Patent Publication Number: US-2005117555-A1

Title: Device and method for auto-switching wireless network

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to wireless network communication, and in particular, to an auto-switching method and device for establishing a communication link between a computer and a wireless peripheral device.  
      2. Description of the Related Art  
      There are two different ways to transmit data or communicate through a network environment. The first way is a wired communication with a cable, and the second way is a wireless communication with an infrared ray, radio frequency or the like. However, due to the convenience in installation and its mobility in use, wireless communication is becoming increasingly popular.  
      The wireless network can be further classified according to its range of data transmission. Examples include a wireless wide area network (WWAN), a wireless local area network (WLAN), and a wireless personal area network (WPAN). The WLAN is a network which can be transmitted in a range of about hundred meters, and is usually applied in a single building or in an office. In practical use, the WLAN will adopt an Access Point to combine with a wired network so as to promote flexibility in use and to enlarge the transmission range. WLAN protocol is now governed by the Institute of Electrical and Electronic Engineers (IEEE), which essentially introduces several wireless communication protocol standards, such as 802.11 serial, HIPERLAN, HOMERF and 1394, etc. Ad-hoc mode and Infrastucture mode are further defined in 802.11 serial. The ad-hoc mode discloses a peer-to-peer (computer to computer, or computer to device) wireless communication, and the infrastructure mode discloses a wireless communication between a wired network and a wireless network via an Access Point.  
      However, the conventional computer peripheral devices typically use radio frequency (RF) to control the operation of a computer system, where each different brand name product has its own different communication protocol for communicating with its own related products. Therefore, it has become more important to allow computer peripheral devices to be incorporated with the prevalent wireless network.  
      Nowadays, a wireless communication between a computer and a peripheral device uses a user assignment mode or auto-searching mode to achieve a link. It is easier to find a network in the auto-searching mode, but this mode can fail to find a proper network when the network has more than one peripheral device since the computer may be led to wrongly connect to an unexpected peripheral device, thereby causing a security problem. In contrast, the user assignment mode is a safe and direct way to achieve the link, but a user interface is needed for a user to assign a network, and the user has to be familiar with, or recognize, a correct network from a plurality of peripheral devices.  
     SUMMARY OF THE INVENTION  
      It is an object of the present invention to provide an efficient method and device to establish a wireless communication link between a computer and at least one peripheral device.  
      The objectives of the present invention can be accomplished by providing a communicating system for establishing a wireless communication between a computer and a wireless peripheral device. The system includes at least one wireless peripheral device, a computer, and a wireless network coupling the peripheral device and the computer. The computer has a wireless network card within the computer, the wireless network card having a detection module which sends a data packet with identification via the wireless network to search for the wireless peripheral device. The peripheral device then sends an acceptable feedback signal based on the identification to the detection module so as to establish a wireless communication. The wireless communication can be based on a standard wireless network communication protocol. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a block diagram of a communication system according to the present invention.  
       FIG. 2  is a block diagram showing a detection module within a wireless network card in the system of  FIG. 1 .  
       FIG. 3  is a flow chart diagram illustrating a communication method according to the present invention.  
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      The following detailed description is of the best presently contemplated modes of carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating general principles of embodiments of the invention. The scope of the invention is best defined by the appended claims.  
      Referring to  FIG. 1 , a computer  10  establishes a wireless connection with a peripheral device  20  or  21 , via a wired network  40 . The wired network  40  can communicate with the peripheral device  21  and  20  via access points  32  and  31 , respectively. The computer  10  can also communicate with the wired network  40  via an access point  30 . Although  FIG. 1  illustrates two peripheral devices  20 ,  21 , it is possible for the computer  10  to communicate with any number (e.g., one, two, three, and more) of peripheral devices.  
      The computer  10  has a wireless network card  15  which complies with a standard wireless network communication protocol, such as but not limited to the 802.11 serial protocol standard enacted by the IEEE. In addition, each peripheral device  20 ,  21  can be a computer mouse, trackball, keyboard, joystick, tablet, touch pad, game controller, scanner, printer, or similar devices. Furthermore, the card  15  can support the usage of an ad-hoc mode and an infrastructure mode. Ad-hoc mode and infrastucture mode are further defined in the 802.11 serial protocol.  
      Here, the peripheral devices  20  and  21  can represent two different networks. The wired network  40  can be wired to the access point  30 , and then wirelessly connected to the access points  31  and  32  based on an infrastructure mode. Meanwhile, the computer  10  can also communicate directly with the peripheral devices  20  and  21  using an ad-hoc mode.  
      Referring to  FIG. 2 , the wireless network card  15  has a detection module  50  that establishes a wireless connection with a wireless peripheral device  20  or  21 . The detection module  50  can search for a plurality of wireless peripheral devices, including peripheral devices  20 ,  21  and other peripheral devices.  
       FIG. 3  is a flowchart that illustrates the operation of the system in  FIG. 1 . If the computer  10  needs to communicate with the wireless peripheral device  21  shown in  FIG. 1 , the detection module  50  of the network card  15  will search the existing networks (step  200 ) to try to establish a linkage or connection (step  201 ) with the peripheral device  21 . To do this, the network card  15  will send a wireless signal to all the peripheral devices, which include  20  and  21 . In step  202 , it is determined whether a connection or linkage with a particular peripheral device (which can be either  20  or  21 ) is successful. The connection can fail because of any number of reasons, including but not limited to, interference in the wireless transmission. If the connection fails, then in step  203 , the detection module  50  will continue trying to establish a connection with a peripheral device for a predetermined period of time (for example, 5 times). If the detection module  50  still cannot establish a connection after this period of time, then processing proceeds to step  200  where the detection module  50  will switch to another peripheral device.  
      On the other hand, if the connection to a peripheral device is established in step  202 , then in step  204 , the detection module  50  will send a data packet with identification to the connected peripheral device.  
      At this time, step  205  determines whether the detection module  50  receives a correct or incorrect feedback signal from the connected peripheral device. In the present example, the detection module  50  wishes to connect with the peripheral device  21 , so an incorrect feedback signal will be received by the detection module  50  from the peripheral device  20 . Conversely, a correct feedback signal will be received by the detection module  50  from the peripheral device  21 .  
      Thus, if the detection module  50  receives an incorrect feedback signal from the peripheral device  20  in step  205 , then processing proceeds to step  201  where the detection module  50  will switch to another peripheral device to try to establish a linkage or connection with this other peripheral device.  
      On the other hand, if the detection module  50  receives a correct feedback signal from the peripheral device  21  in step  205 , then processing continues to step  206  where the detection module  50  will end the searching.  
      According to the present invention, if the system has only one peripheral device (e.g.,  21 ), then the detection module  50  will always successfully establish a linkage so that an incorrect feedback signal should never be received in step  205 .  
      Therefore, the peripheral device  21  can control the operation of the computer  10  via a wireless network. In other words, the peripheral device  21  will send a command to the wired network  40  via the closest access point  32 , and the card  15  will receive a command that complies with a standard wireless network communication protocol, so as to operate the computer  10 . The peripheral device  20  can find another compatible computer to be connected to, using the method described above.  
      In accordance with another embodiment, the peripheral device  20 ,  21  can be a remote-controlled device, and the wireless network card  15  can be built into a house appliance, such as a refrigerator, air conditioner, television, etc.  
      However, the computer  10  can possibly communicate with a plurality of peripheral devices  20 ,  21  when playing a game, and a plurality of peripheral devices  20 ,  21  can communicate with a corresponding computer  10  through a wireless or a wired network. Thus, each user of each separate peripheral device  20 ,  21  can operate his or her own game controller to play an online game.  
      While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof.