore, it is possible to automatically solve the problem that the threshold value is too high and the communication is hindered even if the full burst signal is received without shifting to the normal reception mode. it can.

Further, in the radio apparatus according to the present invention, when updating the threshold value downward, the threshold value updating means lowers the threshold value by a constant value.

In the radio apparatus according to the present invention, the signal type determining means determines that the received signal in the predetermined slot is a full burst signal, and the RSSI of the received signal compared by the RSSI comparing means is the threshold value. If the value is equal to or more than the value, the wireless device in the saving mode that suppresses the current consumption shifts to the normal reception mode. As described above, since a plurality of conditions for shifting to the normal reception mode are provided, it is possible to reduce erroneous recognition of the start of communication, and as a result, it is possible to improve the power saving effect of the saving mode.

Further, in the radio apparatus according to the present invention, the radio apparatus which has shifted to the normal reception mode continues the normal reception mode if it detects the synchronization word from the reception signal of the predetermined slot.

Further, the radio equipment according to the present invention, when the condition that the synchronization word cannot be detected from the received signal in the predetermined slot after the shift to the normal reception mode has continued for the predetermined number of times, The threshold updating means updates the threshold upward. Therefore, even if the saving mode is cancelled, if the ambient noise is high and the error rate is high, and it is not possible to perform substantial communication, the threshold can be updated to an appropriate threshold for such an environment.

Further, in the radio apparatus according to the present invention, when updating the threshold value upward, the threshold value updating means raises the threshold value by a constant value.

In the radio apparatus according to the present invention, the threshold updating means does not change the threshold when the condition is not satisfied, and the threshold updating means when the condition is satisfied. After updating the threshold value upward, the wireless device in the normal reception mode shifts to the saving mode again.
Therefore, even if the start of the communication is erroneously recognized by the determination of the type of the predetermined slot and the comparison between the RSSI and the threshold value, the communication is returned to the saving mode in the case of the invalid communication in which the synchronization word cannot be detected. The power saving effect due to can be further improved.

A threshold value updating method for a wireless device according to the present invention is a threshold value updating method for a wireless device for receiving a signal multiplexed by a time division multiplexing method, and is assigned to the wireless device. R for detecting the received electric field strength (hereinafter referred to as RSSI) of the received signal in the predetermined slot
SSI detection step, comparing the RSSI of the first half of the slot and the RSSI of the second half of the slot of the received signal detected in the RSSI detection step, and a signal type determination step of determining the type of the received signal based on the level difference,
An RSSI comparison step of comparing the RSSI detected in the RSSI detection step with a threshold value, and reception in a predetermined slot after the reception signal of the predetermined slot is determined to be a full burst signal in the signal type determination step. When the RSSI of the signal is equal to or more than a predetermined number of frames and continuously less than the threshold value, the threshold value lower updating step of further updating the threshold value is further included.

The threshold updating method according to the present invention is
The lower threshold updating step lowers the threshold by a certain value.

The threshold updating method according to the present invention is
If the received signal of the predetermined slot is determined to be a full burst signal in the signal type determination step, and the RSSI of the received signal compared in the RSSI comparison step is equal to or greater than the threshold value, a saving mode for suppressing current consumption is performed. There is a normal reception mode shift step in which the wireless device shifts to a normal reception mode.

The threshold updating method according to the present invention is
The wireless device that has shifted to the normal reception mode has a sync word detecting step of detecting a sync word from a reception signal of a predetermined slot, and if the sync word is detected in the sync word detecting step, the normal reception mode is continued.

The threshold updating method according to the present invention is
In the synchronization word detecting step, when the condition that the synchronization word cannot be detected from the received signal in the predetermined slot after the shift to the normal reception mode has continued for the predetermined number of times, the threshold value is updated upward. Upper threshold updating step to perform.

The threshold updating method according to the present invention is
The upper threshold updating step raises the threshold by a constant value.

The threshold updating method according to the present invention is
When the above condition is not satisfied, the above threshold upper updating step is not executed, and when the above condition is satisfied, after the above threshold is updated in the above threshold upper updating step, the normal reception mode There is a saving mode transition step in which the wireless device transitions to the saving mode again.

Further, the threshold value updating program according to the present invention is for causing a computer to execute the threshold value updating method according to claim 8, 9, 10, 11, 12, 13 or 14.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a wireless device, a threshold value updating method and a threshold value updating program according to the present invention will be described below in detail with reference to the drawings. In addition,
In the description of each embodiment, the wireless device and the threshold value updating method according to the present invention will be described in detail, but the threshold value updating program according to the present invention is a program for executing the threshold value updating method. As such, its description is included in the description of the threshold updating method below.

In the communication system in which the wireless device of this embodiment is used, TDMA (Time Division Multiplexing System) is adopted as a multiplexing system, and slots for communication are pre-allocated by the base station. In the slot, the wireless device of this embodiment receives a full burst signal (hereinafter, simply referred to as full burst) or a half burst signal (hereinafter, simply referred to as half burst) from the base station.

The full burst and half burst will be described below with reference to FIG. First, the full burst is a signal when transmitting the actual communication contents, and
As shown in (a), the ramp transient response ramp time (R), the preamble (P), and the communication data (US
C) × 2, a synchronization word (SW), a functional channel identification signal (CI), a low speed associated control channel (SA), and a guard time (G) with no output.

The half burst is a signal transmitted from the base station except for the full burst, as shown in FIG.
, The first half of the slot is composed of a guard time (G), and the second half of the slot is a burst transient response ramp time (R), a preamble (P), and communication data (US).
C), a synchronization word (SW), a functional channel identification signal (CI), and a low speed associated control channel (SA). The received electric field strength (hereinafter referred to as RSSI) during the guard time (G) occupying the first half of the slot is lower than the RSSI of the latter half of the slot (R, P, SW, CI, SA, USC). Therefore, the RSSI of the slot in which the half burst is transmitted has a level difference between the first half and the second half. The RSSI of the slot in which the full burst is transmitted is small, and the level difference between the first half and the second half is small.

Next, the configuration of the radio apparatus of this embodiment for receiving full burst and half burst from the base station will be described with reference to FIG. FIG. 2 is a block diagram showing a wireless device of an embodiment according to the present invention. In the figure, the wireless device of the present embodiment includes an antenna 101,
Radio section 103, decoding section 105, and R in the claims
An RSSI detecting section 107 corresponding to SSI detecting means, a signal type determining section 109 corresponding to signal type determining means, and R
RSSI comparing section 111 corresponding to SSI comparing means and RSSI threshold setting section 11 corresponding to threshold updating means
3, a control unit 115, a first counter unit 117a,
The second counter unit 117b is provided.

The respective constituent elements of the wireless device of this embodiment will be described below. First, the wireless unit 103 performs frequency conversion, filtering, quadrature demodulation, A / D conversion, etc. on the signal received by the antenna 101 and outputs a baseband signal. In addition, the decoding unit 105
The baseband signal from the radio section 103 is decoded and the decoded data is output. In the present embodiment, the decoding unit 105 is realized by the DSP. In addition, power is not supplied to part of the wireless unit 103 and the decoding unit 105 when the wireless device of this embodiment is in the saving mode.

Further, the RSSI detecting section 107 is composed of the radio section 1
No. 03 is used to detect the RSSI of the baseband signal. In the wireless device in the saving mode, the RSSI detection unit 107, as shown in FIG. 3, includes a part of each of the first half and the second half of a slot (hereinafter referred to as a corresponding slot) assigned to the wireless device in one frame.
Only SSI is detected. FIG. 3 is an explanatory diagram showing RSSI of each of full burst and half burst.

Further, the signal type judging section 109 judges whether the signal transmitted from the base station is a full burst or a half burst by comparing the RSSI of the first half of the corresponding slot with the RSSI of the latter half. As shown in FIG. 3, the full burst (b) has RSSI in the first half and the second half.
However, in the half burst (a), the RSSI in the first half corresponding to the guard time (G) shown in FIG. 1 is lower in the half burst (a), and the level difference between the first half and the second half is smaller. Has occurred. Therefore, the signal type determination unit 109 determines the first half RSSI and the second half RSI of the corresponding slot.
When the level difference from SSI is less than or equal to a predetermined value, the received signal is determined to be a full burst. In other words, when the level difference is larger than the predetermined value, it is determined as a half burst.

Further, the RSSI comparison section 111 is
The RSSI in the first half of the corresponding slot detected by the detection unit 107 is compared with a threshold value predetermined by the RSSI threshold value setting unit 113.
When is above a threshold value, a signal is output to the control unit 115. The control unit 115 in the saving mode
For example, the signal is a signal (hereinafter, referred to as a control unit activation signal, which is indicated as “WakeUp” in FIG. 1) having a meaning of instructing to start the operation.

Further, the RSSI threshold setting section 113 is
The RSS of the baseband signal in the RSSI comparison unit 111
The threshold value for comparison with SI is set according to a threshold value update instruction from the control unit 115. In addition,
In the present embodiment, the RSSI detection unit 107, the signal type determination unit 109, the RSSI comparison unit 111, and the RSSI threshold value setting unit 113 are realized by a gate array (G / A).

Also, the control unit 115 detects the sync word (SW) from the decoded data obtained by the decoding unit 105, and performs RSSI based on whether the sync word is detected or not and the RSSI determined from the decoded data. Threshold setting section 11
3 is instructed to update the threshold value. In addition,
When the control unit 115 in the saving mode receives the control unit activation signal from the RSSI comparison unit 111, it starts operating,
Immediately after the operation starts, a signal for activating the decoding unit 105 (hereinafter, referred to as a decoding unit activation signal, which is indicated as “WakeUp” in FIG. 1) and a part of the wireless unit 103 that is not supplied with power during the saving mode. Signal for supplying power to the components of the unit (hereinafter referred to as ON / OFF control signal)
Is output, the saving mode is canceled and the mode shifts to the normal reception mode. That is, the saving mode is the decoding unit 1.
05 (DSP) and some components of the wireless unit 103 are not supplied with power, and in the normal reception mode, these components are also supplied with power.

Further, the first counter section 117a counts how many consecutive frames the RSSI slot smaller than the threshold is received after the received signal is judged to be a full burst by the signal type judging section 109. To do. In addition, the second counter unit 117b counts how many times the control unit 115 cannot detect the synchronization word after the wireless device of the present embodiment shifts from the saving mode to the normal reception mode. Is.

The radio apparatus of the present embodiment having the above-described components has the following conditions: transition from normal reception mode to saving mode, transition condition from saving mode to normal reception mode, and RSSI threshold setting section. The threshold update conditions are set respectively. Hereinafter, in the wireless device of the present embodiment, the operation when transitioning from the normal reception mode to the saving mode and the operation when transitioning from the saving mode including the threshold update (threshold update method) to the normal reception mode , And will be described in detail with reference to FIGS.

[Transition from Normal Reception Mode to Saving Mode] First, conditions and operations when the wireless device of the present embodiment shifts from the normal reception mode to the saving mode will be described with reference to FIG. The wireless device of the present embodiment in the normal reception mode receiving the full burst in the corresponding slot satisfies the following conditions (step S401).
Then, the control unit 115 releases the normal reception mode and shifts to the saving mode (S403).

More specifically, as shown in FIG. 5, when the wireless device of this embodiment receives a half burst in the corresponding slot (slot 2, shaded portion in FIG. 5), the control unit 115 sets the normal reception mode. Cancel and immediately switch to saving mode. The above conditions assume that the wireless device is within the communication area. In addition to the above conditions, when the wireless device in the normal reception mode cannot continuously detect the synchronization word in the corresponding slots of a plurality of frames, the control unit 115 releases the normal reception mode and the wireless device of the present embodiment. Shifts to saving mode. In addition,
This condition assumes that the wireless device is outside the communication area.

Therefore, there are two conditions for shifting from the normal reception mode to the saving mode: reception of a half burst (in range) and detection of a sync word in corresponding slots of a plurality of consecutive frames (outside range). When either one of these conditions is satisfied, the wireless device of this embodiment releases the normal reception mode and shifts to the saving mode.

[Transition from Saving Mode to Normal Reception Mode] Next, the condition and operation when the wireless device of the present embodiment shifts from the saving mode to the normal reception mode,
In addition, the threshold update condition of the RSSI threshold setting unit will be described with reference to FIG. When the wireless device of the present embodiment in the saving mode receiving the half burst in the corresponding slot satisfies the conditions described below, the control unit 115 releases the saving mode and shifts to the normal reception mode.

More specifically, as shown in FIG. 7, when the wireless device of the present embodiment receives a half burst in the corresponding slot (slot 2, shaded portion in FIG. 7) in the saving mode state, When the full burst is received in the slot, the signal type determination unit 109 shown in FIG. 1 determines this (step S501). As described above, the signal type determination unit 109 determines the received signal as a full burst when the level difference between the RSSIs of the first half and the second half of the corresponding slot is less than or equal to a predetermined value. In the present embodiment, if the saving mode is canceled only by the determination, for example, in the vicinity of the fringe of the communication area, the C / N ratio between the ambient noise level and the carrier is low, and the change from half burst to full burst may occur. Even if it recognizes and shifts to the normal reception mode, it may not be possible to perform substantial communication such as demodulation, so refer to the result of comparison between full burst RSSI and threshold value (S503) described below. After confirming the electric field level, the normal mode is entered.

The RSSI of the full burst and the threshold value are compared (S503). When the signal type determination unit 109 determines that the full burst is received in the corresponding slot, the RSS
This is performed by the I comparison unit 111. RSSI comparison unit 11
1 outputs a signal to the control unit 115 when the RSSI in the first half of the corresponding slot is equal to or higher than the threshold value. The signal output at this time is a signal for activating the control unit 115. Therefore, the control unit 115 starts operation by this signal, and first, the decoding unit 105 and the wireless unit 103, which were not supplied with power during the saving mode.
Outputs signals to power some components of the. Therefore, the saving mode is released, and the wireless device of this embodiment immediately shifts to the normal reception mode (S505).

On the other hand, when the RSSI is smaller than the threshold value, the received signal of the corresponding slot is determined to be the full burst reception in the next frame, and the frame (corresponding slot) of the RSSI smaller than the threshold value is received. The number of continuous receptions is counted by the first counter unit 117a. If the number counted by the first counter unit 117a is less than the predetermined value in step S507, the control unit 115 continues the saving mode without shifting to the normal reception mode. On the other hand, when the counted number is equal to or larger than the predetermined value, the control unit 115 determines that the threshold value is too high, and the RSSI threshold value setting unit 1
The threshold value is lowered by a constant value by instructing 13 to update the threshold value downward (S509).

In this way, the wireless device shifts to the normal reception mode if the condition for shifting to the normal reception mode is satisfied after the type of the corresponding slot is determined and the RSSI is compared with the threshold value. In the mode, after shifting to the normal reception mode, an attempt is made to detect the synchronization word included in the full burst of the corresponding slot (capture of synchronization) (S51).
1). The detection of the synchronization word is performed by the control unit 115 based on the decoded data obtained by the decoding unit 105. When the control unit 115 detects the synchronization word, the control unit 115 continues the normal reception mode as it is (S517).

On the other hand, the detection of the sync word is attempted for one frame or a plurality of frames, but when the sync word is still not detected, the saving mode is entered again. At that time, in step S513, the saving mode is shifted to the normal reception mode as described above.
The second counter unit 117b counts the number of consecutive times when the synchronization word cannot be detected. Control unit 115
If the number counted by the second counter unit 117b is less than the predetermined value, the mode becomes the saving mode again.
On the other hand, when the counted number is equal to or more than the predetermined value, the control unit 115 determines that the threshold value is too low, and RS
The SI threshold setting unit 113 is instructed to update the threshold upward to raise the threshold by a certain value (S515), and then the saving mode is resumed.

Therefore, there are three conditions for completely shifting from the saving mode to the normal reception mode: reception of a full burst, RSSI in the first half of the corresponding slot or more, and sync word detection. When all of these conditions are satisfied, the wireless device of the present embodiment cancels the saving mode and shifts to the normal reception mode. When these conditions are not satisfied and the conditions are not satisfied for a predetermined number of frames or a predetermined number of times in succession,
Update the threshold down or up. It should be noted that the lower threshold is updated when a frame whose RSSI in the first half of the corresponding slot is less than the threshold continues for a predetermined number of times, and the upper threshold is updated when a sync word cannot be detected a predetermined number of times. , When it is continuous.

In the above description, the threshold value before being updated is a value stored in the memory or the like as an initial value. However, the value obtained by measuring the RSSI in the state where there is no signal and adding a fixed value to the measured value may be used as the initial value. In addition, since the wireless device in the saving mode may change the oscillation frequency due to changes in the characteristics of the hardware such as the crystal due to heat or the like, the wireless device periodically enters the normal reception mode for a short time in order to adjust the frequency. At this time, the updated threshold value is reset to the initial value.

As described above, according to the wireless device and the threshold value updating method of this embodiment, the R of the corresponding slot is
The threshold value compared with SSI (received field strength) is not fixed, but conditions are set and updated appropriately according to the environment. Therefore, the optimum threshold value setting adapted to fluctuations in ambient noise can be set. It can be carried out. For example, in an environment with high ambient noise, the threshold value is updated upward, and therefore the saving mode is not released in the reception carrier of C / N or less required for reception. Therefore, the power saving effect of the saving mode can be maximized. Further, it is possible to eliminate meaningless communication which has a problem that the decoded data cannot be used because the error rate is high even though the saving mode is canceled.

Further, if the threshold value is updated many times, the effective communication area for the device is narrowed, and even if the wireless device in the saving mode receives the transmission signal from the base station, it is in the normal reception mode. However, since the threshold value is updated downward if the condition is satisfied in this embodiment, the communication can be performed without any trouble.

Further, as a condition for canceling the saving mode and shifting to the normal reception mode, in addition to the judgment of the type of the corresponding slot, the comparison result between the RSSI and the threshold value is also referred to and the normal reception from the saving mode is performed. There are a plurality of conditions for shifting to the normal reception mode such as shifting to the mode. Therefore, erroneous recognition of the start of communication can be reduced, and as a result, the power saving effect in the saving mode can be improved.

Further, whether or not the sync word can be detected is used as a condition for shifting from the normal reception mode to the saving mode again, the type judgment of the corresponding slot and the RSS.
Even if the start of the communication is erroneously recognized by comparing I with the threshold value, if the communication is an ineffective communication in which the synchronization word cannot be detected, the mode returns to the saving mode again, so that the power saving effect of the saving mode is further improved. be able to.

[0050]

As described above, according to the wireless device, the threshold value updating method and the threshold value updating program of the present invention, the threshold value compared with the RSSI of a predetermined slot is not fixed. Since conditions can be set and updated appropriately, the optimum threshold value can be set in accordance with environmental changes.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating each configuration of a full burst (a) and a half burst (b).

FIG. 2 is a block diagram showing a wireless device of an embodiment according to the present invention.

FIG. 3 RS for full burst and half burst
Explanatory diagram showing SI

FIG. 4 is a diagram illustrating a wireless device according to an embodiment of the present invention,
Flowchart explaining the operation when shifting from the normal reception mode to the saving mode

FIG. 5 is an explanatory diagram illustrating a transition from a normal reception mode to a saving mode.

FIG. 6 is a diagram illustrating a wireless device according to an embodiment of the present invention,
Flowchart explaining the operation when shifting from the saving mode to the normal reception mode

FIG. 7 is an explanatory diagram illustrating a transition from the saving mode to the normal reception mode.

[Explanation of symbols]

101 antenna 103 radio unit 105 decryption unit 107 RSSI detector 109 signal type determination unit 111 RSSI comparison section 113 RSSI threshold setting section 115 control unit 117a First counter unit 117b Second counter section

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Munenori Miyachi             3-1, Tsunashima-Higashi 4-chome, Kohoku-ku, Yokohama-shi, Kanagawa             Matsushita Communication Industry Co., Ltd. F term (reference) 5K027 AA11 BB17 CC08                 5K028 BB06 CC02 HH00 KK01 KK12                       LL12 NN05 RR02                 5K067 AA01 AA43 CC04 CC22 DD25                       DD44 DD45 GG11 HH22

Claims (15)

[Claims] 1. A radio apparatus for receiving a signal multiplexed by a time division multiplexing system, the RSSI detecting a received electric field strength (hereinafter, referred to as RSSI) of a reception signal in a predetermined slot assigned to the radio apparatus. Detecting means, signal type determining means for comparing the RSSI of the first half of the slot of the received signal with the RSSI of the second half of the slot, and determining the type of the received signal based on the level difference between them;
An RSSI comparing means for comparing the RSSI detected by the SI detecting means with a threshold value, and a threshold value updating means for updating the threshold value are provided, and the received signal of a predetermined slot is full by the signal type judging means. The RSSI of the received signal in a predetermined slot after it is determined to be a burst signal has a predetermined number of frames or more,
The wireless device, wherein the threshold updating means updates the threshold downward if the threshold is continuously less than the threshold. 2. The radio apparatus according to claim 1, wherein when updating the threshold value downward, the threshold value updating means lowers the threshold value by a constant value. 3. The signal type determination means determines that a received signal in a predetermined slot is a full burst signal, and
RSSI of received signal compared by the RSSI comparing means
If is equal to or more than the threshold value, the wireless device in the saving mode that suppresses the current consumption shifts to the normal reception mode.
The described wireless device. 4. The wireless device which has shifted to the normal reception mode,
4. The radio apparatus according to claim 3, wherein the normal reception mode is continued if a synchronization word is detected from a reception signal of a predetermined slot. 5. When the condition that the synchronization word cannot be detected from the received signal in the predetermined slot after the shift to the normal reception mode has continued for a predetermined number of times, the threshold value updating means is set to the above-mentioned condition. The wireless device according to claim 3, wherein the threshold value is updated upward. 6. The radio apparatus according to claim 5, wherein, when the threshold value is updated upward, the threshold value updating means raises the threshold value by a constant value. 7. The threshold updating means does not change the threshold when the condition is not satisfied, and the threshold updating means updates the threshold upward when the condition is satisfied. 7. The wireless device according to claim 5, wherein the wireless device in the normal reception mode shifts to the saving mode again after the operation. 8. A method of updating a threshold value of a radio apparatus for receiving a signal multiplexed by a time division multiplexing method, comprising: receiving electric field strength (hereinafter, RSSI) of a reception signal in a predetermined slot assigned to the radio apparatus. Signal) that compares the RSSI of the first half of the slot and the RSSI of the second half of the slot of the received signal detected in the RSSI detection step, and determines the type of the received signal based on the level difference. A type determination step, and an RSSI comparison step of comparing the RSSI detected in the RSSI detection step with a threshold value, after the received signal of a predetermined slot is determined to be a full burst signal in the signal type determination step If the RSSI of the received signal in a predetermined slot of the If it is less than have value, the threshold update method characterized by further having a threshold lower updating step of downward updating the threshold. 9. The updating step of lowering the threshold value lowers the threshold value by a constant value.
How to update the described threshold. 10. The received signal in a predetermined slot is determined to be a full burst signal in the signal type determination step, and
RS of the received signal compared in the RSSI comparison step
10. The threshold value according to claim 8 or 9, further comprising: a normal reception mode transition step in which the wireless device in a saving mode for suppressing current consumption shifts to a normal reception mode if SI is equal to or more than the threshold value. How to update. 11. The normal reception mode is provided when the wireless device that has shifted to the normal reception mode has a synchronization word detection step of detecting a synchronization word from a reception signal of a predetermined slot, and if the synchronization word is detected in the synchronization word detection step. 11. Continuing, characterized in that
How to update the described threshold. 12. If the condition that the sync word cannot be detected from the received signal in a predetermined slot after the shift to the normal reception mode is continued a predetermined number of times in the sync word detecting step, 12. The threshold updating method according to claim 10, further comprising an upper threshold updating step for updating the threshold. 13. The threshold value updating method according to claim 12, wherein the threshold value upward updating step raises the threshold value by a constant value. 14. If the condition is not satisfied, the threshold upper updating step is not executed, and if the condition is satisfied, after the threshold is updated in the threshold upper updating step, 14. A saving mode transition step in which the wireless device in the normal reception mode transitions to the saving mode again.
The described wireless device. 15. Claims 8, 9, 10, 11, 12, 1
A threshold updating program for causing a computer to execute the threshold updating method described in 3 or 14.