JP2003092782A - Communication apparatus and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication apparatus and method capable of conducting stable data communication at all times. SOLUTION: The communication device is provided with a transmission reception circuit compatible with the cdma2000 Ix-EV DO system and a transmission reception circuit compatible with the cdma2000 Ix system. When a state of a reception data rate reaching a preset threshold value or below is consecutive for a prescribed period in the case of communication with the cdma2000 Ix-EV DO system, a CPU 7 conducts processing of selecting the communication adopting the cdma2000 Ix system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device and communication having a transmission / reception function corresponding to a plurality of communication systems and performing communication by any one of the communication systems according to the information on the amount of data received within a predetermined period. Regarding the method.

[0002]

2. Description of the Related Art Recently, as a next-generation high-speed wireless communication system
The cdma2000 1x-EV DO method is known. Cdma2000 above
1x-EV DO method is an extension method of cdma2000 1x method, HDR
As a standardized method of (High Data Rate) method, Std.T-64 1S-2000 CS0024 “cdma2 in the radio industry ARIB
000 High Rate Packet Data Air Interface Specificat
standardized by "ion." ARIB T-53 is expanded in Japan, EIA / TIA / IS-95 is expanded in North America, South Korea, etc., and the cdma2000 1x method compatible with the third generation method (3G) is further added. This is a method that aims to improve the communication speed by specializing in data communication.In the cdma2000 lx-EV DO, EV is Evo.
Solution and DO mean Data only.

In the cdma2000 1x-EV DO system, the radio wave condition of the terminal is good by switching the modulation system of the data transmitted to the terminal by the base station based on the information for notifying the radio wave condition received from the mobile terminal. It is possible to use a high data transmission rate with low error resilience when it is low, and a low data transmission rate with high error resilience when the radio wave condition is bad.

Further, in the downlink direction of the cdma2000 1x-EV DO system (direction from the base station to the mobile terminal), the time is divided in units of 1/600 seconds, and communication with only one mobile terminal is performed within that time. It employs time division multiplex access (TDMA), which performs communication with a plurality of mobile terminals by switching the mobile terminals of the communication partner according to time. As a result, it is possible to perform data transmission with optimum power to each mobile terminal, and it is possible to maximize the data communication speed for the mobile terminal.

[0005]

By the way, the above-mentioned cd
The ma2000 1x-EV DO system has the characteristic that the reception state fluctuates significantly depending on environmental conditions. That is,
Radio wave condition (eg received field strength, carrier to interference ratio = CI
In a place with good R), high-speed communication of up to 2.4 Mbps can be realized, but in a place with poor reception, there is a drawback that the communication speed drops to about several tens of kbps. Therefore, in a place where the reception condition is good, downloading of a relatively large amount of data can be completed comfortably in a short time, whereas the radio wave condition is poor and only a low downlink data communication speed can be obtained. If the download of a relatively large amount of data is started in such a situation, it will take a long time to finish the data download, and there has been a problem that it is not possible to provide an environment in which users can perform sufficient services. . Further, in this case, the communication time becomes long and the communication cost becomes high.

[0006] Further, when receiving a service such that moving image data and music data are played back in parallel (streaming playback of moving image and music) while downloading the moving image data and music data, the downlink data of a predetermined value or more is usually used. Communication speed is required, but at this time, if the required downlink data communication speed is not obtained, it may be affected by deterioration of image quality and sound quality, video stop, sound interruption, etc. There was a problem that quality could not be obtained.

[0007] On the other hand, when there are a plurality of other communication devices having a better radio wave condition than the own station in spite of the good radio wave condition described above, these other communication devices are used. Since the channel capacity for data transmission is preferentially assigned to the device, the relatively low data rate continues. In such a case, even though the display screen of the mobile terminal indicates that the radio wave condition is good, it is not possible to receive the data as expected, which gives the user a feeling of distrust. There was also the problem that it could happen.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a communication device and a communication method capable of always performing stable data communication. Specifically, the cdma2000 1x-EV DO system capable of high-speed data communication specialized for the above-mentioned data communication and the above-mentioned cdma2000 1
Equipped with a transmitter / receiver circuit compatible with the x system, cdma2000 1x-EV
In data communication by the DO method, when the information related to the amount of data received within the predetermined period remains below the predetermined threshold for a predetermined period, the communication method is switched to the cdma2000 1x method to ensure stable data communication. Provided are a communication device and a communication method capable of performing the communication.

[0009]

In order to achieve the above-mentioned object, the present invention provides a communication device comprising a plurality of transmitting / receiving means respectively corresponding to a plurality of different communication systems, and performing communication by any of the communication systems. , A communication method selecting means for selecting one of the communication methods based on information about the amount of data received within a predetermined period, and when the selected communication method is different from the communication method currently adopted, A transmission control means for instructing a base station whose line is currently established to transmit information for switching to the selected communication method, and a base station corresponding to the selected communication method from the base station. There is provided a communication device comprising: a switching unit that switches to a transmission / reception unit corresponding to the selected communication method when information is received.

According to this invention, any one of the communication methods installed on the basis of the information relating to the amount of data received within a predetermined period is selected, and communication is performed by the selected communication method. I do. Thus, instead of selecting the communication method to be adopted based on the radio wave condition, by selecting the communication method based on the information related to the amount of data actually received within a predetermined period (for example, the received data rate). , For example, even though the radio wave condition is good, there are multiple communication devices that have better radio wave conditions than the local station, so channels are assigned to these other communication devices, and the data Since this state can be exited even in a state in which the communication cannot be received, it is always possible to accurately grasp whether or not the optimal communication is being performed by the currently adopted communication method. This makes it possible to always provide stable data communication with a certain quality or higher.

The invention described in claim 2 is the same as claim 1.
In the communication device according to, the one communication wireless system is
The downlink data communication speed is predicted on the terminal side based on the reception state of the signal from the base station in the terminal, and the predicted downlink data communication speed is notified by the base station by notifying the base station of the predicted downlink data communication speed. In the case of adopting the data communication method, the wireless communication method selecting means, when the data communication method is adopted, the information regarding the amount of data received within the predetermined period is equal to or less than a preset threshold value. Is continued for a predetermined period (a second predetermined period T (ms) in an embodiment described later), the communication mode is switched to another communication system.

According to this invention, when data communication is performed, the cdma2000 1x-EV DO method, which can realize the highest data rate as one communication method, is preferentially applied to the cdma2000 1x- Comfortable data communication is achieved with the EV DO method, and even if the amount of data received by the cdma2000 1x-EV DO method continues for a specified period of time, comfortable data communication is possible by switching to another communication method. Ensure the minimum required data communication speed for communication. As a result, it is possible to provide a communication device capable of always performing data communication of a certain quality or higher. As another communication method, by adopting a method such as cdma2000 1x method in which a predetermined wireless channel is allocated to each terminal, the channel is allocated to another terminal despite the good radio wave condition described above. Since it is possible to avoid such a situation, it is possible to continue comfortable communication while maintaining the optimum transmission rate.

Further, according to the present invention, in a communication method comprising a plurality of transmitting / receiving means respectively corresponding to a plurality of different communication systems and performing communication by any one of the communication systems, information relating to the amount of data received within a predetermined period. The step of selecting one of the communication methods based on the above, and if the selected communication method is different from the communication method currently adopted, the A step of instructing to transmit information for switching to the selected communication method, and transmitting / receiving corresponding to the selected communication method when the information of the base station corresponding to the selected communication method is received from the base station And a step of switching to a means.

Furthermore, the present invention provides a program for realizing the functions of the above-described communication device, and a computer-readable recording medium recording the program.

Further, the communication device of the present invention includes a so-called CDMA (code division multiple access) system and a PDC (Person).
In addition to mobile phones such as al Digital Cellular System), mobile terminals called PDAs (Personal Digital Assistants) are also included. Here, in the case of the PDA, even if the communication means is built-in, or if the communication means is connected from the outside, the PDA performs the calling (call-in, communication) processing, which will be described later, which is a feature of the present invention.
Those performed by the main body are included in the present invention.

[0016]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an internal configuration when a mobile phone is taken as an example of a communication device according to an embodiment of the present invention. As shown in Figure 1,
The mobile phone according to the present embodiment includes an antenna 1, a multi-reception circuit 3 including a plurality of reception circuits respectively corresponding to a plurality of different wireless communication systems, and a signal processing circuit 5 for digitally processing a signal output from the multi-reception circuit 3. , A CPU 7 for controlling each unit constituting the terminal, a multi-transmission circuit 8 including a plurality of transmission circuits respectively corresponding to a plurality of different wireless communication systems, a ROM 10 storing various programs, a RAM 11, a keypad, Operation unit 12 such as a keyboard, display unit 1 including a liquid crystal display panel, etc.
3 and the second predetermined period are set in advance, the CPU
The timer 14 is provided for counting the second predetermined period according to the instruction of 7.

The multi-reception circuit 3 is a cdma2000 1x-EV
It is equipped with two receiving circuits consisting of a receiving circuit compatible with the DO system and a receiving circuit compatible with the cdma2000 1x system,
The circuit that receives the data from the base station side is switched based on the switching signal input from the CPU 7. Similarly, the multi-transmission circuit 8 also includes two transmission circuits including a transmission circuit compatible with the cdma2000 1x-EV DO system and a transmission circuit compatible with the cdma2000 1x system, and a switching signal input from the CPU 7 Based on this, the circuit that transmits data is switched. As described above, the mobile phone according to the present embodiment includes a plurality of reception circuits and transmission circuits respectively corresponding to a plurality of different wireless communication systems, and these mobile phones are provided with these reception circuits and transmission circuits according to the amount of data received within a predetermined period. Stable data communication is secured by switching the communication method.

Various programs executed by the CPU 7 are stored in the ROM 10, and the CPU 7 stores the R program.
Various processes are performed by loading and executing the program stored in the OM 10. In addition, RAM11
Stores data and the like generated in the process executed by the CPU 7. It should be noted that an external interface (eg, serial port, parallel port, USB, blue-tooth, infrared communication, 10base-T LAN, etc.) with a personal computer (PC) is further provided so that the mobile phone can be used as a wireless modem. You may

Next, the operation of the mobile phone having the above configuration will be described. First, when the user desires to download data, the user operates the operation unit 12 to set information such as a connection destination address required for data communication and data to be downloaded. When a download instruction is issued by such an operation, the download request information is output from the operation unit 12 to the CPU 7. CPU7
When the download start request is received, the cdma2000 1x-EV is sent to the multi-reception circuit 3 and the multi-transmission circuit 8.
A switching signal for selecting the receiving circuit 31 and the transmitting circuit 81 corresponding to the DO method is output. As a result, the multi-reception circuit 3 and the multi-transmission circuit 7 are respectively cdma2000.
The 1x-EV DO system compatible reception circuit 31 and cdma2000 1x-EV DO system transmission circuit 81 are selected.

Subsequently, the CPU 7 outputs to the signal processing unit 5 information related to the download connection destination access input from the operation unit 12, download data, and the like. The information related to the download input to the signal processing unit 5 is digitally processed by the signal processing unit 5, and then cdma2000 1x-
The signal is modulated by the EV DO system compatible transmission circuit 81 based on a predetermined modulation system and transmitted via the antenna 1 to the cdma2000 1x-EV DO system compatible base station 30 (see FIG. 3) in which the line is currently established.

Here, FIG. 3 shows a network configuration diagram including the mobile phone, each base station mounted on the mobile phone corresponding to a plurality of different communication systems, and a central office switch that controls the plurality of base stations. In the figure, reference numeral 30 is a cdma2000 1x-EV DO system compatible base station whose line is currently established with the mobile phone, and reference numeral 50 is a cdma2000 1x system compatible base station existing in an area communicable with the mobile phone. is there. Further, reference numeral 70 is a central office, which controls a plurality of base stations corresponding to different wireless communication systems.

Cdma2000 1x-EV DO compatible base station 30
Upon receiving the information related to the download received from the mobile phone, the base station 30 (hereinafter, abbreviated as "base station 30") receives this information from the local exchange 70 which controls the own station (base station 30).
Send to. The central office switch 70 issues a line connection request to the access destination based on the information regarding the download received from the base station 30. Thus, if the access destination responds to the line connection request, the line between the mobile phone and the download access destination is established, and the data download is started. That is, the download data from the access destination is transmitted to the mobile phone via the central office switch 70 and the base station 30.

At this time, a pilot signal of the base station 30 (a signal indicating the radio wave state between the base station and the mobile phone) is sent to the mobile phone together with the download data from the download access destination. ) Is sent. This pilot signal is an important signal for determining the data communication speed between the mobile phone and the base station, and is transmitted from the base station 30 every 1/600 seconds in a form of being multiplexed with the download data. . The signal in which the pilot signal and the download data are multiplexed is sent to cdma20 of the multi-reception circuit 3 via the antenna 1.
00 Input to the 1x-EVDO system compatible receiving circuit 31.

Cdma2000 1x-EV DO compatible receiver circuit 31
Is a demodulation method corresponding to the modulation method of the received signal received from the base station 30, and demodulates the multiplexed signal from the received signal in the baseband. In the present embodiment, QP
SK (quadriphase phase shift keying), 8PSK
(8 phase shift keying), 16QAM (16 quadri
Demodulation is performed by any one of three types of demodulation method of phase amplitude modulation).

Then, the received data demodulated by the cdma2000 1x-EV DO system compatible receiving circuit 31 is transmitted to the subsequent signal processing circuit 5. First, the signal processing circuit 5
By despreading the spectrum-spread reception multiplexed signal received from the multi-reception circuit 3,
The pilot signal and the download data are separated, and the separated download data is decoded and output to the CPU 7.

On the other hand, the signal processing circuit 5 further obtains Ec / Io (pilot signal strength vs. total received signal strength) based on the pilot signal, and CI based on the following equation (1).
Calculate R (carrier to interference ratio). CIR = (Ec / lo) / (1-Ec / lo) (1) Subsequently, the signal processing circuit 5 calculates the next reception slot timing (here, one slot is based on the calculated CIR).
Predict the CIR value at 1.66ms = 1/600 seconds). The prediction method here is not particularly limited, but a method such as linear prediction may be used as an example. Information indicating how many slots after which the CIR should be predicted is included in various control signals transmitted from the base station when the power of the mobile phone is turned on.

In this way, when the signal processing unit 5 predicts the CIR at the next reception slot timing, the signal processing unit 5 converts the predicted CIR into a DRC value indicating the data communication speed. This can be obtained only by reading the corresponding value by referring to a predetermined conversion table stored in advance in the RAM 11 or the like. Since the DRC (predicted data communication rate) obtained here is a value obtained based on the predicted CIR, it can be called the data communication rate at the next reception slot timing. The value of DRC obtained here is used as the predicted data communication speed. When the signal processing unit 5 obtains the predicted data communication speed by performing the series of processes described above, the signal processing unit 5 transmits this value to the base station.

On the other hand, the data received by the signal processing circuit 5,
That is, the data (downloaded data) received together with the pilot signal from the base station and separated by the signal processing circuit 5 is input to the CPU 7. CP in this way
When U7 acquires the reception data, it determines whether or not to switch the communication method based on the reception data rate D1 (calculated based on the reception data amount received in a preset predetermined period). Perform processing. Below, C
The communication system switching determination process performed by the PU 7 will be described with reference to FIG. The communication system switching determination process shown in FIG. 2 is repeatedly performed by the CPU 7 at a predetermined timing.

First, the CPU 7 determines the reception data rate D1.
Exceeds the threshold value D_LMT stored in advance in the RAM 11 (step SP1 in FIG. 2).
1). Here, the reception data rate D1 is calculated based on the amount of data received by the mobile phone within the first predetermined period Td [ms]. In addition, the first predetermined period Td
The amount of data received within [ms] may be the amount of data received purely from the base station or the exact amount of data calculated on the application. It doesn't matter. For example, as the calculation method of the reception data rate D1, there are the following four methods. 1. The reception data rate output from the signal processing unit 5 is measured in the first predetermined period Td [ms], and the total received data amount is divided by the first predetermined period Td [ms] to obtain the reception data rate. Calculate D1. 2. The instantaneous received data rate is calculated by measuring the amount of received data in one frame, which is the minimum period of wireless communication, and multiplying this amount of received data by the number of frames N received in one second. If this process is continued for 1 second, N instantaneous reception data rates are calculated. And this N
The average of the instantaneous reception data rates (average instantaneous reception data rate) is defined as the reception data rate D1. In this case, the first predetermined period Td [ms] = 1 second. 3. Further, when the first predetermined period Td [ms]> 1 second is set, the calculation of the average instantaneous reception data rate by the above-described second method is repeated for the first predetermined period Td [ms]. Then, the average of the average instantaneous reception data rates in the first predetermined period Td [ms] is calculated as the reception data rate D.
Set to 1. 4. The instantaneous reception data rate itself obtained by the above-mentioned second method is regarded as the reception data rate D1. In this case, the first predetermined period Td [ms] = 1 frame is received.

As a result, the data rate D1 is equal to the threshold value D_L.
If it is less than or equal to MT (“N
O ”), the process proceeds to step SP12, and it is determined whether the timer 14 is running. As a result, if the timer 14 has not started (“NO” in step SP12),
In step SP13, the timer 14 is activated. As a result, the timer 14 starts measuring the preset second predetermined period T (ms). On the other hand, step SP1
If the timer 14 is running in step 2 (step SP
In "12", "YES"), and the processing ends.

On the other hand, if the received data rate D1 exceeds the threshold value D_LMT in step SP11 ("YES" in step SP11), step SP
14 and it is determined whether the timer 14 is running. As a result, if the timer 14 has been started (“YES” in step SP14), the process proceeds to step SP15, the timer 14 is reset, and then the timer 14 is stopped and the process ends. On the other hand, if the timer 14 is not started in step SP14 (step SP1
In "4", "NO"), and the processing ends.

Here, FIGS. 4 and 5 show an example of the temporal transition of the reception data rate D1. 4 and 5, the vertical axis represents the reception data rate or radio wave condition (pilot strength), and the horizontal axis represents time. In both figures, the radio wave state Ph always exceeds T_Cir, which is a threshold value for ensuring comfortable data communication. Then, as shown in both figures, when the reception data rate D1 falls below the threshold value D_LMT at the time t1, the CPU 7 activates the timer 14, and the time counting for the predetermined period T (ms) is started from here. Then, as shown in FIG. 4, a predetermined period T from the time t1 when the reception data rate D1 becomes equal to or less than the threshold value.
Before (ms) elapses, that is, at the time t2, the threshold value D is again determined.
When it is equal to or more than _LMT, the timer 14 is reset and stopped at that time (time t2). On the other hand, as shown in FIG. 5, when the state in which the reception data rate D1 is equal to or lower than the threshold value D_LMT continues for the predetermined period T (ms), the timer 14 times up at the time when the predetermined period T (ms) elapses. Is notified to the CPU 7. Specifically, a signal indicating that the time is up is output from the timer to the CPU 7.

When the CPU 7 receives the signal, it judges that comfortable data communication is not performed, and cdma2000 1x-EV
The switching from the DO system to the cdma2000 system is decided, and the wireless communication system switching process described below is performed.

First, the CPU 7 outputs the communication system switching instruction information to the signal processing unit 5. The output communication system switching instruction information is encoded by the signal processing unit 5, further modulated by the cdma2000 1x-EV DO system compatible transmission circuit 81 of the multi-transmission circuit 3 based on a predetermined modulation system, and passed through the antenna 1. And the base station 3 for which communication is currently established
Sent to 0.

The base station 30 transmits the information from the mobile phone to the central office switching system 70. The central office 70 is the base station 3
When receiving the communication method switching instruction information from 0, the base station 3
The information of the cdma2000 1x system compatible base station associated with 0, that is, the information of the base station 50 is acquired, and this base station 50 is acquired.
Is transmitted to the base station 30. Here, the central office switch 70
Is a base station table in which information of base stations that can be switched is stored in association with each other when the base stations are switched between communication systems within the range of base stations managed by the own station. have. Then, when receiving the communication method switching instruction information from the base station under its own control, by referring to this table, other communication method switching instruction information corresponding to the base station that has transmitted the communication method switching instruction information to the authority. The base station information corresponding to the communication system is acquired, and this base station information is transmitted to the destination of the communication system switching instruction information. Further, when the central office exchange gives base station information corresponding to another communication method to the base station, it stops data transmission to this base station.

The base station 30 changes from the exchange 70 to the base station 5
When the information of 0 is received, this information is transmitted to the mobile phone. By such a process, the information of the base station 50 is demodulated by the cdma2000 1x-EV DO system compatible receiving circuit 31 via the antenna 1 of the mobile phone, subjected to predetermined digital processing by the signal processing circuit 5, and then sent to the CPU 7. Is entered. When the CPU 7 obtains the information of the base station that newly starts communication, the cdma 20 is sent to the multi-reception circuit 3 and the multi-transmission circuit 8 to start communication with the new base station 50.
00 Outputs a switching signal for switching to the 1x system compatible receiving circuit and cdma2000 1x system transmitting circuit. As a result, the multi-reception circuit 3 becomes the cdma2000 1x-EV DO system compatible reception circuit 31.
To the cdma2000 1x system compatible reception circuit 32, and similarly, the multi-transmission circuit 8 switches from the cdma2000 1x-EV DO system compatible transmission circuit 81 to the cdma2000 1x system compatible transmission circuit.

Then, the CPU 7 performs various processes for establishing a line with the cdma2000 1x system compatible base station 50 which is a base station for newly starting communication. This allows cdma2000
When the line with the 1x system compatible base station 50 is established, the base station 50 transmits to the exchange 70 the information indicating that the line has been established with the mobile phone. Upon recognizing that the line with the base station 50 has been established, the central office switching device 70 restarts the interrupted data download to the mobile phone via the base station 50. As a result, the communication system switching is completed, and the download of data by the cdma2000 1x system via the base station 50 is started.

Since the series of processes relating to the switching of the above-mentioned data communication method is necessary only during the period when the data communication is being performed, the CPU 7 compares the above-mentioned received data rate D1 with the threshold value D_LMT. After the process is finished
Once, it is determined whether or not the data communication is continued, and when the data communication is completed, the series of processes relating to the switching of the data communication system, that is, the communication system switching determination process shown in FIG. 2 is completed.

As described above, in this embodiment, cdma20
00 It is premised that data communication is performed using the 1x-EV DO method, but due to factors such as location and other communication devices in the vicinity, the strength of radio waves received by the cdma2000 1x-EV DO method makes data communication comfortable. However, if the received data rate does not show the expected value, it is judged that a comfortable data communication environment cannot be provided to the user and other communication is performed. System is cdma2000 1x
Switch the communication method to the method and secure the lowest data communication speed. In this way, cd that aims at allocating channels to terminals with better radio waves and transmitting data at high speed
In contrast to the ma2000 1x-EV DO method, the cdma2000 1x method always allocates channels to all terminals.
If the radio wave condition is good, comfortable data communication can be secured even by the cdma2000 1x system.

In the above description, cdma2000 1x-
Both the EV DO system compatible base station 30 and the cdma2000 1x system compatible base station 50 are arbitrarily switched within the same wireless communication system range as the user moves. That is,
Normal handover is performed by moving the communication device.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific structure is not limited to this embodiment, and includes a design and the like within a range not departing from the gist of the present invention. Be done.

For example, in the above-described embodiment, the multi-reception circuit 3 and the multi-transmission circuit 8 are both cdma2000 1
The receiver circuit and the transmitter circuit corresponding to the x-EV DO system and the cdma2000 1x system were respectively provided, but the wireless communication system is not limited to these, and the receiving circuit by another wireless communication system,
A transmission circuit may be adopted. That is, a receiving circuit and a transmitting circuit corresponding to a wireless communication system other than the above wireless communication system may be provided in place of the receiving circuit and the transmitting circuit, and the receiving circuit and the transmitting circuit may further include another wireless communication system. It is also possible to add a receiving circuit and a transmitting circuit corresponding to.

Further, the pilot signal transmitted from the base station is information which is always transmitted from the base station every predetermined period regardless of whether the communication device performs data communication or not. With regard to (1), since switching of the wireless communication system during data communication is the gist of the invention, description of the control state when data communication is not performed is omitted.

[0044]

As described above, according to the communication apparatus of the present invention, any one of the communication methods installed based on the information on the amount of data received within a predetermined period can be selected. Select and communicate according to the selected communication method. Thus, instead of selecting the communication method to be adopted based on the radio wave condition, the communication method is selected based on the information related to the amount of data actually received within the predetermined period.
For example, even if the radio wave is good but you cannot receive the data as you want, it is possible to get out of the bad reception data rate by switching the communication method. It is possible to provide stable data communication.

Further, according to the invention described in claim 2, when performing the data communication, the cdma2000 1x-EV DO system which can realize the highest data rate as one communication system is preferentially applied. , This cdma2000 1x-EV DO system realizes comfortable data communication. Also, cdma2000 1x-
Even if the information related to the amount of data received within the specified period by the EV DO method continues for a specified period of time, switching to another communication method is the minimum required for comfortable data communication. Secure the data communication speed. As a result, it is possible to provide a communication device capable of always performing data communication of a certain quality or higher. In addition, by adopting a method such as cdma2000 1x method in which a wireless channel is individually assigned to each terminal as another communication method, it is said that the channel is allocated to another terminal despite the good radio wave condition described above. Since the state can be avoided, it becomes possible to continue comfortable communication while maintaining the optimum transmission rate.

[Brief description of drawings]

FIG. 1 is a block diagram showing an internal configuration when a mobile phone is taken as an example of a communication device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a communication system switching determination process according to an embodiment of the present invention.

FIG. 3 is a diagram showing a network configuration according to an embodiment of the present invention.

FIG. 4 is a diagram showing an example of a temporal transition of a reception data rate.

FIG. 5 is a diagram showing an example of a temporal transition of a reception data rate.

[Explanation of symbols]

1 ... Antenna, 3 ... Multi-reception circuit, 5 ... Signal processing circuit, 7 ... CPU, 8 ... Multi-transmission circuit, 10 ... ROM,
11 ... RAM, 12 ... Operation part, 13 ... Display part, 14 ... Timer, 31 ... cdma2000 1x-EV DO system compatible receiving circuit, 3
2 ... Receiver for cdma2000 1x system, 81 ... cdma2000 1x
-EV DO system compatible transmitter circuit, 82 ... cdma2000 1x system compatible transmitter circuit, 30 ... cdma2000 1x-EV DO system compatible base station,
50 ... cdma2000 1x compatible base station, 70 ... central office switch

Claims (3)

[Claims] 1. A communication device comprising a plurality of transmitting / receiving means respectively corresponding to a plurality of different communication systems, and performing communication by any one of the communication systems, based on information on a data amount received within a predetermined period,
A communication method selecting means for selecting one of the communication methods, and if the selected communication method is different from the communication method currently adopted, the selection is made to the base station to which the line is currently established. Corresponding to the selected communication method when the information of the transmission control means for instructing to transmit the information for switching to the selected communication method and the information of the base station corresponding to the selected communication method is received from the base station. A communication device comprising switching means for switching to transmission / reception means. 2. The one communication method predicts a downlink data communication speed on the terminal side based on a reception state of a signal from a base station in the terminal, and notifies the base station of the predicted downlink data communication speed. Therefore, when the base station is a communication method for communicating data at the predicted downlink data communication speed, and the communication method currently adopted is the communication method, the communication method selecting means is The communication device according to claim 1, wherein when a state in which the information regarding the amount of data received therein is equal to or less than a preset threshold value continues for a predetermined period, the communication method is switched to another communication method. 3. A communication method comprising a plurality of transmitting / receiving means respectively corresponding to a plurality of different communication methods, and performing communication by any one of the communication methods, based on information on a data amount received within a predetermined period,
Selecting one of the communication methods, and if the selected communication method is different from the currently adopted communication method, the selected communication method is applied to the base station to which the line is currently established. The step of instructing to transmit information to the effect of switching to, and, when receiving information of the base station corresponding to the selected communication method from the base station, switching to the transmitting / receiving means corresponding to the selected communication method. A communication method comprising: