Abstract:
A method and apparatus is provided to simultaneously perform a TV reception function and a calling function in a multimode mobile phone supporting two or more communication services. The apparatus comprises a first RF switch separating a received signal into N communication services; M diplexers associated with the communication services, for separating a signal received from the first RF switch into a call signal and a TV signal; a second RF switch for applying the TV signal received from the diplexers to a TV tuner; and a controller for controlling an overall operation of the multimode mobile phone and controlling the first RF switch and the second RF switch according to the received signal.

Description:
PRIORITY 
   This application claims priority under 35 U.S.C. § 119 to an application entitled “Apparatus and Method for Simultaneously Performing TV Reception Function and Calling Function in a Mobile Phone” filed in the Korean Intellectual Property Office on Apr. 22, 2003 and assigned Ser. No. 2003-25429, the contents of which are incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to a mobile terminal such as a mobile phone, and in particular, to an apparatus and method for simultaneously performing a Television (TV) reception function and a calling function in a mobile phone capable of supporting two or more communication services. 
   2. Description of the Related Art 
   In general, a mobile phone supporting Personal Communications Service (PCS) technology, Code Division Multiple Access (CDMA) technology and Global Positioning System (GPS) is called a “tri-mode phone,” and can provide a mobile communication service in different modes. 
   In the tri-mode phone, currently available communication services are classified into a CDMA service having a frequency band of 824 MHz to 894 MHz, a GPS service having a frequency band of 1575.42 MHz, and a PCS service having a frequency band of 1851 MHz to 1989 MHz. A transceiver circuit is included in the tri-mode phone to provide these services. 
     FIG. 1  is a block diagram illustrating an example of a transceiver circuit of a conventional tri-mode phone, which separates a GPS signal and a CDMA signal using a diplexer. As illustrated in  FIG. 1 , the transceiver circuit of a tri-mode phone supporting the CDMA, GPS and PCS services includes first and second GPS band filters  1   a  and  1   b  for filtering a GPS band frequency, a GPS band low-nose-amplifier  2  for amplifying the filtered GPS band frequency, a GPS band frequency-down mixer  3 , a digital demodulation Integrated Circuit (IC)  4  for reception, a duplexer  5  for separation of a transmission signal and a reception signal, a CDMA band low-noise amplifier  6 , a CDMA reception band filter  7 , a CDMA band frequency-down mixer  8 , a phase locked loop (PLL) circuit  9  for synthesis of a GPS band local frequency signal and a CDMA band local frequency signal, a digital modulation IC  10  for transmission, a CDMA band frequency-up mixer  11 , a CDMA band output amplifier  12 , a CDMA transmission band filter  13 , and a CDMA band high-power amplifier  14 . In addition, the tri-mode phone includes a diplexer  31 , an antenna matching circuit  32 , and an antenna  20  having two frequency band characteristics of GPS and CDMA. A separate antenna must be added to the tri-mode phone in order to enable the phone to perform a TV reception function. However, the addition of a separate antenna increases a size of the product and impairs its external appearance. Accordingly, there is a demand for a tri-mode phone capable of enabling a user to talk on the phone while watching TV without the addition of a separate antenna. 
   SUMMARY OF THE INVENTION 
   It is, therefore, an object of the present invention to provide an apparatus and method for simultaneously performing a TV reception function and a calling function in a mobile phone providing two or more communication services. 
   To achieve the above and other objects, there is provided an apparatus for simultaneously performing a TV reception function and a calling function in a multimode mobile phone supporting two or more communication services. The apparatus comprises a first Radio Frequency (RF) switch for separating a received signal into N communication services; M diplexers associated with the communication services, for separating a signal received from the first RF switch into a call signal and a TV signal; a second RF switch for applying the TV signal received from the diplexers to a TV tuner; and a controller for controlling an overall operation of the multimode mobile phone and controlling the first RF switch and the second RF switch according to the received signal. 
   To achieve the above and other objects, there is provided a method for simultaneously performing a TV reception function and a calling function in a multimode mobile phone supporting two or more communication services. The method comprises the steps of separating a received signal into a corresponding communication service; separating the communication service into a call signal and a TV signal, and performing a calling function or a TV reception function. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which: 
       FIG. 1  is a block diagram illustrating an example of a tri-mode phone according to the prior art; 
       FIG. 2  is a block diagram illustrating an example of a tri-mode phone according to an embodiment of the present invention; 
       FIG. 3A  is a block diagram illustrating an example of a detailed structure of the first RF switch in  FIG. 2  according to an embodiment of the present invention; 
       FIG. 3B  is a block diagram illustrating an example of a detailed structure of the second RF switch in  FIG. 2  according to an embodiment of the present invention; 
       FIG. 4A  is a graph illustrating an example of insertion loss of the first diplexer in  FIG. 2  according to an embodiment of the present invention; 
       FIG. 4B  is a graph illustrating an example of insertion loss of the second diplexer in  FIG. 2  according to an embodiment of the present invention; 
       FIG. 5  is a flowchart illustrating an example of a procedure for simultaneously performing a TV reception function and a calling function in a PCS mode in a tri-mode phone according to an embodiment of the present invention; 
       FIG. 6  is a flowchart illustrating an example of a procedure for simultaneously performing a TV reception function and a calling function in a CDMA mode in a tri-mode phone according to an embodiment of the present invention; 
       FIG. 7A  is a graph illustrating an example of insertion loss occurring in a PCS mode of  FIG. 5  according to an embodiment of the present invention; 
       FIG. 7B  is a graph illustrating an example of insertion loss occurring in a CDMA mode of  FIG. 6  according to an embodiment of the present invention; and 
       FIG. 7C  is a graph illustrating an example of insertion loss occurring in a GPS mode according to an embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. In the following description, a detailed description of known functions and configurations has been omitted for conciseness. 
   In the following description, specific details such as the type of RF switch and a signal separated by a diplexer are provided to give a better understanding of the invention. However, the embodiment of the present invention should not be limited to the specific examples disclosed herein. Thus, it would be apparent to those skilled in the art that the invention can be implemented without the specific details or through a modification thereof. 
   Although an embodiment of the present invention will be described herein with reference to a tri-mode phone capable of supporting Code Division Multiple Access (CDMA), Personal Communications Service (PCS), and Global Positioning System (GPS) services, the embodiments of the invention can be applied to a multimode mobile phone supporting various communication services including a Global System for Mobile communication (GSM) service as well as the CDMA, PCS and GPS services. In the embodiment of the present invention, it will be assumed that a calling function is performed when a PCS signal is received at a PCS duplexer in a PCS mode, and also the calling function is performed when a CDMA signal is received at a CDMA duplexer in a CDMA mode. In addition, it will be assumed that a GPS function is performed when a GPS signal is received at a GPS RF switch in a GPS mode, and a TV reception function is performed when a TV signal is received at a TV tuner. It should be appreciated by those skilled in the art that the TV signal comprises an audio and video signal, and a tuner which will be described below can selectively tune to a particular channel. 
   An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. 
     FIG. 2  is a block diagram illustrating an example of a structure of a tri-mode phone according to an embodiment of the present invention.  FIGS. 4A and 4B  are graphs illustrating examples of insertion losses of the first and second diplexers in  FIG. 2 , respectively according to embodiments of the present invention. 
   Referring to  FIG. 2 , a first Radio Frequency (RF) switch  110  is a single-pole-three-throw (SP3T) type switching circuit having one input port P 1 , three output ports P 2 , P 3  and P 4 , and three control ports Vc 1 , Vc 2  and Vc 3 . In the first RF switch  110 , the input port P 1  is connected to an antenna  100 , and the output ports P 2 , P 3  and P 4  are connected to a first diplexer  120 , a second diplexer  130 , and a GPS RF switch  140 , respectively. The control ports Vc 1 , Vc 2  and Vc 3  are controlled by a controller  190 . When only the control port Vc 1  is provided with a ‘High’ signal while the other control ports Vc 2  and Vc 3  are provided with a ‘Low’ signal, the input port P 1  is switched to the output port P 2  connected to the first diplexer  120 . When only the control port Vc 2  is provided with a ‘High’ signal while the other control ports Vc 1  and Vc 3  are provided with a ‘Low’ signal, the input port P 1  is switched to the output port P 3  connected to the second diplexer  130 . In addition, when only the control port Vc 3  is provided with a ‘High’ signal while the other control ports Vc 1  and Vc 2  are provided with a ‘Low’ signal, the input port P 1  is switched to the output port P 4  connected to the GPS RF switch  140 . 
   An embodiment of the present invention will now be described with reference to  FIG. 3A .  FIG. 3A  is a block diagram illustrating an example of a detailed structure of the first RF switch in  FIG. 2  according to an embodiment of the present invention Specifically,  FIG. 3A  shows a detailed structure of the SP3T-type first RF switch  110  having one input port P 1 , three output ports P 2  to P 4 , and three control ports Vc 1 , Vc 2  and Vc 3 . 
   Referring to  FIG. 2 , the first diplexer  120  separates a received RF signal. Specifically, in an embodiment of the present invention, the first diplexer  120  separates a PCS signal assigned a frequency of 1851 to 1989 MHz and a TV signal assigned a frequency of 50 to 700 MHz, and is comprised of a low-pass filter and a high-pass filter. When the tri-mode phone is set to a PCS mode, a signal received from the antenna  100  is switched to the first diplexer  120  by the first RF switch  110  and then separated by the first diplexer  120 . If the separated signal is a PCS signal, the PCS signal is applied to a PCS duplexer  150  to perform a calling function, and if the separated signal is a TV signal, the TV signal is applied to a TV tuner  180  via a second RF switch  160  to perform a TV reception function. The TV reception function can include enabling black and white or color TV viewing on a mobile phone. As is known, the tuner  180  is used to select a desired channel and to scan channels. Referring to  FIG. 4A , insertion loss occurring in the first diplexer  120  is used to separate a PCS signal and a TV signal. As shown in  FIG. 4A  m 1  and m 2  represent insertion loss of a TV band signal, and m 3  and m 4  represent insertion loss of a PCS band signal. It is noted from  FIG. 4A  that the first diplexer  120  used for separation of a PCS signal and a TV signal has low insertion loss. 
   Referring to  FIG. 2 , the second diplexer  130  separates a received RF signal. In the embodiment of the present invention, the second diplexer  130  separates a CDMA signal assigned a frequency of 824 to 894 MHz and a TV signal assigned a frequency of 50 to 700 MHz, and is comprised of a low-pass filter and a high-pass filter. When the tri-mode phone is set to a CDMA mode, a signal received from the antenna  100  is switched to the second diplexer  130  by the first RF switch  110 , and the second diplexer  130  separates the received signal and the received signal is then separated by the second diplexer  130 . If the separated signal is a CDMA signal, the CDMA signal is applied to a CDMA duplexer  170  for separation of a transmission signal and a reception signal to perform a calling function. If the separated signal is a TV signal, the TV signal is applied to the TV tuner  180  via the second RF switch  160  to perform a TV reception function. Shown in  FIG. 4B  is insertion loss occurring in the second diplexer  130  used for separation of a CDMA signal and a TV signal. In  FIG. 4B , M 1  represents insertion loss of a TV band signal, and M 2  represents insertion loss of a CDMA band signal. It is noted from  FIG. 4B  that the second diplexer  130  used for separation of a CDMA signal, and a TV signal has low insertion loss. 
   The second RF switch  160  is a single-pole-double-throw (SPDT) type switching circuit having one input port P 5 , two output ports P 6  and P 7 , and two control ports Vctrl 1  and Vctrl 2 . In the second RF switch  160 , the input port P 5  is connected to the TV tuner  180 , and the output ports P 6  and P 7  are connected to the first diplexer  120  and the second diplexer  130 , respectively. The control ports Vctrl 1  and Vctrl 2  are controlled by the controller  190 . When the control port Vctrl 1  is provided with a ‘High’ signal while the other control port Vctrl 2  is provided with a ‘Low’ signal, the input port P 5  is switched to the output port P 6  connected to the first diplexer  120 . In contrast, when the control port Vctrl 2  is provided with a ‘High’ signal while the other control port Vctrl 1  is provided with a ‘Low’ signal, the input port P 5  is switched to the output port P 7  connected to the second diplexer  130 . 
   An embodiment of the invention will now be discussed with reference to  FIG. 3B .  FIG. 3B  is a block diagram illustrating an example of a detailed structure of the second RF switch in  FIG. 2  according to an embodiment of the present invention. Specifically,  FIG. 3B  is a detailed structure of the SPDT-type second RF switch  160  having one input port P 5 , two output ports P 6  and P 7 , and two control ports Vctrl 1  and Vctrl 2 . 
   Referring to  FIG. 2 , the controller  190  controls the overall operation of the tri-mode phone. According to an embodiment of the present invention, if the tri-mode phone is set to a PCS mode, the controller  190  sets the control port Vc 1  of the first RF switch  110  to ‘High’ and sets the other control ports Vc 2  and Vc 3  to ‘Low’ so that the first RF switch  110  is switched to the first diplexer  120 . In addition, the controller  190  sets the control port Vctrl 1  of the second RF switch  160  to ‘High’ and sets the other control port Vctrl 2  to ‘Low’ so that the second RF switch  160  is switched to the first diplexer  120 . 
   If the tri-mode phone is set to a CDMA mode, the controller  190  sets the control port Vc 2  of the first RF switch  110  to ‘High’ and sets the other control ports Vc 1  and Vc 3  to ‘Low’ so that the first RF switch  110  is switched to the second diplexer  130 . In addition, the controller  190  sets the control port Vctrl 2  of the second RF switch  160  to ‘High’ and sets the other control port Vctrl 1  to ‘Low’ so that the second RF switch  160  is switched to the second diplexer  130 . If the tri-mode phone is set to a GPS mode, the controller  190  sets the control port Vc 3  of the first RF switch  110  to ‘High’ and sets the other control ports Vc 1  and Vc 2  to ‘Low’ so that the first RF switch  110  is switched to the GPS RF switch  140 . 
   An operation of the tri-mode phone will now be described with reference to  FIG. 2 . When the tri-mode phone is set to a PCS mode, the first RF switch  110  and the second RF switch  160  are switched to the first diplexer  120  under the control of the controller  190 . In this case, a signal received via the antenna  100  is applied to the first diplexer  120  via the first RF switch  110 , and then separated by the first diplexer  120 . If the signal separated by the first diplexer  120  is a PCS signal, the PCS signal is applied to the PCS duplexer  150  to perform a calling function. If the signal separated by the first diplexer  120  is a TV signal, the TV signal is applied to the TV tuner  180  via the second RF switch  160  to perform a TV reception function. Meanwhile, if the tri-mode phone is set to a CDMA mode, the first RF switch  110  and the second RF switch  160  are switched to the second diplexer  130  under the control of the controller  190 . In this case, a signal received via the antenna  100  is applied to the second diplexer  130  via the first RF switch  110  and then separated by the second diplexer  130 . If the signal separated by the second diplexer  130  is a CDMA signal, the CDMA signal is applied to the CDMA duplexer  170  to perform a calling function. If the signal separated by the second diplexer  130  is a TV signal, the TV signal is applied to the TV tuner  180  via the second RF switch  160  to perform a TV reception function. In addition, if the tri-mode phone is set to a GPS mode, the first RF switch  110  is switched to the GPS RF switch  140  under the control of the controller  190 . In this case, if a signal received via the antenna  100  is a GPS signal, the GPS signal is applied to the GPS RF switch  140  via the first RF switch  110  to perform a corresponding GPS function. 
     FIG. 5  is a flowchart illustrating an example of a procedure for simultaneously performing a TV reception function and a calling function in a PCS mode in a tri-mode phone according to an embodiment of the present invention. 
   An embodiment of the present invention will now be described in detail with reference to  FIGS. 2 and 5 . 
   If the tri-mode phone is set to a PCS mode in step  301 , the controller  190  proceeds to step  302  where it sets the control ports Vc 1 , Vc 2  and Vc 3  of the first RF switch  110  to ‘High’, ‘Low’ and ‘Low’, respectively so that the input port P 1  of the first RF switch  110  is switched to the output port P 2  connected to the first diplexer  120 . Thereafter, in step  303 , the controller  190  sets the control ports Vctrl 1  and Vctrl 2  of the second RF switch  160  to ‘Low’ and ‘High’, respectively so that the input port P 5  of the second RF switch  160 , connected to the TV tuner  180 , is switched to the output port P 6  which is connected to the first diplexer  120 . 
   If a user of the tri-mode phone sets a TV reception mode through key manipulation, the controller  190  detects a TV signal received from the antenna  100  in step  304 . In step  305 , the TV signal is applied to the first diplexer  120  via the first RF switch  110 , and the first diplexer  120  separates the TV signal and provides the separated TV signal to the second RF switch  160 . In step  306 , the TV signal applied to the second RF switch  160  is provided to the TV tuner  180 . In step  307 , the TV tuner  180  enables the user to watch TV. 
   If a PCS signal is received while the user is watching TV in step  307 , the controller  190  perceives this in step  308 , and then proceeds to step  309 . In step  309 , the PCS signal is applied to the first diplexer  120  via the first RF switch  110 , and in step  310 , the first diplexer  120  separates the PCS signal and provides the separated PCS signal to the PCS duplexer  150 . In step  311 , the PCS duplexer  150  performs a calling function with the received PCS signal. If a call is ended, the controller  190  perceives this in step  312 , and then returns to step  307  to enable the user to continuously watch TV. 
     FIG. 6  is a flowchart illustrating an example of a procedure for simultaneously performing a TV reception function and a calling function in a CDMA mode in a tri-mode phone according to an embodiment of the present invention. 
   An embodiment of the present invention will now be described in detail with reference to  FIGS. 2 and 6 . 
   If the tri-mode phone is set to a CDMA mode in step  401 , the controller  190  proceeds to step  402  where it sets the control ports Vc 1 , Vc 2  and Vc 3  of the first RF switch  110  to ‘Low’, ‘High’ and ‘Low’, respectively so that the input port P 1  of the first RF switch  110  is switched to the output port P 3  connected to the second diplexer  130 . Thereafter, in step  403 , the controller  190  sets the control ports Vctrl 1  and Vctrl 2  of the second RF switch  160  to ‘Low’ and ‘High’, respectively so that the input port P 5  of the second RF switch  160 , connected to the TV tuner  180 , is switched to the output port P 7  which is connected to the second diplexer  130 . 
   If the user of the tri-mode phone sets a TV reception mode through key manipulation, the controller  190  detects a TV signal received from the antenna  100  in step  404 . In step  405 , the TV signal is applied to the second diplexer  130  via the first RF switch  110  and the second diplexer  130  separates the TV signal and provides the separated TV signal to the second RF switch  160 . In step  406 , the TV signal applied to the second RF switch  160  is provided to the TV tuner  180 . In step  407 , the TV tuner  180  enables the user to watch TV. 
   If a CDMA signal is received while the user is watching TV in step  407 , the controller  190  perceives this in step  408 , and then proceeds to step  409 . In step  409 , the CDMA signal is applied to the second diplexer  130  via the first RF switch  110 , and in step  410 , the second diplexer  130  separates the CDMA signal and provides the separated CDMA signal to the CDMA duplexer  170 . In step  411 , the CDMA duplexer  170  performs a calling function with the received CDMA signal. If the user ends a call, the controller  190  perceives this in step  412 , and then returns to step  407  to enable the user to continuously watch TV. 
   In the embodiment of the present invention, when the tri-mode phone is set to a GPS mode, the controller  190  sets the control ports Vc 1 , Vc 2  and Vc 3  of the first RF switch  110  to ‘Low’, ‘Low’ and ‘High’, respectively so that the input port P 1  of the first RF switch  110  is switched to the output port P 4  which is connected to the GPS RF switch  140 . In this case, if a signal received from the antenna  100  is a GPS signal, the GPS signal is applied to the GPS RF switch  140  via the first RF switch  110  to perform a corresponding GPS function. 
     FIG. 7A  is a graph illustrating an example of insertion loss occurring in a PCS mode of  FIG. 5  according to an embodiment of the present invention. Specifically,  FIG. 7A  illustrates insertion loss occurring where the input port P 1  of the first RF switch  110  is switched to the output port P 2 .  FIG. 7B  is a graph illustrating an example of insertion loss occurring in a CDMA mode of  FIG. 6  according to an embodiment of the present invention. Specifically,  FIG. 7B  illustrates insertion loss occurring where the input port P 1  of the first RF switch  110  is switched to the output port P 3 .  FIG. 7C  is a graph illustrating an example of insertion loss occurring in a GPS mode  6  according to an embodiment of the present invention. Specifically,  FIG. 7C  illustrates insertion loss occurring where the input port P 1  of the first RF switch is switched to the output port P 4 . It can be understood from  FIGS. 7A to 7C  that the insertion loss is not high, i.e., 0.25 dB at the minimum. 
   As described above, the tri-mode phone capable of supporting two or more communication services employs RF switches for separating the communication services and diplexers for separating a telephone call signal and a TV signal, thereby simultaneously performing a TV reception function and a calling function with a single antenna. As a result, the invention contributes to a reduction in size and cost of the products. 
   While the invention has been shown and described with reference to a certain embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.