JP2008011452A - Communication terminal device and communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To actualize a long-time telephone call and a long standby time by reducing power consumption by selecting an optimum communication system according to an operation state when a multimode adaptive terminal is currently located where it can be connected to a plurality of systems. <P>SOLUTION: A communication terminal device 100 comprises: a power value management table 115 in which power consumptions of RF transmission and reception parts 102, 103, 106, 107, 110, and 111, base band signal processing parts 104, 108, and 112, and a call control part are recorded; a PMU 114 which selects a radio network for communication of the lowest power consumption out of connectable radio networks by referring to the power value management table 115; and a communication control part 113 which reports a system hand-over request to a base station through the selected radio network. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a communication terminal device such as a multi-mode mobile phone that can be connected to a plurality of wireless networks having different wireless communication standards, and a communication method.

  Examples of the multi-mode wireless reception device that enables access to two or more systems include a dual-mode mobile phone and a multi-mode mobile phone.

  With the development of mobile communication, a plurality of wireless communication systems with different standards are operated in the world. In particular, in recent years, in addition to the GSM (The Global System for Mobile Communications) method and the PDC (Personal Digital Cellular) method, which are called the second generation mobile phone service, the W-CDMA (Wideband-Wideband-) called the third generation mobile phone service. Code Division Multiple Access) and Cdma2000 systems have been put into practical use, and a plurality of wireless communication systems have been operated even in the same region.

  Against this background, there is an increasing demand for multi-mode compatible terminals that can be connected to a plurality of wireless communication systems with the same terminal.

  By making the mobile phone compatible with the multi-mode, it is possible to communicate with the same terminal even in different regions of the wireless communication system, so that convenience is improved. In an area where a plurality of wireless communication systems coexist, for example, by measuring a received electric field level (RSSI) between systems, by performing an intersystem handover for switching to a more optimal system, the call is not disconnected. It becomes possible to communicate stably.

  However, since the multi-mode compatible terminal is configured to be connectable to a plurality of wireless communication systems, the circuit scale increases in proportion to the number of modes, and each inter-system handover and each inter-system handover are realized. Since necessary processing such as reception level measurement in the communication mode is increased as compared with the single mode terminal, there is a problem that power consumption is large and it is difficult to extend the battery time compared to the single mode terminal.

In order to deal with this problem, for example, in Patent Document 1, when the battery voltage decreases and reaches a predetermined value at the time of standby, switching to a communication system with lower current consumption enables long-time standby of the mobile phone. Technology is disclosed.
Japanese Patent Laid-Open No. 11-252006

  However, in such a conventional communication device, although a method for extending the standby time when the battery voltage is reduced has been proposed, the operation when the battery voltage is sufficiently secured, for example, There is no description on how to select a communication system from among a plurality of communication systems that can be connected in accordance with call connection and communication application, so as to achieve the lowest power consumption.

  The present invention has been made in view of such points, and in a multi-mode compatible terminal, when the current location of the terminal can be connected to a plurality of systems, low power consumption can be achieved by selecting an optimal communication system according to the operating state. It is possible to provide a communication terminal device and a communication method that enable long-time communication and long-time standby.

  A communication terminal device of the present invention is a multimode communication terminal device connectable to a plurality of wireless networks with different wireless communication standards, and an RF receiver that demodulates carrier frequencies of the plurality of wireless networks into a baseband signal; An RF transmitter that modulates the carrier frequency of the wireless network to which the baseband signal is connected, a baseband signal processor that performs baseband signal processing of received information signals in accordance with a plurality of wireless communication standards, and communication processing. The power value management table in which the power consumption of the RF transceiver unit, baseband signal processing unit, and call control unit in a predetermined condition is recorded, and the wireless network that can be connected by referring to the power value management table is the most A power management unit for selecting a wireless network capable of communicating with low power consumption, and the power management unit; To a wireless network that cement unit has selected a configuration including a communication control unit for notifying the system handover request to the base station.

  The communication method of the present invention is a communication method for a multi-mode compatible communication terminal apparatus connectable to a plurality of wireless networks having different wireless communication standards, and includes an RF transceiver unit and a baseband signal under predetermined conditions according to communication processing A table setting step for setting a power value management table in which the power consumption of the processing unit and the call control unit is recorded, and communication is possible with the lowest power consumption among the connectable wireless networks with reference to the power value management table A radio network selection step of selecting a radio network, and a step of notifying a base station of a system handover request to the selected radio network.

  According to the present invention, communication can be performed while always using the system with the lowest power consumption according to the amount of data required for communication and the reception level, so that the power consumption of the communication terminal device can be reduced. This is effective, and is effective for long-time communication and long-time communication of a communication terminal device such as a mobile phone.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a communication terminal apparatus according to Embodiment 1 of the present invention. This embodiment is an example applied to a multimode mobile phone as a communication terminal device.

  In FIG. 1, a communication terminal device 100 is a multi-mode mobile phone that can be connected to a plurality of wireless networks with different wireless communication standards. The communication terminal device 100 includes antennas 101, 105, and 109, and a plurality of wireless networks. RF receivers 102, 106, and 110 that demodulate the carrier frequency of the baseband signal, RF transmitters 103, 107, and 111 that modulate the baseband signal to the carrier frequency of the wireless network to which the baseband signal is connected, and a plurality of wireless communications Baseband signal processing units 104, 108, and 112 that perform baseband signal processing of received information signals according to standards, and RF transmission and reception units 102, 103, 106, 107, 110, and 111 under predetermined conditions according to communication processing, Power consumption of baseband signal processing units 104, 108, 112 and call control unit The recorded power value management table 115 and a power management unit (hereinafter referred to as PMU) that selects a wireless network that can communicate with the lowest power consumption from wireless networks that can be connected with reference to the power value management table 115. ) 114, a communication control unit 113 that notifies the base station of a system handover request to the radio network selected by the PMU 114, and an application processing unit 116 that executes various application programs.

  The communication control unit 113 has interfaces with the baseband signal processing units 104, 108, and 112, the PMU 114, and the application processing unit 116, and performs communication control of the connected communication system.

  The power value management table 115 manages the standby power of each wireless processing unit, and the RF reception units 102, 106, 110 and baseband signal processing for each wireless communication standard such as W-CDMA / GSM / PDC as management parameters. Unit 104, 108, 112 consumes average power consumed according to the intermittent recovery time, and power consumption of RF transmitters 103, 107, 111 varies according to the distance from the base station in the communication standard for performing transmission power control. Manage.

  Hereinafter, the operation of the communication terminal apparatus configured as described above will be described.

  When the communication terminal apparatus according to the present embodiment is compatible with three different wireless communication systems of system A, system B, and system C, communication terminal apparatus 100 in FIG. 1 performs the following operation.

  When transmitting and receiving in the system A, the antenna 101 for the system A, the RF receiving unit 102 for the system A that demodulates the carrier frequency received by the antenna 101 into the baseband signal, and the baseband signal for the carrier frequency of the system A The RF transmission unit 103 for system A that performs modulation and the baseband signal processing unit 104 that performs baseband signal processing of the information signal for system A operate. Similarly, when transmitting and receiving in the system B, the antenna 105 for the system B, the RF receiving unit 106 for the system B that demodulates the carrier frequency received by the antenna 105, and the baseband signal are converted into the system B. When the system B RF transmission unit 107 that modulates the carrier frequency of the system B and the baseband signal processing unit 108 that performs baseband signal processing of the information signal for the system B operate and the system C performs transmission and reception, An antenna 109 for C, an RF receiver 110 for system C that demodulates the carrier frequency received by antenna 109 into a baseband signal, and an RF transmitter for system C that modulates the baseband signal to the carrier frequency of system C 111 and baseband signal processing of information signals for system C Band signal processing unit 112 operates. In this case, it is possible to reduce the power consumption of the terminal by reducing or shutting down the power supply voltage for a block in a system that is not connected.

  The power value management table 115 records the power at the standby time of the RF receivers 102, 106, 110, the RF transmitters 103, 107, 111, and the baseband signal processors 104, 108, 112 of the systems A to C. Is done. Here, each power consumption recorded in the power value management table 115 is preferably an estimated value at the time of design or a measured value in a shipping inspection, but it is not necessarily an absolute value of power consumption. It is sufficient to know the magnitude relationship of power consumption with the relative value for each management parameter.

  The power value management table 115 according to the present embodiment is a power value management table in which the power consumption of the RF transmission / reception unit, the baseband signal processing unit, and the call control unit is recorded, and manages the standby power of each wireless processing unit. is doing. As management parameters, first, there is an average power consumption in an RF receiver, a baseband signal processor, and a call controller for each wireless communication standard such as W-CDMA / GSM / PDC. Second, there is an average power consumption in the RF receiver, baseband signal processor, and call controller for each intermittent reception period. Third, there is power consumption in the RF transmitter according to the distance from the base station. According to the power value management based on the first and second parameters, the reception average current for each wireless communication standard can be subdivided and managed for each intermittent reception cycle. According to the power value management by the third parameter, in the CDMA communication standard, the transmission power control is performed, so that the power consumption of the RF transmission unit varies depending on the distance from the base station. It is possible.

  FIG. 2 is a diagram illustrating an example of management contents of the power value management table 115.

  In FIG. 2, the management parameters are the wireless system type, the intermittent reception cycle, and the distance from the base station. In the wireless system, the intermittent reception period can normally be selected from a plurality of standards, the period is determined by the operator, and the mobile terminal operates in accordance with an instruction from the wireless network. As the intermittent reception cycle becomes longer, the standby state becomes relatively longer, so the average power consumption becomes smaller. Therefore, it is necessary to manage power consumption for each intermittent reception cycle of each wireless system. In addition, in the CDMA wireless system, transmission power control is performed, so that the transmission power varies depending on the distance from the base station, and the power consumption of the RF transmitter tends to increase as the distance from the base station increases. Therefore, in a CDMA wireless system, it is necessary to manage power consumption using the distance from the base station as a management parameter. In FIG. 2, it is assumed that the system A is a CDMA wireless system as an example. And according to these management parameters, the power consumption of each block, its total value, and the relative rank of the total value are recorded. Although the power consumption for each block is shown in FIG. 2, the power consumption for each block is not necessarily required, and it is sufficient that the total value or relative order of power consumption is known.

  Returning to FIG. 1, in the PMU 114, the state of the currently connected wireless system and the state of the connectable wireless system are notified from the communication control unit 113, and which wireless system is on standby based on the information in the power value management table 115. Is determined to be the lowest power consumption, and the communication control unit 113 is notified. For example, when the system B is connected to the system A and can be connected to the system A, according to the power value management table 115, it can be seen that the power consumption is lower when the system A is on standby. Therefore, the PMU 114 notifies the communication control unit 113 that power consumption is lower when waiting in the system A.

  The communication control unit 113 notifies the base station of the wireless system connected based on the notification information from the PMU 114 that the power consumption is lower when waiting in the system A. Based on the information from the mobile terminal, the base station issues a system handover request from the system B to the system A to the mobile terminal.

  In this way, it is possible to select a wireless network that can communicate with the lowest power consumption. By performing a system handover to the selected wireless network, it is possible to reduce the power consumption of the mobile phone. You can achieve time standby.

  As described above in detail, according to the present embodiment, communication terminal apparatus 100 includes RF transceivers 102, 103, 106, 107, 110, 111, baseband signal processors 104, 108, 112, and call control. The power value management table 115 in which the power consumption of each part is recorded, and the PMU 114 that selects the wireless network that can communicate with the lowest power consumption among the wireless networks that can be connected with reference to the power value management table 115, and the selected Since the communication control unit 113 for notifying the base station of a system handover request to the wireless network is configured, the power value management table when the wireless communication terminal 100 is connectable to a plurality of wireless networks satisfying the reception performance. By referring to 115, it is possible to select a wireless network capable of communication with the lowest power consumption It made. By performing system handover to the selected wireless network, it is possible to reduce the power consumption of, for example, a mobile phone, and achieve a long standby time of the mobile phone.

  In particular, in this embodiment, a wireless network capable of communicating with the lowest power consumption among communication systems that can be connected in accordance with operations when battery voltage is sufficiently secured, for example, call connection and communication application. There is an excellent effect that can be selected.

  Further, in this embodiment, the power value management table 115 manages the power at the time of standby of each wireless processing unit, so that wireless communication is possible with the lowest power consumption according to each communication mode at the time of standby. A network can be selected.

(Embodiment 2)
Embodiment 2 is an example using a power value management table for managing the power of each wireless processing unit during a voice call.

  FIG. 3 is a diagram showing an example of management contents of the power value management table 200 of the communication terminal apparatus according to Embodiment 2 of the present invention. The overall configuration of the communication terminal apparatus according to the present embodiment is the same as that shown in FIG. That is, the power value management table 200 of the present embodiment is applied instead of the power value management table 115 of FIG.

  In FIG. 3, a power value management table 200 manages the power of each wireless processing unit during a voice call. As management parameters, an RF receiving unit, a baseband signal processing unit, and a communication control unit include W-CDMA / The average power consumption at the time of a voice call consumed according to the voice coding method for each wireless communication standard such as GSM / PDC, and the RF transmitter that varies depending on the distance from the base station in the communication standard for transmission power control Manage power consumption.

  Specifically, the power value management table 200 includes voice calls of the RF receivers 102, 106, 110, the RF transmitters 103, 107, 111, and the baseband signal processors 104, 108, 112 of the systems A to C. The power of the hour is recorded. The management parameters are the wireless system type, the voice encoding method, and the distance from the base station. The voice coding method differs for each wireless system, and when a plurality of voice coding methods or bit rates can be selected in one wireless system, an instruction from the wireless network is received according to the communication environment, One of these is selected and operated. And according to these management parameters, the power consumption of each block, its total value, and the relative rank of the total value are recorded. Although the power consumption for each block is shown in FIG. 3, the power consumption for each block is not necessarily required, and it is sufficient that the total value or relative order of power consumption is known.

  The communication terminal device including the power value management table 200 performs the following communication operation.

  In FIG. 1, the PMU 114 notifies the state of the currently connected wireless system and the state of the connectable wireless system from the communication control unit 113, and uses which wireless system to make a voice call based on the information in the power value management table 200. It is determined whether the lowest power consumption is performed, and the communication control unit 113 is notified. For example, when connected to the system B and can be connected to the system A as well, according to the power value management table 200, it can be seen that the power consumption is lower when the voice call is performed in the system A. Therefore, the PMU 114 notifies the communication control unit 113 that the power consumption of the voice call in the system A is lower.

  The communication control unit 113 notifies the base station of the wireless system that is connected based on the notification information from the PMU 114 that lower power consumption is achieved by making a voice call with the system A. Based on the information from the mobile terminal, the base station issues a system handover request from the system B to the system A to the mobile terminal.

  In this way, it is possible to select a wireless network that can communicate with the lowest power consumption. By performing a system handover to the selected wireless network, it is possible to reduce the power consumption of the mobile phone. A time call can be achieved.

  As described above, according to the second embodiment, the power value management table 200 manages the power during a voice call, and the RF reception unit, the baseband signal processing unit, and the communication control unit are used as management parameters. RF transmission unit that varies depending on the average power consumption during a voice call consumed according to a voice encoding method for each wireless communication standard such as / GSM / PDC and the distance from the base station in the communication standard for transmission power control To manage the power consumption. As a result, when the wireless communication terminal is in a state where it can be connected to a plurality of wireless networks satisfying the reception performance, the wireless network capable of making a voice call with the lowest power consumption is selected by referring to the power value management table 200. By performing system handover to the selected wireless network, it is possible to reduce the power consumption of the mobile phone and achieve a long-time call of the mobile phone.

(Embodiment 3)
The third embodiment is an example using a power value management table for managing communication speed and power during packet communication of each wireless processing unit.

  FIG. 4 is a diagram showing a transition of the processing amount for setting the power value management table of the communication terminal apparatus according to Embodiment 3 of the present invention (hereinafter, this transition is referred to as a power value management table 300). The overall configuration of the communication terminal apparatus according to the present embodiment is the same as that shown in FIG.

  In FIG. 4, a power value management table 300 manages the communication speed and power during packet communication of each wireless processing unit. As management parameters, an RF receiving unit, a baseband signal processing unit, and a communication control unit -Fluctuates according to the average power consumption during voice calls consumed according to the packet communication method and communication speed for each wireless communication standard such as CDMA / GSM / PDC, and the distance from the base station in the communication standard for controlling transmission power It manages the power consumption of the RF transmitter.

  As shown in FIG. 4, the power value management table 300 takes the processing amount of the packet communication method for each wireless system type as a management parameter, and is arranged in the order of the processing amount.

  The PMU 114 notifies the communication control unit 113 of the processing amount necessary for packet communication, the state of the currently connected wireless system, and the state of the connectable wireless system, and performs packet communication based on the information in the power value management table 300. The wireless communication system 113 determines which wireless system will perform the lowest power consumption while satisfying the required processing amount, and notifies the communication control unit 113 of it. For example, when the system A is connected by high-speed packet communication and can be connected to the system B, when the processing amount required for packet communication is not as high as the system A, according to the power value management table 300, It can be seen that switching to the system B packet communication satisfies the processing amount required for communication and becomes the mode with the lowest power consumption. Therefore, the PMU 114 notifies the communication control unit 113 that switching to system B packet communication consumes less power.

  The communication control unit 113 notifies the base station of the connected wireless system based on the notification information from the PMU 114 that switching to the system B packet communication results in lower power consumption. Based on the information from the mobile terminal, the base station issues a system handover request from the system B to the system A to the mobile terminal.

  In this way, it is possible to select a wireless network that can communicate with the lowest power consumption. By performing a system handover to the selected wireless network, it is possible to reduce the power consumption of the mobile phone. Time communication can be achieved.

  As described above, according to the third embodiment, the power value management table 300 manages the power during packet communication, and the RF reception unit, the baseband signal processing unit, and the communication control unit are used as management parameters. RF that fluctuates according to the average power consumption at the time of a voice call consumed according to the packet communication method and communication speed for each wireless communication standard such as / GSM / PDC, and the distance from the base station in the communication standard for transmission power control Manages the power consumption of the transmitter. As a result, when the wireless communication terminal can be connected to a plurality of wireless networks satisfying the reception performance, the wireless network capable of packet communication with the lowest power consumption is selected by referring to the power value management table 300. By performing system handover to the selected wireless network, it is possible to reduce the power consumption of a communication terminal device such as a mobile phone, and to achieve long-time communication of the mobile phone.

(Embodiment 4)
The fourth embodiment is an example of using all or some of the power value management tables of the first to third embodiments.

  FIG. 5 is a diagram for explaining the operation on the time axis of the communication terminal apparatus according to Embodiment 4 of the present invention.

  The communication terminal apparatus according to the present embodiment has a power value management configured by combining all or some of the power value management table 115 in FIG. 2, the power value management table 200 in FIG. 3, and the power value management table 300 in FIG. The PMU 114 includes a wireless network that can communicate with the lowest power consumption among the connectable wireless networks that satisfy the reception performance according to each communication mode during standby, voice call, and packet communication. select.

  The power management operation will be specifically described with reference to FIG. The horizontal axis represents time, and the vertical axis represents the power consumption when performing standby, voice call, and packet communication in each wireless system.

  It is assumed that on the time axis, a transition is made from standby to voice call, and then switched to packet communication.

  The present embodiment is an example when all of the power value management tables 115, 200, and 300 of the first to third embodiments are mounted. According to the present embodiment, when any of the systems A to C can be connected, the system handover (HO) is performed so that the power consumption is optimized at the standby time, the voice call time, and the packet time. ) Is possible.

  Therefore, according to the fourth embodiment, when the wireless communication terminal can be connected to a plurality of wireless networks satisfying the reception performance, the power value management table is referred to, so that the standby state, the voice call, the packet communication can be performed. Depending on each communication mode, it is possible to select the wireless network that can communicate with the lowest power consumption from the connectable wireless networks that satisfy the reception performance, and perform system handover to the selected wireless network. As a result, the power consumption of a wireless communication terminal such as a mobile phone can be reduced, and long-time communication of the mobile phone can be achieved.

  The above description is an illustration of a preferred embodiment of the present invention, and the scope of the present invention is not limited to this.

  In each of the above embodiments, a multi-mode mobile phone corresponding to an RF receiver for each wireless communication standard such as W-CDMA / GSM / PDC has been described. The present invention can be applied to any apparatus that performs communication according to the above, and the type and number of communication methods are not limited.

  In the above embodiment, the name “multi-mode mobile phone” is used. However, this is for convenience of explanation, and it is needless to say that a multi-mode wireless communication device, a communication terminal device, a wireless communication method, and the like may be used. .

  Further, the type, number, connection method, and the like of each circuit unit constituting the multi-mode mobile phone are not limited to the above-described embodiments.

  INDUSTRIAL APPLICABILITY The communication terminal device and communication method according to the present invention are useful for a multi-mode mobile phone that requires a longer operating time.

The block diagram which shows the structure of the communication terminal device which concerns on Embodiment 1 of this invention. The figure which shows an example of the management content of the power value management table of the communication terminal device which concerns on the said embodiment. The figure which shows an example of the management content of the power value management table of the communication terminal device which concerns on Embodiment 2 of this invention. The figure which shows transition of the processing amount which sets the power value management table of the communication terminal device which concerns on Embodiment 3 of this invention. The figure explaining the operation | movement on the time-axis of the communication terminal device which concerns on Embodiment 4 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Communication terminal device 101 Radio system A antenna 102 Radio system A RF receiver 103 Radio system A RF transmitter 104 Radio system A baseband signal processor 105 Radio system B antenna 106 Radio system B RF receiver 107 RF transmission unit for wireless system B 108 Baseband signal processing unit for wireless system B 109 Antenna for wireless system C 110 RF reception unit for wireless system C 111 RF transmission unit for wireless system C 112 Baseband signal processing unit for wireless system C 113 Communication Control Unit 114 Power Management Unit (PMU)
115, 200, 300 Power value management table 116 Application processing unit

Claims (10)

A multi-mode compatible communication terminal device connectable to a plurality of wireless networks with different wireless communication standards,
An RF receiver that demodulates a carrier frequency of a plurality of wireless networks into a baseband signal;
An RF transmitter that modulates the carrier frequency of the wireless network to which the baseband signal is connected;
A baseband signal processing unit that performs baseband signal processing of a received information signal according to a plurality of wireless communication standards;
A power value management table in which the power consumption of the RF transmission / reception unit, baseband signal processing unit, and call control unit in a predetermined condition according to communication processing is recorded;
A power management unit that selects a wireless network that can communicate with the lowest power consumption from wireless networks that can be connected with reference to the power value management table;
A communication control unit for notifying a base station of a system handover request to a radio network selected by the power management unit.   The power value management table includes at least one of power at standby of each wireless processing unit, power at the time of voice call of each wireless processing unit, or communication speed and power at the time of packet communication of each wireless processing unit. The communication terminal apparatus according to claim 1, wherein the communication terminal apparatus is managed.   The communication terminal apparatus according to claim 1, wherein the power value management table manages power consumption of an RF transmission unit that varies according to a distance from a base station in a communication standard for performing transmission power control.   The power value management table includes, as management parameters, average power consumption in an RF reception unit, a baseband signal processing unit, and a call control unit for each wireless communication standard such as W-CDMA / GSM / PDC. Item 2. The communication terminal device according to Item 1.   The communication terminal according to claim 1, wherein the power value management table includes, as management parameters, average power consumption in an RF reception unit, a baseband signal processing unit, and a call control unit for each intermittent reception period of each method. apparatus.   The communication terminal apparatus according to claim 1, wherein the power value management table has, as a management parameter, average power consumption during a voice call that is consumed according to a voice encoding method for each wireless communication standard.   The communication terminal apparatus according to claim 1, wherein the power value management table includes, as a management parameter, average power consumption during a voice call that is consumed according to a packet communication method and a communication speed for each wireless communication standard.   The power management unit selects a wireless network that can communicate with the lowest power consumption among connectable wireless networks that satisfy reception performance according to each communication mode during standby, voice call, or packet communication. The communication terminal device according to claim 1, wherein the communication terminal device is selected. A communication method of a multi-mode compatible communication terminal device connectable to a plurality of wireless networks with different wireless communication standards,
A table setting step for setting a power value management table in which the power consumption of the RF transmission / reception unit, baseband signal processing unit, and call control unit in a predetermined condition according to communication processing is recorded;
A wireless network selection step of selecting a wireless network capable of communicating with the lowest power consumption from wireless networks connectable with reference to the power value management table;
And a step of notifying a base station of a system handover request to a selected wireless network. In the table setting step, a power value management table having average power consumption in the RF reception unit, baseband signal processing unit, and call control unit for each wireless communication standard such as W-CDMA / GSM / PDC is set as a management parameter. Along with managing the power consumption of the RF transmitter that varies depending on the distance from the base station in the communication standard for transmission power control,
In the wireless network selection step, the average power consumption for each wireless communication standard is compared with the power consumption of the RF transmitter, and the lowest power consumption among the connectable wireless networks satisfying the reception performance. The communication method according to claim 9, wherein a communicable wireless network is selected.

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