JPH10233728A - Radio telephone set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the radio telephone set in which a frequency is effectively utilized when an error rate of the digital modulation system is small. SOLUTION: An error rate measurement section 15 is provided with a reception section 13 to measure an error rate. When the error rate is small, the error correction capability of an error correction coding section 12 and an error correction decoding section 14 is decreased to reduce a transmission speed. Then in the case of the time division multiplex access(TDMA), number of multiplexity is increased to obtain lots of slot from one carrier. That is, the frequency is utilized effectively by reducing the transmission speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital modulation type radio telephone.

[0002]

2. Description of the Related Art In recent years, mobile communications such as mobile phones have been widely used in various aspects of society. Hereinafter, a conventional wireless telephone device will be described with reference to the drawings.

FIG. 3 is a block diagram showing a configuration of a conventional wireless telephone device. In FIG. 3, 1 is a transmission unit, 2 is an error correction coding unit that performs error correction coding on an information signal, 3 is a modulation unit that performs digital modulation on a signal after error correction coding,
Reference numeral 4 denotes a transmission radio unit for frequency-converting a signal after digital modulation into a radio frequency band. Reference numeral 5 denotes an antenna switch for switching transmission / reception signals in a time-division manner, and reference numeral 6 denotes an antenna for transmitting / receiving a signal in a radio frequency band. 7 is a receiving unit, 8
Is a receiving radio unit for converting the frequency of the radio frequency band to an intermediate frequency, 9 is a demodulating unit for digitally demodulating the frequency-converted signal, and 10 is an error correction decoding for decoding the digitally demodulated signal into the original information signal. It is a chemical department.

[0004] The operation of the conventional wireless telephone device configured as described above will be described below. First, at the time of transmission, the transmission section 1 performs error correction coding on an information signal such as a voice signal in the error correction coding section 2 and performs digital modulation such as phase shift keying in the modulation section 3. Further, the transmission radio section 4 converts the frequency to a radio frequency band. In the antenna switch 5, the transmission radio unit 4 in the transmission unit 1 is connected to the antenna 6, and a signal from the transmission radio unit 4 is supplied to the antenna 6,
A wireless signal is transmitted from the antenna 6.

At the time of reception, a radio signal is received by the antenna 6, and the antenna switch 5 connects the antenna 6 and the reception radio section 8 in the reception section 7, and the signal received by the antenna 6 is transmitted to the reception radio section 8. Supply. The receiving unit 7 converts the signal of the radio frequency band into an intermediate frequency by the receiving radio unit 8, performs digital demodulation such as phase shift keying by the demodulating unit 9, and decodes the original information signal by the error correction decoding unit 10. I do.

The antenna switch 5 switches between transmission and reception signals in a time-division manner. Also, the antenna switch 5
Switches a plurality of transmission / reception signals in a time-division manner. Each of these signals is divided into slots by time division. Thereby, a plurality of signals can be transmitted by one carrier. This connection method of the wireless system is called time division multiple access (hereinafter abbreviated as TDMA). With the above operation, communication with the wireless telephone device becomes possible.

[0007]

However, in the above-mentioned conventional radio telephone apparatus, since fixed error correction coding is performed, error correction is performed more than necessary in a propagation path condition with a small error rate. , Transmission speed increases,
In the case of the TDMA system, many slots cannot be obtained with one carrier, and the number of multiplexes is reduced, that is, there is a problem that the frequency cannot be used effectively.

[0008] The present invention solves the above-mentioned problems, and it is possible to obtain many slots with one carrier and increase the number of multiplexes, that is, to enable effective use of the frequency, in a channel condition with a small error rate. It is an object of the present invention to provide a wireless telephone device.

[0009]

According to a first aspect of the present invention, there is provided a transmitting unit for transmitting a radio signal using a digital modulation system, a receiving unit for receiving a radio signal of a digital modulation system, and a transmitting unit. An error correction coding unit for performing error correction coding on the information signal; a modulation unit for performing digital modulation on an output signal of the error correction coding unit; and a frequency conversion of an output signal of the modulation unit into a radio frequency band. A transmission radio unit, a reception radio unit in the reception unit for frequency-converting a signal in a radio frequency band to an intermediate frequency, a demodulation unit for digitally demodulating an output signal of the reception radio unit, and an output of the demodulation unit. An error correction decoding unit that demodulates the signal into an original information signal, and an error rate measurement unit that measures an error rate and changes the error correction capability of the error correction encoding unit and the error correction decoding unit according to the error rate. Established

According to a second aspect of the present invention, there is provided a transmitting section for transmitting a radio signal using a digital modulation scheme, a receiving section for receiving a radio signal of a digital modulation scheme, and an information signal in the transmitting section. An error correction encoding unit that performs error correction encoding, a modulation unit that performs digital modulation on an output signal of the error correction encoding unit, and a transmission radio unit that frequency-converts an output signal of the modulation unit into a radio frequency band. A receiving radio unit for converting a signal in a radio frequency band into an intermediate frequency in the receiving unit, a demodulating unit for digitally demodulating an output signal of the receiving radio unit, and an output signal of the demodulating unit as an original information signal And an error rate measuring section for measuring an error rate and changing the modulation scheme of the modulation section and the demodulation section according to the error rate.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 has the effect of measuring the error rate in an error rate measuring section, changing the error correction coding capability according to the error rate, and changing the radio frequency bandwidth. .

The second aspect of the present invention has an effect that the error rate is measured by the error rate measuring unit, and the radio frequency bandwidth is changed by changing the digital modulation method according to the error rate.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of a wireless telephone apparatus according to Embodiment 1 of the present invention. In the transmission unit 11, reference numeral 3 denotes a modulation unit for performing digital modulation on a signal after error correction coding, and reference numeral 4 denotes a transmission radio unit for frequency-converting the signal after digital modulation into a radio frequency band. It is. Reference numeral 12 denotes an error correction encoding unit that performs error correction encoding by changing the error correction capability based on the error rate measurement result of the error rate measurement unit 15. 5 is an antenna switch for switching transmission and reception signals,
Reference numeral 6 denotes an antenna for transmitting and receiving signals in a radio frequency band, which are the same as those in the conventional example.

In the receiving unit 13, a receiving radio unit 8 converts the frequency of the radio frequency band into an intermediate frequency.
Reference numeral 9 denotes a demodulation unit for digitally demodulating the frequency-converted signal, which is the same as the conventional example. An error correction decoding unit 14 decodes the digitally demodulated signal into an original information signal in the same manner as the error correction method of the error correction encoding unit 12. Reference numeral 15 denotes an error rate measurement unit that measures an error rate and changes the error correction coding scheme of the error correction coding unit 12 and the error correction decoding unit 14 according to the error rate.

The operation of the conventional wireless telephone device configured as described above will be described below. First, at the time of transmission, the transmission unit 11 performs error correction coding on an information signal such as a voice signal in the error correction coding unit 12, and performs digital modulation such as phase shift keying in the modulation unit 3. Further, the transmission radio section 4 converts the frequency to a radio frequency band. The antenna switch 5 connects the transmitting radio unit 4 and the antenna 6 in the transmitting unit 11, supplies a signal from the transmitting radio unit 4 to the antenna 6, and transmits a radio signal from the antenna 6.

At the time of reception, a radio signal is received by the antenna 6, and the antenna switch 5 connects the antenna 6 and the reception radio section 8 in the reception section 13, and transmits the signal received by the antenna 6 to the reception radio section 8. Supply. The receiving unit 13 converts the signal of the radio frequency band into an intermediate frequency by the receiving radio unit 8, performs digital demodulation such as phase shift keying by the demodulating unit 9, and decodes the original information signal by the error correction decoding unit 14. I do.

The error rate measuring section 15 measures the error rate,
When the error rate is small, it is judged that the condition of the propagation path is good,
The error correction encoding is performed by lowering the error correction capability of the error correction encoding unit 12. For example, usually, error correction coding is performed by an adaptive differential pulse code modulation (hereinafter, abbreviated as ADPCM) method having a high error correction capability, but when the condition of the propagation path is good,
Error correction is performed by an adaptive predictive coding (hereinafter abbreviated as APC) method, which has a lower error correction capability than the ADPCM method. A
The transmission speed of the DPCM system is 32 kbps, and APC
Since the transmission rate of the system is 16 kbps, the transmission rate after error correction coding is halved compared to the conventional example, and TD
In the case of the MA system, the number of signals that can be multiplexed with one carrier is double that of the conventional example.

In the receiving section 13, the input received signal is frequency-converted and digitally demodulated, and then decoded in the error correction decoding section 14 into the original information signal with the error correction capability lowered by the error rate measuring section 15. . For example, the transmission unit 11
In the case where the error correction encoding unit 12 performs error correction encoding according to the APC method, the error correction decoding unit 14
Then, error correction decoding is performed by the same APC method.

Since the transmission rate after error correction is reduced to half, many signals can be transmitted by one carrier, and the frequency can be effectively used. For example, usually 32k
Error correction coding is performed by the ADPCM method with a transmission rate of bps, and APC of 16 kbps is used when the condition of the propagation path is good.
By performing the error correction coding by the method, the transmission speed after the error correction coding is reduced to half of that of the conventional example, so that one carrier can transmit twice as many signals. According to the above operation, a wireless telephone device capable of effectively using the frequency when the error rate is small, that is, when the condition of the propagation path is good, is enabled.

(Embodiment 2) FIG. 2 is a block diagram showing a configuration of a wireless telephone apparatus according to Embodiment 2 of the present invention. In the transmission section 16, reference numeral 2 denotes an error correction coding section for performing error correction coding on an information signal, and 4 denotes a transmission radio section for frequency-converting a signal after digital modulation into a radio frequency band. It is. Reference numeral 17 denotes a modulation unit that performs digital modulation by changing the modulation method based on the error rate measurement result of the error rate measurement unit 20. Reference numeral 5 denotes an antenna switch for switching transmission / reception signals, and reference numeral 6 denotes an antenna for transmitting / receiving signals in a radio frequency band, which are the same as in the conventional example.

In the receiving unit 18, a receiving radio unit 8 converts the frequency of the radio frequency band into an intermediate frequency.
An error correction decoding unit 10 decodes the digitally demodulated signal into the original information signal, which are the same as in the conventional example. Reference numeral 19 denotes a demodulation unit that performs digital demodulation using a demodulation method corresponding to the modulation method of the modulation unit 17. Reference numeral 20 denotes an error rate measurement unit that measures an error rate and changes the modulation method of the modulation unit 17 and the demodulation unit 19 according to the error rate.

The operation of the conventional wireless telephone device configured as described above will be described below. First, at the time of transmission, the transmission section 16 performs error correction coding on an information signal such as a voice signal in the error correction coding section 2 and performs digital modulation such as phase shift keying in the modulation section 17. Further, the transmission radio section 4 converts the frequency to a radio frequency band. The antenna switch 5 connects the transmission radio unit 4 and the antenna 6 in the transmission unit 16, supplies a signal from the transmission radio unit 4 to the antenna 6, and transmits a radio signal from the antenna 6.

At the time of reception, a radio signal is received by the antenna 6, and the antenna switch 5 connects the antenna 6 to the reception radio section 8 in the reception section 18, and transmits the signal received by the antenna 6 to the reception radio section 8. Supply. The receiving unit 18 converts the signal in the radio frequency band to an intermediate frequency in the receiving radio unit 8, performs digital demodulation such as phase shift keying in the demodulating unit 19, and decodes the signal into the original information signal in the error correcting decoding unit 10. I do.

The error rate measuring section 20 measures the error rate,
When the error rate is small, it is judged that the condition of the propagation path is good,
The frequency utilization rate is increased by changing the modulation method of the modulator 17. For example, digital modulation is usually performed by two-phase shift keying (hereinafter abbreviated as BPSK), but when the condition of the propagation path is good, four-phase phase shift keying (hereinafter referred to as QPSK) having a higher frequency utilization rate than BPSK. (Abbreviated)
Performs digital modulation. Since the frequency utilization rate of BPSK is 1 bit / s / Hz at the maximum and the frequency utilization rate of QPSK is 2 bits / s / Hz at the maximum, the frequency bandwidth after digital modulation is の of the conventional example, and the frequency conversion is performed. After that, the occupied frequency bandwidth of the radio signal transmitted from the antenna 6 via the antenna switch 5 becomes half that of the conventional example.

The receiving section 18 converts the frequency of the received signal, and then demodulates the signal at the error rate measuring section 20.
Digital demodulation is performed by the modulation method changed by the above. For example, when the modulation unit 17 in the transmission unit 16 performs digital modulation using QPSK, the demodulation unit 19 in the reception unit 18 performs digital demodulation using the same QPSK.

Since the occupied frequency bandwidth of the radio signal is reduced, many signals can be transmitted in the same bandwidth.
Effective use of frequency can be achieved. For example, usually up to 1 bi
Digital modulation is performed with BPSK having a frequency utilization rate of t / s / Hz, and when the condition of the propagation path is good, a maximum of 2 bits / s
By performing digital demodulation with QPSK having a frequency utilization rate of / Hz, the frequency bandwidth after digital modulation is reduced to 1/2 of that of the conventional example, and the occupied frequency bandwidth is also reduced to 1/2. Thus, twice as many signals can be transmitted.
According to the above operation, a wireless telephone device capable of effectively using the frequency when the error rate is small, that is, when the condition of the propagation path is good, is enabled.

[0027]

As described above, according to the present invention, the error rate measuring section is provided in the receiving section, the error rate is measured, and when the error rate is small, the error of the error correction coding section and the error correction decoding section is reduced. By reducing the correction capability, the transmission speed is reduced. Therefore, in the case of the TDMA system, many slots can be obtained with one carrier, and the number of multiplexes increases, that is,
The reduced transmission speed allows effective use of frequencies. In addition, when the error rate is small, by changing the modulation scheme of the modulation unit and the demodulation unit, the occupied frequency bandwidth is reduced, and the frequency can be used effectively.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a wireless telephone device according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing a configuration of a wireless telephone device according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a conventional wireless telephone device.

[Explanation of symbols]

 2 error correction coding unit 3 modulation unit 4 transmission radio unit 5 antenna switch 6 antenna 8 reception radio unit 9 demodulation unit 10 error correction decoding unit 11 transmission unit 12 error correction coding unit 13 reception unit 14 error correction decoding unit 15 Error rate measuring section 16 Transmitting section 17 Modulating section 18 Receiving section 19 Demodulating section 20 Error rate measuring section

Claims (2)

[Claims] 1. A transmitting unit for transmitting a radio signal using a digital modulation method, a receiving unit for receiving a radio signal using a digital modulation method, and an error in the transmitting unit for performing error correction coding on an information signal. A correction encoding unit, a modulation unit that performs digital modulation on an output signal of the error correction encoding unit, a transmission radio unit that frequency-converts an output signal of the modulation unit into a radio frequency band, and in the reception unit, A receiving radio unit for converting a signal in a radio frequency band to an intermediate frequency, a demodulating unit for digitally demodulating an output signal of the receiving radio unit, and an error correction decoding for demodulating an output signal of the demodulating unit to an original information signal A wireless telephone device comprising: a measuring unit that measures an error rate and changes an error correction capability of the error correction encoding unit and the error correction decoding unit based on the error rate. 2. A transmission unit for transmitting a radio signal using a digital modulation method, a reception unit for receiving a radio signal using a digital modulation method, and an error in the transmission unit for performing error correction coding on an information signal. A correction encoding unit, a modulation unit that performs digital modulation on an output signal of the error correction encoding unit, a transmission radio unit that frequency-converts an output signal of the modulation unit into a radio frequency band, and in the reception unit, A receiving radio unit for converting a signal in a radio frequency band to an intermediate frequency, a demodulating unit for digitally demodulating an output signal of the receiving radio unit, and an error correction decoding for demodulating an output signal of the demodulating unit to an original information signal A wireless telephone device comprising: a measuring unit that measures an error rate and changes a modulation scheme of the modulation unit and the demodulation unit according to the error rate.