JPH099348A - Mobile body communication terminal equipment - Google Patents

Abstract

PURPOSE: To use a mobile body communication terminal equipment connected to a general telephone line network via a common radio base station even when the mobile body is moved at a high speed over a wide range and to reduce the communication cost for the use as much as possible. CONSTITUTION: The terminal equipment is provided with a 1st radio terminal equipment function of connecting to a general telephone line network 100 as a terminal equipment through radio connection to a PHS radio base station 103, a 2nd radio terminal equipment function of connecting to the line network 100 as a terminal equipment through radio connection to a PDC radio base station 104, and a function changeover control means 205 switching the 1st radio terminal equipment function or the 2nd radio terminal equipment function to select the 1st or the 2nd radio the network 100 as a function at need. Thus, one set of the terminal equipment 200 uses communication by comparatively low cost by means of the PHS or communication by comparatively high cost by means of the PDC as reqiored.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique effective when applied to a mobile communication terminal, and further to a mobile phone terminal which is connected (linked) to a wired general telephone network via a wireless transmission line. Therefore, the present invention relates to a technique effectively used for a terminal of, for example, a personal handyphone system (hereinafter, referred to as PHS) or a personal digital cellular system (hereinafter, referred to as PDC).

[0002]

2. Description of the Related Art As a mobile communication terminal, so-called mobile phone terminal, which is wirelessly connected to a general telephone network, a PHS terminal adapted to PHS, which is constructed assuming use in a relatively narrow area, There is a PDC terminal that is compatible with a PDC built assuming use in a relatively large area (for example, "Nikkei Electronics 1" published by Nikkei BP).
See the September 12, 1994 issue (no. 617), pp. 71-96 <Special feature: Mobile phone packaging technology competing for weight reduction and price reduction>.

Both the PHS terminal and the PDC terminal are connected to a general telephone line via radio wave propagation from the nearest base station among a large number of joint radio base stations forming a so-called cell, which is a radio service zone of a predetermined area. Connected to the net.

In this case, the PHS terminal is
With a relatively small wireless output (for example, 10 mW), the same carrier frequency is used for transmission and reception in a time-divisional manner, so that two-way wireless communication (duplex communication) in a relatively small moving area can be realized. It has a wireless terminal function.

On the other hand, the PDC terminal has a relatively large radio output (for example, several hundred mW to several W) for the base station, and relatively different carrier frequencies are used for transmission and reception. It has a wireless terminal function that enables two-way wireless communication in a wide moving area.

[0006]

However, it has been clarified by the present inventors that the above-described technology has the following problems.

That is, in the PHS, since the radio service area covered by one base station, that is, the area of a cell is small, it is not suitable for use while moving in a wide range at high speed. However, the fact that the cell area is small has the advantage that the restriction on frequency resources is small and the number of usable terminals per unit area can be increased. Although the number of base stations is large due to the small cell area, the size of each base station can be greatly simplified, and it does not take up much space, such as in a building or underground mall. It can be installed easily, and low communication cost (call charge) can be realized. Furthermore, since the transmission frequency and the reception frequency are the same, wireless communication between PHS terminals is also possible.

Contrary to the PHS, the PDC has a large radio service area covered by one base station, that is, a cell area, so that it can be used while moving in a wide range at high speed. . However, the wide area of the cell has a disadvantage that the number of usable terminals per unit area cannot be large because the restriction on frequency resources is large. Further, since the cell area is large, the number of base stations to be arranged can be small, but the scale of each base station becomes large, and thus the communication cost becomes considerably higher than that of PHS. Further, since the transmission frequency and the reception frequency are different, wireless communication between PDC terminals cannot be performed.

As described above, the PHS can use the terminal at a relatively low communication cost, but there is a problem that the PHS cannot be used when moving in a wide range at high speed, while the PDC has a wide range. It can be used even when moving at high speed, but there is a problem that the communication cost becomes high.

An object of the present invention is to enable a mobile communication terminal connected to a general telephone network through a common radio base station to be used even when moving at a high speed in a wide range. It is an object of the present invention to provide a technique that enables the communication cost associated with use to be reduced as much as possible.

The above and other objects and characteristics of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0012]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, the first wireless terminal function of connecting as a terminal to the general telephone line network by wirelessly connecting to the PHS wireless base station and the terminal to the general telephone line network by wirelessly connecting to the PDC wireless base station. Connect as second
And a function switching control means for switching between the first wireless terminal function and the second wireless terminal function.
The wireless terminal function and the second wireless terminal function are switched and used as needed.

[0014]

According to the above-mentioned means, with one terminal,
It is possible to selectively use relatively low cost communication by PHS and relatively high cost communication by PDC as needed.

Thus, the mobile communication terminal connected to the general telephone line network through the common radio base station can be used even when moving in a wide range at high speed, and accompanying the use thereof. The object of being able to reduce communication costs as much as possible is achieved.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same reference numerals denote the same or corresponding parts.

FIG. 1 shows an embodiment of a mobile communication terminal to which the technique of the present invention is applied. 100 is a general telephone line network, 101 is a fixed telephone terminal, and 102 is a base unit of a cordless telephone. 103 is a PHS joint radio base station (first type radio base station), 104 is a PDC joint radio base station (second type radio base station), and 200 is a mobile communication terminal according to the present invention. A mobile phone terminal, 11 is an antenna for wireless transmission / reception, and L is a telephone line.

Here, the base unit 102 of the cordless telephone is a telephone subscriber who personally installs it at home.
It is compatible with the joint radio base station 203 for PHS.

The mobile phone terminal 200 includes a wireless communication execution unit 2
01, a PHS mode execution unit 202, a PDC mode execution unit 203, a monitor unit 204 for detecting the electric field strength of a wireless reception signal, and a mode switching control unit 205, and a PHS terminal function (first wireless terminal function). The PDC terminal function (second wireless terminal function) can be switched and set as necessary.

The radio communication execution unit 201 is operated as a low output radio transmission means when the PHS terminal function is set, and is operated as a low output radio transmission means when the PDC terminal function is set.

The radio terminal functions of PHS and PDC respectively transmit and receive digitized call signals to and from other mobile communication terminals via a radio transmission line shared by time division multiplexing. Equipped with multiple circuits.

The PHS terminal function is implemented by the wireless communication execution unit 201.
And the PHS mode execution means 202. PD
The C terminal function is formed by the wireless communication execution unit 201 and the PDC mode execution unit 203. That is, the PHS terminal function and the PDC terminal function share a part of the circuit for realizing the function.

In the PHS terminal function, the same carrier frequency fo is used for transmission and reception in a time-division manner with a relatively low radio output (10 mW), so that it is premised on bidirectional radio communication in a relatively narrow area. The PHS mode (first communication mode) is executed. In the PDC terminal function, two-way wireless communication in a relatively wide area can be performed by using carrier frequencies f1 and f2 which are different from each other for transmission and reception with a relatively large wireless output (several hundred mW to several W). The presumed PDC mode (second communication mode) is executed.

The mode switching control means 205 automatically switches and sets each mode according to a predetermined priority order based on the electric field strength of the radio reception signal detected by the monitor section 204. That is, the first selection mode for wireless connection in the PHS mode to the private base unit 102 connected to the general public telephone network 100 as a terminal, and the second selection mode for the wireless connection to the public PHS wireless base station 103 in the PHS mode. The selection mode and the third selection mode for wirelessly connecting to the public PDC radio base station 104 in the PDC mode are set in the first, second, and third priorities based on the received electric field strength of the radio signal from the base station. Switch setting.

FIG. 2 is a flowchart showing the procedure for automatically switching the communication mode described above. As shown in FIG. 2, the communication mode is selected by giving priority to the PHS mode, which has a low communication cost, and the communication is performed. The costly PDC mode is selected only when wireless connection in the PHS mode is not possible.

As described above, the PHS can be operated by one terminal.
A mobile communication terminal connected to a general telephone line network through a shared radio base station can be used in a wide range by selectively using the relatively low-cost communication by PDC and the relatively high-cost communication by PDC as necessary. While it can be used even when moving at high speed, it is possible to reduce the communication cost associated with its use as much as possible.

FIG. 3 shows a system comparison between the above-mentioned PHS mode and PDC mode.

FIG. 4 shows an example of cell arrangement states in the PHS mode and PDC mode, respectively.
Indicates a PHS cell, and Zb indicates a PDC cell.

FIG. 5 shows an example of communication frame configurations in the PHS mode and PDC mode.

In the PHS mode, as shown in FIG. 5A, one carrier frequency fo is on the time axis, four receiving slots R1, R2, R3, R4 and four transmitting slots T1, T2. T3 and T4 are set, and a set of transmission / reception slots Rx and Tx (R1 and T1, R2 and T2, R3 and Tx).
By allocating one bidirectional communication channel to each of R3 and R4, T4), one carrier frequency fo can be multiplexed and used simultaneously by a maximum of four PHS terminals in the same cell.

In the PDC mode, as shown in FIG. 5B, the carrier frequency is the reception frequency (transmission frequency from the base station to the terminal) f1 and the transmission frequency (transmission frequency from the terminal to the base station) f2. , And three slots R1, R2, R3 and T1, T2, T3 are set on the time axis of each frequency f1, f2, and each transmission / reception slot Rx, T
By assigning one bidirectional communication channel to each of the x groups (R1 and T1, R2 and T2, R3 and T3), two carrier frequencies f1 and f2 can be simultaneously used by up to three PDC terminals in the same cell. It can be used multiple times.

In this case, in the PHS mode, since the receiving slot Rx and the transmitting slot Tx are set to the same carrier frequency fo, the slots R1, R2, R3, R4 and T4 are set.
It becomes necessary to match the timing Tp between 1, T2, T3 and T4 among a plurality of terminals. In order to match this timing, the range that one base station can cover, that is, the cell area cannot be made too large. This is because when the cell area is large, the difference in radio wave propagation time caused by the distance between the base station and the terminal causes an error in the timing Tp. Therefore, in the PHS mode, four bidirectional communication channels can be secured with one carrier frequency fo,
The cell area cannot be increased.

On the other hand, in the PDC mode, the receiving slot R
x and the transmission slot Tx are set so as to be assigned to the dedicated carrier frequencies fo and f1, respectively, so that the error of the slot timing Tp due to the propagation propagation time is not so serious, and therefore the range that one base station can cover, The cell area can be increased,
Even if two carrier frequencies f1 and f2 are used, only three bidirectional communication channels can be secured.

As described above, the PHS mode can be used only in a situation where the PHS mode does not move in a narrow range so fast, but the restrictions on the number of terminals that can be simultaneously used are loose, and the base station can be small in size, so that the cost can be reduced. Can be used.
Further, the PDC mode has a severe restriction on the number of terminals that can be used at the same time, and the base station becomes large in scale, so that the use cost is inevitably high. Instead, it can be used even in situations in which a large area is moving at high speed.

FIG. 6 shows an embodiment of the detailed configuration of the mobile communication terminal shown in FIG.

In the figure, 1 is a wireless transmission / reception unit,
Reference numeral 11 is a wireless antenna, 5 is a codec section that performs coding and decoding processing of a call signal, 6 is an operation panel, and 7 is a logic control unit configured using a microprocessor.

The wireless transmission / reception unit 1 includes a demultiplexer 12, a transmission / reception changeover switch 13, a wireless reception unit 2, and a demodulator 2.
1, a radio transmission unit 3, a modulator 31, a frequency synthesizing circuit 41 using a PLL, a time division multiplexing circuit 42, a reception electric field strength detection circuit (RSSI) 43, and the like. The wireless reception unit 2 and the wireless transmission unit 3 have PH
In order to correspond to the two types of modes, S and PDC, the reception frequency band and the transmission frequency band are switched and the transmission output level is switched between high and low. Duplexer 12
Is used to separate a reception signal from the antenna 11 and a transmission signal to the antenna 11 when transmitting and receiving are simultaneously performed with different frequencies in the PDC mode. The transmission / reception change-over switch 13 is used to switch the antenna 11 to the receiving unit 2 side or the transmitting unit 3 side at a high speed in the PHS mode when transmitting and receiving at the same frequency in a time division manner.

The codec section 5 is an ADPCM (Adaptiv) for coding / decoding a call signal in the PHS mode.
e Differential Pulse Code
Modulation) codec unit 52, VSELP (Ve) that performs coding / decoding processing of a call signal in the PDC mode.
center Sum Excited LinearPr
edition) codec section 53 and a codec switching section 51 for switching the two codecs 52 and 53 according to the PHS / PDC mode. Reference numeral 54 is a speaker for acoustically reproducing the reception signal, and reference numeral 55 is a microphone for converting the transmission sound into the transmission signal.

The logic control unit 7 incorporates a mode switching control unit 71 for performing switching setting control of the PHS / PDC mode based on the output of the reception electric field strength detection circuit 43 by software. With this mode switching control unit 71,
By switching and setting the transmission / reception frequency band and the transmission output level of the wireless transmission / reception unit 1, the selection of the codecs 52 and 53, the multiplexing method of the transmission signal and the reception signal, and the like, while sharing many parts of the circuit, the PHS terminal function And PD
The C terminal function can be switched and set.

FIG. 7 shows an embodiment of a more detailed configuration of the portion of the wireless transmission / reception unit 1 shown in FIG.

In the figure, the wireless receiving unit 2 has a P
A low noise amplifier 21 corresponding to two frequency bands fo and f1 of HS and PDC, an RF bandpass filter 22 for extracting a reception signal of a target frequency band fo or f1, a mixer 23 for frequency conversion (downverter), a frequency conversion The IF band pass filter 24 for extracting the intermediate frequency signal generated by the IF section 25 including the intermediate frequency amplification section, the second frequency conversion section and the AGC section, and the QPSK (Qua
adult Phase Shift Shift Keyin
g) The demodulator 26 and the like.

The radio transmission unit 3 includes a QPSK modulator 31, an IF section 32, an IF band pass filter 33,
Mixer 34, R for frequency conversion (upverter)
F band pass filter 35, two frequency bands fo and f2 of PHS and PDC and two types of transmission output (low output /
The high-frequency output amplifier 36 and the like correspond to the high output.

The frequency synthesizing circuit 41, based on the temperature-compensated high-precision reference frequency signal fs, local signal fxo / fx1 for frequency conversion in the receiving unit 2.
And PLL-combining the local signal fxo / fx2 for frequency conversion in the transmission unit 3.

A double balanced modulator (DBM) is used for the mixers 23 and 34 for performing frequency conversion. A part or the whole of the circuit in the transmitting / receiving unit 1 described above is 1
Alternatively, it is integrated into a plurality of semiconductor chips.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

In the above description, the case of applying the invention made by the present inventor to a mobile phone terminal which is the field of application which is the background of the invention has been mainly described, but the invention is not limited thereto and, for example, a mobile facsimile terminal. Alternatively, it can be applied to a mobile data terminal.

[0047]

The following is a brief description of an outline of typical inventions among the inventions disclosed in the present application.

That is, a mobile communication terminal connected to a general telephone network through a common radio base station can be used even when moving in a wide range at high speed.
The effect that the communication cost associated with its use can be reduced as much as possible is obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a mobile communication terminal to which the technology of the present invention is applied.

FIG. 2 is a flow chart showing a schematic operation in a part of the mobile communication terminal according to the present invention.

FIG. 3 is a table showing a system comparison of PHS mode and PDC mode included in the mobile communication terminal according to the present invention.

FIG. 4 is a diagram showing an example of cell arrangement states in PHS mode and PDC mode.

FIG. 5 is a timing chart showing an example of communication frame configurations in PHS mode and PDC mode.

FIG. 6 is a block diagram showing an example of a detailed configuration of a mobile communication terminal according to the present invention.

FIG. 7 is a block diagram showing an embodiment of a more detailed configuration of a mobile communication terminal according to the present invention.

[Explanation of symbols]

100 general telephone line network 101 fixed telephone terminal 102 parent device of cordless telephone 103 wireless base station of PHS (first type wireless base station) 104 wireless base station of PDC (second type wireless base station) 200 Mobile phone terminal which is a mobile communication terminal by 11 Antenna for wireless transmission / reception L Telephone line fo Transmission / reception frequency (PHS mode) f1 Reception frequency (PDC mode) f2 Transmission frequency (PDC mode) 1 Radio transmission / reception unit 11 Antenna 12 Duplexer 13 transmission / reception switch 2 wireless reception unit 21 low noise amplifier 22 RF bandpass filter 23 mixer 24 IF bandpass filter 25 IF section 26 QPSK demodulator 3 wireless transmission unit 31 QPSK modulator 32 IF section 33 IF bandpass filter 34 mixer ( Upverter ) 34 35 RF band pass filer 36 High frequency output amplifier 41 Frequency synthesizer circuit 42 Time division multiplexing circuit 43 Received field strength detection circuit (RSSI) 5 Codec section 51 Codec switching section 52 ADPCM codec section 53 VSELP codec section 54 Acoustic sound reception signal Speaker for playback 55 Microphone for transmission 7 Logic control unit 71 Mode switching control section

Claims (7)

[Claims] 1. A first wireless terminal function of connecting to a general telephone network as a terminal by wirelessly connecting to a first type wireless base station, and a wireless connection to a second type wireless base station. Second connection to a general telephone network as a terminal
Wireless terminal function and function switching control means for switching between the first wireless terminal function and the second wireless terminal function, and the first wireless terminal function uses the same carrier frequency in time division for transmission and reception. By doing so, the first communication mode based on the assumption of a two-way wireless call in a relatively narrow area is executed, and the second wireless terminal function uses a carrier wave frequency different from each other for transmission and reception, and thus is relatively wide. A mobile communication terminal characterized by executing a second communication mode on the premise of two-way wireless communication in an area. 2. The function switching control means has a priority control means for setting the first communication mode prior to the second communication mode, and only when the wireless connection in the first communication mode is not secured. The mobile communication terminal according to claim 1, wherein the communication mode of 2 is set. 3. The mobile communication device according to claim 1, wherein the function switching means switches the function of the wireless terminal based on the received electric field strength of the wireless signal from the base station. 4. The first wireless terminal function for executing the first communication mode and the second wireless terminal function for executing the second communication mode are mutually provided with a part of a circuit for realizing the function. The mobile communication terminal according to claim 1, wherein the mobile communication terminal is shared. 5. The function switching control means includes a first selection mode for wirelessly connecting in a first communication mode to a private base unit connected to a general public telephone network as a terminal, and a wireless base station of a first type. The second selection mode for wirelessly connecting in the first communication mode and the third selection mode for wirelessly connecting to the second type wireless base station in the second communication mode are set to the reception electric field of the wireless signal from the base station. The mobile communication terminal according to any one of claims 1 to 4, wherein the mobile communication terminal is set to be switched between the first, second, and third priorities based on the strength. 6. The first wireless terminal function has a relatively low output wireless transmission means, while the second wireless terminal function has a relatively high output wireless transmission means. The mobile communication terminal according to any one of 5. 7. The first and second wireless terminal functions respectively transmit / receive a digitized call signal to / from another mobile communication terminal via a wireless transmission path shared by time division multiplexing. The mobile communication terminal according to claim 1, further comprising a time division multiplexing circuit.