JPH11284554A - Multimode radio equipment and diversity receiving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower the occurrence probability of disconnection of call when a user moves between service areas in different radio communication systems by performing diversity between a first radio communication system and a second radio communication system, when the intensity of a received signal is equal to or less than a specified reference value. SOLUTION: A signal which is transmitted from a base station of the system S1 is received by an antenna 101, and the intensity of the received signal is measured by a signal intensity measuring instrument 121. A measurement result of the signal intensity is controlled and supplied to a switch circuit 141. A line connection request is originated with respect to a base station of the system S2, when the received signal intensity becomes equal to or less than the specified reference value by the switch circuit 141. Then when the line is secured, the radio communication system is controlled so that the diversity is performed between the system S1 and S2, by validating receiving systems (e.g., a PDC reception system) corresponding to the other system S2 in addition to the system S1 (e.g., a PHS reception system) which is valid at present.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multimode radio and a diversity reception method capable of selectively receiving signals of a plurality of different types of radio communication systems in the field of mobile communication.

[0002]

2. Description of the Related Art At present, various types of wireless communication systems are present in a mixed state. For example, even when attention is paid only to domestic land mobile communication, the difference between the analog system and the digital system, as well as the frequency band used, is considered. There are many types and types of wireless communication systems with different assignments.

[0003] Under such circumstances, recently, there has been an increasing demand for a multi-mode radio capable of selectively transmitting and receiving signals of a plurality of radio communication systems with one terminal. For example, the European cellular system G
SM (Global System for Mobile) and DCS-1800
(Digital Cellular System 1800) multi-mode radios and the like are known. The background of the emergence of such multi-mode radios is not only the miniaturization and cost reduction of radios due to the progress of LSI technology, but also the communication by using service areas individually covered by a plurality of radio communication systems. Increasing the possible area is an example.

[0004]

However, in such a multimode radio, when a user who roams from one radio communication system to another radio communication system accidentally enters a dead zone, the position of the user before the movement is changed. There is a problem that a call is disconnected even though the communication area is within a service area where the communication system can communicate. In addition to the dead zone, in a place where the reception intensity fluctuates with time due to fading or the like, there has been a problem that a call disconnection is likely to occur similarly.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been made in consideration of the above-mentioned problems. An object of the present invention is to provide a radio device and a diversity receiving method.

[0006]

In order to achieve the above object, a multi-mode radio according to the present invention comprises a receiving means for receiving signals of a plurality of types of wireless communication systems, and a receiving means for receiving signals of the plurality of types. First strength measuring means for measuring the strength of a signal of the first wireless communication system, second strength measuring means for measuring the strength of a signal of the second wireless communication system received by the receiving means, During reception of the signal of the wireless communication system, when the strength of the received signal measured by the strength measuring means corresponding to the one wireless communication system is equal to or less than a predetermined reference value, the first wireless communication system and the second wireless communication system are connected to each other. And diversity means for performing diversity with a wireless communication system.

As described above, the multimode radio of the present invention, when receiving a signal of one radio communication system, when the strength of the received signal of the one radio communication system falls below a predetermined reference value, Diversity between the first wireless communication system and the second wireless communication system, that is, by selecting a wireless communication system capable of ensuring better line connection and performing a process of receiving the signal, a different wireless communication is performed. When a user moves between service areas of the system, it is possible to prevent the occurrence of communication disconnection due to a dead zone or fading with a high probability.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a receiving section of a multimode radio according to a first embodiment of the present invention. This multi-mode radio is, for example, a PHS (Personal Handy-pho
ne System) and PDC (Personal Digital Cellular)
Two wireless communication systems (hereinafter simply referred to as system S1,
Called S2. ) Is supported. However, the type and number of wireless communication systems are not limited to this, and the type and number of systems to be combined can be freely changed.

As shown in FIG. 1, the multimode radio includes an antenna 101, a filter 111, a signal strength measuring device 121, and a PHS detection circuit 131 as components corresponding to the receiving system of the system (PHS) S1. Have
As components corresponding to the receiving system of the system (PDC) S2, there are an antenna 102, a filter 112, a signal strength measuring device 122, and a PDC detection circuit 132. Further, this multi-mode radio is provided with each system S1, S2
A reception mode that is made effective among three reception modes of diversity between the system S1 / system S2 / each system S1 and S2 based on the signal reception intensity measured by the signal intensity measuring devices 121 and 122 of the reception system of FIG. Is provided with a control and switch circuit 141 for switching between.

Next, the receiving operation of the multi-mode radio will be described with reference to the flowchart of FIG.

The multimode radio of the present embodiment has a PH
Communication between two wireless communication systems S1 and S2 of S and PDC is possible, and in a normal reception mode, for example, only a PHS reception system corresponding to the system S1 is activated.

The signal transmitted from the base station of the system S1 is received by the antenna 101 (step 11), a signal of a desired channel is extracted from the received signal by the filter 111, and the signal strength measuring device 121 and the PHS detection circuit are used. 13
1 respectively. The received signal is detected and demodulated by the PHS detection circuit 131 and output as a signal that has been subjected to reception processing by the multi-mode radio through the switch circuit 141.

On the other hand, the signal strength measuring device 121
1 is measured (step 12), and the measurement result is supplied to the control and switch circuit 141. The control and switch circuit 141 determines that the received signal strength I1 is equal to or less than a predetermined reference value X1 when the user moves out of the service area of the system S1 or when the user enters a dead zone in the service area (step S1). 1
3) Call a line connection request to the base station of the system S2 (step 14), and if a line is secured, a receiving system corresponding to the other system S2 in addition to the currently effective system S1 (for example, PHS receiving system) (For example, a PDC receiving system) is enabled, and control is performed so as to perform diversity between the systems S1 and S2 (step 15).

The diversity between the two systems S1 and S2 is compared by comparing the respective signal intensities I1 and I2 measured by the signal intensity measuring devices 121 and 122 of the respective receiving systems (steps 16 and 17). This is performed by selecting a signal detected and demodulated by the detection circuit 131 or 132 of the higher system by the switch circuit 141 (steps 18 and 19).

When the signal of the system S2 is selected, the filter 11
At 2, the signal corresponding to the desired channel is selected and introduced to the signal strength measuring device 122 and the PDC detection circuit 132, respectively. The received signal is demodulated by the PDC detection circuit 132, and the demodulated signal is output through the switch circuit 141. Even when only the receiving system corresponding to the system S2 is valid, the received signal strength is measured by the signal strength measuring device 122, and the measurement result is transmitted to the control and switch circuit 141.
Will be introduced. When the intensity I2 of the received signal of the system S2 becomes equal to or less than the reference value X2, the control and switch circuit 141 simultaneously activates the receiving system of the other system S1 in addition to the currently valid receiving system of the system S2. As a result, diversity reception is performed between the two systems S1 and S2 as described above.

As described above, in the multimode radio of the present embodiment, the strength of the received signal of one radio communication system is monitored, and when the value of the received signal falls below a predetermined reference value, the other radio communication system is monitored. And the receiving system of the currently effective system is enabled to perform diversity reception between the two systems. Accordingly, when the user moves between service areas of a plurality of wireless communication systems, for example, when the position in the service area of the destination system is in a dead zone, a signal is received by the reception system corresponding to the source system. Since the call can be received, a call disconnection does not occur.

Note that the signal strength measuring devices 121 and 122 corresponding to the respective systems S1 and S2 may be arranged at the subsequent stage of the corresponding detection circuits 131 and 132, respectively.

As shown in FIG. 3, the diversity reception between the two systems S1 and S2 is based on the minimum reception sensitivities A1 and A1 at which the permissible communication quality is guaranteed in the reception systems corresponding to the respective systems S1 and S2. The difference D1, D2 between A2 and the measured received signal strengths I1, I2 of the source system.
A comparison may be made (step 27), and the demodulated signal of the system having the larger difference may be selected (steps 28 and 29). The magnitude of the difference between the minimum receiving sensitivity and the received signal strength almost corresponds to the communication quality, and when the demodulated signal on the system side with the larger difference is selected, the judgment is made based only on the magnitude of the received strength. , Better communication quality can be obtained, and more effective diversity reception can be realized.

For example, if the received signal strength of the PHS is -50d
When the received signal strength of Bm and PDC is -55 dBm, the minimum receiving sensitivity of PHS that can obtain the allowable communication quality is-
Assuming that the minimum receiving sensitivity of 97 dBm and PDC is -116 dBm, the difference D is 47 dB in PHS, P
The DC becomes 61 dB, and PDC is selected.

In the above embodiment, the diversity reception period between the two different systems S1 and S2 is:
The case of selecting the signal of the system with the higher received signal strength for the purpose of preventing a call disconnection has been described. However, in order to reduce the system usage fee borne by the user, the system with the lower usage fee is selected. May be selected.

Further, from the viewpoint of service treatment for the subscriber, a system of a specific provider may be preferentially selected, and the system may be switched to another system only when the system cannot cope.

Next, a multi-mode wireless device according to a second embodiment of the present invention will be described.

FIG. 4 shows the configuration of the receiving section of the multimode radio of the second embodiment. As shown in the figure, the multi-mode wireless device includes a wideband antenna 201 that covers a frequency band of a plurality of wireless communication systems, for example, PHS and PDC systems.

At the time of diversity reception of each wireless communication system, signals of both systems are received by the wideband antenna 201. The signals of both systems received by the wideband antenna 201 are introduced into bandpass filters 211 and 212 having a pass bandwidth corresponding to the frequency band used by each system, and the signals of each system are output from the bandpass filters 211 and 212. Are separated and extracted.

The subsequent operation is the same as in the first embodiment. That is, the signals passing through the bandpass filters 211 and 212 are introduced into signal strength measuring devices 221 and 222, respectively, where the signal strength is measured.
The signals are introduced into the detection circuits 231 and 232 and detected and demodulated. Each demodulated signal is output through a switch circuit 241 that is switched based on the result of the received signal strength measurement obtained by the signal strength measuring devices 221 and 222 corresponding to each system.

The multi-mode radio of the present embodiment has an effect that the same effect as that of the first embodiment can be obtained with one broadband antenna, and the radio device can be downsized. produce.

Next, an example of a method for switching diversity reception in the above embodiment will be described.

In FIG. 5, the wireless communication system before switching is S1, and the wireless communication system after switching is S2. Also, C _{i, k} and U _{i, k} are respectively the system S
1, the k-th reception channel slot of the i-th user in S2. It is assumed that the signal strength of the received signal decreases on average during reception of the signal of the system S1, and a system switching request occurs at the timing of C1 _{, k} .
In this case, since the timing of the C _{1, k} of the signal system S1 overlaps the receiving slot U _{1, m} of the m-th idle channel U ₁ connection schedule circuit system S2, use the guard time of the system S2 Then, the system is switched, and the communication of the system S2 is started from the slot U1 _{, m + 1} .

In such a case, in the multimode radio of this embodiment, the system is switched after the reception of the slot C _{1, k + 1} of the system S1 immediately before U _{1, m + 1} is completed. The communication of S2 is started. As a result, it is possible to smoothly perform system switching without generating switching noise that occurs at the time of diversity switching.

In the multimode radio shown in FIG. 4, the bandpass filters 211 and 212 or the detection circuit 2
The parts after 31 and 232 are not limited to those having a circuit configuration composed of a combination of passive elements and active elements.
It may be configured by a radio device in which a function equivalent to software is incorporated in a digital signal processing circuit such as a P (Digital Signal Processor). When such a software defined radio is used, there is an advantage that it can be applied to various wireless communication systems only by rewriting software in the DSP.

[0032]

As described above, according to the present invention,
During reception of a signal of one wireless communication system, when the strength of the received signal of the one wireless communication system falls below a predetermined reference value, or when the strength of the measured received signal and the inherent minimum receiving sensitivity are different. When the difference is equal to or less than a predetermined reference value, diversity between the first wireless communication system and the second wireless communication system, that is, a wireless communication system capable of securing a better line connection is selected. By performing the signal receiving process, it is possible to prevent with high probability the occurrence of communication disconnection due to a dead zone or fading when the user moves between service areas of different wireless communication systems.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a receiving unit of a multimode wireless device according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a receiving operation of the multi-mode wireless device of FIG. 1;

FIG. 3 is a flowchart showing another receiving operation of the multi-mode wireless device in FIG. 1;

FIG. 4 is a diagram illustrating a configuration of a receiving unit of a multimode wireless device according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a switching method in diversity reception according to the present invention.

[Explanation of symbols]

 101, 102 Antenna 111, 112 Filter 121, 122 Signal Strength Measuring Device 131 PHS Detection Circuit 132 PDC Detection Circuit 141 Control and Switching Circuit

Claims (4)

[Claims] A receiving unit that receives signals of a plurality of types of wireless communication systems; a first strength measuring unit that measures the strength of a signal of the first wireless communication system received by the receiving unit; Second strength measuring means for measuring the strength of the signal of the second wireless communication system received by the receiving means; and strength measurement corresponding to the one wireless communication system while receiving the signal of the one wireless communication system. And diversity means for performing diversity between the first wireless communication system and the second wireless communication system when the strength of the received signal measured by the means is equal to or less than a predetermined reference value. Multimode radio. 2. The multi-mode radio according to claim 1, wherein said diversity means selects one of the radio communication systems based on the strength of each received signal measured by said strength measuring means. Multi-mode radio. 3. The multi-mode radio according to claim 1, wherein said diversity means is configured to determine a difference between a strength of each received signal measured by said strength measuring means and a minimum receiving sensitivity specific to a system. A multi-mode radio, wherein one radio communication system is selected. 4. A diversity receiving method for a multi-mode wireless device for selectively receiving signals of a plurality of types of wireless communication systems, the method comprising: receiving a signal from one of the wireless communication systems; measuring a strength of the received signal; A diversity receiving method for a multi-mode wireless device, comprising: performing diversity between the plurality of wireless communication systems when the measured signal strength is equal to or less than a predetermined reference value.