JP3271066B2 - Receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving apparatus suitable for use in a receiving section for receiving and demodulating a signal in a mobile terminal such as a cellular telephone.

[0002]

2. Description of the Related Art In recent years, a spread spectrum communication system (hereinafter, referred to as a spread spectrum communication system) that performs communication by spreading a modulated wave in a spectrum band several hundred to several thousand times wider than the bandwidth of information.
The SS (Spectrum Spread) method) has attracted attention. In this SS system, a carrier is modulated by a PN sequence (PN code) (pseudo-noise code) on a transmitter side to spread a frequency spectrum, and the spread spectrum signal is transmitted to a receiver. It has been made like that. Then, in the receiver, after undergoing a despreading (correlation) process using a PN sequence generated by a code generator having the same structure as the transmitter, demodulation (baseband demodulation)
Thus, data is obtained.

In the SS system, in order to demodulate a signal in a receiver, the pattern of the PN sequence needs to match as described above, and its phase must also match. That is, communication can be established only when the PN sequence used on the transceiver side is the same sequence and the phases match. If this property is used, it is possible to use a large number of channels (circuits) by using the same frequency band and by using different PN sequences. A method of realizing channel identification by a PN sequence and performing multiple access (multiplexing) is CDMA (Code Division Multiple Access: Code Devis).
Ion Multiple Access) method.

FIG. 6 is a block diagram showing an example of the configuration of a conventional cellular telephone to which the CDMA system is applied. To the multipliers 1 and 2, a signal S _{in obtained} by converting a signal from a transmitter of a base station into an IF frequency (intermediate frequency) is supplied through an input terminal. Here, this I
The F frequency and f _in.

On the other hand, from a voltage-controlled oscillator (VCO) 3 corresponding to a frequency error Δf, which will be described later, supplied from a frequency error detector 43 via a loop filter (LF) 9 composed of a low-pass filter, A signal S _vco having a frequency f _VCO substantially equal to the IF frequency f _in is output to the multiplier 1 and the phase shifter 4. The phase shifter 4 receives the signal S from the VCO 3
The phase of _vco is shifted (rotated) by π / 2 and output to multiplier 2.

[0006] The multiplier 1 multiplies the signal S _in by S _VCO ,
A signal component having the same phase as the phase reference point (hereinafter, referred to as an I-channel signal) is output. At the same time, the multiplier 2 outputs the signal S
_In is multiplied by the signal S _VCO shifted in phase by π / 2 to output a signal component orthogonal to the phase reference point (hereinafter, referred to as a Q channel signal). That is, quadrature detection is performed by the multipliers 1 and 2 and the phase shifter 4.

The signals of the I and Q channels are despreader 41
And is despread by the same PN sequence as that on the transmitter side. The I and Q channel signals (despread data) despread by the despreader 41 are supplied to a data demodulation unit 42 and a frequency error detection unit 43. The data demodulation unit 42 demodulates the data using the I and Q channel signals and outputs the data to the data processing unit 44.

The data processing unit 44 includes a data demodulation unit 42
From the output data, the voice information and control information sent from the transmitter are extracted based on a predetermined format. The audio information is supplied to a subsequent circuit (not shown) and is subjected to predetermined processing. The control information is supplied to the control circuit 45, and the control circuit 45 performs a predetermined process based on the control information. Further, the control circuit 45 controls the despreader 41, the data demodulator 42, and the frequency error detector 43.

Here, the signals of the I or Q channels output from the multipliers 1 and 2 respectively include the frequency f _VCO of the signal S _VCO output from the _{VCO 3} and the frequency (IF frequency) f _{in of the} input signal S _in. Are the same, a baseband signal (a signal with an IF frequency of 0 Hz) is obtained.

However, cellular telephones are often used, for example, in a running car or train.
In this case, due to the Doppler effect, the frequency f _in of the signal S _in is, deviates from the original value. Thus, the frequency f
A _VCO and f _in is not the same, the difference, that is an amount corresponding to the frequency error _{△ f (= f in -f VCO} ), each signal of the I or Q channel output from the multiplier 1 or 2, the original Deviates from the baseband position.

When the deviation becomes large, the data demodulation section 42 cannot accurately demodulate data.

Therefore, the frequency error detecting section 43 calculates the I and Q channel signals despread by the despreader 41
Detect the frequency error Δf and set it to 0 Hz,
The frequency f _VCO of the signal S _VCO output from the _{VCO 3} is controlled via the LF 9.

That is, multipliers 1 and 2, phase shifter 4, despreader 41, frequency error detector 43, LF9, and VC
The loop composed of O3 forms a so-called PLL,
In this system, V so that the frequency error Δf is 0 Hz,
CO3 is controlled, whereby the data demodulation unit 42
Accurate data demodulation is performed.

The signal transmitted from the transmitter of the base station comprises a data channel composed of communication data such as voice information and a pilot channel composed of a predetermined fixed value. For detecting the error Δf, a signal of a pilot channel is usually used.

In a cellular telephone, a plurality of routes (e.g., a radio wave transmitted from a transmitter of one nearby base station is directly received, or a radio wave is received by being reflected by a reflector such as a building). Path) is received (hereinafter, a path is formed).

Further, when the cellular telephone is located at substantially the same distance from a plurality of base stations, a path is formed with each of the plurality of base stations.

In the cellular telephone shown in FIG. 6, for example, a path having the highest reception level is selected from the plurality of paths described above.

However, when the cellular telephone is located far from the base station, there is a case where a sufficient S / N cannot be obtained even if the path having the highest reception level is selected.

Therefore, of the plurality of paths (a plurality of paths from one base station and a path from each of the plurality of base stations), not only one but also a plurality of two or more paths are demodulated. A method of combining demodulation results to improve S / N (hereinafter, referred to as a diversity RAKE receiving method) has been proposed.

FIG. 7 shows an example of the configuration of a cellular telephone to which the diversity rake receiving method is applied. In addition,
In the figure, portions corresponding to those in FIG. 6 are denoted by the same reference numerals.

The cellular telephone shown in FIG. 7 is similar to a demodulation processing circuit comprising a despreader 41, a data demodulation unit 42, a frequency error detection unit 43, a data processing unit 44, and a control circuit 45 surrounded by a dotted line in FIG. Fingers 5a to 5c having demodulation processing circuits 6a to 6c, respectively, are provided, and demodulated data or frequency errors output from the respective components are combined by a data combiner 51 or a frequency error combiner 52. I have.

It should be noted that I from each of the multipliers 1 and 2
Alternatively, the Q channel signal is supplied to the searcher 53 in addition to the fingers 5a to 5c.
In searcher 53, I and Q channel signals and PN
By multiplying the sequence by shifting its phase within one period of the PN sequence, that is, by taking the correlation between the I and Q channel signals and the PN sequence within one period of the PN sequence, Each of the plurality of paths received by the cellular telephone is searched and identified, and the path to be demodulated by each of the fingers 5a to 5c is determined. The delay time (path position) of the path for which demodulation is determined (hereinafter referred to as path information) is supplied to the fingers 5a to 5c. Thereby, in each of the fingers 5a to 5c,
6 based on the path information output from the searcher 53.
The demodulation is performed in the same manner as in the above.

From the fingers 5a to 5c, demodulated data or frequency errors obtained by demodulating the respective paths are output to the data combiner 51 or the frequency error combiner 52. The data combiner 51 includes the fingers 5a to 5
The demodulated data respectively output from c are combined (added) and output (hereinafter, the combined demodulated data is referred to as combined demodulated data). As a result, demodulated data with an improved S / N can be obtained.

The frequency error combiner 52 synthesizes (adds) the frequency error Δf output from the frequency error detector 43 (FIG. 6) constituting the fingers 5a to 5c (hereinafter, the synthesized frequency error Δf). Is referred to as a composite frequency error), and is output to the VCO 3 via the LF9.

Here, in the searcher 53, the one suitable for combining among a plurality of paths forming a multipath (for example, the level (corresponding to the signal strength of the path, The finger having the higher correlation value) is selected as necessary, and the fingers 5 are demodulated so as to demodulate this path.
a to 5c (demodulation processing circuits 6a to 6c) are respectively controlled.

Therefore, if the cellular telephone has three fingers 5a to 5c, for example, as shown in FIG.
Of the plurality of paths, three paths are selected in descending order of level, and each of the three paths is demodulated by each of the fingers 5a to 5c.

On the other hand, since the cellular telephone is normally used while moving, the same path is not always demodulated by the fingers 5a to 5c during a call. Depending on the power)
The paths demodulated by the fingers 5a to 5c are switched.

The finger in which the path to be demodulated is switched temporarily stops the output of the demodulated data in preparation for the preparation. In this case, the combined demodulated data output from the data combiner 51 (the frequency error combiner 52
(Similarly, the synthesized frequency error output from) is suddenly reduced.

Further, when the output of the demodulated data from the finger whose operation has been stopped is started, the power of the combined demodulated data suddenly increases.

Not all of the fingers 5a to 5c perform demodulation operations at all times, and are controlled by the searcher 53 so that they operate as needed (for example, demodulation of one path is sufficient). When the S / N has been obtained, one of the fingers 5a to 5c operates, and when it is necessary to add a plurality of demodulated data to obtain the S / N, two of them are required. Or three are made to work).

That is, the searcher 53 activates or deactivates the respective fingers 5a to 5c as necessary, so that the power of the combined demodulated data suddenly increases or decreases. I do.

Further, even when the fingers 5a to 5c perform demodulation continuously in time, the power of the demodulated data output from each of the fingers 5a to 5c is, for example, multipath fading. The power varies depending on the influence, the difference in the propagation path of the path, and the like, whereby the power of the combined demodulated data also varies.

The change in power of the composite demodulated data (similarly for the composite frequency error) as described above is caused by the data combiner 51.
Since the power of the circuit (not shown) at the subsequent stage (or the frequency error combiner 52) is adversely affected, its power needs to be constant.

Therefore, the data combiner 51 shown in FIG.
(The same applies to the frequency error combiner 52). As shown in FIG. 8, for example, an arithmetic unit 61 and an arithmetic unit 6 forming an AGC circuit are provided.
2, 63, an intensity storage unit 64, a time constant adding circuit 65, and a ROM 66. In the data combiner 51 shown in the figure, first, demodulated data output from the fingers 5a to 5c (FIG. 7) is input to an arithmetic unit 61 and added to be combined demodulated data. The combined demodulated data is output to arithmetic unit 62. The arithmetic unit 62 multiplies the combined demodulated data from the arithmetic unit 61 by a predetermined constant supplied from the ROM 66 and outputs the result.

The combined demodulated data output from the arithmetic unit 62 is output to a subsequent circuit and supplied to the arithmetic unit 63. In addition to the combined demodulated data, the arithmetic unit 63 stores an amplitude value (hereinafter, referred to as “hereinafter”) corresponding to a desired power for the combined demodulated data stored in the intensity storage unit 64 in advance.
X (referred to as a desired amplitude value) is supplied to the
Subtracts the desired amplitude value X from the combined demodulated data from the arithmetic unit 62 and supplies it to the ROM 66 via the time constant adding circuit 65.

That is, assuming that the amplitude of the synthesized demodulated data output from the arithmetic unit 62 is A, the arithmetic unit 63 outputs the difference M (= A−A) between the amplitude A of the synthesized demodulated data and the desired amplitude value X.
X) is output.

In the ROM 66, a value of X / A is stored in advance at an address M. The ROM 66 uses the value input from the computing unit 63 via the time constant adding circuit 65 as an address and stores the value in advance in the address. The stored value is output to the arithmetic unit 62.

Therefore, if the value input to the ROM 66 from the arithmetic unit 63 via the time constant adding circuit 65 is M,
The value X / A is output from the ROM 66 to the arithmetic unit 62 as a predetermined constant.

The arithmetic unit 63 outputs the value M when the synthetic demodulated data having the amplitude A is input thereto, that is, the synthetic demodulated data having the amplitude A is output from the arithmetic unit 62. It's time to read the ROM
When a predetermined constant X / A is supplied to the arithmetic unit 62 from the arithmetic unit 66, the arithmetic unit 62 performs an operation of X / A × A, and corresponds to the desired amplitude value X (= X / A × A). The composite demodulated data of the power is output.

The time constant adding circuit 65 gradually changes its own output from a currently output value to a value supplied from the calculator 63 with a predetermined time constant. , Whereby the fingers 5a to 5c
Even if the amplitude of the demodulated data output from the MOD changes instantaneously, the output of the data combiner 51 (arithmetic unit 62) does not follow the change.

By the way, recently, as described above, the CD
As an application of the cellular telephone system using the MA system,
There has been proposed a system that can use a cellular telephone not only outdoors but also indoors such as a building where radio waves (signals) from a base station are difficult to reach directly. For example, PCS (Personal Communication Services),
Distributed Antenna
The method using a) is one of them.

Here, FIG. 9 shows an example of the configuration of a system using a distributed antenna. In this system, a signal from a base station transmitter is output as radio waves from a base station antenna and output via a cable to a distributed antenna installed in a building. I have.

When the cellular telephone is located outdoors, the radio wave output from the antenna of the base station is received. When the cellular telephone is located in a building, the radio wave transmitted from the transmitter is received. A signal is received via a distributed antenna.

As shown in FIG. 9, the distributed antenna includes a plurality of indoor antennas mounted at required positions in a building and a PN connecting them.
Time interval between bits constituting the sequence (reciprocal of the PN sequence bit rate (eg, 8 Mbps or 16 Mbps))
It consists of a delay circuit that delays the path by a longer time τ.

In a building (indoor) where such distributed antennas are installed, in addition to direct paths from a plurality of indoor antennas (hereinafter, referred to as direct paths), they may be, for example, a wall or the like. Although a path reflected by an obstacle in the building (hereinafter, referred to as a reflection path) is also formed, the distance between the indoor antenna and the cellular phone is short. The difference between the position of the direct path and the position of the reflection path) is shorter than the time τ described above.

Therefore, the direct path and the reflection path cannot be separated (identified) by PN sequences having different phases. Therefore, according to the distributed antenna, a multipath having the same number of separable paths as the number of indoor antennas and a delay time τ of each path is substantially formed in the building. .

Therefore, when the cellular telephone shown in FIG. 7 is used in a building in which a distributed antenna composed of a number of indoor antennas equal to or less than the number of fingers is installed, energy from the indoor antenna is used. ,
The path can be received with little loss, and a good S / N can be obtained.

[0048]

As described above, when the cellular telephone of the diversity rake receiving system shown in FIG. 7 is used indoors with the distributed antenna shown in FIG. Since the signal strengths of the paths output from the indoor antennas are almost equal and the propagation distance of the paths is considerably shorter than in the case of the outdoor, the paths output from the plurality of indoor antennas are separated by the fingers 5a to 5c, respectively. The amplitudes of the demodulated data obtained by demodulation are all substantially the same.

Therefore, when the cellular telephone is used indoors, the power of the combined demodulated data obtained by adding the demodulated data output from the fingers 5a to 5c hardly changes.

As described above, indoors, although the power of the combined demodulated data hardly changes, FIG.
It is indispensable to operate the AGC circuits (the arithmetic units 62 and 63, the intensity storage unit 64, the time constant adding circuit 65, and the ROM 66) as shown in FIG. Rather, it is unnecessary control, and because of such unnecessary control, AG
Activating the C circuit wastes power.

The present invention has been made in view of such a situation, and aims to reduce unnecessary control and power consumption.

[0052]

According to a first aspect of the reception apparatus of the present invention, signals received from multipath, selecting means for selecting a search the individual paths to demodulation path selection Hand
A plurality of demodulating means for demodulating each path selected by the stage and outputting demodulated data; a combining means for combining demodulated data output from each of the plurality of demodulating means to output combined demodulated data; and a combined demodulated data. calculating means for outputting by multiplying a predetermined constant, based on the number of paths that have selection means selected, characterized <br/> have a determination means for determining a predetermined constant.

[0053]

[0054] The second receiving apparatus of the present invention, the demodulation of signals received from multi-paths, retrieves the individual paths, and selecting means for selecting a path for demodulating the respective paths selected by the selection means A plurality of demodulating means for outputting demodulated data, a combining means for combining demodulated data output from each of the plurality of demodulating means, and outputting combined demodulated data, and a signal for each of the demodulated data outputted from the plurality of demodulating means.
A plurality of detecting means for detecting the signal intensity ;
Control means for controlling the operation;
Generates a predetermined constant based only on the detected signal strength.
And a predetermined constant to the synthesized demodulated data.
And a calculating means for outputting the same .

[0055]

According to the first receiving apparatus of the present invention , the multi-path
Individual paths are searched from the received signal
A path to be demodulated is selected. In addition, the selected
Are demodulated, and the resulting demodulated data is
The data is combined to form combined demodulated data. Synthesized demodulated data
Is output after being multiplied by a predetermined constant.
The constant is determined based on the number of selected paths.

[0056]

[0057] In the second receiving apparatus of the present invention, Mar
The path to demodulate is selected from the received signal that is
The demodulation means selects the selected path and
Each is demodulated. Then, the data obtained from multiple demodulation
Demodulated data is synthesized, and the synthesized demodulated data is output.
You. On the other hand, the demodulated data demodulated by the
Of multiple detection means for detecting the signal strength of each data
Is controlled and the signal detected by the operating detecting means is
A predetermined constant is generated based only on the signal strength. Soshi
Multiplied by a predetermined constant and output.
It is.

[0058]

FIG. 1 is a block diagram showing the configuration of an embodiment of a cellular telephone to which a receiving apparatus according to the present invention is applied. In the figure, the same reference numerals are given to portions corresponding to the case in FIG.

Therefore, this cellular telephone is provided with a data combiner 7, a frequency error combiner 8, or a searcher 10 instead of the data combiner 51, the frequency error combiner 52, or the searcher 53.
It is configured similarly to the cellular telephone of FIG.

In searcher 10, first, similarly to searcher 53 in FIG.
By correlating with the N sequence, the positions of a plurality of paths received by the cellular telephone are searched and identified, and the paths to be demodulated by the fingers 5a to 5c are determined. If the number of paths is one, one of the demodulation processing circuits 6a to 6c forming the fingers 5a to 5c demodulates one path for which demodulation is determined. Controlled.

Further, if the number of paths determined to be demodulated is 2
If the number of demodulation processing circuits 6a to 6c is two, the control is performed so as to demodulate the path. The demodulation processing circuits 6a to 6c are controlled to perform path demodulation.

The searcher 10 controls the demodulation processing circuits 6a to 6c as described above, and supplies the number of paths for demodulation to the data combiner 7 and the frequency error combiner 8 as control signals.

On the other hand, the demodulation processing circuits 6a to 6c forming the fingers 5a to 5c perform demodulation processing under the control of the searcher 10, and output demodulated data and frequency errors. The demodulated data or the frequency error is supplied to the data combiner 7 or the frequency error combiner 8
Respectively.

The data combiner 7 (similarly to the frequency error combiner 8) is configured as shown in FIG. 2. First, the demodulated data supplied from the demodulation processing circuits 6a to 6c forming the fingers 5a to 5c are processed by the arithmetic unit 11 Are combined (added) at the same time to obtain combined demodulated data.

That is, in the arithmetic unit 11, when any one of the fingers 5a to 5c is performing a demodulation operation, the demodulated data is obtained when any two of the fingers are performing a demodulation operation. The sum of the two demodulated data is
If all of them are performing the demodulation operation, the sum of the three demodulated data is output as the combined demodulated data.

The synthesized demodulated data is supplied to the arithmetic unit 12. The arithmetic unit 12 adds the switch S
A predetermined constant from the multiplier generator 13 supplied via W1 is multiplied and output.

[0067] Multiplier generator 13, 1 as a predetermined constant, √2 or √3 occurred, and to output to terminals a _1, b ₁ or c _1, the switch SW1. The switch SW1 is connected to the terminal a _{1 according} to the number of demodulation paths supplied from the searcher 10 (FIG. 1).
Or selecting one of c _1.

[0068] That is, the switch SW1, when the number of paths to demodulate was 3,2,1, are made terminal a _1, b _1, c ₁ and to select, respectively.

Therefore, the number of demodulating paths is 3, 2, 1
In this case, the multiplier 12 is supplied with predetermined constants 1, # 2, and # 3 from the multiplier generator 13 via the switch SW1.

Here, when the cellular telephone (FIG. 1) is used in a building (indoor) where the distributed antenna shown in FIG. 9 is installed, for example, as described above, the fingers 5a to 5a are used. The power (and therefore the amplitude) of the demodulated data (similarly to the frequency error) obtained by demodulating the path in each of 5c is almost the same.

Therefore, in this case, the fingers 5a to 5c
Is the demodulation operation, and if the amplitude of the added value (synthesized demodulated data) of the demodulated data (same for the frequency error) from each is β, only any two of the fingers 5a to 5c Is operating, the amplitude of the sum of the demodulated data obtained from the two fingers is approximately β / √2, and when only one of the fingers 5a to 5c is operating, The amplitude of the demodulated data obtained from one of the fingers is expected to be approximately β / √3.

From the above, the arithmetic unit 12 multiplies the amplitude of the combined demodulated data by 1 when the combined demodulated data is the added value of the three demodulated data and the amplitude of the combined demodulated data is β. Demodulated data will be output.
When the combined demodulated data is the sum of two demodulated data, and therefore the amplitude is β / √2, the amplitude of the combined demodulated data is multiplied by √2, and the combined demodulated data having the amplitude β is output. Will be. Furthermore, if the combined demodulated data is 1
When the amplitude is β / √3, the amplitude of the combined demodulated data is multiplied by √3, and the combined demodulated data having the amplitude β is output.

In the frequency error combiner 8 as well, as in the case of the data combiner 7 described above, a composite frequency error having a constant amplitude is output regardless of the number of operating fingers 5a to 5c. Is done.

As described above, for example, the configuration of an indoor-only cellular telephone such as in a building where the distributed antenna shown in FIG. 9 is installed can be as shown in FIGS. 1 and 2, for example. Without providing a complicated AGC circuit as shown in FIG. 8, only by controlling the switch SW1, it is possible to obtain composite demodulated data (combined frequency error) having a constant amplitude, that is, a constant power.

Further, by designing a subsequent circuit (not shown) for processing the combined demodulated data on the assumption that the optimum power of the combined demodulated data is a value corresponding to the amplitude β, processing with less errors can be achieved. It becomes possible.

By the way, when the cellular telephone (FIG. 1) shown in FIG. 1 is used outdoors, as described above, the signal strength at the time of reception differs depending on the path due to the difference in the propagation path. Therefore, fingers 5a through 5
c Since the power of each output demodulated data is not always the same, but rather different, it is possible to obtain the synthesized demodulated data having a constant power even when performing the same processing as in the indoor case described above. It is difficult.

Therefore, when the cellular telephone (FIG. 1) shown in FIG. 1 is used not only indoors but also for indoors and outdoors, the searcher 10 is made to perform the processing shown in the flowchart of FIG. .

That is, first, in step S1,
By correlating the I and Q channel signals with the PN sequence, each of the plurality of paths received by the cellular telephone is searched and identified, and the process proceeds to step S2, where the signal strength of the searched and identified paths is reduced. , As a predetermined range that can be considered substantially constant, for example, 10 to 1
A path of 1 dB (a path having a signal intensity in the range of 10 to 11 dB is assumed to be demodulated to obtain demodulated data having an amplitude of approximately β / √3) is detected.

Then, the process proceeds to step S3, where it is determined how many paths whose signal strength is in the range of 10 to 11 dB have been detected. If it is determined in step S3 that there is no path whose signal strength is in the range of 10 to 11 dB, the process proceeds to step S4, and a message indicating that demodulation cannot be performed (demodulation is not possible) is performed on a not-shown LCD or speaker, for example. Etc., and the process ends.

In step S3, when the signal strength is 1
When it is determined that one path in the range of 0 to 11 dB is detected, the process proceeds to step S5, and the searcher 10
To start demodulation of the path, fingers 5a to 5a
controls any one of c, and the switch SW1 of the data combiner 7 (frequency error combiner 8 as well) (Fig. 2), performs control for switching to the terminal c ₁ side, the process ends.

As a result, from the arithmetic unit 11 (FIG. 2) of the data combiner 7, the combined demodulated data having an amplitude of approximately β / √3 (the demodulated data demodulated by any one of the fingers 5a to 5c) Is output, and the combined demodulated data is multiplied by √3 in the arithmetic unit 12 to obtain combined demodulated data having an amplitude of β.

Further, if it is determined in step S3 that two paths with signal strengths in the range of 10 to 11 dB have been detected, the process proceeds to step S6, where the searcher 10
Controls two of the fingers 5a to 5c so as to start demodulation of the path, and sets the switch SW1 (FIG. 2) of the data combiner 7 to
Performs control to switch to the terminal b ₁ side, the process ends.

As a result, the arithmetic unit 11 (FIG. 2) of the data combiner 7 outputs synthesized demodulated data having an amplitude of approximately β / √2 (demodulated data demodulated by any two of the fingers 5a to 5c). (Combined value) is output, and the combined demodulated data is multiplied by √2 in the arithmetic unit 12 to obtain combined demodulated data having an amplitude of β.

If it is determined in step S3 that three or more paths with signal strengths in the range of 10 to 11 dB have been detected, the process proceeds to step S7, and the searcher 1
0 is 3 in the path, for example, in descending order of signal strength.
Finger 5 to start demodulation of each of the three paths.
controls the respective a to 5c, the switch SW1 of the data combiner 7 (FIG. 2) performs control for switching to the terminal a ₁ side, the process ends.

As a result, from the arithmetic unit 11 (FIG. 2) of the data combiner 7, synthesized demodulated data having an amplitude of substantially β (an added value of the demodulated data demodulated by the fingers 5a to 5c) is output. The demodulated data is multiplied by one in the arithmetic unit 12 to obtain synthesized demodulated data having an amplitude of β.

As described above, by performing control to demodulate the paths that can be regarded as having substantially the same signal strength to the fingers 5a to 5c, the amplitude is substantially constant, that is, the power is substantially constant, with a simple circuit configuration. Can be obtained as synthesized demodulated data (frequency error).

Next, FIG. 4 is a block diagram showing the configuration of a second embodiment of the cellular telephone to which the receiving device of the present invention is applied. In the figure, the same reference numerals are given to portions corresponding to the case in FIG. Also, in FIG. 4, the searcher 32 searches and identifies the paths constituting the multipath, similarly to the searcher 53 shown in FIG.
Although the paths to be demodulated are assigned to the fingers 5a to 5c (demodulation processing circuits 6a to 6c), the control lines for that purpose are omitted because the figure becomes complicated.

In the cellular telephone shown in FIG. 4, fingers 5a to 5c include not only demodulation processing circuits 6a to 6c but also RSSI (Recieved singal) signals for detecting signal strengths of paths demodulated by demodulation processing circuits 6a to 6c. Streng
th Indicater) circuits 21a to 21c.

In the fingers 5a to 5c, FIG.
In the same manner as in the above case, based on the control of the searcher 32, the demodulation processing circuits 6a to 6c perform demodulation processing on the path, and output demodulated data and frequency errors.

Further, in the fingers 5a to 5c, RS
The demodulation processing circuit 6a is provided by the SI circuits 21a to 21c.
Output from the despreader 41 (FIG. 6) constituting
Alternatively, the signal of the Q channel (this signal is the frequency error △ in the frequency error detection unit 43 (FIG. 6) described above).
As in the case of the detection of f, the signal of the pilot channel is normally used.) The sum of the squares is calculated, and the calculation result is used as the signal strength of the path demodulated by the demodulation processing circuits 6a to 6c. It is outputted to the terminal a ₂ through the operation unit 22. In addition, as at least one of the fingers 5a to 5c, for example, R
The signal strength calculated by the SSI circuit 21a is
₂ other, is also output to the terminal b ₂ via the operation unit 33.

The demodulated data or the frequency error output from the demodulation processing circuits 6a to 6c is calculated by the arithmetic unit 27 or 28.
, And are added to be combined demodulated data or a combined frequency error, respectively.

The combined demodulated data or combined frequency error is supplied to arithmetic units 29 and 30, respectively. The arithmetic unit 29 or 30 is supplied with a predetermined constant from the ROM 26 to be described later in addition to the synthesized demodulated data or the synthesized frequency error. Multiply by a predetermined constant and output. The combined demodulated data output from the arithmetic unit 29 is sent to a predetermined processing circuit (not shown) by the arithmetic unit 30.
The composite frequency error output from LF9 is equal to VC
O3.

The cellular telephone shown in FIG. 4 is operated by the user to be turned on when the cellular telephone is used indoors, and turned off when the cellular telephone is used outdoors.
An operation unit 31 operated to the state is provided.

The operation section 31 may be a mechanical switch, for example, or may be turned on / off by voice or the like.
It is good also as an electronic switch which can perform F.

When the cellular telephone is used outdoors, the operation unit 31 is turned off by the user. Operation unit 3
1 outputs an outdoor mode control signal to the searcher 32 when turned off.

When the searcher 32 receives the outdoor mode control signal from the operation unit 32, the searcher 32 performs outdoor mode processing.
That is, the searcher 32 stops the operation of, for example, the RSSI circuits 21b and 21c as at least one of the RSSI circuits 21a to 21c constituting the fingers 5a to 5c by performing the indoor mode processing described later. when had the initiates the operation, at the same time, the switch SW2, and if that has selected the terminal b ₂ side, switch to the terminal a ₂ side.

Accordingly, in this case, the arithmetic unit 22 receives signals from the operating RSSI circuits 21a to 21c, respectively.
The signal strength of the path demodulated by each of the demodulation processing circuits 6a to 6c is supplied.

These three RSSI circuits 21a to 21c
Signal strength from, in the calculator 22 are combined (added), the combined value (hereinafter, referred to as the combined signal strength) is outputted to the terminal a _2.

As described above, the switch SW2 is now
Since selects the terminal a ₂ side, synthesized but combined signal strength of three signal strength is supplied to the calculator 23 via the switch SW2.

The arithmetic unit 23 is supplied with a predetermined value stored in the intensity storage unit 24 in addition to the combined signal intensity.

The amplitude storage unit 24 stores a signal corresponding to a desired amplitude value, that is, a signal corresponding to a desired amplitude value X with respect to the synthesized demodulated data output from the arithmetic unit 29 (synthesized frequency error output from the arithmetic unit 30). Strength (hereinafter referred to as desired signal strength)
X 'is stored in advance.

Therefore, in the arithmetic unit 23, the desired signal intensity X ′ corresponding to the desired amplitude value X is subtracted from the combined signal intensity output from the arithmetic unit 22 and supplied to the ROM 26 via the time constant adding circuit 25. You.

That is, assuming that the composite signal intensity output from the arithmetic unit 22 is A ′, the arithmetic unit 23 outputs the difference M ′ (= A′−X ′) between the composite signal intensity A ′ and the desired signal intensity X ′. ) Is output.

Here, it is assumed that when the combined signal strength having the value A ′ is output from the arithmetic unit 22, the combined demodulated data having the amplitude A is output from the arithmetic unit 27.

The ROM 26 stores X / A at address M '.
Is stored in advance, and the ROM 26 uses the value input from the arithmetic unit 23 via the time constant adding circuit 25 as an address, and outputs the value stored in advance at that address to the arithmetic units 29 and 30. It has been made like that.

Therefore, when the value input to the ROM 26 from the arithmetic unit 23 via the time constant adding circuit 25 is M ', the X / A
Is output as a predetermined constant.

The operation unit 23 outputs a value of M '
Since the combined demodulated data having the amplitude A is output from the computing unit 27 to the computing unit 29, R
When a predetermined constant X / A is supplied from the OM 26 to the arithmetic unit 29, the arithmetic unit 29 performs a multiplication of X / A × A to obtain a desired amplitude value X (= X / A × A). The combined demodulated data of the corresponding power is output.

The time constant adding circuit 25 has the same configuration as the time constant adding circuit 65 shown in FIG.

In the arithmetic unit 30, the amplitude of the synthesized frequency error is also multiplied by a predetermined constant supplied from the ROM 26 and output. Since the amplitude of the synthesized frequency error and the amplitude of the synthesized demodulated data are in a proportional relationship, as described above, the synthesized frequency error is multiplied by the same predetermined constant as that of the synthesized demodulated data, so that the desired power can be synthesized. A frequency error is obtained.

On the other hand, when the cellular telephone is used indoors, the operation unit 31 is turned on by the user. When turned on, the operation unit 31 outputs a control signal of the indoor mode to the searcher 32.

When the searcher 32 receives the control signal of the outdoor mode from the operation unit 32, it performs the process of the indoor mode.
That is, the searcher 32 has at least one of the RSSI circuits 21a to 21c constituting the fingers 5a to 5c.
For example, when the RSSI circuits 21b and 21c are operating, the operation is stopped, and at the same time,
To select the terminal b ₂ side switch SW2.

[0112] the terminal b ₂ via the operation unit 33 from the RSSI circuit 21a, the signal strength of the path that is demodulated by the demodulation processing circuit 6a is supplied. The arithmetic unit 33 outputs the input signal to the 3 (RSSI circuit of the device (the RSSI circuit 21a
21c) / (the number of RSSI circuits (RSSI circuits 21b and 21c) that have stopped operating-the number of RSSI circuits (RSSI circuits 21a) that are operating))) the b _2, 3 times the signal strength of the signal strength of the path that is demodulated by the demodulation processing circuit 6a is supplied.

[0113] is supplied to the terminal b _2, which was 3 times the signal strength from the RSSI circuit 21a, the switch SW
2 is input to the arithmetic unit 23, and is hereinafter referred to as the arithmetic unit 23.
Intensity storage unit 24, time constant adding circuit 25, and ROM 2
6, the same processing is performed.
Is supplied with a predetermined constant.

Here, when the operation unit 31 is turned on, that is, when the cellular telephone is in a building (indoor) where the distributed antenna shown in FIG. 9 is installed, for example.
As described above, the powers (same in amplitude) of the demodulated data (same in frequency error) obtained by demodulating the path in each of the fingers 5a to 5c are almost the same as described above.

Therefore, the signal intensities output from the RSSI circuits 21a to 21c have substantially the same value.

As described above, when the cellular telephone is used indoors, the combined signal strength obtained by adding the signal strengths output from the RSSI circuits 21a to 21c, and one of the RSSI circuits 21a to 21c, For example, three times the signal intensity output from the RSSI circuit 21a is equal.

Therefore, in this case, even if a predetermined constant is read from the ROM 26 corresponding to a value obtained by triple the signal strength from the RSSI circuit 21a, the synthesized demodulated data (synthesized frequency error) of the desired power is not obtained. Will be obtained.

Further, in this case, since the operation of the RSSI circuits 21b and 21c of the RSSI circuits 21a to 21c is stopped, power consumption can be reduced.

Although the embodiment in which the receiving apparatus of the present invention is applied to a cellular telephone has been described above, the present invention can be applied to a receiving apparatus for receiving and demodulating a signal other than the cellular telephone.

In the present embodiment, the number of fingers provided on the apparatus is three, that is, the fingers 5a to 5c. However, the number of fingers is not limited to this, and the number of fingers may be adjusted, for example, to balance cost and performance. The number can be two or more in consideration.

In the embodiment shown in FIG. 4, the operation section 31 is provided, and the searcher 32 is set to the indoor / outdoor mode in accordance with the ON / OFF state. However, the present invention is not limited to this. Absent. That is, as shown in FIG. 5, for example, the first bit of the frame of the received signal is used as a determination bit, and the value of this determination bit is set to, for example, 0 or 1 when a signal is transmitted from an outdoor antenna. In the case where a signal is transmitted from an indoor distributed antenna, it may be set to, for example, 1 out of 0 and 1.

In this case, the operation unit 31 is provided on the cellular telephone.
Instead of this, a block for detecting the determination bit at the head of the frame may be provided, and the mode of the searcher 32 may be changed according to the detection result.

Further, in this case, the detection of the decision bit is
In addition to performing the communication at the time of the actual call, for example, the cellular telephone may be configured to perform the communication periodically, and the communication may be performed at the time of the periodic communication.

[0124]

According to the first receiver of the present invention, Mar
Individual paths are searched from the received signal
Then, a path to be demodulated is selected. Furthermore, that selected
Demodulated paths are demodulated and the resulting demodulated data
Are combined to form combined demodulated data. Synthetic demodulation data
Data is output after being multiplied by a predetermined constant.
Constant is determined based on the number of paths selected.
You. Therefore, if the path respective signal intensities constituting the multipath is substantially constant, the power of the combined demodulated data, thereby enabling to easily be controlled substantially constant.

[0125]

According to the second receiving apparatus of the present invention , the multi
The path to be demodulated is selected from the received signal
In the plurality of demodulation means, the selected path
Each is demodulated. And obtained from multiple demodulation means
Demodulated data is synthesized, and the synthesized demodulated data is output.
You. On the other hand, the demodulated data demodulated by the
Of multiple detection means for detecting the signal strength of each data
Is controlled and the signal detected by the operating detecting means is
A predetermined constant is generated based only on the signal strength. Soshi
Multiplied by a predetermined constant and output.
It is. Therefore, the power consumption of the device can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a cellular telephone to which a receiving device of the present invention is applied.

FIG. 2 is a more detailed block diagram of a data combiner 7 (frequency error combiner 8) of the embodiment of FIG.

FIG. 3 is a flowchart illustrating an operation of the embodiment of FIG. 1;

FIG. 4 is a block diagram showing a configuration of a second embodiment of the cellular telephone to which the receiving device of the present invention is applied.

FIG. 5 is a diagram illustrating a determination bit.

FIG. 6 is a block diagram showing a configuration of an example of a conventional cellular telephone.

FIG. 7 is a block diagram showing a configuration of an example of a conventional cellular telephone of the diversity rake receiving system.

8 is a more detailed block diagram of the data combiner 51 (frequency error combiner 52) of FIG.

FIG. 9 is a diagram illustrating a distributed antenna.

[Explanation of symbols]

 1, 2 Multiplier 3 VCO (Voltage Controlled Oscillator) 4 Phaser 5a to 5c Finger 6a to 6c Demodulation Processing Circuit 7 Data Combiner 8 Frequency Error Combiner 9 LF (Loop Filter) 10 Searcher 11, 12 Computing Unit 13 Multiplier Generator 21a To 21c RSSI circuit 22, 23 arithmetic unit 24 intensity storage unit 25 time constant adding circuit 26 ROM 27 to 30 arithmetic unit 31 operation unit 32 searcher 33 arithmetic unit 41 despreader 42 data demodulation unit 43 frequency error detection unit 44 data processing unit Reference Signs List 45 control circuit 51 data combiner 52 frequency error combiner 53 searcher 61 to 63 arithmetic unit 64 intensity storage unit 65 time constant adding circuit 66 ROM

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) H04J 13/00-13/16 H04B 1/69-1/713 H04B 7/02-7/12

Claims (4)

(57) [Claims] 1. A multipath received signal,
Selection means for searching for an individual path and selecting a path to be demodulated, demodulating each path selected by the selection means,
A plurality of demodulating means for outputting a demodulated data, said plurality of combining the demodulated data output from the demodulation means, respectively, and synthesizing means for outputting a combined demodulated data, said combined demodulated data is multiplied by a predetermined constant output Operation
And means, based on the number of the path selected by the selecting unit, the receiving apparatus characterized by having a determining means for determining the predetermined constant. 2. The receiving apparatus according to claim 1, wherein said selecting means selects a path having a signal strength within a predetermined range. From a received signal wherein has a multi-path,
Selection means for searching for an individual path and selecting a path to be demodulated, demodulating each path selected by the selection means,
A plurality of demodulating means for outputting a demodulated data, combining the demodulated data output from each of the plurality of demodulating means, combining means for outputting the combined demodulated data, said demodulated data respectively by the plurality of demodulating means outputs
A plurality of detecting means for detecting the signal strength of the plurality of detecting means , control means for controlling the operation of the plurality of detecting means, and the signal strength detected by the operating detecting means.
Generating means for generating a predetermined constant based only on the degree, and multiplying the combined demodulated data by the predetermined constant and outputting the result.
Receiver and having an operation means that. (4) The control means is based on a predetermined control signal.
And at least one of the plurality of detection means
Stop working The reception according to claim 3, characterized in that:
apparatus.