JP2003110454A - Multi-mode radio apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-mode radio apparatus having a simple structure without increasing a circuit scale for carrying out radio communication at a high frequency band of about 5 GHz band. SOLUTION: The multi-mode radio apparatus includes a first antenna for radio communication at high frequency band at 2 GHz, an analog signal processing circuit connected with the first antenna, a digital signal processing circuit connected with the analog signal processing circuit, a second antenna for radio communication at high frequency band at 5 GHz, a frequency conversion circuit connected between the second antenna and the analog signal processing circuit for converting the high frequency signal in frequency between the 2 GHz band and 5 GHz band, and a switch for connecting the analog signal processing circuit to the first antenna during the radio communication at 2 GHz band and connecting the analog signal processing circuit to the frequency conversion circuit during the radio communication at 5 GHz band.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multimode radio device using a plurality of frequency bands, and particularly to a 2 GHz band and a 5 GHz band.
The present invention relates to a multimode wireless device that uses a high frequency band such as a z band.

[0002]

2. Description of the Related Art In recent years, expectations for so-called multi-mode radios in which a plurality of communication systems can be used by one radio have increased. Under these circumstances, the wireless function unit is realized by software to achieve multi-mode.
So-called software defined radios have been proposed and are in the limelight.

As a conventional example of the software defined radio, for example, the one disclosed in Japanese Patent Laid-Open No. 11-317777 is known. This software-defined radio frequency-converts the signals of a narrow band system such as a mobile phone into a base band collectively for each system band, and outputs the conversion result to A
A / D conversion is performed and a narrow band desired channel signal is selected by digital signal processing.

The analog signal processing unit of such a software defined radio has a plurality of frequency band signals (for example, PDC).
Is 800 MHz and 1.5 GHz, PHS is 1.9 GHz, W-CDMA is 2 GHz, and the like, and a system band (PDC or PHS is about 20 MHz, W-C).
It has wide band characteristics such that it can collectively process about 60 MHz in DMA.

However, there is a limit to the multiband and wideband of the analog signal processing section. In the case of a silicon process for manufacturing a circuit using a semiconductor element mainly made of silicon, it is about 2 GHz. That is, 2 GHz in the above W-CDMA is close to the limit performance of the circuit. When using a compound semiconductor such as gallium arsenide, the upper limit frequency can be increased to 5 to 10 GHz. However, the cost is not suitable for use in consumer products such as mobile phones and wireless LANs, and the former is often used.

In recent years, wireless LANs using the 5 GHz band (for example, IEEE802.11a, etc.) have been actively used in the limelight, and a large demand is expected to continue in the future.

As a technique used to realize a wireless LAN,
The software defined radio as described above is suitable in view of the fact that mobile communication systems such as public mobile phones currently have an upper limit of around 2 GHz. However, regarding the wireless function of the 5 GHz band that cannot be handled by the conventional software defined radio, the above-mentioned performance limit of the analog signal processing unit becomes a problem.

Therefore, it is conceivable to combine a conventional 5 GHz band radio with a conventional software radio having a 2 GHz band radio function. Specifically, a public mobile communication system having a multiband, wideband analog signal processing unit (hereinafter referred to as an analog unit for software defined radio) used in software defined radio technology up to a maximum of 2 GHz is further provided for about 5 GHz. Wireless L that can be processed
It may be applied to the AN or the fourth generation wireless system. In this case, for the 5 GHz band, 2 GHz
Separately from the one for, prepare an analog part of another system and combine these two analog parts.

In such a conventional case, there is a problem in that two radios are simply combined, the circuit scale of the radio is expanded, and the cost is increased.

FIG. 3 is a diagram showing a schematic structure of such a conventional 5 GHz-compatible mobile phone / multi-mode radio for a wireless LAN. In FIG. 3, 101 is a software radio analog section, 102 is a software radio digital section, 103 is a 5 GHz compatible analog section, 10
Reference numeral 4 denotes a 2 GHz band antenna, and 105 denotes a 5 GHz band antenna.

In the digital section 102 of the software defined radio, due to the programmability utilizing its versatility,
It is possible to provide a modulation / demodulation function for a 5 GHz system by changing the software configuration. However, as for the analog part, the wide band analog part 101 having an upper limit of about 2 GHz cannot support the analog part. Therefore, the analog part 103 corresponding to 5 GHz is separately provided. 5
The GHz-compatible analog unit 103 frequency-converts the received signal to the baseband, and also converts the frequency of the baseband signal to a high frequency for transmission.

As described above, when a system using various frequency bands is handled by using the conventional technique, the digital unit uses the software radio technology so that only the software is modified or rewritten without adding or changing the hardware. The analog part is 2G
A wide-band analog section whose upper limit is in the vicinity of the Hz band cannot be used, and a front-end section suitable for the system is required.

[0013]

As described above, the conventional multi-mode radios for mobile phones / wireless LANs include:
Since a plurality of wireless units are simply arranged in parallel in the inside, there is a problem that the circuit scale increases, portability and portability are impaired, and costs increase. Here, as an example, a wireless LAN using the 5 GHz band is used.
However, it goes without saying that this problem also applies to other systems that use a high frequency band that exceeds the upper limit of frequencies that can be handled by the wideband analog unit for software defined radio 101.

The present invention has been made in consideration of such circumstances, and provides a multi-mode radio which can perform radio communication in a high frequency band of about 5 GHz band with a simple configuration without increasing the circuit scale. The purpose is to

[0015]

In order to solve the above problems and achieve the object, the present invention is configured as follows.

(1) A multi-mode radio device according to the present invention comprises an analog signal processing means for analog signal processing a high frequency signal in the first frequency band and a digital signal processing means for digital signal processing the high frequency signal in the first frequency band. And frequency conversion means that is connected to the analog signal processing means and frequency-converts a high-frequency signal between the first frequency band and a second frequency band that is a frequency band higher than the first frequency band. It is characterized by doing.

(2) A multi-mode radio device according to the present invention is the multi-mode radio device according to (1) above, and further includes an antenna used for radio communication of high-frequency signals in the first frequency band, and the first mode. Switching means for connecting the analog signal processing means to the antenna during radio communication of high frequency signals in the frequency band, and connecting the analog signal processing means to the frequency conversion means for radio communication of high frequency signals in the second frequency band, It is characterized by including.

(3) A multi-mode radio device according to the present invention is the multi-mode radio device according to any one of (1) and (2) above, and the radio communication of the high frequency signal in the first frequency band. Sometimes, the power supply to the frequency conversion means is cut off.

(4) In the multimode radio device of the present invention, a first antenna used for radio communication of a high frequency signal in a first frequency band, an analog signal processing circuit connected to the first antenna, and the analog A digital signal processing circuit connected to the signal processing circuit, a second antenna used for wireless communication of high-frequency signals in a second frequency band that is a frequency band higher than the first frequency band, the second antenna, and A frequency conversion circuit which is connected between the analog signal processing circuit and frequency-converts a high frequency signal between the first frequency band and the second frequency band; and the analog signal processing circuit during radio communication of the first frequency band. To the first antenna, and a switch that connects the analog signal processing circuit to the frequency conversion circuit during wireless communication in the second frequency band. And butterflies.

(5) A multi-mode radio device according to the present invention is the multi-mode radio device described in (4) above, and
The frequency conversion circuit frequency-converts a high-frequency reception signal of the second frequency band received by the second antenna into a high-frequency reception signal of the first frequency band, and outputs the down-converter to the analog signal processing circuit; An up-converter for inputting the high-frequency transmission signal in the first frequency band from the analog signal processing circuit, converting the frequency into the high-frequency transmission signal in the second frequency band, and outputting the high-frequency transmission signal to the second antenna; And a frequency synthesizer connected to the converter.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of a multimode radio device according to an embodiment of the present invention. As shown in the figure, the multi-mode radio of this embodiment includes a software radio wideband analog section 101 and a software radio digital section 102. In FIG. 1, the same functional blocks as those used in FIG. 3 are designated by the same reference numerals.

Wideband analog section 1 for software defined radio
01 through 2GH via one connection end of the switch 10.
The z-band antenna 104 is connected. Further, the high frequency conversion unit 1 is connected to the analog unit 101 via the other connection end of the switch 10 and the switch 11. A 5 GHz band antenna 105 is connected to the high frequency converter 1.

The high frequency converter 1 is, as shown in FIG. 1, a low noise amplifier (LNA).
2. Reception pass filter (Band Pass Filter: B)
PF) 3, down converter 4, power amplifier (Power
Amplifier: PA) 5, a transmission band pass filter 6, an up converter 7, and a frequency synthesizer 8.

The high frequency converter 1 converts the frequency of a high frequency received signal in the 5 GHz band or the like input from the antenna 105 during reception to a frequency that can be handled by the broadband analog unit 101 for software radio of 2 GHz or less. On the other hand, at the time of transmission, the high frequency transmission signal of 2 GHz or less generated in the wide band analog unit 101 for software defined radio is frequency-converted into the 5 GHz band or the like so that it can be transmitted from the antenna 105.

In a system using a high frequency such as 5 GHz (for example, IEEE 802.11a), the main purpose is high-speed data transmission and the bandwidth per channel is 20.
It is about MHz. In addition, in order to avoid the influence of multipath fading, a multicarrier transmission method such as OFDM (Orthogonal Frequency division multiple) is used.
x) etc. are generally used.

The bandwidth of about 20 MHz is strangely almost the same as the total bandwidth used in the land mobile communication system such as a mobile phone. This is shown in FIG.
As can be seen from the comparison between (b) and (b), the characteristics of the analog part required for transmission and reception of high-speed multicarrier transmission technology (b)
And the characteristics (a) of the analog part disclosed in software radio technology and the like (see, for example, Japanese Patent Application Laid-Open No. 11-317777), that is, when the band is collectively analog-selected and the channel is digitally selected. The characteristics of the analog part of are very similar except for the carrier frequency.

The present invention has been made by paying attention to this point, and the wideband analog section 1 used for the software defined radio is provided.
01, 5GH to absorb the difference in carrier frequency
Only by adding a high frequency frequency conversion unit 1 for converting a high frequency such as z band to a frequency of 2 GHz band or less,
It is possible to easily add another frequency to a conventional radio unit for a multi-mode mobile communication terminal.

The operation of the multimode radio device of this embodiment will now be described.

First, when the 5 GHz band wireless LAN or the like is used, the switch 10, so that the high frequency converter 1 is connected to the broadband analog section 101 for the software defined radio.
11 is set. At this time, the 2 GHz band antenna 10
4 is invalid.

Here, the 5 GHz band (for example, 5.15 GHz to 5.25 GHz) is used for wireless communication,
The bandwidth per channel is 20 MHz. That is, there are a total of 5 channels in a 100 MHz width of 5.15 GHz to 5.25 GHz.

In the present embodiment, for convenience of description, these channels are sequentially arranged from the low frequency side to 1 channel (center frequency 5.16 GHz), 2 channels (center frequency 5.18 GHz) ,. ． ． , 5 channels (center frequency 5.24 GHz).

Wideband analog section 1 for software defined radio
01 is, for example, 1895MH used in PHS
It is assumed that the setting is such that transmission / reception of z to 1915 MHz is possible.

First, when transmitting and receiving using one channel, the center frequency of 5.
The high frequency reception signal of 16 GHz ± 10 MHz is amplified by the LNA 2 to an appropriate electric power, the unnecessary frequency component is removed by the BPF 3, and then the down converter 4 performs frequency conversion. At this time, the frequency synthesizer 8
The oscillation frequency f1 is set to 3255 MHz, and the received signal is frequency-converted into a signal of 1905 MHz ± 10 MHz.

This signal is output from the high frequency converter 1 and is supplied to the software analog wideband analog unit 101 via the switches 10 and 11. The wideband analog unit 101 frequency-converts the signal from the high-frequency converter 1 into a baseband. The obtained baseband signal is further converted into a digital signal by A / D conversion and subjected to predetermined demodulation processing and the like by the digital section 102 to obtain an original signal.

In the case of transmission, signal processing is carried out in the reverse order of reception. That is, the transmission signal generated by the digital unit 102 is converted into an analog signal by the wideband analog unit 102, and further, 1905 MHz ± 10 MHz.
Frequency is converted to the signal of. This transmission signal is converted into a 5.16 GHz 1-channel signal by the high frequency converter 1, and is radiated from the antenna 105.

Similarly, by setting the oscillation frequency of the frequency synthesizer 8 to f2 = 3275 Mz,
The received signal of 2 channels centered on 5.18 GHz is 1
The frequency is converted to 905 ± 10 MHz.

As described above, the broadband analog section for software defined radio 101 performs the baseband processing of the multichannels of OFDM in the same manner as the PHS collectively downconverts the signals of a plurality of channels to the baseband. Convert to signal. In addition, the software defined radio digital unit 102 similarly performs a demodulation operation based on the baseband signal converted into a digital signal.

On the other hand, when operating in the 2 GHz band wireless communication, 2
The switches 10 and 11 are arranged so that the GHz antenna 104 is connected to the broadband analog unit 101 for software defined radio.
Is set. At this time, the 5 GHz band antenna 105 is invalid. Here, it is preferable to cut off the power supply to the high-frequency frequency conversion unit 1 because power saving can be achieved.

In the multi-mode radio device of the present embodiment described above, a radio unit which has conventionally required to have two or more systems is added to the wide band analog unit 101 with an additional circuit block for high frequency conversion which has a relatively simple structure. It is possible to make one system by itself, and it is possible to easily realize a system that can use a high frequency such as 5 GHz with a simple configuration. Therefore, the multi-mode portable wireless terminal has a large number of effects in downsizing, weight reduction, and cost reduction.

The present invention is not limited to the above-mentioned embodiment and can be variously modified and carried out. For example, in the above-described embodiment, the case where OFDM is performed has been described, but the present invention is not limited to this. It goes without saying that the bandwidth of one channel is not limited to 20 MHz.

[0042]

As described above, according to the present invention,
It is possible to provide a multi-mode wireless device that can perform wireless communication in a high frequency band with a simple configuration without increasing the circuit scale.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a multi-mode radio device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a high-frequency wireless band (2 GHz PHS and 5 GHz multi-carrier system).

FIG. 3 is a diagram showing a schematic configuration of a multi-mode radio device according to a conventional example.

[Explanation of symbols]

1 ... High frequency converter 2. Low noise amplifier (LNA) 3 ... Bandpass filter for reception (BPF) 4 ... Down converter 5 ... Power amplifier (PA) 6 ... Bandpass filter for transmission (BPF) 7 ... Upconverter 8 ... Frequency synthesizer 10, 11 ... Switch 101 ... Broadband analog section for software defined radio 102 ... Software radio digital section 104 ... 2 GHz band antenna 105 ... 5 GHz band antenna

Claims (5)

[Claims] 1. An analog signal processing means for processing a high frequency signal in a first frequency band as an analog signal, a digital signal processing means for processing a high frequency signal in the first frequency band as a digital signal, and an analog signal processing means connected to the analog signal processing means. And a frequency conversion means for frequency-converting a high-frequency signal between the first frequency band and a second frequency band which is a higher frequency band than the first frequency band. . 2. An antenna used for wireless communication of a high frequency signal in the first frequency band, and an analog signal processing means connected to the antenna during wireless communication of a high frequency signal in the first frequency band,
The multi-mode radio device according to claim 1, further comprising: a switching unit that connects the analog signal processing unit to the frequency converting unit during wireless communication of a high frequency signal in a frequency band. 3. The multi-mode radio device according to claim 1, wherein power supply to the frequency conversion means is cut off during radio communication of the high frequency signal in the first frequency band. . 4. A first antenna used for wireless communication of a high frequency signal in a first frequency band, an analog signal processing circuit connected to the first antenna, and a digital signal processing connected to the analog signal processing circuit. A circuit, a second antenna used for wireless communication of a high-frequency signal in a second frequency band, which is a frequency band higher than the first frequency band, and a circuit connected between the second antenna and the analog signal processing circuit. A frequency conversion circuit that frequency-converts a high-frequency signal between the first frequency band and the second frequency band, and the analog signal processing circuit is connected to the first antenna during wireless communication in the first frequency band, A switch that connects the analog signal processing circuit to the frequency conversion circuit during wireless communication in the second frequency band, the multimode wireless device. 5. The frequency conversion circuit frequency-converts a high frequency reception signal of the second frequency band received by the second antenna into a high frequency reception signal of the first frequency band and outputs the high frequency reception signal to the analog signal processing circuit. A down converter, and an up converter that inputs the high frequency transmission signal of the first frequency band from the analog signal processing circuit, converts the frequency of the high frequency transmission signal of the second frequency band into the high frequency transmission signal, and outputs the high frequency transmission signal to the second antenna. The multi-mode radio according to claim 4, further comprising: a frequency synthesizer connected to the down converter and the up converter.