Abstract:
A wireless wide area network (WWAN) to Ethernet converter comprises a subscriber identity module (SIM) interface, for accessing data stored in a SIM card; a radio frequency (RF) circuit, for receiving in the WWAM an RF signal associated with the data stored in the SIM card and for converting between the RF signal and a baseband signal; a digital signal processor (DSP), coupled to the RF circuit, for processing the baseband signal; and an Ethernet control device, coupled to the DSP, for converting between the processed baseband signal and an Ethernet signal.

Description:
CROSS REFERENCE TO RELATED PATENT APPLICATION 
       [0001]    This patent application is based on Taiwan, R.O.C. patent application No. 98110249 filed on Mar.  27 ,  2009 . 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a communication system, and more particularly, to a wireless wide area network (WWAN) to Ethernet converter and a communication system thereof. 
       BACKGROUND OF THE INVENTION 
       [0003]    The mobile telecommunication cellular network provides substantial communication convenience to people. Although the modern mobile telecommunication cellular network is capable of proving all types of voice and data communication services, compared to a wired network such as a local area network (LAN), the mobile telecommunication cellular network has far less bandwidth and reliability than the wired network. Furthermore, since there are many service providers for the mobile telecommunication cellular network, communication between two mobile phones from two different service providers may cost more than the two mobile phones using a same service provider. Although a communication application that integrates wireless regional area network (WRAN) technology such as Wi-Fi with Internet phone technology such as VoIP has been developed to reduce communication fees, operative coverage and popularity of the WRAN are lackluster, such that these types of applications have not effectively achieved the intended market penetration. 
         [0004]    Remote control is one of the numerous applications of mobile communication, and a user may use a mobile phone to control a remote electronic device or computer. Since this type of application system uses the Internet to control the electronic device or computer connected to it, the electronic device or computer needs its own exclusive and fixed Internet protocol (IP) address to perform the remote control—such a prerequisite imposes an unfavorable factor on the prevalence of the application of remote control. 
         [0005]    In view of the foregoing, there is a need for a new device and a system, which are capable of achieving free mobile communication without changing current mobile networks or Internet structures, such that high bandwidth and high stability of a wired regional network are effectively implemented. In addition, remote control of a device or computer can be performed even without exclusive and fixed (e.g., IP) addresses. 
       SUMMARY OF THE INVENTION 
       [0006]    One object of the present invention is to provide a WWAN to Ethernet converter and a communication system thereof, which are capable of effectively implementing high frequency band and high stability of a wired regional network and providing remote control of a device or computer. 
         [0007]    According to an embodiment of the present invention, a converter comprises: a subscriber identity module (SIM) interface, for accessing data stored in a SIM card; a radio frequency (RF) circuit, for receiving within a WWAN an RF signal associated with the data stored in the SIM card, and converting between the RF signal and a baseband signal; a digital signal processor (DSP), coupled to the RF circuit, for processing the baseband signal; and an Ethernet control device, coupled to the DSP, for converting between the processed baseband signal and an Ethernet signal. 
         [0008]    According to an embodiment of the present invention, when a first communication device and a second communication device are from a same service provider, the first communication device applies a first signal converter to communicate with the second communication device via a WWAN, or the first communication device directly communicates with the second communication device via the WWAN. When the first communication device and the second communication device are from different service providers, the first communication device communicates with the second communication device through the first signal converter, the Internet and a second signal converter. 
         [0009]    According to another embodiment of the present invention, a first communication device may control a first modem and an electronic device at a remote end through a first signal converter, or control another electronic device at the remote end through the first signal converter, the first modem and the Internet. Alternatively, the first communication device may use the first signal converter to control the remote electronic device directly coupled to the first signal converter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a schematic diagram of a WWAN to Ethernet converter in accordance with an embodiment of the present invention. 
           [0011]      FIG. 2  is a schematic diagram of a data transmission system between a WWAN and an Ethernet in accordance with an embodiment of the present invention. 
           [0012]      FIG. 3  shows a schematic diagram of a remote control system between a WWAN and an Ethernet in accordance with another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0013]      FIG. 1  shows a WWAN to Ethernet converter  10  in accordance with an embodiment of the present invention. The WWAN may be but not limited to a mobile telecommunication cellular network, which is based on a specification such as Worldwide Interoperability for Microwave Access (WIMAX), Universal Mobile Telecommunications System (UMTS), General Packet Radio Services (GPRS), Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA) CDMA2000, Wideband CDMA (WCDMA) or High-Speed Downlink Packet Access (HSDPA). In this embodiment, the converter  10  comprises a SIM card interface  100 , an RF circuit  102 , a digital signal processor (DSP)  104  and an Ethernet control device  106 . The SIM interface  100  accesses data stored in a SIM card  11 , e.g., phone numbers and a personal identification number (PIN). The RF circuit  102  receives or transmits through an antenna  12  in the WWAN an RF signal corresponding to the data, e.g., the phone numbers stored in the SIM card. The RF circuit  102  converts the received RF signal to a baseband signal or converts the baseband signal to an RF signal to be transmitted. The DSP  104 , coupled to the RF circuit  102  through a DSP/direct memory access (DMA) bus  132  and a digital baseband/RF (DigRF) interface  105 , processes the baseband signal. The Ethernet control device  106 , coupled to the DSP  104 , converts between the processed baseband signal and an Ethernet signal. In this embodiment, the Ethernet control device  106 , following the IEEE 802.3 specification, mainly comprises a media access control (MAC)/physical layer PHY module  1060 , and an Ethernet transceiver  1062 . The converter  10  connects to an external computer  13  or a modem  14  through the Ethernet transceiver  1062 . 
         [0014]    The converter  10  further comprises a processing module  110  such as a micro-controller unit (MCU), and is coupled to the DSP  104  and the Ethernet control device  106  through a basic virtual component interface/advanced microcontroller bus architecture such as a Basic Virtual Component Interface/Advanced Microcontroller Bus Architecture bus (BVCI/AMBA Bus)  130  and a Multi-Communications Device (MCD) DMA Bus  128 , respectively. The processing module  110  determines to transmit the processed baseband signal to the Ethernet control device  106  or the DSP  104  according to content of the processed baseband signal. Specifically, the processed baseband signal comprises a first message of a destination, and a storage unit  112  coupled to the processing module  110  stores a plurality of second messages. The processing module  110  compares the first message to the plurality of second messages to generate a comparison result, and determines to transmit the processed baseband signal to the Ethernet control device  106  or the DSP  104  according to the comparison result. For example, when the comparison result indicates that the first message corresponds to one of the plurality of second messages, the processing module  110  transmits the processed baseband signal to the DSP  104 , and generates and transmits another RF signal via the RF circuit  102 . On the contrary, when the comparison result indicates that the first message does not correspond to any of the plurality of second messages, the processing module  110  transmits the processed baseband signal to the Ethernet control device  106  to generate an Ethernet signal. In this embodiment, the converter  10  further comprises an arbiter  114  for coordinating the DSP  104  and the processing module  110 . 
         [0015]    In addition, the converter  10  further comprises other devices and circuits, for example, it comprises DMA controllers  116 A and  116 B, for controlling memory access requirements of the storage unit  112 ; a pulse code modulation (PCM)  118  for controlling an audio sub-system  120 ; a Viterbi decoder  122  for decoding signals; an equalizer  124  for adjusting frequency spectrum factors; and a shared memory  126 . 
         [0016]    With the foregoing architecture of converter  10  in mind,  FIG. 2  shows a data transmission system  2  between a WWAN and an Ethernet in accordance with an embodiment of the present invention. The data transmission system  2  mainly comprises a first communication device  20 A and a first signal converter  22 A. The first communication device  20 A (e.g., a mobile phone) operative within the WWAN has a first SIM interface  201  A for accessing data stored in a first SIM card  203 A. The first communication device  20 A generates a first RF signal, which is associated with the first SIM card  203 A and a second SIM card  223 A, and comprises predetermined data such as digital data, audio data or video data. The first signal converter  22 A (e.g., the converter  10  illustrated in  FIG. 1 ) has a second SIM interface  221 A for accessing data stored in the second SIM card  223 A. In an embodiment, the first SIM card  203 A and the second SIM card  223 A are from a same service provider. When the first communication device  20 A calls the first signal converter  22 A, since the first RF signal is associated with the data stored in the second SIM card  223 A, the first signal converter  22 A receives and converts the first RF signal to an Ethernet signal, such that the predetermined data is transmitted via the Ethernet. 
         [0017]    The data transmission system  2  further comprises a second communication device  20 B and a second signal converter  22 B. The second signal converter  22 B (e.g., the converter  10  illustrated in  FIG. 1 ) is coupled to the first signal converter  22 A via the Internet  24  (e.g., an Ethernet) through a first modem  23 A and a second modem  23 B. The second signal converter  22 B has a third SIM interface  221 B for accessing data stored in a third SIM card  223 B. The second signal converter  22 B also receives an Ethernet signal from the first signal converter  22 A via the Internet  24 , converts the Ethernet signal to a second RF signal associated with data stored in the third SIM card  223 B and a fourth SIM card  203 B, and transmits the predetermined data via the WWAN. In addition, the second communication device  20 B (e.g., a mobile phone), operative within the WWAN, has a fourth SIM interface  201 B for accessing data stored in the fourth SIM card  203 B. In an embodiment, the third SIM card  223 B and the fourth SIM card  203 B are from a same service provider. When the second signal converter  22 B calls the second communication device  20 B, since the second RF signal is associated with data stored in the fourth SIM card  203 B, the second communication device  20 B receives the second RF signal and receives the predetermined data via the WWAN. 
         [0018]    The data transmission system  2  may comprise an electronic device  26 A (e.g., a computer) coupled to the first signal converter  22 A in a same LAN through a network control module  260 A and a first modem  23 A, and the electronic device  26 A is used for receiving the Ethernet signal and obtaining the predetermined data. The data transmission system  2 , comprising another electronic device  26 B (e.g., a computer) coupled to the first signal converter  22 A through the second module  23 B and the Internet  24 , is used for receiving the Ethernet signal and obtaining the predetermined data. Generally, the electronic device  26 B comprises an Internet protocol (IP) address, with which the Ethernet signal is associated. 
         [0019]    In an example of the data transmission system  2 , when the first communication device  20 A (e.g., a mobile phone) wishes to communicate with the second communication device  20 B (e.g., a mobile phone), the first communication device  20 A transmits a message associated with the second communication device  20 B to the first signal converter  22 A. The processing module  110  of the first signal converter  22 A then prompts the data transmission system  2  according to the message to selectively perform one of following operations. 
         [0020]    Under a first condition that it is determined the first communication device  20 A and the second communication device  20 B are from a same service provider, that is, the first SIM card  203 A and the fourth SIM card  203 B are from a same service provider, since under this situation communication fees are rather low, the first communication device  20 A communicates with the second communication device  20 B (referring to a route  21 A illustrated in  FIG. 2 ) via the WWAN (or a mobile communication network) through the first signal converter  22 A. 
         [0021]    Under a second condition that it is determined that the first communication device  20 A is from a different service provider from the second communication device  20 B, that is, the first SIM card  203 A and the fourth SIM card  203 B are from different service providers, since under this situation communication fees are rather high, the first communication device  20 A communicates with the second communication device  20 B through the first signal converter  22 A, the Internet  24 , the second signal converter  22 B and the second communication device  20 B, so as to reduce the communication fees. Particularly, the first signal converter  22 A first converts the RF signal of the first communication device  20 A to a first Ethernet signal for controlling the first modem  23 A. A second Ethernet signal is then generated via the Internet  24  and the second modem  23 B, and the second signal converter  22 B converts the second Ethernet signal to a second RF signal to be transmitted to the second communication device  20 B. 
         [0022]    Under a third condition, with respect to the situation that the first communication device  20 A and the second communication device  20 B are from a same service provider, another approach that the first communication device  20 A directly communicates with the second communication device via the WWAN (referring to a route  21 B illustrated in  FIG. 2 ) may also be implemented. 
         [0023]    In another application of the data transmission system  2 , when the first communication device  20 A (e.g., a mobile phone) wishes to control the electronic device  26 A (e.g., a computer), the first signal converter  22 A first receives an RF signal from the first communication device  20 A. After processing (e.g., decoding) the RF signal to a baseband signal, the first signal converter  22 A converts the processed baseband signal to an Ethernet signal for controlling the first modem  23 A and the electronic device  26 A (referring to  FIG. 2 ) coupled to the first modem  23 A or directly controlling the electronic device  26 A (referring to  FIG. 3 ). In the situation that the first communication device  20 A and the second communication device  20 B are from different service providers, referring to  FIG. 3 , the electronic device  26 A is directly coupled to the first signal converter  22 A through the network control module  260 A instead of the first modem  23 A to receive the Ethernet signal. In the foregoing examples of remote control, the electronic device  26 A needs no exclusive and fixed IP address. Therefore, the first communication device  20 A directly controls the electronic device  26 A through the first signal converter  22 A. In another example of remote control, referring to  FIG. 2 , the first communication device  20 A controls another electronic device  26 B (e.g., a computer) through the first signal converter  22 A, the first modem  23 A, the Internet  24  and the second modem  23 B. 
         [0024]    While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not to be limited to the above embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.