U.S. patent application number 12/684256 was filed with the patent office on 2010-05-06 for multimode wireless communication apparatus and high frequency integrated circuit therefore.
Invention is credited to May Suzuki, Satoshi Tanaka, Akio Yamamoto, Taizo Yamawaki.
Application Number | 20100113089 12/684256 |
Document ID | / |
Family ID | 33111890 |
Filed Date | 2010-05-06 |
United States Patent
Application |
20100113089 |
Kind Code |
A1 |
Suzuki; May ; et
al. |
May 6, 2010 |
MULTIMODE WIRELESS COMMUNICATION APPARATUS AND HIGH FREQUENCY
INTEGRATED CIRCUIT THEREFORE
Abstract
A multimode wireless communication apparatus including a radio
frequency unit having controllable communication mode and a control
unit for periodically making the radio frequency unit operate in a
mobile telephone mode and, after predetermined time, switching the
mode to a wireless LAN mode, wherein if occurrence of an incoming
call event is detected when the radio frequency unit is in standby
reception in the mobile telephone mode, the control unit suppresses
the switching to the wireless LAN mode and determines whether the
communication in the mobile telephone mode should be continued or
not.
Inventors: |
Suzuki; May; (Kokubnji,
JP) ; Yamawaki; Taizo; (Tokyo, JP) ; Tanaka;
Satoshi; (Kokubunji, JP) ; Yamamoto; Akio;
(Hiratsuka, JP) |
Correspondence
Address: |
BRUNDIDGE & STANGER, P.C.
1700 DIAGONAL ROAD, SUITE 330
ALEXANDRIA
VA
22314
US
|
Family ID: |
33111890 |
Appl. No.: |
12/684256 |
Filed: |
January 8, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10372269 |
Feb 25, 2003 |
7657282 |
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12684256 |
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Current U.S.
Class: |
455/552.1 |
Current CPC
Class: |
H04W 88/06 20130101 |
Class at
Publication: |
455/552.1 |
International
Class: |
H04W 88/06 20090101
H04W088/06; H04M 1/00 20060101 H04M001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 23, 2002 |
JP |
2002-307792 |
Claims
1. A multimode wireless communication apparatus comprising: a radio
frequency unit having controllable communication mode; and a
control unit for making said radio frequency unit operate
periodically in a first communication mode and, after predetermined
time interval, switching from the first communication mode to a
second communication mode, and said control unit includes
determining means for suppressing the switching of said radio
frequency unit to the second communication mode when occurrence of
a predetermined event is detected from a signal received during a
period in which said radio frequency unit is operating in the first
communication mode and determining whether communication in the
first communication mode should be continued on or not.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] The present application claims priority from Japanese Patent
Application No. 2002-307792, filed Oct. 23, 2002 and is a
Continuation Application of U.S. application Ser. No. 10/372,269,
filed Feb. 25, 2003, the contents of which are incorporated by
reference.
BACKGROUND OF THE INVENTION
[0002] (1) Field of the Invention
[0003] The present invention relates to a multimode wireless
communication apparatus conformed with a plurality of communication
standards and a high frequency integrated circuit therefor.
[0004] (2) Description of the Related Art
[0005] Communication modes (communication protocols) in wireless
terminals are broadly divided into a wireless communication
protocol for mobile telephone network such as GSM, EDGE, GPRS, PDC,
cdmaOne, cdma2000, and W-CDMA each using a public network of a wide
area (hereinafter, called public network wireless communication
protocol), and a communication protocol for wireless LAN such as
IEEE802.11a, 11b, 11g, and 11h and HiperLAN/2 using a local
network. The wireless communication protocol using a local network
also includes, for example, a short-range wireless communication
protocol such as by Bluetooth or UWB.
[0006] In the specification, the local network wireless
communication protocol includes the above short-range wireless
communication protocol. A wireless terminal (wireless communication
apparatus) having two communication modes, one for the public
network wireless communication protocol and the other for local
network wireless communication protocol will be called a multimode
wireless terminal.
[0007] In the field of wireless communication, recently, a mobile
telephone network having a wide service area is rapidly spreading.
Meanwhile, in the metropolitan area, information service using a
local high-speed network such as a wireless LAN has also started.
Thus, various wireless communication systems coexist today. A
mobile telephone terminal has advantages such that a communication
area is wide and communication can be continued even when the user
is moving among cells at high speed. However, the bit rate is as
low as 9.6 to 384 kbits/second and the communication cost is
expensive. On the other hand, at present, information service areas
of a wireless LANs are limited to, for example, service areas
called hot spots in the metropolitan area. Unlike mobile telephone
systems, the wireless LAN cannot provide communication service to
the user who is moving at high speed. However, as compared to a
mobile telephone, the wireless LAN can provide a higher bit rate
service (for example, 22 to 54 Mbps), its communication cost is
overwhelmingly cheaper, and there exist a number of service areas
which are free of communication charges.
[0008] Consequently, the demand for a multimode terminal adapted to
a plurality of communication standards, so that both of the
services can be received by a single wireless terminal is
increasing. A multimode wireless terminal conventionally proposed
has plural kinds of transceivers adapted to different communication
protocols (communication modes), so that the user can selectively
use one of communication modes or use two modes in parallel
independently of each other.
SUMMARY OF THE INVENTION
[0009] As described above, the mobile telephone network and the
wireless LAN have contradictory advantages and disadvantages.
Consequently, it is considered to be more advantageous from the
viewpoints of power consumption and communication costs of a
wireless terminal to use the communication functions of a mobile
telephone network and a wireless LAN while dynamically switching
communication modes in accordance with the service area and user's
purpose, than to use the communication functions independently of
each other.
[0010] However, a conventional multimode terminal does not switch
the communication modes at all or switching of the communication
modes is up to the user. Therefore, the terminal functions are not
efficiently used. A conventional multimode wireless terminal having
a plurality of transceivers for respective communication modes has
a problem of a large circuit scale. A terminal which shares a
transceiver circuit for a plurality of communication modes has a
problem that it takes time to switch the communication modes.
[0011] An object of the invention is to provide a multimode
wireless communication apparatus capable of switching the
communication mode at high speed.
[0012] Another object of the invention is to provide a multimode
wireless communication apparatus having a radio frequency unit
commonly used in a plurality of communication modes and capable of
switching the communication mode at high speed.
[0013] Another object of the invention is to provide a multimode
wireless communication apparatus capable of executing two
communication modes in a time sharing manner.
[0014] Further another object of the invention is to provide a high
frequency integrated circuit for a multimode wireless communication
apparatus capable of switching the communication mode at high
speed.
[0015] To achieve the above objects, a multimode wireless
communication apparatus of the invention comprises: a radio
frequency unit having controllable communication modes; and a
control unit for making the radio frequency unit operate
periodically in a first communication mode and, after predetermined
time interval, switching the communication mode to a second
communication mode, and the control unit includes determining means
for suppressing the switching of the radio frequency unit to the
second communication mode when occurrence of a predetermined event
is detected from a signal received during a period in which the
radio frequency unit is operating in the first communication mode
and determining whether communication in the first communication
mode should be continued or not.
[0016] More specifically, the radio frequency unit is comprised of
a high frequency integrated circuit including at least one analog
component having operation characteristic controllable with a
reference parameter value, and the control unit switches the
communication mode of the radio frequency unit by changing the
reference parameter value for determining the operation
characteristic of the high frequency integrated circuit.
[0017] According to an embodiment of the invention, the high
frequency integrated circuit includes a reference register in which
the reference parameter value for determining the operation
characteristic of the analog component is set, a first register for
storing a parameter value for the first communication mode, a
second register for storing a parameter value for a second
communication mode, and a switch for selectively supplying the
parameter value stored in one of the first and second registers to
the reference register, and the control unit switches the
communication mode of the radio frequency unit by controlling the
switch to change the reference parameter value set in the reference
register.
[0018] A key feature of the invention resides in that the
determining means determines whether the first communication mode
should be continued or switched to the second communication mode in
accordance with a predetermined mode selection rule.
[0019] In an embodiment of the invention, the above determining
means has means to inquire a user which operation mode to select
next in accordance with the mode selection rule, and selects either
the first communication mode or the second communication mode in
accordance with the instruction from the user. The radio frequency
unit includes a transmission power amplifier connected to an on/off
controllable power source, and the control unit turns off the power
source for the transmission power amplifier before switching the
operation mode of the radio frequency unit and, after the operation
mode is switched, turns on the power source for the transmission
power amplifier.
[0020] According to the invention, a high frequency integrated
circuit for a multimode wireless communication apparatus including
at least one analog component having operation characteristic
controllable with a reference parameter value, comprises: a
reference register in which the reference parameter value for
determining the operation characteristic of the analog component is
set; a first register for storing a first parameter value for a
first communication mode; a second register for storing a second
parameter value for a second communication mode; a switch for
selectively connecting one of the first and second registers to the
reference register so as to set the first parameter value or the
second parameter value as the reference parameter value; a switch
control circuit for controlling the switch in accordance with a
mode selection signal supplied from an external signal line; and a
write control circuit for writing a parameter for the first mode
and a parameter for the second mode supplied from the external
signal line to the first and second registers, respectively. The
mode selection signal is supplied to the switch control circuit via
the write control circuit.
[0021] The other objects and characteristic configurations of the
invention will become apparent from description of embodiments with
reference to the following drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a diagram showing the configuration of a wireless
communication apparatus (multimode wireless terminal) to which the
invention is applied.
[0023] FIG. 2 is a diagram showing an example of a sequence of
switching a communication mode in the multimode wireless terminal
of the invention.
[0024] FIG. 3A is a configuration diagram showing an example of a
conventional RF-IC control circuit for a multimode wireless
terminal.
[0025] FIG. 3B is a diagram for explaining a parameter setting
sequence for switching the communication mode in a conventional
RF-IC.
[0026] FIG. 4A is a block diagram showing a first embodiment of an
RF-IC control circuit for a multimode wireless terminal according
to the invention.
[0027] FIG. 4B is a diagram for explaining a parameter setting
sequence for switching the communication mode in the multimode
wireless terminal of the first embodiment of the invention.
[0028] FIG. 5 is a block diagram showing a second embodiment of the
RF-IC control circuit for the multimode wireless terminal according
to the invention.
[0029] FIG. 6 is a block diagram showing a third embodiment of the
RF-IC control circuit for the multimode wireless terminal according
to the invention.
[0030] FIG. 7A is a block diagram showing a fourth embodiment of
the RF-IC control circuit for the multimode wireless terminal
according to the invention.
[0031] FIG. 7B is a diagram for explaining a parameter setting
sequence for switching the communication mode in a multimode
wireless terminal of the fourth embodiment of the invention.
[0032] FIG. 8A is a flowchart showing a mode switching control
routine executed by a control processor 16 in FIG. 1 in the
multimode wireless terminal of the first embodiment of the
invention.
[0033] FIG. 8B is a flowchart showing the details of incoming call
processing 520 in FIG. 8A.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] In a wireless communication system designed on the premise
that a terminal performs communication while moving from cell to
cell, such as a mobile telephone, in order to enable a wireless
terminal (mobile terminal) to be located whenever a call is made
for the terminal, each of the mobile terminals executes a
communication protocol for registering its position to a base
station which is reachable from it's present position. Even when
the user does not perform communication, each mobile terminal
periodically receives a specific signal transmitted from a base
station nearby, thereby monitoring the necessity to register it's
position to a new base station and the presence or absence of a
call to the terminal itself. Such a signal receiving process is
generally called standby reception. In order to increase available
communication time of a mobile terminal by suppressing the
consumption of it's battery, the repeating cycle of the standby
reception is set to be relatively long (about 1 second) and a
protocol is determined so as to complete each standby receiving
process in short time.
[0035] On the other hand, in a wireless communication system
designed on the premise of using a local high-speed network such as
a wireless LAN, there is no rule in the communication standard
regarding an intermittent standby reception processing as performed
in a mobile telephone terminal. Therefore, in order to make the
user obtain information service from a wireless LAN while moving
around, each wireless terminal has to periodically measure the
signal intensity of a common channel in the wireless LAN and
determine whether the terminal can communicate with the wireless
LAN in the present position or not. A terminal once connected to
the wireless LAN basically enters a receivable state, monitors data
on the network, and receives the desired data.
[0036] The multimode wireless terminal of the invention is
characterized in that, in order to enable communication in both
communication modes of a mobile telephone terminal and a wireless
LAN terminal, the operation mode of the terminal is automatically
switched to a local network wireless communication mode (wireless
LAN mode) at intervals of standby receptions periodically repeated
in the mobile telephone mode.
[0037] FIG. 2 shows an example of a sequence of switching the
communication mode in a multimode wireless terminal according to
the invention.
[0038] According to the invention, as shown in FIG. 2, during
intervals T12 (211, 212, . . . ) between intermittent standby
receptions T11 (201, 202, . . . ) of a mobile telephone mode
(public network wireless communication mode) repeated in
predetermined cycles T1, the communication mode of the terminal is
changed to the wireless LAN mode (local network wireless
communication mode). The mobile telephone mode is one of, for
example, GSM, PDC, EDGE, GPRS, cdmaOne, cdma2000, and W-CDMA, and
the wireless LAN mode is one of, for example, IEEE802.11a,
IEEE802.11b, IEEE802.11g, IEEE802.11h, HiperLAN/2, Bluetooth, and
UWB.
[0039] If the terminal is located in an area where the wireless LAN
can be used, by using the periods T12, a packet transmission and
receiving processing via the wireless LAN is executed. At the time
of switching the communication mode, there is the possibility that
a transmission signal spectrum goes out of a restricted range
(spectrum mask) defined by a wireless communication standard due to
a transient response of a power amplifier or the like in a
transmitter circuit. Consequently, as shown by .DELTA.t in FIG. 2,
switching of the communication mode is executed after the power
source for a transmission power amplifier is turned off once.
[0040] In the case where there is an incoming call during the
standby reception period T11 of the mobile telephone mode, the
incoming call is treated in accordance with a mode selection rule
designated by the user in advance. For example, when a mobile
telephone preference mode is designated as the mode selection rule,
the mobile telephone mode is continued, as shown by a period T13 in
FIG. 2, even after a standby reception period 203 in which an
incoming call is detected, and communication via the wireless LAN
is interrupted until speech communication is finished.
[0041] If a wireless LAN preference mode is designated as the mode
selection rule, an incoming call is ignored and, after the standby
reception period 203, communication in the wireless LAN mode in the
period T12 is repeated. The communication mode after the incoming
call may be selected according to the choice of the user each time
an incoming call is detected. Specifically, when a user selection
mode is designated as the mode selection rule, automatic switching
to the wireless LAN mode is stopped, the user is requested to
select a communication mode on which priority is to be placed, and
the operation mode is switched to a communication mode designated
by the user.
[0042] FIG. 1 is a configuration diagram showing an example of a
multimode wireless terminal to which the mode switching shown in
FIG. 2 is applied.
[0043] The multimode wireless terminal is comprised of: a front end
unit 11 connected to an antenna 10; a radio frequency unit 12
connected to the front end unit 11; a radio frequency unit
interface 13 including an analog to digital (A/D) converter 131 and
a digital to analog (D/A) converter 132; a baseband unit 14
including a modulation and demodulation unit (modem) 141 and a
digital signal processor (DSP) 142; a control processor (CPU) 16
connected to the DSP 142 via an internal bus 18; a user interface
15; and a random access memory (RAM) 17A and a read only memory
(ROM) or flash memory 17B connected to the internal bus 18. The
switching of the communication mode of the terminal is conducted by
the control processor 16 in cooperation with the DSP 142.
[0044] The radio frequency unit 12 includes at least a radio
frequency integrated circuit (RF-IC) 30 subjected to mode switching
control which will be described later and a transmission power
amplifier (PA) 40. The user interface 15 is comprised of an analog
interface 15A connected to the DSP 142 and a digital (data)
interface 15B connected to the internal bus 18 and the modem 141.
The analog interface 15A is coupled with a speaker 20 and a
microphone 21. A display unit 22 and a keyboard 23 are coupled with
the digital interface 15B.
[0045] A received signal from the antenna 10 is input to the front
end unit 11, separated from a transmission signal by an antenna
switch (or duplexer) and filtered. After that, the resultant signal
is input to the radio frequency unit 12. The RF-IC 30 of the radio
frequency unit 12 has circuit functions of a filter, an amplifier,
a mixer, and the like and the received signal is converted to a
baseband signal by the RF-IC 30. The baseband signal output from
the RF-IC 30 is converted to a digital signal by the A/D converter
131 in the interface 13 and the digital signal is demodulated by
the modem 141 in the baseband unit 14. When a demodulated signal is
a voice signal, it is processed by the DSP 142 and the processed
signal is output to the analog interface 15A. In the case where the
demodulated signal is data, the data is output to the digital
interface 15B or internal bus 18.
[0046] The transmission voice signal input from the microphone 21
and the transmission data output from the control processor 16 are
subjected to a process such as error correction coding or the like
by the DSP 142. The resultant signal is modulated by the modem 141.
The modulated transmission signal is converted to an analog signal
by the D/A converter 132 and, after that, the analog signal is
converted to a radio frequency transmission signal in a desired
frequency band by the RF-IC 30 in the radio frequency unit 12. The
radio frequency transmission signal is amplified by the power
amplifier 40 and filtered by the front end unit 11. After that, the
resultant signal is transmitted from the antenna 10.
[0047] The control processor (CPU) 16 executes various programs for
data processing or communication control in response to the user
operation from the keyboard 23. The control processor 16 also
executes a communication mode switching control routine which will
be described later and performs setting of various parameters to
the RF-IC 30 and a mode switching via the DSP 142. The setting of
parameters and the mode switching are instructed to the RF-IC 30
via a signal line L1. Turn-on/off of the power source for the
transmission power amplifier 40 is instructed via a signal line
L2.
[0048] FIG. 3A shows main components of a control circuit of a
conventional RF-IC for a multimode wireless terminal. For simpler
explanation, the diagram shows, as components of the RF-IC, a
filter 32, a variable gain amplifier 33, and a mixer 34 which
construct a receiving circuit and, in correspondence with the above
components, a plurality of reference registers (a filter
coefficient register 302, a gain adjustment register 303, and a
local frequency register 304) which are formed in a reference
register block 300. In an actual RF-IC, the receiving circuit
includes other analog components in addition to the above
components. On the substrate of the RF-IC, not only the above
receiving circuit but also a transmission circuit having an
operation characteristic controllable with reference parameter
values is formed.
[0049] In the multimode wireless terminal, as shown in FIG. 3A, by
employing a circuit configuration in which the operation
characteristics of some of the analog components formed on the
RF-IC are changed depending on the value of reference parameters
set in the reference register block 300, a plurality of different
communication modes are realized by a single RF-IC. Reference
parameters to be set in the reference register block 300 vary
according to the kind of analog components. For example, the
parameter for a mixer which is set in the reference register 304
indicates the frequency of a local signal to be supplied to the
mixer. The parameter for the variable gain amplifier set in the
reference register 303 indicates a gain coefficient of an
amplifier. The parameter for a filter set in the reference register
302 indicates a filter coefficient.
[0050] Each of reference parameter may be comprised of a multi-bit
parameter in which each bit designates the potential of one of
terminals of an analog component. For example, "0" bit corresponds
to GND potential and "1" bit corresponds to Vdd. In the case of
correcting the characteristic of a nonlinear component such as the
power amplifier by predistortion or the like, the parameter to be
set in the reference register may also include a calibration
correction value.
[0051] In the conventional RF-IC, these reference parameters are
supplied from an external signal input pin 31 to a configuration
value write control circuit 305. By switching a switch 306 by the
configuration value write control circuit 305, the parameters are
selectively set into the specific registers 302 to 304 in the
reference register block 300. Each of the analog components such as
the filter 32, variable gain amplifier 33, and mixer 34 operates
with an operation characteristic depending on the reference
parameter value indicated by the corresponding reference
register.
[0052] The external signal line used for setting the above
parameters into the reference registers is generally of a serial
bus type for sequentially transferring data bit by bit, in order to
realize smaller size of an IC package by reducing the number of
external signal pins of the RF-IC as much as possible.
[0053] In a conventional multimode wireless terminal, switching of
the operation mode of the RF-IC is realized by changing the
reference parameters in response to a user operation. In this case,
each time the mode is switched, for example, as shown in FIG. 3B,
all of parameters P302, P303, P304, . . . to be set in the
reference register block 300 have to be supplied serially from the
external signal input pin 31. Consequently, hundreds of clocks is
required to switch the mode.
[0054] The conventional RF-IC is adopted on a premise that the mode
switching is of low frequency such that one communication mode
selected by the user continues for several minutes or longer. In
this case, if the user sets the terminal in the wireless LAN mode,
the terminal loses the function of a mobile telephone. Therefore,
as long as the user does not switch the operation mode of the
terminal to the mobile telephone mode by re-setting the reference
parameters, standby reception of the mobile telephone is not
executed.
[0055] FIG. 4A shows a first embodiment of the control circuit of
the RF-IC 30 for a multimode wireless terminal according to the
invention.
[0056] As described by referring to FIG. 2, in order to frequently
switch the communication mode of the multimode wireless terminal in
relatively short cycles, the values of various reference parameters
set in the reference register block 300 of the RF-IC 30 have to be
changed at high speed.
[0057] When all of the reference parameters are input from the
external signal input pin 31 each time the mode is switched as in
the conventional technique, overhead for setting the parameters
increases and, as a result, the operation period in the wireless
LAN mode has to be shortened.
[0058] For example, when it is assumed that the reference register
block 300 of the RF-IC 30 has 24 registers each having a 16-bit
width, in order to set parameters from the serial bus (signal line
L1), 384(=16.times.24) clocks are necessary. If the operation clock
of the RF-IC 30 is 15 MHz, it takes about 25 msec for the parameter
setting. Therefore, if the standby reception processing is repeated
at the intervals of one second, there is a problem such that half
of the period T1 shown in FIG. 2 would be consumed for the
parameter setting for the mode switching.
[0059] To reduce the overhead of the parameter setting to the
reference register block 300 which occurs at the time of switching
the communication mode, in the first embodiment of the invention,
the RF-IC 30 is provided with a parameter storing register block
400. When the power source of the terminal is turned on,
configuration parameter values to be used as reference parameters
for respective communication modes are supplied from the signal
line L1 and stored in the register block 400. Each time the
switching of the communication mode is required, the configuration
parameter values of a desired mode are transferred from the
register block 400 to the reference register block 300 in
parallel.
[0060] For example, when a mobile telephone is defined as a mode 1
and the wireless LAN is defined as a mode 2, parameter storing
registers 402 to 404 for the mode 1 and parameter storing registers
412 to 414 for the mode 2 are prepared in the parameter storing
register block 400, in correspondence with the registers 302 to 304
in the reference register block 300. The configuration parameter
bits stored in one of the registers 402 and 412 are selectively
transferred in parallel to the register 302 via a mode switch 312
in accordance with the communication mode. Similarly, configuration
parameter bits stored in one of the registers 403 and 413 are
selectively transferred in parallel to the register 303 via a mode
switch 313, and configuration parameter bits stored in one of the
registers 404 and 414 are selectively transferred in parallel to
the register 304 via a mode switch 314.
[0061] The mode switches 312 to 314 connect either the group of
parameter storing registers 402 to 404 for the mode 1 or the group
of the parameter storing registers 412 to 414 for the mode 2 to the
group of the registers 302 to 304.
[0062] With the configuration, for example, when the terminal power
is turned on, various configuration parameters are supplied to the
RF-IC in the form described by referring to FIG. 3B and the
parameters for the modes 1 and 2 are set in the parameter storing
registers 402 to 404 and parameter storing registers 412 to 414,
respectively. After that, only by changing the set value (mode
selection bit) in the mode register 311, the reference parameter
values in the parameter reference registers 302 to 304 can be
instantaneously changed.
[0063] The location of the register area to which the configuration
parameter is to be written can be designated by, for example, a
control code output to the signal line L1 from the DSP 142 prior to
the parameter itself. Therefore, a configuration value write
controller 401 can control a switch 411 in accordance with the
control code received from the signal line L1, so that the
parameter values received from the signal line L1 are selectively
set in the registers in the parameter storing register block 400.
By setting a mode selection bit received thereafter from the signal
line L1 to the mode register 311, it is able to operate the
switches 312 to 314 so as to change the reference parameter values,
thereby switching the communication mode of the RF-IC 30 at high
speed.
[0064] According to the embodiment, initial setting of
configuration parameters in the parameter storing register block
400 takes relatively long time. However, in order to switch the
communication mode of the RF-IC 30, for example, as shown by CNT1
and CNT2 in FIG. 4B, it is sufficient to supply short control data
including a mode selection bit to the RF-CI 30. Consequently, the
switching of the operation mode can be completed in short time At
equivalent to only a few clocks.
[0065] FIGS. 8A and 8B show flowcharts of a mode switching control
routine 500 corresponding to the first embodiment. The control
routine 500 is executed by the control processor (CPU) 16 when the
power of the terminal is turned on.
[0066] The control processor 16 executing the mode switching
control routine 500 sets, first, the configuration parameters for
the mode 1 into the parameter storing registers 402 to 404 on the
RF-IC 30 via the DSP 142 (step 501). Various parameter values
required for the configuration parameters for the mode 1 and mode 2
are stored in advance in a parameter table in the ROM 17B.
Therefore, when the control processor 16 transmits the
configuration parameters for the mode 1 read out from the ROM
together with the write control command to the DSP 142, the DSP 142
transfers the received parameters together with a control code for
the write control circuit 401 to the signal line L1, and the write
control circuit 401 in the RF-IC 30 selectively writes the
parameters received from the signal line L1 to the registers 402 to
404 specified by the control code. Like in step 501, the control
processor 16 sets the configuration parameters for the mode 2 to
the parameter storing registers 412 to 414 in the RF-IC 30 in
cooperation with the DSP 142 (step 502).
[0067] After the parameter initial setting, the control processor
16 instructs the DSP 142 to execute the initial processing in the
mode 1 (mobile telephone mode) (step 503). In response to the
instruction, the DSP outputs to the signal line L1 an instruction
of switching the communication mode to the mode 1 and executes a
predetermined communication procedure for registering the terminal
position to a base station of the mobile telephone network. The
instruction of switching the communication mode to the mode 1
output to the signal line L1 includes a mode selection bit
indicative of switching to the mode 1 and a control code indicating
that the destination of the mode selection code is the mode
register 311.
[0068] On completion of registration of the terminal position, the
control processor 16 starts a timer T1 (step 504) and instructs the
DSP 142 to switch the radio frequency unit to the mode 1 (step
505). Upon receiving the mode switching instruction from the
control processor 16, the DSP 142 once turns off the power source
of the transmission power amplifier 40 via the signal line L2,
outputs an instruction of switching to the mode 1 to the signal
line L1, and returns the power source of the transmission power
amplifier 40 to the on state. By the operation, standby reception
of predetermined time T11 is started. By monitoring a signal output
from the modem 141 to the internal bus 18 during the standby
reception period T11, the control processor 16 determines whether
an incoming call event occurs or not (step 506).
[0069] If there is an incoming call in the mode 1, the control
processor 16 executes an incoming call processing 520 shown in FIG.
8B. If there is no incoming call during the standby reception
period T11, the control processor 16 instructs the DSP 142 to
switch the radio frequency unit to the mode 2 (wireless LAN mode)
(step 507).
[0070] When the switching instruction to the mode 2 is received
from the control processor 16, the DSP 142 turns off the power
source of the transmission power amplifier 40 via the signal line
L2, outputs a switching instruction to switch the operation mode of
the radio frequency unit to the mode 2 to the signal line L1, and
returns the power source of the transmission power amplifier 40 to
the on state. The switching instruction to the mode 2 includes the
mode selection bit indicative of switching to the mode 2 and a
control code indicating that destination of the mode selection bit
is the mode register 311.
[0071] After switching the RF-IC 30 to the mode 2, the control
processor 16 executes the data transmission and receiving
processing for the wireless LAN until interruption of the timer T1
occurs (step 509). When interruption of the timer T1 occurs (step
508), the control processor 16 returns to step 505 and instructs
the DSP 142 to switch the RI-IC 30 to the mode 1.
[0072] By the control procedure, as long as there is no incoming
call to the terminal, the data transmission and receiving
processing for the wireless LAN can be executed at the intervals of
the standby reception periods. That is, the incoming call standby
reception processing in the mode 1 and the data transmission and
receiving processing for the wireless LAN in the mode 2 are
executed in a time sharing manner.
[0073] In the incoming call processing 520, as shown in FIG. 8B,
the mode selection rule designated by the user in advance is judged
(step 521). When a speech preference mode is designated as the mode
selection rule (step 530), the control processor 16 executes an
output processing for indicating the incoming call (step 531). The
incoming call is notified to the user, for example, by outputting
flashing display indicative of an incoming call on the display unit
22 or outputting a melody indicative of an incoming call to the
speaker 20. The control processor 16 waits for a response from the
user to the incoming call (step 532). If there is no response, the
control processor 16 repeats the incoming call indication 531 until
the calling party disconnects the call (step 533).
[0074] When the user performs an input operation to respond to the
incoming call, the wireless terminal enters a speech mode in which
voice signals are communicated via the DSP. The control processor
16 monitors disconnection of the call in this state (step 534).
When the call is disconnected, the control processor 16 returns to
step 504 in FIG. 8A, restarts the timer T1, and repeats the steps
505 to 509.
[0075] When a wireless LAN preference mode is designated as a mode
selection rule (step 550), the control processor 16 records
incoming call data such as incoming call time and telephone number
of the caller into the RAM 17A (step 551), disconnects the call
(step 522), and returns to step 507 in FIG. 8A. In this case, the
incoming call is ignored and, by using the intervals between the
call standby reception periods, the data transmission and receiving
processing for the wireless LAN is intermittently executed. It is
also possible to omit the disconnection of the call (step 522) and
allow the caller to disconnect the call.
[0076] When a user's selection preference mode is designated as a
mode selection rule (step 540), the control processor 16 outputs a
menu screen (or icon) for mode selection on the display unit 22
(step 541) and treats the incoming call in accordance with the
communication mode selected by the user on the menu screen. If the
user selects the speech preference mode, steps 531 to 534 are
executed. If the user selects the wireless LAN preference mode,
steps 551 and 552 are executed.
[0077] In the first embodiment described above, the multimode
terminal capable of switching between two kinds of communication
modes has been described. There is, however, a case that selectable
three or more kinds of communication modes are desired to be
offered, depending on a service area where the wireless terminal
exists. If a frequent mode switching occurs among all of
communication modes, a number of registers equal to the number of
kinds of communication modes have to be prepared in the parameter
storing register block 400 in correspondence with registers in the
reference register block 300. In this case, the number of parameter
storing registers and the circuit scale of the RF-IC 30 increases.
In order to reduce the circuit scale of the RF-IC 30, for example,
it is sufficient to make specific groups of configuration
parameters always reside in the parameter storing register block
400 with respect to communication modes which are frequently
switched, and to supply the other configuration parameters with
respect to a communication mode having relatively long switching
intervals from the ROM 17B to the parameter storing register block
400 each time the communication mode is selected.
[0078] FIG. 5 shows a second embodiment of the control circuit of
the RF-IC 30 for the multimode wireless terminal according to the
invention.
[0079] For example, in a wireless terminal of a carrier frequency
hopping type, which selects a frequency to be used from a group of
carrier frequencies according to a predetermined sequence different
for each user terminal to perform communications while periodically
switching the carrier frequency, the local frequency to be set in a
mixer has to be changed for every call. When the carrier frequency
hopping is employed as the mobile telephone mode (mode 1),
reference parameters to be set in the local frequency configuration
register 304 in the RF-IC 30 have to be updated for each call. In
this case, it is not sufficient to switch the parameter storing
registers like the first embodiment.
[0080] The second embodiment is directed to shorten the time
required to change the reference parameters under such conditions.
In the second embodiment, for the local frequency configuration
register 304, reference parameters are set from the DSP via the
signal line L1 and the state of the register 304 is monitored by
the mode judging and switching circuit 312. For the other reference
registers (302 and 303) in the reference register block 300, the
mode judging and switching circuit 312 changes the reference
parameters by switching the status of the switches 312 and 313 at a
predetermined timing. Selection of a communication mode is
performed based on the value of at least a part of parameters set
in the register 304.
[0081] According to the embodiment, parameter data to be supplied
from the external signal input pin 31 at the time of operation mode
switching is only a parameter value for local frequency, so that
the communication mode can be switched at higher speed as compared
with the prior art.
[0082] FIG. 6 shows a third embodiment of the control circuit in
the RF-IC 30 for the multimode wireless terminal according to the
invention.
[0083] In the first and second embodiments, configuration
parameters are loaded from the external input pin 31 via the
configuration value write controller 401 to all of registers
prepared in the parameter storing register block 400 at the time of
initial setting. However, depending on the wireless communication
method, some parameters to be set in the RF-IC are unconditionally
determined and will not be changed later. For example, in W-CDMA as
a third generation mobile telephone, the frequency characteristics
of the output signal are specified by a standard.
[0084] Consequently, an FIR filter coefficient on the output signal
side decided at the time of circuit design will not be changed
later.
[0085] In such a case, it is unnecessary to write the same
parameter values into the parameter storing register each time the
initial setting is performed. For example, like in the register 402
in FIG. 6, a register as a part of the parameter storing register
block 400 may be replaced with a ROM for holding fixed parameters.
When the filter coefficient for the mode 2 is also a fixed value,
the register 412 can be also replaced with a ROM. By replacing a
part of the register area 400 with a ROM as described above, it is
able to shorten the time required for parameter initial setting and
to reduce power consumption.
[0086] FIG. 7A shows a fourth embodiment of the control circuit of
the RF-IC 30 for the multimode wireless terminal according to the
invention.
[0087] In the first embodiment, configuration parameter values are
transferred as reference parameter values from the parameter
storing register block 400 to all of the parameter reference
registers (302 to 304). In an actual application, there is a case
such that configuration parameters have to be set from the
parameter storing register block 400 with respect to only a part of
the reference registers.
[0088] The fourth embodiment is characterized in that, for example,
like an amplifier gain parameter, a specific parameter of which set
value is desired to be changed even in the same communication mode
depending on special situations such as a radio propagation state
in a wireless path is supplied from the external signal input pin
31 to the parameter reference register 303, and the other
parameters are set from the parameter storing register block 400 to
the parameter reference register.
[0089] In the embodiment, for example, special parts such as mixers
34A and 34B, which become difficult to share the same circuit
depending on a combination of selectable communication modes or
analog components to be dedicated to respective modes because it is
advantageous from the viewpoint of performance and power
consumption, are excluded from targets of parameter switching. For
some parts of which parameter set values are the same even when the
communication mode changes, it is naturally unnecessary to switch
the configuration parameters.
[0090] In the embodiment, as shown in FIG. 7B, it is sufficient to
supply control data CNT1 and CNT2 including, for example, a control
code P401, a mode selection bit P311, and an amplifier gain
adjustment parameter P303 to the RF-IC 30 each time the
communication mode is switched.
[0091] As described above, according to the invention, by properly
combining parameter transfers from the holding register to the
reference register in balance in accordance with the required
performance of an analog component, the time required to switch the
communication mode can be shortened while suppressing increase in
the scale of the IC and the influence on performance.
[0092] In the embodiment shown in FIG. 8B, any one of the speech
preference mode, wireless LAN preference mode, and user's selection
preference mode is designated according to the mode selection rule
in the incoming call processing. However, further another mode may
be designated according to the mode selection rule. For example, a
parallel execution mode of executing voice communication by a
mobile telephone and data communication by a wireless LAN in
parallel in a time sharing manner may be designated.
[0093] Since voice data is transmitted and received every 125
.mu.sec, data of the wireless LAN can be communicated in a time
sharing manner by using the intervals of voice data communication
in the parallel execution mode. According to the invention, since
the communication mode can be switched at high speed, for example,
by increasing the operation speed of the RF-IC 30, control
processor 16, and DSP 142 or decreasing the data bit rate of the
wireless LAN in the parallel execution mode, it is able to offer
such a form of communication service that the user is allowed to
perform speech communication by a mobile telephone in parallel with
display of received data from the wireless LAN to the display unit
22.
[0094] As obvious from the foregoing embodiments, according to the
invention, the communication mode can be switched at high speed.
Consequently, it is able to provide a multimode wireless terminal
capable of executing plural kinds of communication modes of
different communication protocols, like the mobile telephone and
the wireless LAN communication, while periodically switching the
communication modes.
[0095] In the embodiments, the multimode terminal for switching the
communication mode between the mobile telephone mode (public
network wireless communication) and the wireless LAN mode (local
network communication) has been described. The method of switching
the communication mode according to the invention is also
applicable to a combination of communication modes other than the
embodiments. For example, alternate switching may be performed
between first and second communication modes of the wireless LAN in
order to detect a wireless LAN system from which the terminal can
receive data, so that a user can enjoy information distribution
service provided by the detected wireless LAN system.
* * * * *