JPH10190564A - Terminal equipment of portable telephone system and receiving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption when an inner battery is used and to surely receive information from a base station when power is supplied from an external power terminal in the terminal equipment of a portable telephone system. SOLUTION: Whether or not external power is supplied from the external power terminal 42 is detected by an external power detecting circuit 45. A signal from the base station is intermittently received in a stand-by state. In this case, when the inner battery 41 is used, the timing to be a reception mode is set long. When external power is used from the external power terminal 42, the timing to be the reception mode is set short. Thus, a duration time is made to be long in using the inner battery and the signal from the base station is surely received in using external power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a CDMA (Code
The present invention relates to a terminal device of a mobile phone system suitable for use in a mobile phone system of a Division Multiple Accesss type.

[0002]

2. Description of the Related Art In recent years, multi-dimensional connections have been made possible by using a pseudo-random code as a spreading code to spread the carrier of a transmission signal by spectrum spreading and changing the pattern and phase of the code sequence of the spreading code. Attention has been paid to a CDMA cellular telephone system.

In the CDMA system, a spread spectrum system is used as a communication system. In the spread spectrum method, at the time of transmission, a carrier is primary-modulated by transmission data, and the primary-modulated carrier is subjected to PN modulation.
(Pseudorandom Noise) code is multiplied and the carrier is PN
Modulated by code. As the primary modulation, for example, balanced QPSK modulation is used. Since the PN code is a random code, when the carrier is modulated by the PN code, the frequency spectrum is broadened.

At the time of reception, the same PN as the transmitting side is used.
The sign is multiplied. At the time of reception, if the phase matches with the same PN code as at the time of transmission, despreading is performed and a primary modulation output is obtained. By demodulating this primary modulation output, received data is obtained.

In the spread spectrum method, in order to despread a signal at the time of reception, the same PN code as that of the transmitting side is required for not only the pattern but also the phase. Therefore, by changing the pattern and phase of the PN code, multi-dimensional connection becomes possible. The one that enables multidimensional connection by making the pattern and phase of the code sequence of the spreading code different is called a CDMA system.

[0006] Conventionally, as a cellular telephone system, F
A DMA (Frequency Division Multiple Accesss) system and a TDMA (Time Division Multiple Accesss) system are used. However, in the FDMA system and the TDMA system, it has become difficult to cope with a rapid increase in the number of users.

[0007] In other words, the FDMA system performs multidimensional connection using channels of different frequencies, and the cellular telephone system of the analog system exclusively uses the FDMA system.

However, in the FDMA system, the frequency use efficiency is poor, and the number of channels tends to be insufficient for a sudden increase in the number of users. If the channel spacing is narrowed to increase the number of channels, the influence of adjacent channels becomes more susceptible and the sound quality deteriorates.

[0009] The TDMA system divides the use time by compressing transmission data with time and shares the same frequency. The TDMA system is now widely used as a digital cellular telephone system. doing. In the TDMA system, although the frequency use efficiency is improved as compared with the case of using only the FDAM system, the number of channels is limited, and the shortage of the number of channels is feared as the number of users increases rapidly.

[0010] On the other hand, the CDMA system has excellent interference resistance and is hardly affected by adjacent channels.
For this reason, the frequency use efficiency increases, and more channels can be achieved.

In the FDAM system and the TDMA system,
Susceptible to multipath fading.

That is, as shown in FIG.
From the base station 201 to the mobile terminal 202, the radio wave from the base station 201 directly reflects to the mobile terminal 202, and the radio wave from the base station 201 reflects to the building 203A to reach the mobile terminal 202. , A path P3 in which radio waves from the base station 201 are reflected on the building 203B and reach the mobile terminal 202.
Etc. There are multiple paths.

Radio waves from base station 201 are transmitted to portable terminal 202.
The paths P2 and P3, in which the radio waves from the base station 201 are reflected on the buildings 203A and 203B and reach the mobile terminal 202, have a delay compared to the path P1 directly reaching the mobile terminal 202. Therefore, as shown in FIG. 5, the portable terminal 102 outputs the signal S1 from the path P1 and the signal S1 from the path P2 at different timings.
2. The signal S3 from the path P3 arrives. When the signals S1, S2, and S3 from the plurality of paths P1, P2, and P3 interfere with each other, fading occurs. In the FDAM system and the TDMA system, the influence of fading due to such multipath is a problem.

On the other hand, in the CDMA system, by adopting the diversity RAKE system, the effect of fading due to multipath can be reduced and the S / N ratio is reduced.
The ratio can be improved.

In the diversity RAKE system, signals S1, S2, and S3 of a plurality of paths as described above are
, Receivers 221A, 221B and 221C capable of receiving signals from a plurality of paths respectively are prepared. Then, the code in each path is captured by the timing detector 222, and this code is set in the receivers 221A, 221B, and 221C of the paths P1, P2, and P3. The signals of the paths P1, P2, and P3 are demodulated by the receivers 221A, 221B, and 221C, respectively, and the received outputs are combined by the combining circuit 222.

In the spread spectrum system, it is difficult to receive interference by each path. And, in this way, a plurality of paths P
If the received outputs from P1, P2, and P3 are demodulated, and the demodulated outputs from these multiple paths are combined, the signal strength increases, the S / N ratio can be improved, and the effect of fading due to multipath is reduced. Can be reduced.

In the above example, for the sake of explanation, the configuration of the diversity RAKE system is shown by the three receivers 221A, 221B and 221C and the timing detector 222. However, in the cellular telephone terminal of the diversity RAKE system, As shown in FIG. 7, fingers 251A, 251B and 251C for obtaining demodulated output of each path, a searcher 252 for detecting multipath signals, and a data combiner for combining demodulated data of each path. 25
3 are provided.

In FIG. 7, a received signal of a spread spectrum signal converted into an intermediate frequency is supplied to an input terminal 250. This signal is supplied to the quasi-synchronous detection circuit 255. The quasi-synchronous detection circuit 255 is a multiplication circuit, and the quasi-synchronous detection circuit 255 multiplies the signal from the input terminal 250 by the output of the PLL synthesizer 256. The output of the PLL synthesizer 256 is controlled by the output of the frequency combiner 257, and the quasi-synchronous detection circuit 255 performs quadrature detection on the received signal.

The output of the quasi-synchronous detection circuit 255 is supplied to an A / D converter 258. A / D converter 258
This signal is converted into a digital signal. On this occasion,
The sampling frequency of the A / D converter 258 is set to a frequency sufficiently higher than the frequency of the PN code used for spread spectrum, so-called oversampling is performed.

The output of the A / D converter 258 is supplied to fingers 251A, 251B, and 251C.
It is supplied to the searcher 252. Fingers 251A, 25
Reference numerals 1B and 251C despread signals in each path, synchronously capture signals, demodulate data, and detect frequency errors.

The searcher 252 captures the code of the received signal and determines the code of each path to be set for the fingers 251A, 251B, 251C. That is, the searcher 252 includes a despreading circuit that performs despreading by multiplying the received signal by the PN code. And the controller 25
Under the control of 8, the phase of the PN code is moved, and the correlation with the received code is obtained. The code of each path is determined based on the correlation between the set code and the received code.

The output of the searcher 252 is
8 is supplied. Controller 258 includes searcher 25
2, each finger 251A, 251B,
The phase of the PN code for 251C is set. Fingers 251A, 251B, 251C, based on this,
The phase of the N code is set, the received signal is despread, and the received signal in each path is demodulated.

The data demodulated by the fingers 251A, 251B and 251C is supplied to a data combiner 253. The data combiner 253 combines the received signals of each path. The combined signal is output from output terminal 259.

The fingers 251A, 251B, 25
At 1C, a frequency error is detected. This frequency error is supplied to the frequency combiner 257. The output of the frequency combiner 257 controls the oscillation frequency of the PLL synthesizer 256.

[0025]

In a cellular telephone system, incoming call information, base station information, and the like are transmitted from a base station. In order to receive the information from the base station, the portable terminal of the cellular telephone system is set to the reception mode intermittently in the standby state.

It is preferable to shorten the timing of the intermittent reception mode in order to reliably receive information from the base station. However, the mobile terminal of the mobile phone system is usually driven by an internal battery, and it is necessary to save power and extend the duration of the battery. If the timing of the reception mode is shortened, the power consumption increases accordingly. For this reason, it is preferable to prolong the timing of the reception mode to suppress the power consumption.

Some portable terminals of the cellular telephone system are provided with an external power supply terminal so that they can be driven by an external power supply. In those provided with such an external power supply terminal, for example, power is supplied to the external power supply terminal of the portable terminal from a cigarette lighter or the like in an automobile,
A mobile terminal can be used. In this way, when power is supplied from the external power supply terminal, unlike when using the internal battery, there is not much need to extremely reduce power consumption. It is desired that information can be reliably received from a base station.

Therefore, an object of the present invention is to reduce the power consumption when the internal battery is used, and to reduce the power consumption when the power is supplied from the external power supply terminal.
An object of the present invention is to provide a terminal device of a mobile phone system capable of reliably receiving information from a base station.

[0029]

SUMMARY OF THE INVENTION The present invention relates to an external power supply detecting means for detecting whether or not external power is supplied, reception control during normal reception, and low power consumption for reducing power consumption. A terminal device for a mobile phone system, comprising: a power control setting unit that switches between reception control and a power control unit, wherein the power setting unit is switched between when external power is supplied and when external power is not supplied.

The present invention detects whether or not an external power supply is supplied, and controls reception during normal reception and power consumption when the external power supply is supplied and when the external power supply is not supplied. This is a reception method of a mobile phone system that switches between reception control for low power consumption in the case of reducing power consumption.

When the internal battery is used, the reception state is set at a relatively long set time, so that the power consumption can be reduced and the duration of the internal battery can be extended. Further, when driven by the external power supply from the external power supply terminal, the reception state is set at each relatively short set time, so that the information from the base station can be reliably received.

[0032]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a portable terminal of a CDMA cellular telephone system to which the present invention can be applied. In this portable terminal, a diversity RAKE system in which signals from a plurality of paths are simultaneously received and the signals are combined is employed as a receiving system.

In FIG. 1, an audio signal is input to the microphone 1 during transmission. This audio signal is supplied to the A / D converter 2, and the A / D converter 2 converts the analog audio signal into a digital audio signal. A /
The output of the D converter 2 is supplied to the audio compression circuit 3.

The voice compression circuit 3 compresses and codes a digital voice signal. As the compression encoding method,
Various types have been proposed. For example, QCELP (Qu
For example, a coding rate such as alcomm Code Excited Linear Coding which can select a plurality of coding speeds depending on the nature of the voice of the speaker and the congestion of the communication channel can be used. QCEL
In P, 4
Encoding rates (9.6 kbps, 4.8 kbps,
(2.4 kbps, 1.2 kbps), and coding can be performed at a minimum speed to maintain speech quality. Of course, the audio compression method is not limited to this.

The output of the audio compression circuit 3 is supplied to a convolutional encoding circuit 4. The convolution coding circuit 4 adds a convolutional code error correction code to the transmission data. The output of the convolutional encoding circuit 4 is an interleave circuit 5
Supplied to The transmission data is interleaved by the interleave circuit 5. The output of the interleave circuit 5 is supplied to a spread spectrum circuit 6.

The carrier is primarily modulated by the spread spectrum circuit 6 and further spread with a PN code. That is, primary modulation of transmission data is performed by, for example, balanced QPSK modulation, and further multiplied by a PN code. Since the PN code is a random code, multiplying the PN code in this way widens the frequency band of the carrier wave and spreads the spectrum. In addition, as a modulation method of transmission data,
For example, although balanced QPSK modulation is used, various modulation schemes have been proposed, and another modulation scheme may be used.

The output of the spread spectrum circuit 6 is supplied to a D / A converter 8 via a band pass filter 7. The output of the D / A converter 8 is supplied to the RF circuit 9.

The RF circuit 9 includes a PLL synthesizer 11
Supplies a local oscillation signal. By the RF circuit 9, D
The output of the A / A converter 8 is multiplied by the local oscillation signal from the PLL synthesizer 11, and the frequency of the transmission signal is converted to a predetermined frequency. The output of the RF circuit 9 is supplied to the transmission amplifier 10 and power-amplified, and then supplied to the antenna 12. Then, a radio wave from the antenna 12 is transmitted to the base station.

At the time of reception, a radio wave from the base station is received by the antenna 12. Since the radio wave from the base station is reflected from a building or the like, it forms a multipath and reaches the antenna 12 of the mobile terminal. When the mobile terminal is used in a car or the like, the frequency of the received signal may change due to the Doppler effect.

The reception output from the antenna 12 is supplied to the RF circuit 20. A local oscillation signal is supplied from the PLL synthesizer 11 to the RF circuit 20. RF circuit 20
As a result, the received signal is converted into an intermediate frequency signal having a predetermined frequency.

The output of the RF circuit 20 is supplied to the quasi-synchronous detection circuit 22 via the intermediate frequency circuit 21. The output of the PLL synthesizer 23 is supplied to the quasi-synchronous detection circuit 22. The frequency of the output signal from the PLL synthesizer 23 is controlled by the output of the frequency combiner 32. The received signal is subjected to quadrature detection by the quasi-synchronous detection circuit 22.

The output of the quasi-synchronous detection circuit 22 is supplied to an A / D converter 24. The output of the quasi-synchronous detection circuit 22 is digitized by the A / D converter 24.
At this time, the sampling frequency of the A / D converter 24 is set to a frequency higher than the frequency of the PN code used for spread spectrum, so-called oversampling. The output of the A / D converter 24 is supplied to fingers 25A, 25B, 25C,
It is supplied to the searcher 28.

As described above, at the time of reception, a multipath signal is received. Fingers 25A, 25B, 25C
Respectively perform despreading by multiplying the multipath received signal by a PN code, and demodulate data from the despread output. Further, from the fingers 25A, 25B, and 25C, a received signal level in each path and a frequency error in each path are output.

The searcher 28 captures the code of the received signal and determines the code of each path set to the fingers 25A, 25B, 25C. That is, the searcher 28
Has a despreading circuit for multiplying a received signal by a PN code to perform despreading. Then, under the control of the controller 29, the phase of the PN code is moved, and the correlation with the received code is obtained. The code of each path is determined based on the correlation value between the set code and the received code. The code determined by the controller 29 is set to the fingers 25A, 25B, 25C.

The received data of each path demodulated by the fingers 25A, 25B, 25C is transmitted to the data combiner 30.
Supplied to The data combiner 30 combines the received data of each path. The output of the data combiner 30 is supplied to the AGC circuit 33.

The signal strength in each path is obtained by the fingers 25A, 25B and 25C. The signal strength in each path from the fingers 25A, 25B, 25C is represented by an RSSI (Received Signal Strength Indicator).
It is supplied to the combiner 31. RSSI combiner 31
As a result, the signal strength in each path is synthesized. This R
The output of the SSI combiner 31 is supplied to the AGC circuit 33, and the output of the ASI circuit
The gain of the C circuit 33 is controlled.

The frequency error in each path from the fingers 25A, 25B, 25C is
Supplied to The frequency combiner 32 combines the frequency errors in each path. The output of the frequency combiner 32 is supplied to the PLL synthesizers 11 and 23, and the frequencies of the PLL synthesizers 11 and 23 are controlled according to the frequency error.

The output of the AGC circuit 33 is supplied to a deinterleave circuit 34. The deinterleaving circuit 34 deinterleaves the received data corresponding to the interleaving on the transmitting side. The output of the deinterleave circuit 34 is supplied to a Viterbi decoding circuit 35. The Viterbi decoding circuit 35 decodes a convolutional code by soft decision and maximum likelihood decoding. The Viterbi decoding circuit 35 performs an error correction process. The output of the Viterbi decoding circuit 35 is supplied to the audio decompression circuit 36.

For example, the QCEL
The audio signal transmitted after being compressed and encoded by P is expanded, and the digital audio signal is decoded. This digital audio signal is supplied to the D / A converter 37. D /
The digital audio signal is returned to the analog audio signal by the A converter 37. This analog audio signal is supplied to the speaker 38.

This portable telephone terminal has an internal battery 41
, And can be driven by an external power supply from the external power supply terminal 42. The power from the internal battery 41 is supplied to a terminal 43A of the switch circuit 43, and the output of the external power terminal 42 is supplied to a terminal 43B of the switch circuit 43. An external power detection circuit 45 for detecting whether or not power is supplied to the external power terminal 42;
The switch circuit 43 is controlled by the external power supply detection circuit 45. The output of the switch circuit 43 is supplied to the power supply circuit 44.

When the external power is not supplied, the switch circuit 43 is set to the terminal 43 A side, and the power from the internal battery 41 is supplied to the power circuit 44. When external power is supplied to the external power terminal 42,
The switch circuit 43 is set on the terminal 43B side, and power from the external power supply terminal 42 is supplied to the power supply circuit 44. The power supply circuit 44 forms a power supply necessary for the circuits of each unit in the mobile phone terminal, and this power is supplied to the circuits of each unit in the mobile phone terminal.

As described above, this portable telephone terminal is provided with the external power supply terminal 42 and can be driven by the external power supply from the external power supply terminal 42. For this reason,
For example, when used in a car, a power from a car battery can be supplied to the external power terminal 42 using a cigar lighter or the like and used. When driven by an external power supply in this way, the mobile phone can be used without concern for the capacity of the internal battery 41.

When driven by an external power supply as described above, the mobile phone can be used without worrying about the capacity of the internal battery 41, so that the timing of the reception mode can be shortened.

That is, at the terminal of the cellular telephone system, incoming call information, base station information, and the like are transmitted from the base station. In order to receive the information from the base station, the reception mode is set intermittently in the standby state. It is preferable to shorten the timing of the reception mode in order to reliably receive information from the base station. However, if the timing of the reception mode is shortened, the power consumption increases and the battery 41 Time is shortened. However, when the external power terminal 42 is provided, power can be supplied to the external power terminal 42 of the mobile terminal from, for example, a cigarette lighter in an automobile, and the mobile terminal can be used. There is no need to worry too much, and the timing of the reception mode can be shortened, so that information from the base station can be reliably detected.

That is, the output of the external power supply detection circuit 45 is
It is supplied to the controller 29. When the controller 29 is in the standby state, the processing shown in the flowchart of FIG. 2 is performed.

As shown in FIG. 2, in the standby state,
From the output of the external power supply detection circuit 45, it is determined whether or not external power is supplied from the external power supply terminal 42 (step ST1). If the external power source is determined not to be supplied from the external power supply terminal 42, the timing of the intermittent reception is set to a time T ₁ (step ST2). Then, it is determined whether set time has elapsed T ₁ (step ST3), after a lapse of the set time T _1, a predetermined reception time is set to the reception mode (step ST4).

[0057] In step ST1, the external power from the external power supply terminal 42 if it is judged to be supplied, the timing of the intermittent reception is set to a shorter time T ₂ from the time T ₁ (step ST5). Then, it is determined whether the set time T ₂ has elapsed (step ST6), after a lapse of the set time T _2, a predetermined reception time is set to the reception mode (step ST4).

FIG. 3 is a comparison of the operation in the standby state when the battery is driven by the internal battery 41 and when the battery is driven by the external power supply from the external power supply terminal. As shown in FIG. 3A, when using the internal battery 41, the relatively long every set time T _1, is set to the receiving state. Therefore, power consumption can be reduced.
On the other hand, as shown in FIG.
When it is driven by an external power source from, the relatively short every set time T _2, is set to the receiving state. Therefore, it is possible to reliably receive information from the base station.

In the above example, the terminal is a CDMA cellular telephone system.
The present invention is not limited to the DMA system, and can be similarly applied to an FDMA system or a TDMA system cellular telephone terminal.

[0060]

According to the present invention, when the internal battery is used, the reception state is set at a relatively long set time, so that the power consumption can be reduced and the duration of the internal battery can be extended. be able to. Further, when driven by the external power supply from the external power supply terminal, the reception state is set at each relatively short set time, so that the information from the base station can be reliably received.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a CDMA mobile phone terminal to which the present invention can be applied.

FIG. 2 is a flowchart used to describe a CDMA mobile phone terminal to which the present invention can be applied;

FIG. 3 is a timing chart used to explain a CDMA type mobile phone terminal to which the present invention can be applied;

FIG. 4 is a schematic diagram used for explaining a multipath.

FIG. 5 is a waveform diagram used for explaining multipath.

FIG. 6 is a block diagram used for describing a diversity RAKE method.

FIG. 7 is a block diagram illustrating an example of a diversity RAKE receiver.

[Explanation of symbols]

29 ... controller, 41 ... internal battery,
42 ... external power supply terminal, 45 ... external power supply detection circuit

Claims (6)

[Claims] 1. An external power supply detecting means for detecting whether external power is supplied, a power control setting for switching between reception control during normal reception and reception control for low power consumption when reducing power consumption. Means for switching the power setting means between when the external power is supplied and when the external power is not supplied. 2. The terminal device of a mobile phone system according to claim 1, wherein said power control means sets said low power consumption reception control when said external power is not supplied. 3. The terminal device of the mobile phone system according to claim 1, wherein the reception control for low power consumption has a longer intermittent reception timing than the reception control at the time of the normal reception. Detecting whether or not an external power supply is supplied, and controlling reception during normal reception and power consumption when the external power supply is supplied and when the external power supply is not supplied. A reception method for a mobile phone system, which switches between reception control for low power consumption and reduction in power consumption. 5. The receiving method of a mobile phone system according to claim 4, wherein said power control means sets said low power consumption reception control when said external power is not supplied. 6. The receiving method for a mobile phone system according to claim 4, wherein in the reception control for low power consumption, the timing of the intermittent reception is made longer than the reception control at the time of the normal reception.