JP2005167390A - Wireless receiver and AGC control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce averaging operation amount while determining the average receiving signal power of a specific channel accurately when the average receiving signal power of that channel is determined, and to reduce a dynamic range required for an operating unit. <P>SOLUTION: A control signal C12 designates the operation mode of an AGC section and a receiving signal power average section. The control signal C12 further includes designation for fixing the gain level after it is updated. The AGC section calculates receiving power in a receiving signal power average section designated by the control signal C12 and calculates a gain level. The gain level is then updated from G (0) to G (1). Furthermore, the operating state of a gain amplifier is transited to a gain level fixing mode according to the designation for fixing the gain level, and the gain amplifier is controlled not to update the gain level from G (1) until the designation for fixing the gain level is released. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a radio reception apparatus and an AGC control method in a communication system employing a system such as W-CDMA.

  For example, in a W-CDMA (Wideband-Code Division Multiple Access) type mobile communication system, the wireless reception apparatus can transmit data addressed to its own device and other users in the same channel in any area of weak electric field or strong electric field. In order to correctly identify the addressed data, it is necessary to suppress the amplitude of the input signal of the A / D converter within a predetermined range. For this purpose, an AGC (Automatic Gain Control) circuit is generally provided in a wireless receiver.

  The basic operation of the AGC circuit is to measure received signal power, generate a control signal by comparison with a target value, and change the gain (amplification gain) of the variable gain amplifier by the control signal.

  FIG. 9 is a diagram showing, on the time axis, the procedure of AGC control of the conventional radio receiving apparatus along with the gain level of the gain amplifier (for example, see Patent Document 1).

In response to the AGC initialization instruction (control signal C1), the wireless reception device returns from the sleep state or the like in the intermittent reception mode at time t1. In response to this instruction, the AGC circuit initializes the internal state and sets the gain level of the gain amplifier to the initial value G (0). Next, an AGC control instruction (control signal C2) for controlling the operation of the normal AGC circuit after the initialization process is issued. In response to this instruction, the AGC circuit starts measurement of the received power (period from time t2 to t3), calculates a gain level based on the measured received power, etc., and sets the gain level of the gain amplifier to G ( Update from 0) to G (1). Thereafter, AGC control starting from time t5, t8,... Is also performed under the same instruction (control signal C2) as the instruction at time t2, and the gain levels are G (1), G (2),.・ ・ Updated from time to time. In addition, each control instruction is issued at regular intervals or at arbitrary timing.
JP-A-8-251058

  However, conventional wireless receivers average received signal power over multiple symbols, such as a paging channel (PICH: Pading Indicator CHannel) during intermittent reception or a call response channel (AICH: Acquisition Indicator CHannel) during random access. If the gain level of the gain amplifier is updated by AGC control while receiving a channel that needs to be received, the gain level differs for each symbol, and the average received signal power of the channel can be accurately obtained. There is a problem that you can not.

In order to solve this problem, there is also a method of averaging received signal power in consideration of the gain level in each symbol as follows. For example, let N be the symbol length of a channel for which the received signal power needs to be averaged, and S (1), S (2),..., S (N) for the reception amplitude of each symbol. If the levels in the amplitude dimension are G (1), G (2),..., G (N), the average value _{V_AVE} of the received signal power is given by the following equation: _{V_AVE} = | {S (1) × 1 / G (1) + S (2) × 1 / G (2) +…
+ S (N) × 1 / G (N)} / N | ² (Formula 1)
Is calculated by However, as in (Equation 1), in order to consider the gain level in each symbol, a multiplication operation is required, which increases the amount of calculation. In addition, an input / output range (dynamic range) that covers the level range that can be taken by the amplified signal is required from the arithmetic unit, which increases the circuit scale and the size of the mobile terminal device.

  The present invention has been made in view of this point, and when obtaining the average received signal power of a channel that needs to average received signal power over a plurality of symbols, the average received signal power of this channel is accurately calculated. It is an object of the present invention to provide a radio receiver and an AGC control method capable of reducing the amount of calculation for averaging while reducing the dynamic range required for the calculator.

  The wireless receiver of the present invention includes an averaging unit that averages received power of a specific channel over a plurality of symbols, an amplifying unit that amplifies a received signal with an amplification gain according to the received power of the received signal, And a control unit that controls the amplification gain of the amplification unit to be constant during a period in which the averaging unit performs averaging.

  The radio reception apparatus according to the present invention employs a configuration in which, in the above configuration, the specific channel is a paging channel in the intermittent reception mode or a call response channel in random access.

  In the radio receiving apparatus according to the present invention, in the above configuration, the control means has a predetermined timing before a timing at which the averaging means starts averaging the control signal indicating that the amplification gain of the amplifying means is constant. The structure which transmits with is adopted.

  The radio reception apparatus according to the present invention employs a configuration in which, in the above configuration, the predetermined timing is determined based on a time required for the amplification means to obtain an amplification gain corresponding to the reception power of the reception signal.

  According to these configurations, in a period of receiving a channel that needs to average received power over a plurality of symbols, such as a paging channel in the intermittent reception mode or a call response channel in random access, AGC control is performed. Since the amplification gain is made constant, the average reception signal power of this channel can be accurately obtained, the amount of calculation for averaging can be reduced, and the dynamic range required for the calculator can be reduced.

  A mobile terminal apparatus according to the present invention employs a configuration including any one of the radio reception apparatuses described above.

  According to this configuration, it is possible to provide a mobile terminal device having the same effects as described above.

  In the AGC control method of the present invention, the amplification gain of AGC control is made constant during the period of receiving the paging channel in the intermittent reception mode or the call response channel in the random access.

  An AGC control program according to the present invention includes an averaging step of averaging received power of a specific channel received over a plurality of symbols, and an amplifying step of amplifying the received signal with an amplification gain corresponding to the received power of the received signal. And a control step of controlling the amplification gain in the amplification step to be constant during a period in which the averaging is performed in the averaging step.

  According to this method or program, AGC control is performed in a period in which a channel that requires reception power to be averaged over a plurality of symbols, such as a paging channel in the intermittent reception mode or a call response channel in random access, is received. Therefore, while calculating the average received signal power of this channel accurately, it is possible to reduce the amount of calculation for averaging and reduce the dynamic range required for the calculator.

  As described above, according to the present invention, when the average received signal power of a channel that needs to average received signal power over a plurality of symbols is obtained, the average received signal power of this channel is accurately obtained. In addition to reducing the amount of calculation for averaging, the dynamic range required for the calculator can be reduced. Therefore, the power consumption of the arithmetic unit can be reduced and the circuit scale can be reduced.

  The gist of the present invention is that the received power needs to be averaged over a plurality of symbols, such as a paging channel (PICH: Pading Indicator CHannel) in the intermittent reception mode or a call response channel (AICH: Acquisition Indicator CHannel) in random access. In a period in which a certain channel is received, the amplification gain of AGC (Automatic Gain Control) control is made constant.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Here, a mobile terminal apparatus in a mobile communication system will be described as an example of a radio reception apparatus. The first embodiment is a case where a paging channel is received in the intermittent reception mode, and the second embodiment is a case where a call response channel is received in random access.

(Embodiment 1)
In a W-CDMA communication system, PICH is a channel used when a mobile terminal apparatus determines whether a radio signal addressed to itself is received from a base station apparatus (incoming call determination). Control information for each mobile terminal apparatus is transmitted from the base station apparatus through this channel by time division multiplexing.

  FIG. 1 is a diagram showing the relationship between the frame structure of this PICH and the received power averaging section for obtaining the received power of the PICH (see 3GPP TS 25.211).

  As shown in this figure, the PICH received power averaging section is in the range from the symbol bK to the symbol bK + L−1 (the number of target PICH symbols L) in one received signal frame, and the PICH is from the symbols b0 to bM. -1 is transmitted in the range of -1, whereas the averaged section of the received power is only a specific part.

  FIG. 2 is a diagram for explaining the relationship between the return process in the intermittent reception mode of the mobile terminal apparatus and the PICH received power averaging section.

  In the intermittent reception mode, the mobile terminal device is in a sleep state until the control signal C11 is generated. During this period, in the mobile terminal device, only a circuit such as a counter that generates a control signal C11 (a signal that triggers a return from the sleep state) operates at a fixed or arbitrary time.

  As described above, in the PICH, control information for each mobile terminal apparatus is time-division multiplexed, and each mobile terminal apparatus uniquely knows the timing at which its own control information is transmitted. Therefore, in the intermittent reception mode, it is normally in the sleep state, temporarily returns from the sleep state in accordance with the timing at which the control information addressed to itself is transmitted, receives the PICH, determines whether there is an incoming call, If it is determined that the incoming call has been received, the state transitions to the sleep state again. With this operation, the mobile terminal apparatus can suppress power consumption.

  The time t11 is a time at which a trigger (control signal C11) for starting preparation for receiving the PICH is issued (more precisely, at a timing earlier by the signal length of the control signal C11), and the mobile terminal apparatus In anticipation of the time required from the start of intermittent return processing to the start of PICH reception, a trigger is issued at a timing that is a predetermined time before time t14 at which the PICH addressed to itself is transmitted. Then, the PICH is received during the period from t14 to t16, and whether or not there is an incoming call is determined.

  Thus, the mobile terminal apparatus knows in advance the period during which the PICH addressed to itself is transmitted. Therefore, the mobile terminal apparatus according to the present embodiment performs AGC control so that the gain (amplification gain) level of the gain amplifier is constant during this period.

  FIG. 3 is a block diagram showing the main configuration of the mobile terminal apparatus according to the present embodiment that enables the AGC control described above.

  The mobile terminal apparatus according to the present embodiment includes an antenna 101, an RF unit 102, a gain amplifier 103, an A / D converter (ADC) 104, an AGC unit 105, a control unit 106, a demodulation unit 107, and an incoming call determination unit 108. .

  Each part of this mobile terminal apparatus performs the following operations.

  The RF unit 102 performs processing such as frequency conversion and amplification on the radio signal received by the antenna 101. The A / D converter 104 quantizes the amplified signal to obtain a digital signal. The demodulator 107 demodulates this digital signal. The AGC unit 105 measures the received power of the radio signal amplified by the RF unit 102, and receives the gain level of the gain amplifier 103 in the RF unit 102 so that the input level to the A / D converter 104 is constant. Adjust according to. The control unit 106 controls the operation mode of the AGC unit 105 (specific parameters include initialization timing, sleep period, operation period, etc.), received power measurement period, and the like.

  Next, the AGC control method of the mobile terminal apparatus according to the present embodiment having the above configuration will be described in detail with reference to the drawings.

  FIG. 4 is a diagram illustrating, on the time axis, the AGC control procedure after the mobile terminal apparatus according to the present embodiment returns from the sleep state together with the gain level of the gain amplifier 103.

  As described above, the control unit 106 considers the PICH transmission start time t14 addressed to itself, and issues the control signal C11 for instructing to return from the sleep state at a timing (time t11) a predetermined time ago. The mobile terminal apparatus starts the intermittent return processing by this control signal C11, and the AGC unit 105 sets the internal state initialization and the gain amplifier initial level.

  Next, the control unit 106 issues an AGC control instruction control signal C12 (time t12), and instructs the AGC unit 105 about the operation mode and the received signal power average interval. In addition, the control signal C12 includes an instruction to fix the gain level after the gain level of the gain amplifier 103 is updated.

  The AGC unit 105 calculates received power in the received signal power average section specified by the control signal C12, and calculates the gain level of the gain amplifier 103 based on this received power. Then, the gain level of the gain amplifier 103 is updated from G (0) to G (1) (time t13). Further, the AGC unit 105 changes the operating state of the gain amplifier 103 to the gain level fixing mode according to the instruction to fix the gain level, and sets the gain level until the control unit 106 cancels the gain level fixing instruction. The gain amplifier 103 is controlled not to update from G (1).

  Note that the time 12 at which the control signal C12 is issued takes into account the time required for each process of calculation of received power in AGC control, gain calculation, gain level update of the gain amplifier 103, and transition to the gain level fixed mode. The time is adjusted so that a series of processing is completed before the reception start time t14.

  The incoming call determination unit 108 receives the PICH at times t14 to t16, and determines whether there is an incoming call. Here, the incoming call determination is performed using a quadrant in which the demodulated signal appears on the IQ plane and a ratio between the received signal power of the PICH and the received signal power of the common channel (CPICH: Common Pilot Channel). At this time, the received signal power of each channel is expressed as follows.

First, PICH symbol length is N, PICH symbol reception amplitude is P (1), P (2),..., P (N), and CPICH symbol reception amplitude is C (1), C (2 ,..., C (N), and G (1), G (2),. At this time, between each symbol, the level of the gain amplifier is fixed,
G (1) = G (2) = ... = G (N) (Formula 2)
The relationship holds.

Therefore, the average value _{VP_AVE} of the received signal power of the PICH is
_{VP_AVE} = | 1 / G (1) {P (1) + P (2) +... + P (N)} / N | ²
... (Formula 3)
Can be calculated by Similarly, the average value V _{C_AVE} of CPICH received signal power is
_{V C_AVE = | 1 / G (} 1) {C (1) + C (2) + ... + C (N)} / N | 2
... (Formula 4)
Can be calculated by Therefore, the ratio of the received signal power of PICH and CPICH is
_{VP_AVE} / _{VC_AVE} = | P (1) + P (2) +... + P (N) | ² / | C (1) + C (2) +.
+ C (N) | ² (Formula 5)
Can be calculated by:

  In this way, by obtaining the average power between the symbols for each channel and comparing them, the received signal power ratio can be obtained, and there is no need to consider the gain level of the gain amplifier 103 at all.

  Further, the control unit 106 issues a new AGC control instruction (control signal C13) to the AGC unit 105 so that the gain level fixed mode of the gain amplifier 103 is canceled after the reception of the PICH is completed (time t15). ). In response to this instruction, the AGC unit 105 starts processing for obtaining the next gain level. Subsequent processing is the same as normal AGC control. This time t15 is also a timing a predetermined time before the PICH reception completion time t16 in consideration of the time required for each process such as reception power calculation.

  In addition, when the incoming call determination unit 108 determines that the call has not been received, the determination result is notified to the control unit 106, and the mobile terminal apparatus according to the present embodiment transitions to the sleep state again.

  As described above, according to the present embodiment, the gain level in each symbol of the received signal needs to be considered in order to keep the amplification gain of AGC control constant during the period in which the paging channel is received in the intermittent reception mode. Thus, the amount of calculation in incoming call determination can be reduced and the dynamic range required for this calculator can be reduced. Therefore, it is possible to reduce the power consumption of the computing unit and reduce the circuit scale of the mobile terminal device.

  In the present embodiment, the case where the channel for comparing the PICH and the received signal power is the CPICH has been described as an example, but the channel to be compared may be a channel different from the CPICH. At this time, for example, when the averaging start position of the received signal power of the channel to be compared is a timing before the averaging start position of the PICH, in the AGC control until the averaging of the channel is started. The reception power average interval included in the control signal C12 is adjusted and the time at which the control signal C12 is generated is adjusted so that the update of the gain level and the transition to the level fixing mode are completed.

(Embodiment 2)
In a W-CDMA communication system, when a plurality of mobile terminal apparatuses randomly access a base station apparatus through the same common channel, the mobile terminal apparatus first transmits a channel called a preamble to the base station apparatus. The base station apparatus that has received this preamble returns a response to the preamble to the mobile terminal apparatus via the AICH. The response from this base station apparatus consists of ACK or NACK, and the mobile terminal apparatus that has received ACK can access (data communication) the base station apparatus.

  FIG. 5 is a diagram showing the relationship between the AICH frame configuration and the received power averaging section for obtaining the AICH received power (see 3GPP TS 25.211).

  As shown in this figure, the AICH received power averaging section is in the range from the symbol a0 to the symbol aM-1 (number of target AICH symbols M), and even when viewed from the access frame length, it is viewed from the access slot length. Even it has become a specific part.

  FIG. 6 is a diagram for explaining the relationship between the AICH received power averaging section and the random access processing in the mobile terminal apparatus.

  The mobile terminal apparatus transmits a preamble to the base station apparatus at times t22, t28, t31,. This process is repeated until an AICH that is a response to the preamble is transmitted from the base station apparatus. For example, assuming that the time when the mobile terminal apparatus transmits the preamble is t22, it is expected that the AICH is received by the mobile terminal apparatus at time t24 after the response delay time of the base station apparatus has elapsed.

  Therefore, the mobile terminal device attempts to receive AICH at time t24, which is the timing matched with the response delay time of the base station device. Then, at time t26, it is determined whether or not AICH has been transmitted. Since the AICH is a channel that the base station apparatus transmits only at the time of response, the AICH is not transmitted when the base station apparatus does not respond for reasons such as low preamble transmission power. Therefore, the mobile terminal apparatus measures the reception signal power of the AICH to determine whether or not the AICH is actually transmitted at the AICH reception timing (time t24 in the above example). Based on the ratio of the received signal power of the common channel (CPICH), the presence or absence of a response from the base station apparatus is determined.

  The mobile terminal apparatus performs retransmission of the preamble, start of data reception, or stop of random access according to the determination result of the AICH determination. In FIG. 6, an example in which it is determined that the AICH is not transmitted from the base station device at time t26, and a case in which it is determined that the AICH is transmitted from the base station device and an ACK response is returned at time t33. An example is shown. If an ACK response is returned, the mobile terminal device starts data communication (time t34).

  Since the mobile terminal device knows about the response delay time of the base station device, it can predict the timing (period) at which the AICH addressed to itself returns after transmitting the preamble. Therefore, the mobile terminal apparatus according to the present embodiment performs AGC control so that the amplifier level (amplification gain) of the gain amplifier is constant during this period.

  FIG. 7 is a block diagram showing the main configuration of the mobile terminal apparatus according to the present embodiment that enables the above AGC control. Note that this mobile terminal apparatus has the same basic configuration as the mobile terminal apparatus shown in FIG. 3, and the same components are denoted by the same reference numerals and description thereof is omitted.

  This mobile terminal apparatus is characterized in that the control unit 201 receives a notification that a preamble has been transmitted from a preamble transmission unit (not shown), and performs AGC control based on the notification.

  FIG. 8 is a diagram showing the AGC control procedure according to the present embodiment on the time axis together with the gain level of the gain amplifier 103.

  In random access, the mobile terminal apparatus is not in the sleep state in the intermittent reception mode as described in the first embodiment, and the AGC unit 105 calculates received power according to the AGC control instruction from the control unit 201. The gain level of the gain amplifier 103 is updated.

  The control unit 201 issues an AGC control instruction control signal C21 at a time t21 that is prior to the time t22 at which the preamble is transmitted. This control signal C21 is for AICH reception performed at time t24, and instructs the AGC unit 105 about the operation mode and the received signal power average interval. In addition, the control signal C21 includes an instruction to fix the gain level after the gain level of the gain amplifier 103 is updated.

  The AGC unit 105 calculates received power in the received signal power average interval according to this instruction, and calculates the gain level of the gain amplifier 103 based on this received power. Then, the gain level of the gain amplifier 103 is updated from G (1) to G (2) (time t23). Further, the AGC unit 105 changes the operating state of the gain amplifier 103 to the gain level fixing mode in accordance with the instruction to fix the gain level, and sets the gain level until the control unit 201 cancels the gain level fixing instruction. The gain amplifier 103 is controlled not to update from G (2).

  Note that the time t21 at which the control signal C21 is issued takes into account the time required for each process of calculation of received power in AGC control, gain calculation, gain level update of the gain amplifier 103, and transition to the gain level fixed mode. The time is adjusted so that a series of processing is completed before the reception start time t24.

  The AICH determination unit 202 receives the AICH from time t24 to t26 and determines whether or not there is transmission. Here, the transmission determination is performed using a quadrant in which the demodulated signal appears on the IQ plane and a ratio of the reception signal power of the AICH and the reception signal power of the common channel (CPICH). Also in the ratio of the AICH to CPICH received signal power, the same calculation as the PICH at the time of intermittent return shown in the first embodiment can be applied. In other words, the received signal power ratio can be obtained by obtaining the average power between symbols for each channel and comparing them, and there is no need to consider the gain level of the gain amplifier 103 at all.

  Further, the control unit 201 issues a new AGC control instruction (control signal C22) to the AGC unit 105 so that the gain level fixing mode of the gain amplifier 103 is canceled after the reception of the AICH is completed (time t25). ). In response to this instruction, the AGC unit 105 starts processing for obtaining the next gain level. Subsequent processing is the same as normal AGC control.

  As described above, according to the present embodiment, the gain level in each symbol of the received signal needs to be considered in order to keep the amplification gain of AGC control constant during the period when the call response channel is received in random access. Thus, the amount of computation in call response channel transmission determination can be reduced and the dynamic range required for this computing unit can be reduced. Therefore, it is possible to reduce the power consumption of the computing unit and reduce the circuit scale of the mobile terminal device.

  In the present embodiment, the case where the channel for comparing the AICH and the received signal power is CPICH has been described as an example, but the channel to be compared may be a channel different from CPICH. At this time, for example, when the averaging start position of the received signal power of the channel to be compared is a timing before the averaging start position of the AICH, the AGC control is started before the averaging of the channel is started. The reception power average section included in the control signal C21 is adjusted and the time at which the control signal C21 is issued is adjusted so that the update of the gain level and the transition to the level fixing mode are completed.

  The radio reception apparatus according to the present invention is not limited to the first and second embodiments, and can be implemented with various modifications. For example, Embodiments 1 and 2 can be implemented in combination as appropriate.

  The radio reception apparatus according to the present invention can be used in a communication system using a system other than CDMA, and thus, a radio reception apparatus having the same operation and effect as described above can be provided.

  Here, the case where the present invention is configured by hardware has been described as an example, but the present invention can also be realized by software.

  The radio receiving apparatus according to the present invention has an effect of reducing the circuit scale, and can be applied to a W-CDMA mobile communication system and the like.

The figure which shows the relationship between the frame structure of PICH, and a reception electric power average area | region The figure for demonstrating the relationship between the reset process in a discontinuous reception mode, and a PICH receiving power average area. FIG. 2 is a block diagram showing the main configuration of a mobile terminal apparatus according to Embodiment 1 The figure which showed the procedure of AGC control concerning Embodiment 1 on the time axis with the gain level The figure which shows the relationship between the frame structure of AICH, and a reception power averaging area. The figure for demonstrating the relationship between an AICH received power average area and a random access process. FIG. 3 is a block diagram showing the main configuration of a mobile terminal apparatus according to Embodiment 2 The figure which showed the procedure of AGC control concerning Embodiment 2 on the time axis with the gain level The figure which showed the procedure of AGC control of the conventional radio | wireless receiver on a time-axis with a gain level

Explanation of symbols

103 Gain Amplifier 105 AGC Unit 106, 201 Control Unit 108 Incoming Call Determination Unit 202 AICH Determination Unit C11-C13, C21, C22 Control Signal

Claims (7)

Averaging means for averaging the received power of a specific channel over a plurality of symbols;
Amplifying means for amplifying the received signal with an amplification gain corresponding to the received power of the received signal;
Control means for controlling the amplification gain of the amplification means constant during a period in which the averaging means performs averaging;
A wireless receiver characterized by comprising: The specific channel is
A paging channel in intermittent reception mode or a call response channel in random access,
The wireless receiver according to claim 1. The control means includes
Transmitting a control signal indicating that the amplification gain of the amplification means is constant at a predetermined timing before the timing at which the averaging means starts averaging;
The wireless receiver according to claim 1. The predetermined timing is
Determined based on the time required for the amplification means to obtain an amplification gain according to the received power of the received signal;
The wireless receiver according to claim 3.   A mobile terminal device comprising the wireless reception device according to claim 1.   An AGC control method characterized in that the amplification gain of AGC control is made constant during a period in which a paging channel in the intermittent reception mode or a call response channel in random access is received. An averaging step of averaging the received power of a particular channel received over multiple symbols;
An amplification step of amplifying the received signal with an amplification gain according to the received power of the received signal;
A control step for controlling the amplification gain in the amplification step to be constant during a period in which the averaging is performed in the averaging step;
An AGC control program that causes a computer to execute.

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