JP2003115773A - Radio equipment and method for controlling gain thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide radio equipment capable of establishing communication in a short time from the start of reception, and a method for controlling the gain of the radio equipment. SOLUTION: This radio equipment is provided with an AGC 111 for adjusting a reception signal level, a carrier judging circuit 119 for judging the kind of the reception signal, a digital filter 121 capable of being rewritten into a state that route Nyquist characteristics are written or a state that any filter characteristic is not written, a level judging circuit 123 for judging the signal level of the signal passing through the digital filter 121, and a gain setting circuit 127 for setting the gain of the AGC 111 based on the level judged by the level judging circuit 123. The digital filter 121 and the level judging circuit 123 are realized by a DSP 129. The digital filter 121 is put into a state that any filter characteristic is not written while gain control is being performed before communication between the radio equipment and a base station is established, and put into a state that the route Nyquist characteristics are written after the communication between the radio equipment and the base station is established.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio apparatus that requires linear reception and a gain control method for the radio apparatus, and more particularly to a radio apparatus and a gain control method for the radio apparatus that establish communication in a short time from the start of reception. Regarding

[0002]

2. Description of the Related Art For a digital radio apparatus that requires linear reception, an automatic gain control circuit (AGC: Automa) for performing reception at an appropriate level even when the input signal strength changes.
tic Gain Controller) and a filter for optimizing transmission characteristics by efficiently using frequency bands are essential components.

FIG. 9 shows a block diagram of a conventional radio apparatus having an AGC and a filter. Conventional wireless devices
As shown in the figure, the antenna 11, the interference wave removing filters 13a and 13b, the analog filter 13c for removing the adjacent channel interference wave, and the LNA (Low Noise Amplifie).
r) 15, the mixer 17, the local oscillator 19, and the AG
C21, a quadrature demodulator (Q-DEM) 23 and a local oscillator 25, an ADC 27 that performs A / D conversion, a digital filter 31 such as a root Nyquist filter, a level determination circuit 33 that determines the level of a received signal, AGC2
A gain setting circuit 35 for setting a gain of 1;
And a detection circuit 37 for detecting the received signal.

In the conventional wireless device, the ADC 2
The received signal A / D-converted in 7 is the digital filter 31.
After being filtered by, the level determination circuit 33 determines the level, and the gain setting circuit 35 determines the level according to the determination result.
Sets the gain of AGC21. In addition, when a signal of a strong electric field is input, in order to set the signal strength to an appropriate level, the conventional wireless device alternately performs the level determination in the level determination circuit 33 and the gain control (gain setting) by the gain setting circuit 35. Need to be repeated multiple times.

[0005]

However, in the above-described conventional wireless device, the A / D converted received signal is input to the level determination circuit 33 via the digital filter 31, and the digital filter 31 causes a delay. Since this occurs, the time required for each gain control becomes longer by the delay time in the digital filter 31. Therefore, since the time from the start of reception in the conventional wireless device to the establishment of communication becomes longer according to the delay time,
There is a risk of disconnection.

Further, in a radio communication system which employs TDMA (Time Division Multiplexing) as a multiplexing system, when the time for gain control such as preamble is set short for one slot, If the time required for gain control is long, it is necessary to perform gain control over multiple slots, that is, multiple frames, so it takes time to establish communication (communication establishment delay), and in the worst case communication is established. There is a fear that you cannot do it.

To solve such a problem, a wireless device having no digital filter 31 may be considered. However, if reception is performed without passing through the digital filter 31, intersymbol interference may occur or an error may occur due to noise. It is not preferable because a failure such as a decrease in the rate occurs. Therefore, the digital filter 31 is an essential component for the conventional wireless device. Therefore, the digital filter 3
It has been desired to provide a wireless device that does not have the above-mentioned problems even if the wireless device is provided with 1.

[0008] In particular, in general radio equipment for performing press talk communication such as disaster prevention radio, it is necessary to accurately and surely convey the contents of communication, and situations such as disconnection of the talk, delay in establishment of communication, and failure to establish communication are a matter of business. Very unfavorable in nature. Therefore, if a conventional wireless device is used as a mobile device or a base station in a wireless communication system used in such a business, it can be said that the problem of the conventional wireless device should be solved.

The present invention has been made in view of the above problems and circumstances, and provides a radio apparatus and a gain control method for the radio apparatus capable of establishing communication in a short time from the start of reception. It is an object.

[0010]

In order to solve the above problems, a radio apparatus according to the present invention is a radio apparatus that linearly receives a time division multiplexed signal and can be changed by an instruction from the outside. Signal amplifying means for amplifying a received signal with a gain, first filter means capable of filtering the signal amplified by the signal amplifying means, and signal amplified by the signal amplifying means or filtered by the first filter means The wireless device, the level determining means for determining the level of the signal thus obtained, and the first gain setting means for setting the gain of the signal amplifying means based on the signal level determined by the level determining means. When the wireless device receives a burst signal containing communication content in a predetermined slot that is assigned in advance, the above-mentioned record is received in the slot before the predetermined slot in the next frame. The level determination of the signal amplified by the signal amplification means by the channel determination means and the gain setting by the first gain setting means, and after the reception of the burst signal in the predetermined slot of the next frame, the first filter means. The level of the signal filtered by is judged and the gain is set.

Therefore, in the gain control performed first after receiving the burst signal, the level determination and the gain setting are performed without filtering by the first filter means, so that the level determination and the gain setting are set as one set. The time required for the gain control per one time is short, and the gain of the signal amplification means can be optimally set in a short time. Therefore, the time from the start of reception (burst signal reception) to the establishment of communication is shortened, and problems such as disconnection of the talk and delay in establishment of communication do not occur. Further, since the filtering is performed by the first filter means after the communication is established, the communication can be performed without troubles such as intersymbol interference and reduction of error rate.

Further, in the radio apparatus according to the present invention, even when the radio apparatus does not receive the burst signal in the predetermined slot, the radio apparatus is amplified by the signal amplifying means every predetermined time. Performs signal level judgment and gain setting.

The wireless device according to the present invention is the first device described above.
Is rewritable, the first filter means before the predetermined frame of the next frame is in a state in which no information about the filter characteristic is written, and the first filter means after the predetermined slot of the next frame. The first filter means is in a state in which a predetermined filter characteristic is written.

Further, in the radio apparatus according to the present invention, when the radio apparatus stops receiving the burst signal in a predetermined slot, the first filter means is rewritten to a state in which no filter characteristic is written. .

The wireless device according to the present invention is the first device.
The filter means and the level determination means are configured on the same signal processing circuit, and no electric power is supplied to the signal processing circuit while the wireless device is not receiving a burst signal in a predetermined slot, When the wireless device receives a burst signal in a predetermined slot, power is supplied to the signal processing circuit.

Further, in the radio apparatus according to the present invention, power is supplied to the signal processing circuit at the time of level determination and gain setting performed at predetermined time intervals when the radio apparatus is not receiving a burst signal in a predetermined slot. To be done.

Further, in the radio apparatus according to the present invention, the reception of the burst signal in the predetermined slot by the radio apparatus is judged by the signal judging means for judging the kind of the signal received in the predetermined slot.

Further, the radio apparatus according to the present invention comprises second filter means provided before the signal amplifying means, which is capable of filtering the signal amplified by the signal amplifying means, and the radio apparatus has a predetermined size. When no burst signal is received in the slot, the signal amplified by the signal amplifying means is filtered by the second filter means, and then the signal determining means determines the type of signal.

Since the signal used in determining the type of received signal (whether it is a burst signal or not) is the signal filtered by the second filter means, the signal determining means can accurately determine the type of signal. You can Also,
Since the wireless device does not have to frequently perform level determination until the burst signal is received, a low current consumption state in which power is not supplied to the level determination means and the first filter means while the burst signal is not received. However, the signal type can be accurately determined even in such a state.

Further, the wireless device according to the present invention is the second device.
Is rewritable, and when the wireless device receives a burst signal in a predetermined slot, it is rewritten to a state in which no information regarding filter characteristics is written in the second filter device, and the wireless device When the burst signal is not received in the predetermined slot, the information about the filter characteristic is written in the second filter means.

The radio apparatus according to the present invention further comprises second gain setting means for setting the gain of the signal amplifying means when the radio apparatus is not receiving a burst signal in a predetermined slot, and the signal amplifying means is provided. The means for setting the gain is switched to the first gain setting means or the second gain setting means when the burst signal is received in a predetermined slot and when the burst signal is not received in the predetermined slot. .

Further, the gain control method for a radio apparatus according to the present invention, in order to linearly receive a time division multiplexed signal,
A method for controlling a gain of a wireless device, comprising a signal amplifying means for amplifying a received signal with a gain that can be changed according to an instruction from the outside, wherein a burst signal including communication content is received in a predetermined slot pre-allocated to the wireless device. Then, based on the first level determination step of determining the level of the burst signal amplified by the signal amplification means in the slot before the predetermined slot of the next frame, and the signal level determined in the first level determination step. A first gain setting step of setting the gain of the signal amplifying means, and a first filtering step of filtering the burst signal amplified by the signal amplifying means in a predetermined slot of the next frame; Determining the level of the signal filtered in the first filtering step; A level determination step of the second
And a second gain setting step of setting the gain of the signal amplifying means based on the signal level judged in the level judging step.

Further, in the gain control method according to the present invention, in the predetermined slot before receiving the burst signal, the second filtering step of filtering the signal amplified by the signal amplifying means, and the second filtering step. The first signal determination step of determining the type of the signal filtered by, and after receiving the burst signal in the predetermined slot, in the predetermined slot of the next frame, the type of the signal amplified by the signal amplifying means The second signal determination step for determining is performed.

Further, a radio apparatus according to the present invention is a radio apparatus for linearly receiving a time-division multiplexed signal, and a signal amplifying means for amplifying a received signal with a gain changeable by an instruction from the outside. First filter means capable of filtering the signal amplified by the signal amplifying means, and level determining means for determining the level of the signal amplified by the signal amplifying means or the signal filtered by the first filter means A first gain setting unit that sets the gain of the signal amplifying unit based on the signal level determined by the level determining unit, and the wireless device is provided in a predetermined slot pre-assigned to the wireless device. When a burst signal including communication contents is received, it is amplified by the signal amplification means by the level determination means in the preamble section of the next reception slot. Performs gain setting by the level determination and the first gain setting means signal, after reception of the preamble section performs level determination and a gain setting of the filtered signal by said first filter means.

Further, in the radio apparatus according to the present invention, the radio apparatus is amplified by the signal amplifying means at every predetermined time even when the radio apparatus does not receive the burst signal in the predetermined slot. Performs signal level judgment and gain setting.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a radio apparatus of the present invention will be described in detail below in the order of [first embodiment] and [second embodiment] with reference to the drawings. The wireless device according to the embodiments described below is a digital wireless device that requires linear reception and is used as a mobile device or a base station. A wireless communication system using the wireless device according to the present invention is mainly used as a communication system for communication, and TDMA (Time Division Multiplexing System) is adopted as its multiplexing system. A wireless device used as a mobile device can be in either a saving mode for suppressing current consumption or a normal reception mode.

[First Embodiment] FIG. 1 is a block diagram showing a radio apparatus according to a first embodiment of the present invention. In the figure, the wireless device of the present embodiment has an antenna 101
An interference filter 103a, 103b, an analog filter 103c for removing an adjacent channel interference wave,
LNA (Low Noise Amplifier) 105 and mixer 10
7 and the local oscillator 109, and an automatic gain control circuit (AGC: Automati) corresponding to the signal amplifying means in the claims.
c Gain Controller) 111 and a quadrature demodulator (Q-DE
M) 113 and local oscillator 115, and ADC 117
And a carrier determination circuit 119 corresponding to the signal determination means.
And a rewritable digital filter corresponding to the first filter means (hereinafter, simply referred to as a digital filter) 1
21 and a level determination circuit 12 corresponding to the level determination means
3, a detection circuit 125, and a gain setting circuit 127 corresponding to the first gain setting means.

The digital filter 121, the level determination circuit 123, and the detection circuit 125 are DSP (Digital
Signal Processor) 129, and the DSP 129 is not supplied with power during the saving mode. Further, the carrier determination circuit 119 and the gain setting circuit 127 are realized by the gate array (G / A) 131, and power is supplied even in the saving mode. Further, the carrier determination circuit 119 is unnecessary when the wireless device is used as a base station.

The components of the wireless device of this embodiment will be described below. First, the AGC 111 receives the analog filters 103 a to 10 a through the antenna 101.
3c, which adjusts the level of the reception signal that has passed through the LNA 105 and the mixer 107.
A signal having a level corresponding to the gain set by 7 is output. In addition, the quadrature demodulator 113 uses the AGC1
The signal output from 11 is subjected to quadrature demodulation.
The quadrature baseband signals of the component and the Q component are output.
Further, the ADC 117 is for A / D converting the orthogonal baseband signal.

Further, the carrier determination circuit 119 is provided with an ADC.
The quadrature baseband signal output from 117 is used to determine whether the received signal is a half burst or a full burst, which will be described later. When it is determined that the wireless device of this embodiment has received the full burst during the saving mode, the DSP 12
Start 9. The digital filter 121 is a filter that can be rewritten into a state in which information regarding the root Nyquist characteristic is written or a state in which no information regarding the filter characteristic is written. As will be described later, the filter characteristic is not written during gain control (during high-speed operation) performed before the wireless device of the present embodiment establishes communication with the base station, and communication with the base station is performed. After the establishment (during stable operation), the root Nyquist characteristic is written. FIG. 2 shows the characteristics of the digital filter 121 in the state (a) in which the root Nyquist characteristic is written and in the state (b) in which the filter characteristic is not written.

The level decision circuit 123 decides the level of the quadrature baseband signal passed through the digital filter 121. In addition, the gain setting circuit 127
Is for setting the gain of the AGC 111 based on the level determined by the level determination circuit 123. Further, the detection circuit 125 detects a quadrature baseband signal.

<When the wireless device is a mobile device> Next, the operation of the wireless device of this embodiment having the above-described components will be described in detail. In the following description, the wireless device of this embodiment is used as a mobile device, and the multiplexing system of the wireless communication system using this wireless device is TDMA (time division multiplex system) as described above. Further, a slot (downstream slot) for the base station to transmit a signal to the wireless device of the present embodiment is pre-allocated by the base station, and the base station uses the slot to transmit a full burst signal or a half burst signal (half burst signal to the wireless device. (Described later) is transmitted. It should be noted that signals are transmitted to wireless devices (mobile devices) of other groups in slots other than the slot.

The full burst signal (hereinafter, simply referred to as full burst) and the half burst signal (hereinafter, simply referred to as half burst) will be described below with reference to FIG. First, the full burst is a signal for transmitting the actual communication contents, and as shown in FIG. 3A, the burst transient response ramp time (R) and the preamble (P) are used.
, Communication data (USC) × 2, sync word (SW)
, Functional channel identification signal (CI), low speed associated control channel (SA), and guard time (G) with no output
It consists of and.

The half burst is a signal transmitted from the base station when the full burst is not transmitted. As shown in FIG. 3B, the guard burst (G) and the burst transient are the same as the half burst. Response lamp time (R)
, Preamble (P), communication data (USC),
Sync word (SW) and functional channel identification signal (CI)
And a low speed associated control channel (SA). However, the preamble (P) time is longer than the full burst (about 10 times), and the guard time (G) occupies most of the first half of the slot.

Under the conditions described above, the signal transmitted from the base station in the assigned slot is a half burst, and the wireless device (mobile device) of this embodiment is in the saving mode. The operation when the device (mobile device) receives the full burst, enters the normal reception mode, and returns to the saving mode again will be described with reference to FIG. The digital filter 121 is in a state in which the filter characteristic is not written when the wireless device continues to receive the half burst in the assigned slot.

First, when the wireless device of this embodiment is in the saving mode, when the first full burst as a reception start instruction is received (step S101), the carrier determination circuit 119 activates the DSP 129 (step S10).
3). Note that the first full burst has a meaning of a reception start instruction for the wireless device. Next, the level determination circuit 123 determines the level of the signal in the slot unrelated to the wireless device following the first full burst (step S105). Since the digital filter 121 at this time is in a state where the filter characteristic is not written, the quadrature baseband signal output from the ADC 117 is input to the level determination circuit 123 without delay. Further, it is desirable that the level signal determined by the level determination circuit 123 is a signal in an unrelated slot immediately before the second full burst.

Next, the gain setting circuit 127 determines a gain according to the level judged by the level judging circuit 123, and sets this gain in the AGC 111 (step S107). The gain control by the level determination and the gain setting is repeated until the preamble section ends (step S109).

The gain control performed by the radio apparatus of this embodiment will be described below in more detail with reference to FIG. The timing at which the wireless device of the present embodiment performs gain control is after receiving the first full burst and before receiving the second full burst transmitted in the corresponding slot in the next frame. Irrelevant slots (half burst)
During the preamble (P). As shown in FIG. 5, the gain of the AGC 111 is set to the maximum during the burst transient response ramp time (R) before the preamble before performing the gain control. Next, in the preamble (P), the level determination and the gain setting described above are performed, and the level determination and the gain setting are performed again after a predetermined period of time.

By performing the above gain control, the AGC
When the gain of 111 becomes optimum, the digital filter 12
The root Nyquist characteristic is written in 1 (step S
111). In this way, the gain of the AGC 111 is optimally set, and after the root Nyquist characteristic is written in the digital filter 121, the second full burst is received in the corresponding slot in the next frame. When the second full burst is received, the gain of the AGC 111 is optimal, and the detection circuit 125 can detect the quadrature baseband signal, so that communication can be started. Therefore, in the wireless device of the present embodiment, communication is established at the time of receiving the second full burst, and the wireless device enters the normal reception mode (step S113). Moreover,
Since the root Nyquist characteristic is written in the digital filter 121 at this time, there is some delay due to filtering, but problems such as intersymbol interference and reduction in error rate due to noise hardly occur.

As described above, since the full burst is not so long as the half burst but the preamble time is provided, the level judgment and the gain determination are performed even during the second and subsequent full burst receptions. Settings are made. However, the actual gain setting is not performed at this time, but after the full burst is received and before the full burst in the next frame is received.
Therefore, in the third and subsequent full burst receptions, the level is adjusted by the AGC 111 by the gain determined in the full burst of the immediately preceding frame.

After the reception is performed in this way, when the base station receives a half burst instead of a full burst in the corresponding slot, the radio apparatus of the present embodiment determines that the reception is completed ( Step S11
5). It should be noted that the end of reception is determined by the CI in the burst signal.
(Functional channel identification signal). When it is determined that the reception is completed, the DSP 129 causes the digital filter 121 to
Is rewritten to a state in which the filter characteristic is not written (step S117). When the rewriting of the digital filter 121 is completed, the power supply to the DSP 129 is stopped and the wireless device shifts to the saving mode (step S119).

As described above, when the wireless device of the present embodiment is used as a mobile device, the wireless device in the saving mode receives the first full burst and then the second full burst in the corresponding slot in the next frame. Since the gain of the AGC 111 can be optimally set before the burst is received, the time from the start of reception to the establishment of communication is only one frame.

The above description is about the operation when the full burst is received from the base station. However, when the half burst is continuously received in the corresponding slot, the radio apparatus of the present embodiment has a fixed time interval. The gain control is performed by releasing the saving mode. At this time,
The wireless device of the present embodiment activates the DSP 129 to activate the digital filter 1 as in the case of receiving the full burst.
Gain control is performed by rewriting 21 and determining the level. The timing for releasing the saving mode by itself is measured by a counter (not shown).

<When the wireless device is a base station> Next, when the wireless device of this embodiment is used as a base station and the multiplexing system of the wireless communication system using this wireless device is TDMA, the present embodiment The operation of the wireless device of the embodiment will be described. It should be noted that the slot (uplink slot) in which the mobile device transmits a signal to the wireless device (base station) is assigned in advance by the wireless device, and the mobile station transmits a burst signal (described later) to the wireless device using the slot. . Signals from mobile stations of other groups are transmitted in slots other than the slot.

A burst signal (hereinafter, simply referred to as a burst) transmitted from the mobile device will be described below with reference to FIG. First, as shown in FIG. 6, the structure of the burst differs between the first burst and the second burst and thereafter. First
A burst is a signal transmitted first when a call is started, and as shown in FIG. 6A, a guard time (G) with no output and a preamble (L) for a linearizer
P), a burst transient response ramp time (R), a preamble (P), a synchronization word (SW), a low speed associated control channel (SA), and communication data (USC).

On the other hand, after the second burst, as shown in FIG. 6B, the guard time (G) is the same as in the first burst.
A ramp transient response ramp time (R), a preamble (P), communication data (USC) × 2, a synchronization word (SW), and a low speed associated control channel (SA). However, the preamble (P) time is the first
Shorter than burst (about 1/40). Conversely, the preamble (P) time is long in the first burst.

Under the conditions described above, the operation of the radio apparatus (base station) of this embodiment when the first burst is transmitted from the mobile station in the assigned slot will be described. It should be noted that the digital filter 12 when a burst is not transmitted to the wireless device in the assigned slot
1 is a state in which the filter characteristic is not written.
Also, since the wireless device is used as a base station, it does not enter the saving mode like a mobile device, and the DSP 12
9 is always running.

First, when the wireless device of this embodiment receives the first burst, the gain of the AGC 111 is set to the maximum in the burst transient response ramp time (R) of the first burst. Next, in the preamble (P), the level determination circuit 1
The level determination by 23 and the gain setting by the gain setting circuit 127 are performed, and after a predetermined time, the level determination and the gain setting are performed again. When the gain of the AGC 111 is optimized by performing such gain control, the root Nyquist characteristic is written in the digital filter 121.

In this way, when the gain of the AGC 111 is optimally set and the root Nyquist characteristic is written in the digital filter 121, the communication data (USC) of the first burst after the preamble can be detected by the detection circuit 125. , Can start communication. Therefore, the wireless device of this embodiment is gain-controlled by the preamble of the first burst, and communication is established when the synchronization word is detected.

The gain of the AGC 111 at the time of receiving the communication data (USC) in the first burst is the first gain.
It is set by the preamble of the burst, but in the second burst, it is the gain set from the level average value of the entire communication data (USC) of the first burst, and after the third burst, it is the gain of the entire previous burst. It is the gain set from the level average value.

As described above, when the radio equipment of this embodiment is used as a base station, the gain of the AGC 111 can be optimally set within the time of the preamble of the first burst.

As described above, regardless of whether the wireless device of this embodiment is used as a mobile device or a base station, the gain to be initially performed after reception is started. In the control, the level determination and the gain setting are performed without filtering by the digital filter 121. Therefore, the time required for each gain control with the level determination and the gain setting as one set is short, and the gain of the AGC 111 is set in a short time. It can be set optimally. Therefore, since the time from the start of reception to the establishment of communication is shortened, problems such as disconnection of the talk and delay in establishment of communication do not occur. Further, since the root Nyquist characteristic is written in the digital filter 121 after the communication is established, the communication can be carried out without troubles such as intersymbol interference and reduction in error rate.

Furthermore, the time required for gain control per operation is short, and the level determination and gain control that can be performed during the preamble can be performed a sufficient number of times. Therefore, the quadrature demodulator 113 can be used. And ADC1
Even if the dynamic range of 17 is narrow, the gain of the AGC 111 can be set to an optimum level during the preamble. Therefore, the quadrature demodulator 113 and the ADC 1
The dynamic range of 17 can be narrowed.

[Second Embodiment] In the wireless device of the first embodiment, the AGC after starting reception by full burst reception
In order to set the gain of 111 at high speed, the DSP 129 including the digital filter 121 is activated to rewrite the digital filter 121. However, since the carrier determination circuit 119 performs the carrier determination (determination of whether the received signal is a half burst or a full burst) in the saving mode based on the signal that has not been digitally filtered, which is output from the ADC 117.
The carrier determination circuit 119 cannot perform accurate carrier determination due to the influence of the adjacent interfering wave.

Therefore, in order to make an accurate carrier determination, the DSP 129 is activated and the digital filter 12 is activated.
It is necessary to make a carrier determination based on the signal filtered by 1 and then the DSP 129
There is a problem in that the current consumption cannot be reduced because it must be activated at all times.

A wireless device according to the second embodiment, which can accurately make a carrier determination in the saving mode with a low current, will be described below. FIG. 7 is a block diagram showing a wireless device of the second embodiment according to the present invention. In the figure, the same parts as those in FIG. 1 (first embodiment) are designated by the same reference numerals and the description thereof will be omitted.

The wireless device of the second embodiment shown in FIG.
In addition to the components included in the wireless device of the first embodiment,
A rewritable digital filter 201 corresponding to the second filter means in the claims and a fixed gain setting circuit 203 corresponding to the second gain setting means are provided. The digital filter 201 is the digital filter 1 provided in the DSP 129 of the first embodiment.
DSP 12 provided outside the DSP 129 separately from 21
9 is a rewritable filter. In this embodiment, like the digital filter 121 in the DSP 129, either the state in which the root Nyquist characteristic is written or the state in which the filter characteristic is not written can be taken. The current consumption of the digital filter 201 is DSP
Although the rewriting speed is lower than that of the digital filter 121 in the DSP 129,
Slow compared to.

Further, the fixed gain setting circuit 203 provided separately from the gain setting circuit 127 is constructed so that the fixed gain setting circuit 203 and the gain setting circuit 127 are selectively used, and the fixed gain is set to the AGC111. It is for setting to. Fixed gain setting circuit 203
The gain set by may be a predetermined constant value or the previous gain set by the gain setting circuit 127 which may be set by the DSP 129. The carrier determination circuit 119, the fixed gain setting circuit 203, and the gain setting circuit 127 are realized by the gate array (G / A) 205.

Next, the operation of the radio apparatus of this embodiment having the above-described components will be described in detail. Even in the wireless device of this embodiment, the multiplexing method is T
In DMA, a slot (downstream slot) in which a base station transmits a signal to a wireless device (mobile station) is pre-allocated by the base station, and the base station uses the slot to perform full burst or half burst to the wireless device. Send.

Hereinafter, the wireless device (mobile device) in the saving mode receives the full burst to enter the normal reception mode,
FIG. 8 shows the operation when returning to the saving mode again.
Will be described with reference to. The digital filter 201 is in a state in which the root Nyquist characteristic is written when the wireless device continues to receive the half burst in the assigned slot, and the digital filter 121 in the DSP 129 is written in the filter characteristic. Not in a state. Further, no power is supplied to the DSP 129, and the fixed gain setting circuit 20 is supplied to the AGC 111.
A fixed gain is set by 3.

First, when the wireless device of the present embodiment is in the saving mode, when the first full burst as the reception start instruction is received (step S201), the carrier determination circuit 119 activates the DSP 129 (step S20).
3). Next, when the DSP 129 starts up, the DSP 129
Rewrites the digital filter 201 to a state in which the filter characteristic is not written, and switches the gain setting source of the AGC 111 from the fixed gain setting circuit 203 to the gain setting circuit 127 (step S205). Then the first
The level determination circuit 123 determines the level of the signal in the slot irrelevant to the wireless device following the full burst for the second time (step S207). Since the digital filter 201 and the digital filter 121 in the DSP 129 at this time are in a state where the filter characteristics are not written, the quadrature baseband signal output from the ADC 117 is input to the level determination circuit 123 without delay.

Next, the gain setting circuit 127 determines the gain according to the level judged by the level judging circuit 123, and sets this gain in the AGC 111 (step S209). The gain control by the level determination and the gain setting is repeated until the preamble section ends (step S211). When the gain of the AGC 111 is optimized by performing the gain control, the root Nyquist characteristic is written in the digital filter 121 in the DSP 129. (Step S213). In this way A
After the gain of the GC 111 is optimally set and the root Nyquist characteristic is written in the digital filter 121 in the DSP 129, the second full burst is received in the corresponding slot in the next frame, and communication is established at this point. The normal reception mode (step S21)
5).

After the reception is performed in this way, when the base station receives the half burst instead of the full burst in the corresponding slot, the radio apparatus of the present embodiment determines that the reception is completed ( Step S21
7). When it is determined that the reception is completed, the DSP 129 writes the root Nyquist characteristic in the digital filter 201,
The digital filter 121 in the DSP 129 is rewritten so that the filter characteristic is not written, and the gain setting circuit 127 is switched to the fixed gain setting circuit 203 (step S219). When these operations are completed, DS
The power supply to P129 is stopped, and the wireless device shifts to the saving mode (step S221).

The above description is about the operation when the full burst is received from the base station. However, even when the half burst is continuously received in the corresponding slot, the saving mode is canceled by itself at regular intervals. do it,
The DSP 129 is activated to activate the digital filters 121, 20.
Similar gain control is performed by rewriting 1 and determining the level. Even at this time, the timing at which the saving mode is canceled by itself is measured by a counter (not shown).

As described above, according to the radio apparatus of this embodiment, the root filter Nyquist characteristic is written in the digital filter 201 while the half burst is continuously received, and the carrier determination circuit 119 is digital. The carrier is determined based on the signal filtered by the filter 201. At this time, DS
Since power is not supplied to P129, carrier determination can be accurately performed even in the complete saving mode. Therefore, the wireless device according to the present embodiment can accurately perform carrier determination with a low current.

The digital filters 121 and 2 described above
Although 01 is described as a rewritable filter, a filter having a root Nyquist characteristic and a short circuit having no filter characteristic may be electronically switchable.

[0067]

As described above, according to the wireless device and the gain control method of the wireless device of the present invention, in the gain control performed first after receiving the burst signal, the first filter means performs filtering. Since the level determination and the gain setting are performed without setting the level determination and the gain setting as one set, the time required for each gain control is short, and the gain of the signal amplification means can be optimally set in a short time. it can. Therefore, the time from the start of reception (burst signal reception) to the establishment of communication is shortened, and problems such as disconnection of the talk and delay in establishment of communication do not occur. Further, since the filtering is performed by the first filter means after the communication is established, the communication can be performed without troubles such as intersymbol interference and reduction of error rate.

[Brief description of drawings]

FIG. 1 is a block diagram showing a wireless device of a first embodiment according to the present invention.

FIG. 2 is an explanatory diagram showing characteristics of a digital filter 121 in a state (a) where a root Nyquist characteristic is written and a state (b) where a filter characteristic is not written.

FIG. 3 is an explanatory diagram illustrating each configuration of a full burst (a) and a half burst (b).

FIG. 4 is a flowchart illustrating an operation when the wireless device (mobile device) of the first embodiment enters the normal reception mode and returns to the saving mode again.

FIG. 5 is an explanatory diagram illustrating gain control performed by the wireless device according to the first embodiment.

FIG. 6 is an explanatory diagram illustrating each configuration of a first burst (a) and a second burst and thereafter (b).

FIG. 7 is a block diagram showing a wireless device of a second embodiment according to the present invention.

FIG. 8 is a flowchart illustrating an operation when the wireless device (mobile device) of the second embodiment enters the normal reception mode and returns to the saving mode again.

FIG. 9 is a block diagram showing a conventional wireless device.

[Explanation of symbols]

101 antenna 103a-103c analog filter 105 LNA 107 mixer 109,115 Local oscillator 111 Automatic gain control circuit (AGC) 113 Quadrature demodulator (Q-DEM) 117 ADC 119 Carrier decision circuit 121,201 Digital Filter 123 Level judgment circuit 125 detection circuit 127 gain setting circuit 129 DSP 131,205 Gate array (G / A) 203 Fixed gain setting circuit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04L 27/22 H04L 27/22 D (72) Inventor Reiko Otomo 4-3 Tsunashima East, Kohoku Ward, Yokohama City, Kanagawa Prefecture No. 1 F term in Matsushita Communication Industrial Co., Ltd. (reference) 5J100 JA01 KA01 LA01 LA09 LA10 LA11 QA01 SA02 5K004 AA01 AA05 BA02 FA09 FG02 FH01 FH04 5K061 AA04 BB12 CC52 5K067 AA14 CC04 EE02 GG11 HH21

Claims (14)

[Claims] 1. A radio apparatus for linearly receiving a time-division multiplexed signal, the signal amplifying means amplifying a received signal with a gain that can be changed by an external instruction, and the signal amplifying means amplified by the signal amplifying means. First filter means capable of filtering a signal; level determination means for determining the level of the signal amplified by the signal amplification means or the signal filtered by the first filter means; and determined by the level determination means First gain setting means for setting the gain of the signal amplifying means based on the signal level, and the wireless device receives a burst signal including communication content in a predetermined slot pre-allocated to the wireless device. Then, in the slot before the predetermined slot of the next frame, the level determination means determines the level of the signal amplified by the signal amplification means. And gain setting by the first gain setting means, and after receiving the burst signal in the predetermined slot of the next frame, level determination and gain setting of the signal filtered by the first filter means are performed. Wireless device. 2. Even when the wireless device does not receive a burst signal in a predetermined slot, the wireless device can perform level determination and gain setting of the signal amplified by the signal amplifying means at predetermined time intervals. The wireless device according to claim 1, which is performed. 3. The first filter means is rewritable, and the first filter means before a predetermined frame of the next frame is in a state in which no information regarding filter characteristics is written, The wireless device according to claim 1 or 2, wherein the first filter means after a predetermined slot of the frame is in a state in which a predetermined filter characteristic is written. 4. When the wireless device stops receiving the burst signal in a predetermined slot, the first filter means is rewritten to a state in which no filter characteristic is written. The described wireless device. 5. The first filter means and the level determination means are configured on the same signal processing circuit, and the signal processing circuit is provided to the signal processing circuit while the wireless device is not receiving a burst signal in a predetermined slot. 5. The wireless device according to claim 1, 3 or 4, wherein power is not supplied to the signal processing circuit and power is supplied to the signal processing circuit when the wireless device receives a burst signal in a predetermined slot. 6. The power is supplied to the signal processing circuit at the time of level determination and gain setting performed at predetermined time intervals when the wireless device is not receiving a burst signal in a predetermined slot. The wireless device according to item 2, 3, 4 or 5. 7. The reception of the burst signal in a predetermined slot by the wireless device is judged by a signal judgment means for judging the type of the signal received in the predetermined slot. The wireless device according to 3, 4, 5 or 6. 8. A second filter means provided before the signal amplifying means, capable of filtering the signal amplified by the signal amplifying means, wherein the radio device receives a burst signal in a predetermined slot. 8. The wireless device according to claim 7, wherein when there is no signal, the signal amplified by the signal amplifying unit is filtered by the second filter unit and then the type of the signal is determined by the signal determining unit. 9. The second filter means is rewritable, and when the wireless device receives a burst signal in a predetermined slot, no information regarding filter characteristics is written in the second filter means. 9. The wireless device according to claim 8, wherein when the wireless device does not receive a burst signal in a predetermined slot, the information about the filter characteristic is written in the second filter means. 10. A second gain setting means for setting the gain of the signal amplifying means when the wireless device does not receive a burst signal in a predetermined slot, and the means for setting the gain of the signal amplifying means comprises: , When the burst signal is received in the predetermined slot and when the burst signal is not received in the predetermined slot, the first
10. The wireless device according to claim 8, wherein the gain setting means or the second gain setting means is switched. 11. A gain control method for a radio apparatus, comprising a signal amplification means for amplifying a received signal with a gain that can be changed by an instruction from the outside in order to linearly receive a time division multiplexed signal. When a burst signal including communication content is received in a predetermined slot pre-assigned to the wireless device, a first level for determining the level of the burst signal amplified by the signal amplifying means in the slot before the predetermined slot of the next frame A determination step and a first gain setting step of setting the gain of the signal amplifying means based on the signal level determined in the first level determination step, and in the predetermined slot of the next frame, the signal A first filtering step of filtering the burst signal amplified by the amplifying means; A second level determining step for determining the level of the signal filtered in the tuning step, and a second gain setting for setting the gain of the signal amplifying means based on the signal level determined in the second level determining step. A gain control method comprising the steps of: 12. In a predetermined slot before receiving a burst signal, a second filtering step of filtering the signal amplified by the signal amplifying means, and a type of the signal filtered in the second filtering step are determined. A first signal determination step to
The second signal determining step of determining the type of the signal amplified by the signal amplifying means is performed in a predetermined slot of the next frame after the burst signal is received in the predetermined slot. 11. The gain control method according to item 11. 13. A wireless device for linearly receiving a time-division multiplexed signal, the signal amplifying means amplifying a received signal with a gain changeable by an instruction from the outside, and the signal amplifying means amplified by the signal amplifying means. First filter means capable of filtering a signal; level determination means for determining the level of the signal amplified by the signal amplification means or the signal filtered by the first filter means; and determined by the level determination means First gain setting means for setting the gain of the signal amplifying means based on the signal level, and the wireless device receives a burst signal including communication content in a predetermined slot pre-allocated to the wireless device. Then, in the preamble section of the next reception slot, the level determination means determines the level of the signal amplified by the signal amplification means. And a gain setting by the first gain setting means, and after the reception of the preamble section, level determination and gain setting of the signal filtered by the first filter means are performed. 14. Even when the wireless device does not receive a burst signal in a predetermined slot, the wireless device determines the level of the signal amplified by the signal amplifying means and sets the gain at every predetermined time. The wireless device according to claim 1, which is performed.