JP2001186070A - Wireless communication terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a CDMA wireless communication terminal that efficiently uses a given number of inverse spread circuits so as to realize enhanced speech quality and suppress useless power consumption. SOLUTION: An automatic gain control means 105 controls gains of amplifiers 2a, 2b on the basis of an AGC value so that a received signal level becomes a prescribed level. A reception antenna selection control section 111 changes a connection assignment ratio to a plurality of the inverse spread sections 9a-9n of each antenna branch depending on the quantity of each AGC value to an antenna branch #1 of an antenna 1a and an antenna branch #2 of an antenna 1b. Each selection circuit 12 connects either of the antenna branches #1, #2 to the inverse spread section 9 under the control of the reception antenna selection control section 111.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving system in a CDMA wireless communication terminal and a circuit configuration thereof.

[0002]

2. Description of the Related Art In mobile communication, a plurality of spatially separated antennas are prepared, and signals from the plurality of antennas are selected / selected.
By combining, the receiving sensitivity is improved. This is known as antenna diversity. In addition, automatic gain control (AGC) is performed on each receiving antenna in order to reduce fading amplitude fluctuation.

FIG. 9 shows the configuration of a conventional CDMA receiver. A plurality of antennas 1a and 1b and amplifiers 2a and 2b so that the reception signal of each antenna becomes a reference reception level.
Alternatively, an automatic gain control circuit (AGC circuit) 5 for controlling the reception gain using the attenuators 3a and 3b, and an A / D converter 4
a, 4b, D / A converters 6a, 6b, a matched filter 8 for detecting the multipath timing of the received signal of each antenna, and the timing of the multipath to be received is from any antenna. Signal search circuit 7 for determining whether or not N despreading circuits (finger circuits) 9a and 9b
9m and 9n, and a combining circuit 10 for combining N despreading circuit outputs to obtain a detection output. In FIG. 9, A
A frequency conversion process is inserted before the D converters 4a and 4b, but is not shown for convenience of explanation.

[0004] Each of the D / A converters 6
The AGC values input to a and 6b mean a difference between a preset reference reception level and a reception level of a signal actually received by each antenna. That is, if the reception level at the antenna end is high, the AGC value for that antenna branch will be a small value. Conversely, if the reception level at the antenna end is low, the AGC value for that antenna branch will have a large value.

The gain of the received signal of each antenna is controlled by an automatic gain control circuit 5 so as to be a reference amplitude level, and a signal detection circuit 7 and N despreading circuits 9a to 9n.
Is input to The signal detection circuit 7 uses the matched filter 8 to measure the reception timing and signal strength of the desired wave to determine a reception path, and determines the timing of the multipath for despreading for each antenna branch by each despreader 9a. To 9n. The despreaders (finger circuits) 9a to 9n are equally allocated to each antenna in order to obtain the effect of antenna diversity, and despread the input signal from the antenna when the despread timing notified from the signal detection circuit triggers. The signal is spread and output to the synthesis circuit 10. In the synthesizing circuit 10, the signals input from the respective despreaders 9a to 9n are stored in a built-in buffer or the like, and are synthesized at the timing of the slowest reception path to produce a detection output.

[0006]

As a first problem, in the conventional method, the strength of multipath is obtained for each antenna,
In order to determine the multipath to be received, the received signals after automatic gain control from multiple antennas are input to the matched filter, and the received power at each antenna branch is large by despreading using a spreading code for timing detection. Multipaths are determined and assigned to fingers, and signals after despreading of each antenna branch are rake-combined to provide detection outputs. However, depending on how the user uses the wireless communication terminal,
For example, if an antenna is held down by hand or the reception level of that antenna is extremely lower than the reception level of another antenna for some reason, automatic gain control (AGC) is used to set the desired level. Not only a received wave component but also a high noise component is amplified at the same time, and a received signal having a low SIR value is assigned to a finger, so that there is a problem that limited finger resources are wasted.

As a second problem, in the conventional method, a received signal of an antenna whose reception level is extremely low as compared with other antennas is amplified to a reference reception level by automatic gain control (AGC). There was a problem of wasteful consumption.

[0008] As a third problem, in the conventional method, the assignment of the multipath to the finger is determined based on the signal strength of the multipath that is the output of the matched filter. If so,
When the RSSI value or SIR value of the signal after despreading is different between the antenna branches, the ratio of finger assignment of each antenna is not dynamically controlled, and limited finger resources are not efficiently used. There were also problems.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a CDMA radio terminal apparatus,
It is an object of the present invention to efficiently use a given number of despreading circuits, improve speech quality, and suppress unnecessary power consumption.

[0010]

A CDMA radio communication terminal according to the present invention comprises first and second antennas, first and second amplifying means for amplifying a signal received by each of the antennas, Automatic gain control means for controlling the gain of each of the amplifying means so that the level of the received signal amplified by each of the amplifying means becomes a reference level; and multipath reception from the received signal amplified by each of the amplifying means. Signal search means for detecting the timing, at the timing notified from the signal search means, to despread the received signal using a spreading code, a plurality of despreading means more than the number of antennas,
A receiving antenna selection control means for selectively connecting one of the received signals from the first and second antennas to each of the despreading means; a detection output by synthesizing a signal supplied from each of the despreading means; The receiving antenna selection control means, wherein the reception antenna selection control means responds to the magnitude of the gain control value of the automatic gain control means for the first and second amplification means provided for the first and second antennas. Then, the connection allocation ratio of each antenna to the plurality of despreading means is changed. Therefore, efficient use of the limited despreading circuit and improvement of speech quality are realized.

The reception antenna selection control means includes: an antenna reception signal corresponding to an amplification means whose gain control value of the automatic gain control means is higher than a certain threshold; or
An antenna reception signal whose relative value to a gain control value of another amplifying means is higher than a certain threshold is not assigned to the despreading means. Further, the automatic gain control means stops the gain control of the amplification means corresponding to the antenna reception signal not allocated to the despreading means. Therefore, unnecessary power consumption can be suppressed by not performing unnecessary despreading processing or automatic gain control.

Further, the CDMA wireless communication terminal of the present invention comprises:
First and second antennas, first and second amplifying means for amplifying signals received by the respective antennas, and a level of a received signal amplified by each of the amplifying means becomes a reference reception level. Automatic gain control means for controlling the gain of each of the amplifying means, signal search means for detecting a multipath reception timing from the received signal amplified by each of the amplifying means, and timing notified from the signal search means A plurality of despreading means equal to or more than the number of antennas for despreading the received signal using a spreading code; and selecting one of the received signals from the first and second antennas for each despreading means. Receiving antenna selection control means to be connected to each other, communication quality measuring means for measuring the RSSI value or SIR value of the signal output from each despreading means, and signal input from each despreading means. And it comprises a synthesizing means for a detection by combining with a weight proportional to the magnitude of the RSSI value or SIR values of the corresponding received signal is notified from the communication quality measurement unit output. As a result, it is possible to improve the communication quality.

Further, the CDMA radio communication terminal of the present invention comprises a first antenna, a second antenna, a signal search means for detecting a multipath reception timing from a signal received by each antenna, and a signal search means. At the notified timing, a plurality of despreading means for despreading the received signal using a spreading code, and each of the despreading means selectively selecting one of the received signals from the first and second antennas. , A communication quality measuring means for measuring an RSSI value or an SIR value of a signal output from each despreading means, a signal provided from each despreading means, and a detection output. The receiving antenna selection control means, when the same path is received by the first and second antennas, the RSSI measured by the communication quality measuring means. Or according to the magnitude of SIR values,
The supply allocation ratio of each antenna reception signal to each despreading means is changed. This also makes it possible to realize efficient use of the limited despreading circuit and improvement of speech quality.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a main configuration of a wireless communication terminal according to the present embodiment.

As shown in this figure, the radio communication terminal of this embodiment comprises a plurality of antennas 1a and 1b, amplifiers 2a and 2b for automatic gain control, and attenuators 3a and 3a for automatic gain control.
3b, A / D converters 4a and 4b, an automatic gain control unit (AGC circuit) 105, D / A converters 6a and 6b,
The signal search unit 107, the matched filter 8, the reception antenna selection control unit 111, and the N selectors 12a and 12b
To 12n and N despreaders (finger circuits) 9a, 9
b to 9n and a synthesizing unit 10.

The automatic gain control unit 105 controls each antenna 1
The gain control of the received signals is performed using the amplifiers 2a and 2b or the attenuators 3a and 3b so that the received signals a and 1b have the reference amplitude level. As a result, the gain-controlled reception signal for each antenna is input to the signal search unit 107, the reception antenna selection control unit, and the N selectors 12a to 12n.

The AGC value input from the automatic gain control unit 105 to each of the D / A converters 6a and 6b and the reception antenna selection control unit 111 is based on a preset reference reception level and is actually received by each antenna. Means the difference from the received signal level. That is, if the reception level at the antenna end is high, the AGC value for that antenna branch will be a small value. Conversely, if the reception level at the antenna end is low, the AGC value for that antenna branch will have a large value.

The receiving antenna selection control unit 111 monitors the gain control value for each antenna branch of the automatic gain control unit 105, determines the connection allocation ratio of each antenna branch to the finger according to the value, and determines the ratio. Each antenna branch input is set to N selectors 12a to 12a to conform.
12n are used to connect to N despreading units. Also, the connection state is notified to the signal search unit 107.

According to the AGC value of each antenna branch,
As a method of determining the connection allocation ratio of each antenna branch to the finger, a method using the table of FIG. 2 and a method of FIG.
There are two methods of using the table.

FIG. 2 is a table used by the reception antenna selection control section 111 to determine the connection allocation ratio of each antenna branch to a finger. The table is provided, for example, by the reception antenna selection control section 111. Here, the received signal of antenna 1a is divided into antenna branch # 1, antenna 1b
Is referred to as antenna branch # 2,
For example, assuming that the AGC value of antenna branch # 1 is A1 and the AGC value of antenna branch # 2 is A2, reception antenna selection control section 111 refers to the table in FIG. 2 to obtain the finger assignment index of each antenna branch. Get a number. In this case, the finger assignment indexes of antenna branch # 1 and antenna branch # 2 are F
1, F2, and the size of F1 and F2 is, for example, 1: 2.
Determines the ratio of antenna branches # 1 and # 2 to fingers to be 1: 2. The inputs of antenna branches # 1 and # 2 are connected to despreading sections 9a to 9n using N selectors 12a to 12n at a ratio of 1: 2, and the connection state is determined by a signal search section. Notify 107.

Further, for example, when the reception level of the antenna 1a is extremely reduced due to the user holding down the antenna 1a with a hand or some trouble in the antenna 1a, the automatic gain control unit 105 operates the antenna 1a. It is assumed that the AGC value of branch # 1 has become extremely high.
In that case, the AGC value of antenna branch # 1 in FIG.
From A1, a preset threshold value (Ama
x), which is A3 which is a value equal to or greater than the value, and the reception antenna selection control unit 111 refers to the table of FIG. 2 to obtain the finger assignment index value of the antenna branches # 1 and # 2 as
Since 0 and F2 are obtained, respectively, the allocation ratio of the antenna branches # 1 and # 2 to the fingers is determined to be 0: 1.
That is, it is determined that the received signal of antenna branch # 1 is a signal full of noise having a low SIR value and has no effect even if rake combining is performed, and no signal is assigned to the finger at all. This means assigning to all available fingers.

FIG. 3 is also a table used by the reception antenna selection control unit 111 to determine the connection allocation ratio of each antenna branch to a finger. The reception antenna selection control unit 111 first calculates and obtains the AGC average value of all the antenna branches # 1 and # 2,
FIG. 3 shows the difference between the C value and the average value of all the antenna branch AGCs.
By referring to the table, a numerical value as a finger assignment index of each antenna branch is obtained. In this example,
A set of “difference between the AGC value of antenna branch # 1 and the average value of all antenna branch AGCs” and a set of “difference between the AGC value of antenna branch # 2 and the average value of all antenna branches AGC” are (A1, A2), respectively. ), (A3, A4),
The case of (A5, A6) is shown, and A0 indicates the position of the AGC average value of the antenna branches # 1 and # 2.

In FIG. 3, AGC of antenna branch # 1
The difference between the AGC value and the average value of all the antenna branches AGC is A1, and the AGC value of the antenna branch # 2 and all the antenna branches A
When the difference from the GC average value is A2, the reception antenna selection control unit 111 obtains F2 and F2 as finger assignment indexes of the antenna branches # 1 and # 2, respectively.
The finger allocation ratio between antenna branch # 1 and antenna branch # 2 is determined to be 1: 1. In this case, the finger allocation ratio is not changed due to a slight difference in the AGC value for each antenna branch.

In FIG. 3, AGC of antenna branch # 1
The difference between the AGC value and the average value of all the antenna branches AGC is A3, and the AGC value of antenna branch # 2 and all the antenna branches A
When the difference from the GC average value is A4, the reception antenna selection control unit 111 obtains F1 and F3 as finger assignment indexes of the antenna branches # 1 and # 2, respectively.
The finger assignment ratio between antenna branch # 1 and antenna branch # 2 is determined to be 1: 3. In this case, since the reception level of antenna branch # 1 has decreased and the AGC value has increased, the finger assignment ratio of antenna branch # 1 has been reduced, and instead the finger of antenna branch # 2 having a higher reception level and a lower AGC value. This is an example in which the assignment ratio to the group is largely determined.

In FIG. 3, AGC of antenna branch # 1
The difference between the AGC value and the average value of all the antenna branches AGC is A5, and the AGC value of the antenna branch # 2 is all the antenna branches A
When the difference from the GC average value is A6, receiving antenna selection control section 111 obtains 0 and F4 as finger assignment indices of antenna branches # 1 and # 2, respectively. Therefore, antenna branch # 1 and antenna branch # 2 Is determined to be 0: 1. In this case, the reception level of antenna branch # 1 is extremely reduced,
It becomes A5 which is a value equal to or more than a preset threshold value (Amax), and it is determined that the received signal of the antenna branch # 1 is a signal full of noise having a low SIR value and has no effect even if rake combining is performed. , No finger is assigned at all, and instead the finger is assigned only to antenna branch # 2 having a high reception level and a low AGC value.

When the signal search unit 107 obtains the reception timing and signal strength of the desired wave using the matched filter 8, the connection information to the despreading unit of each antenna branch notified from the reception antenna selection control unit 111 is obtained. Based on
The reception path is determined, and the timing of multipath for despreading for each antenna branch is notified to each of the despreading units 9a to 9n.

The despreading units (finger circuits) 9a to 9n
The demultiplexing timing notified from the signal search unit 107 triggers the despreading of the input signal from the antenna and the synthesizing unit 10
Output to

The synthesizing unit 10 stores the signals input from the respective despreading units in a built-in buffer or the like, and synthesizes the signals at the timing of the slowest reception path to obtain a detection output.

For example, the receiving antenna selection control unit 111
Determines the connection ratio of the antenna branches # 1 and # 2 to the despreading unit to 1: 2, the antenna branch # 1 to the despreading unit 9n, and the antenna branch # 2 to the two despreading units 9a and 9b. And the connection information is assigned to the signal search unit 1.
07, the signal search unit 107 determines based on the output result of the matched filter 8 as shown in FIG.
A despreading unit is assigned to each antenna branch in the order of the multipath with the highest power value, and the corresponding despreading unit is notified of the timing of the multipath to be despread. Figures 4 (a) and 4
(B) shows a state in which one pilot signal transmitted from the base station is received at the times T0, T1, and T2 by reflecting the building or the like or directly to the antennas 1a and 1b of the terminal device. .

In this case, the signal search unit 107 sets the despreading unit 9a to the path at the time T0 of the antenna branch # 2, the despreading unit 9b to the path at the time T1 of the antenna branch # 2,
Then, the time T of the antenna branch # 1 is supplied to the despreading unit 9n.
Each despreading unit is notified of the despreading timing so as to despread one path.

As a result, the combining circuit 10 performs weighted rake combining on the antenna branch # 2 having a relatively high reception level as compared with the antenna branch # 1, and performs automatic gain control for each antenna input. By changing the allocation ratio of each antenna to the despreading circuit in accordance with the magnitude of the value, efficient use of the limited despreading circuit and improvement in communication quality are realized.

For example, when the reception level of antenna branch # 1 is extremely reduced, reception antenna selection control section 111 sets the connection ratio of antenna branches # 1 and # 2 to the despreading section to 0: 1. That is, antenna branch # 1
Is determined not to be allocated to the despreading unit, the antenna branch # 2 is allocated to the three despreading units 9a, 9b, and 9n, and the connection information is notified to the signal searching circuit 107. Is based on the output result of the matched filter 8 as shown in FIG. 4, assigns a despreading unit to each antenna branch in the order of the multipath with the highest power value, and despreads to the corresponding despreading unit. Notify path timing.

In this case, the path of the antenna branch # 2 at time T0 is passed to the despreading unit 9a, the path of the antenna branch # 2 at time T1 is passed to the despreading unit 9b, and
The despreading unit is notified of the despreading timing so as to despread the path at time T2 of antenna branch # 2 to n. Therefore, as a result, in the combining circuit 10, only three multipaths of the antenna branch # 2 are rake-combined, and the automatic gain control value of the antenna input becomes extremely higher than those of other antenna inputs. In this case, by not assigning the antenna to the despreading circuit, it is possible to realize efficient use of the limited despreading circuit and improvement of communication quality.

Further, reception antenna selection control section 111
Notifies the automatic gain control unit 105 that the antenna branch # 1 is no longer allocated to the despreading unit, so that the automatic gain control unit 105
By stopping automatic gain control (AGC) (amplification control), unnecessary power consumption can be suppressed. However, when the reception level of the antenna branch # 1 recovers to the reference threshold or more, the automatic gain control unit 105 sets the automatic gain control (A
GC), and the reception antenna selection control unit 11
By notifying to 1, it becomes possible to restart the control of assigning each antenna branch to a finger based on the AGC value.

Next, a second embodiment of the present invention will be described. FIG. 5 is a block diagram illustrating a main configuration of the wireless communication terminal according to the present embodiment.

As shown in this figure, the radio communication terminal of this embodiment has a plurality of antennas 1a and 1b, amplifiers 2a and 2b for automatic gain control, and attenuators 3a and 3a for automatic gain control.
3b, A / D converters 4a and 4b, an automatic gain control unit (AGC circuit) 205, D / A converters 6a and 6b,
The signal search unit 207, the matched filter 8, the reception antenna selection control unit 211, and the N selectors 12a and 12b
To 12n and N despreading units (finger circuits) 9a, 9
b to 9n, a communication quality measuring unit 13, and a rake combining unit 210 for performing maximum ratio combining.

The AGC value input from the automatic gain control unit 205 to each of the D / A converters 6a and 6b and the reception antenna selection control unit 211 is based on a preset reference reception level and is actually received by each antenna. Means the difference from the received signal level. That is, if the reception level at the antenna end is high, the AGC value for that antenna branch will be a small value. Conversely, if the reception level at the antenna end is low, the AGC value for that antenna branch will have a large value.

After the gains of the received signals of the antennas 1a and 1b are controlled by the automatic gain control unit 205 so as to have a reference amplitude level, the direct signal search unit 207 and the selector 1
At 2a to 12n, the signals are selectively input to N despreading units 9a to 9n. The signal search circuit 207 uses the matched filter 8 to measure the reception timing and signal strength of the desired wave to determine a reception path, and issues an instruction to connect each antenna branch to each despreading unit to the reception antenna selection control unit. Notify 211. Further, the signal search circuit 207 notifies the despreaders 9a to 9n of the timing of the multipath to be despread.
The receiving antenna selection control section 211 includes the selectors 12a to 12a.
2n, each antenna branch is connected to each despreading unit as instructed by the signal search circuit 207. The despreading units (finger circuits) 9a to 9n despread the input signal from the antenna triggered by the despreading timing notified from the signal search unit 207, and synthesizer 210 and communication quality measuring unit 1
Output to 3. The communication quality measuring unit 13 includes despreading units 9a to 9a.
9n for each received signal output from
The R value is measured, and the measurement result is notified to the combining unit 210. In the combining circuit 210, the signals input from the despreaders 9a to 9n are stored in a built-in buffer or the like, and each received signal notified from the communication quality measurement unit 13 at the timing of the slowest reception path. RSSI value of each path / SI
A weight proportional to the R value is added to each of the received signals and the signals are combined to obtain a detection output.

Here, the received signal of the antenna 1a is called antenna branch # 1, and the received signal of the antenna 1b is called antenna branch # 2.
7, the antenna branch # of FIG.
4, the path at time T0 of the antenna branch # 2 in FIG.
It is assumed that the paths at the time T1 of the antenna branch # 1 in FIG. 4 are respectively assigned to the antenna branches, and a detection output of high reception quality is obtained according to the detection processing described above. However, if the reception level of the antenna branch # 1 drops extremely for some reason, the automatic gain control unit 205
In some cases, it may be necessary to set the AGC value of the antenna branch # 1 to be equal to or higher than a preset threshold value in order to raise the reception level of the antenna branch # 1 to the reference reception level. Further, the difference between the AGC value of antenna branch # 1 and the average value of all antenna branch AGCs may be equal to or larger than a preset threshold. In such a case, the automatic gain control (AGC) (amplification control) for the antenna branch # 1 is stopped, so that the received signal of the antenna branch # 1 received by the despreading unit 9n is not received because the automatic gain control is not performed. The level will be lower.
Therefore, the RSSI / S measured by the communication quality measuring unit 13
The IR value decreases, and consequently, the weight for antenna branch # 1 when combined by combining section 210 also decreases. Therefore, when the automatic gain control value of a certain antenna input is extremely higher than that of another antenna input, the gain control (amplification control) for the antenna system is not performed, so that the antenna branch is despread. Even if it is assigned to a circuit, it is possible to suppress wasteful power consumption while maintaining the effect of sound quality improvement by maximum ratio synthesis.

Of course, even in this case, if the signal search unit 207 or the reception antenna selection control unit changes the number of despreading units assigned to each antenna branch according to the output AGC value of the automatic gain control unit 205, the despreading is further performed. Effective use of circuits and improvement of sound quality can be achieved.

Next, a third embodiment of the present invention will be described.

FIG. 6 is a block diagram showing a main configuration of the wireless communication terminal according to the present embodiment.

As shown in this figure, the wireless communication terminal of this embodiment has a plurality of antennas 1a and 1b,
7, a matched filter 8, a reception antenna selection controller 311, N selectors 12a, 12b to 12n, and N
It has despreading units (finger circuits) 9a, 9b to 9n, a communication quality measuring unit 313, and a combining unit 10.

The signals received by the antennas 1a and 1b are input to the direct signal search unit 307 and the N despreading units 9a to 9n selectively by the selectors 12a to 12n.

The reception antenna selection control section 311 determines the connection allocation ratio of each antenna branch to the finger according to the RSSI value / SIR value for each despread signal (for each path) notified from the communication quality measurement section 313. Each antenna branch input is divided into N selectors 12a according to the ratio.
-12n are used to connect to N despreading units. Further, it notifies the signal search unit 307 of the connection state.

When the same path is received by a plurality of antenna branches, a method of determining the connection allocation ratio of each antenna branch to a finger according to the RSSI value / SIR value of each path is shown in FIG. 7 and a method using the table of FIG. 8.

FIG. 7 is a table used by the reception antenna selection control section 311 to determine the connection allocation ratio of each antenna branch to a finger. The table is provided, for example, by the reception antenna selection control section 311. Here, the received signal of antenna 1a is divided into antenna branch # 1, antenna 1b
Is referred to as antenna branch # 2,
For example, at time T0 at antenna branches # 1 and # 2 in FIG.
Path # 1 and path # 2 respectively,
I will call it. The reception antenna selection control unit 3 indicates that the signal search unit 307 receives the path # 1 on the antenna branch # 1 and the path # 2 on the antenna branch # 2.
11 is notified. The reception antenna selection control unit 311 includes:
RSSI value / SIR of path # 1 of antenna branch # 1
Value is R1, RSSI of path # 2 of antenna branch # 2
When the value / SIR value is notified from the RSSI / SIR measurement result that the value is R2, a numerical value as a finger assignment index of each antenna branch is obtained by referring to the table of FIG. In this case, the finger assignment indices of antenna branch # 1 and antenna branch # 2 are F1 and F2, respectively.
Since it can be seen that the sizes of F1 and F2 are, for example, 1: 2, the reception antenna selection control unit 311 determines the assignment ratio of the antenna branches # 1 and # 2 to the fingers to be 1: 2. And antenna branches # 1 and #
2 are input to the N selectors 12a to 12n using 1:
It connects to the despreading units 9a to 9n so that the ratio becomes 2, and notifies the signal search unit 307 of the connection state.

Further, for example, when the user presses the antenna 1a with a hand or when a failure occurs in the antenna 1a, the reception quality of the antenna 1a is extremely reduced, and the RSSI value of the path # 1 of the antenna branch # 1 is reduced. / S
It is assumed that the IR value has dropped extremely. In this case, the RSSI value / SIR value of the path # 1 of the antenna branch # 1 in FIG.
min) or less, which is R3. The reception antenna selection control unit 311 obtains 0 and F2 as finger assignment index values of the antenna branches # 1 and # 2 by referring to the table of FIG.
The assignment ratio of fingers 1 and # 2 is determined to be 0: 1. In other words, it is determined that the received signal of antenna branch # 1 is a signal full of noise having a low RSSI value / SIR value, which is ineffective even when rake-combined, and is not assigned to any finger. This means assigning the received signal to all available fingers.

FIG. 8 is also a table used by the reception antenna selection control section 311 to determine the connection allocation ratio of each antenna branch to a finger. The table is provided, for example, by the reception antenna selection control section 311. The reception antenna selection control unit 311 first calculates and obtains an average RSSI / SIR value of the same path received by the antenna branches # 1 and # 2. Next, refer to the table of FIG. 8 based on the difference between the RSSI value / SIR value of the path received by each antenna branch and the RSSI / SIR average value of the same path received by all antenna branches. Obtains a numerical value as a finger assignment index of each antenna branch. In this example, “the difference between the RSSI value / SIR value of the path # 1 of the antenna branch # 1 and the RSSI / SIR average value of the same path received by all the antenna branches”;
"RSSI value / SI of path # 2 of antenna branch # 2
The difference between the R value and the RSSI / SIR average value of the same path received by all antenna branches ”is
(R1, R2), (R3, R4), (R5, R6), where R0 is the antenna branches # 1 and # 2
3 shows the position of the RSSI / SIR average value.

In FIG. 8, path # of antenna branch # 1
1 and the average RSSI / SIR value of the same path received in all antenna branches is R1, and the RSSI value / path of antenna # 2 in path # 2 is
If the difference between the SIR value and the RSSI / SIR average value of the same path received by all antenna branches is R2, the reception antenna selection control unit 311 sets the antenna branch # 1
Since F2 and F2 are obtained as the finger assignment indexes of # 1 and # 2, respectively, the finger assignment ratio of antenna branch # 1 and antenna branch # 2 is determined to be 1: 1.
In this case, even if there is a slight difference in the reception quality (RSSI / SIR) of the same path received for each antenna branch, the allocation ratio of each antenna branch to the finger is not changed. .

In FIG. 8, path # of antenna branch # 1
The difference between the RSSI value / SIR value of 1 and the RSSI / SIR average value of the same path received by all antenna branches is R3, and the RSSI value / path of path # 2 of antenna branch # 2 /
If the difference between the SIR value and the RSSI / SIR average value of the same path received by all antenna branches is R4, the reception antenna selection control unit 311 sets the antenna branch # 1
Since F1 and F3 are obtained as finger assignment indices of # 1 and # 2, respectively, the finger assignment ratio of antenna branch # 1 and antenna branch # 2 is determined to be 1: 3.
In this case, since the reception quality (RSSI / SIR) of the path received by the antenna branch # 1 has decreased, the finger allocation ratio of the antenna branch # 1 is reduced, and the same path having good reception quality is received instead. This is an example in which the assignment ratio of the existing antenna branch # 2 to the fingers is determined to be large.

In FIG. 8, path # of antenna branch # 1
The difference between the RSSI value / SIR value of 1 and the average value of RSSI / SIR of the same path received in all the antenna branches is R5, and the RSSI value / path of the path # 2 of the antenna branch # 2 is R5.
When the difference between the SIR value and the RSSI / SIR average value of the same path received in all antenna branches is R6, the reception antenna selection control unit 311 sets the antenna branch # 1
0 and F as finger assignment indices of
4, the finger assignment ratio between antenna branch # 1 and antenna branch # 2 is determined to be 0: 1. In this case, the reception quality (RSSI / SIR) of the path received by antenna branch # 1 is extremely reduced, and becomes R5 which is equal to or less than a preset threshold (Rmin), It is determined that the received signal of antenna branch # 1 is a signal full of noise with a low SIR value that has no effect even if rake combining is performed, and no signal is assigned to the finger at all, and instead a path with high reception quality is received. This is an example in which a finger is assigned only to antenna branch # 2.

When the signal search unit 307 obtains the reception timing and signal strength of the desired wave using the matched filter 8, the connection information to the despreading unit of each antenna branch notified from the reception antenna selection control unit 311 is obtained. Based on
The reception path is determined, and the timing of multipath for despreading for each antenna branch is notified to each of the despreading units 9a to 9n.

The despreading units (finger circuits) 9a to 9n
The demultiplexing timing notified from the signal search unit 307 triggers the despreading of the input signal from the antenna, and the synthesizing unit 10
Output to

The synthesizing unit 10 stores the signals input from the respective despreading circuits in a built-in buffer or the like, and synthesizes the signals at the timing of the slowest reception path to obtain a detection output.

For example, the receiving antenna selection control section 311
Determines the connection ratio of the antenna branches # 1 and # 2 to the despreading unit to 1: 2, the antenna branch # 1 to the despreading unit 9n, and the antenna branch # 2 to the two despreading units 9a and 9b. And the connection information is assigned to the signal search unit 3
07 is notified. In this case, the signal search unit 307
Based on the output result of the matched filter 8 as shown in the above, a despreading unit is assigned to each antenna branch in the order of the multipath with the highest power value, and the timing of the multipath to be despread to the corresponding despreading unit is determined. Notice. in this case,
The path of the antenna branch # 2 at time T0 is transmitted to the despreading unit 9a, the path of the antenna branch # 2 at time T1 is transmitted to the despreading unit 9b, and the antenna branch # 1 is transmitted to the despreading unit 9n.
Is notified to each despreading unit so as to despread the path at time T1. Therefore, as a result, the combining circuit 10 performs weighted rake combining on the antenna branch # 2 having a path having relatively better reception quality than the antenna branch # 1. Therefore, when the same path is received by a plurality of antennas, the connection allocation ratio of each antenna to the despreading circuit is changed according to the magnitude of the RSSI value or SIR (Eb / I0) value of the despread output signal. By doing so, efficient use of the limited despreading circuit and improvement in speech quality can be realized.

Also, for example, when the reception quality of the path received in antenna branch # 1 is extremely reduced, reception antenna selection control section 311 determines the connection ratio of antenna branches # 1 and # 2 to the despreading section. Is set to 0: 1, that is, the antenna branch # 1 is not allocated to the despreading unit, and the antenna branch # 2 is set to the despreading units 9a and 9a.
4b and 9n, and when the connection information is notified to the signal search circuit 307, the signal search circuit 307
Based on the output result of the matched filter 8 as shown in the above, a despreading unit is assigned to each antenna branch in the order of the multipath with the highest power value, and the timing of the multipath to be despread to the corresponding despreading unit is determined. Notice. in this case,
The path of the antenna branch # 2 at time T0 is transmitted to the despreading unit 9a, the path of the antenna branch # 2 at time T1 is transmitted to the despreading unit 9b, and the antenna branch # 2 is transmitted to the despreading unit 9n.
Is notified to each despreading unit so as to despread the path at time T2. As a result, the synthesis circuit 10
Then, only three multipaths of antenna branch # 2 are rake-combined. Accordingly, when the same path is received by a plurality of antennas, the despread output signal RS
When the SI value or the SIR (Eb / I0) value is extremely low as compared with the other values, by not assigning the antenna to the despreading circuit, the efficient use of the limited despreading circuit and the improvement of the speech quality can be achieved. Improvement can be realized.

[0059]

According to the present invention, by changing the automatic gain control value for each antenna input or the RSSI value / SIR value, the assignment ratio of each antenna to the despreading circuit is changed.
Efficient use of limited despreading circuit and improvement of communication quality can be realized.

Further, when the automatic gain control value of a certain antenna input is extremely higher than that of another antenna input, the antenna is not assigned to the despreading circuit, so that the efficiency of the limited despreading circuit is improved. By using the automatic gain control for antennas that are no longer assigned to the despreading circuit,
Wasteful power consumption can be suppressed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part configuration of a wireless communication terminal according to a first embodiment of the present invention.

FIG. 2 is a table (part 1) for determining a finger assignment ratio of each antenna branch based on an AGC value.

FIG. 3 is a table (part 2) for determining a finger assignment ratio of each antenna branch based on an AGC value.

FIG. 4 shows a multi-pass output example of a matched filter.

FIG. 5 is a block diagram showing a main configuration of a wireless communication terminal according to a second embodiment of the present invention.

FIG. 6 is a block diagram showing a main configuration of a wireless communication terminal according to a third embodiment of the present invention.

FIG. 7 is a table (part 1) for determining a finger assignment ratio of each antenna branch based on an RSSI value or an SIR value.

FIG. 8 is a table (part 2) for determining a finger assignment ratio of each antenna branch based on an RSSI value or an SIR value.

FIG. 9 is a block diagram showing a configuration of a conventional CDMA receiver.

[Explanation of symbols]

1a, 1b ... antenna, 2a, 2b ... AGC amplifier,
3a, 3b: AGC attenuator, 4a, 4b: A / D converter, 5, 105, 205 ... automatic gain control unit, 6a,
6b D / A converter, 7, 107, 207, 307
... Signal search unit, 8 ... matched filter, 9a, 9b-9
m, 9n... despreading section (finger circuit), 10, 210.
Combining units, 111, 211, 311 ... Reception antenna selection control units, 12a, 12b to 12n ... Selectors (switches)
13, 313: Communication quality measuring unit.

Claims (8)

[Claims] A first and a second antenna, first and second amplifying means for amplifying a signal received by each of the antennas, and a level of a received signal amplified by each of the amplifying means is a reference. Automatic gain control means for controlling the gain of each of the amplifying means so as to be at a level; signal search means for detecting a multipath reception timing from the received signal amplified by each of the amplifying means; and notification from the signal search means. A plurality of de-spreading means for de-spreading the received signal using a spreading code at a given timing; and selectively outputting one of the received signals from the first and second antennas to each of the de-spreading means. Receiving antenna selection control means to be connected; and combining means for combining signals supplied from the respective despreading means to generate a detection output, wherein the reception antenna selection control means comprises the first and second antennas. The connection allocation ratio of each antenna to a plurality of despreading means is changed according to the magnitude of the gain control value of the automatic gain control means for the first and second amplifying means provided for each of the antennas. Wireless communication terminal. 2. The reception antenna selection control means includes: an antenna reception signal corresponding to an amplification means whose gain control value of the automatic gain control means is higher than a certain threshold; or a gain control value of another amplification means. 2. The wireless communication terminal according to claim 1, wherein an antenna reception signal whose relative value is higher than a certain threshold value is not assigned to the despreading means. 3. The wireless communication terminal according to claim 2, wherein said automatic gain control means stops gain control of an amplification means corresponding to an antenna reception signal not allocated to said despreading means. 4. A first and a second antenna, first and second amplifying means for amplifying a signal received by each of the antennas, and a level of a received signal amplified by each of the amplifying means is a reference. Automatic gain control means for controlling the gain of each of the amplifying means so as to have a reception level; signal search means for detecting a multipath reception timing from a reception signal amplified by each of the amplifying means; and the signal search means A plurality of de-spreading means for de-spreading the received signal using a spreading code at a timing notified from, and selecting one of the received signals from the first and second antennas for each of the de-spreading means. Receiving antenna selection control means to be connected to each other, communication quality measuring means for measuring the signal quality of the signal output from each despreading means, and signal input from each despreading means for communication quality measurement. Wireless communication terminal, characterized by comprising synthesizing means with a weight proportional to the level of the signal quality of the received signal corresponding notified from unit combined to a detection output. 5. The receiving antenna selection control means according to claim 1, wherein:
And changing the connection allocation ratio of each received signal to a plurality of despreading means in accordance with the magnitude of the gain control value of the automatic gain control means with respect to the amplification means provided for the second antenna. The wireless communication terminal according to claim 4. 6. An automatic gain control means for amplifying a gain for an antenna whose gain control value is higher than a certain threshold value or for an antenna whose relative value to another gain control value is higher than a certain threshold value. The wireless communication terminal according to claim 4, wherein the control is stopped. 7. A first and a second antenna, a signal search means for detecting a multipath reception timing from a signal received by each antenna, and a signal received from the signal search means at a timing notified from the signal search means. A plurality of despreading means for despreading using a spreading code; and a receiving antenna selection control means for selectively connecting one of the received signals from the first and second antennas to each of the despreading means; A communication quality measuring means for measuring the quality of the signal output from each despreading means; and a synthesizing means for synthesizing a signal provided from each despreading means to produce a detection output, wherein the reception antenna selection control means When the same path is received by the first and second antennas, each of the received signals of each antenna is determined according to the magnitude of the RSSI value or SIR value measured by the communication quality measuring means. CDMA system wireless communication terminal, wherein the changing the feed allocation ratio to the spreading means. 8. The reception antenna selection control means, wherein an antenna is connected to a despreading means for despreading a path whose signal quality measured by the communication quality measurement means is lower than a certain threshold, or A wireless communication terminal, wherein connection of an antenna to a despreading means for despreading a path whose relative value to a signal quality measured by the communication quality measuring means is lower than a certain threshold value or less is stopped.