Abstract:
An access point (AP) ( 20 A) for automatically switching channels includes a transceiving module ( 201 ), a channel quality evaluation module ( 207 ) and a channel switching module ( 209 ). The transceiving module is provided for communicating with another AP ( 20 B). The channel quality evaluation module is provided for evaluating quality of the communication channels between the APs, generating an evaluation result comprising communication channels with different transmission qualities, and selecting a channel with best quality as communication channel between the APs. The channel switching module is provided for selecting a channel with best quality and switching the current communication channel to the channel with best quality. A method for automatically switching channels applied between two APs is also provided in the present invention to avoid interferences appearing in the signal transmission process without manual operation.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to wireless network devices, and particularly to an access point and a method for switching channels thereof. 
         [0003]    2. Description of Related Art 
         [0004]    Wireless access points (AP) are commonly used for information transmission in the existing digital home network. One of the common wireless topologies includes two APs wirelessly connected together and communicating with each other over radio channels. In practical applications, the radio channels used by two APs are prone to be interference caused by radio signals transmitted from other electronic devices, such as a microwave oven, which can lower the transmission quality between the two APs. 
         [0005]    A conventional way to avoid the interference is switching the radio channels from one currently used to another. Nevertheless, switching channels between the two APs is usually performed manually, which is rather inconvenient. Besides, coordination between two APs is also very important during channel switching because disconnection between the APs may happen when the APs cannot successfully communicate and coordinate with each other. Therefore, automatic switching of channels between the APs based on well coordination to improve transmission quality is desired. 
       SUMMARY OF THE INVENTION 
       [0006]    One aspect of the present invention provides an access point (AP) that is adapted for communicating with another AP. The AP includes a transceiving module, a channel quality evaluation module, and a channel switching module. The transceiving module is provided for communicating with another AP. The channel quality evaluation module is provided for evaluating quality of the communication channels between the APs, generating an evaluation result comprising communication channels with different transmission qualities, and selecting a channel with best quality between the APs. The channel switching module is provided for selecting a channel with best quality and switching the current communication channel to the channel with best quality. 
         [0007]    Another aspect of the present invention provides a method for automatic switching of channels between two APs. 
         [0008]    Other advantages and novel features of the present invention will be drawn from the following detailed description of a preferred embodiment and a preferred method with the attached drawings, in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a schematic diagram of an application environment of an exemplary embodiment of the present invention; 
           [0010]      FIG. 2  is a schematic diagram of functional modules of an access point (AP) of  FIG. 1 ; 
           [0011]      FIG. 3  is a schematic diagram of functional modules of another AP of  FIG. 1 ; 
           [0012]      FIG. 4  is a flowchart of a method for switching channels in accordance with another exemplary embodiment of the present invention; and 
           [0013]      FIG. 5  is a detailed flowchart of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]      FIG. 1  is a schematic diagram of an application environment of an exemplary embodiment of the present invention. 
         [0015]    A source media player  10  is connected to an access point (AP)  20 A through a cable. Another AP  20 B is connected to a subordinate media player  30  through a cable. The APs  20 A and  20 B communicate with each other over radio channels. In this embodiment, the AP  20 A and the AP  20 B are homogeneous. The data played by both the source media player  10  and the subordinate media player  30 , are multimedia data streams. 
         [0016]    In other embodiments, the AP  20 A and the AP  20 B may be mobile terminals (MTs). 
         [0017]      FIG. 2  is a schematic diagram illustrating functional modules of the AP  20 A of the exemplary embodiment of the present invention.  FIG. 3  is a schematic diagram of functional modules of the AP  20 B of the exemplary embodiment of the present invention. 
         [0018]    The AP  20 A includes a transceiving module  201 , a role assigning module  203 , an identification code generating module  205 , a channel quality evaluation module  207 , a channel switching module  209 , and a channel information storing module  211 . The AP  20 B similarly includes a transceiving module  201 ′, a role assigning module  203 ′, an identification code generating module  205 ′, a channel quality evaluation module  207 ′, a channel switching module  209 ′, and a channel information storing module  211 ′. The functional modules of the AP  20 A are the same as those of the AP  20 B. For simplicity, only the functional modules of the AP  20 A are disclosed hereinafter. 
         [0019]    The transceiving module  201  is provided for communicating with the AP  20 B. 
         [0020]    The role assigning module  203  is provided for assigning the roles to the AP  20 A and the AP  20 B. In this embodiment, the role of the AP  20 A may be an initiator or cooperator AP. If the AP  20 A were the initiator AP, then the AP  20 B would be the cooperator AP, or vice versa. 
         [0021]    The identification code generating module  205  is provided for randomly generating identification codes based on the role of the AP  20 A. The identification codes are stored in the channel information storing module  211  and transmitted to the AP  20 B via the transceiving module  201 . In this embodiment, the identification codes include the identification codes of the initiator AP and the cooperator AP. 
         [0022]    The channel quality evaluation module  207  is provided for assessing available communication channels between the APs  20 A and  20 B, and generating an evaluation result comprising quality information on the communication channels, and then selecting a communication channel with best quality. 
         [0023]    The channel switching module  209  is provided for switching from a current communication channel to the channel with the best quality after receiving a channel switching response from the AP  20 B. 
         [0024]    The channel information storing module  211  is provided for storing quality information on all the available communication channels between the APs  20 A and  20 B. 
         [0025]      FIG. 4  is a flowchart of a method for switching channels in accordance with an exemplary embodiment of the present invention. 
         [0026]    In step S 401 , the role assigning module  203  assigns roles for a AP  20 A and another AP  20 B. The AP  20 A requests the AP  20 B to assign the AP  20 A as the initiator AP and assign the AP  20 B as the cooperator AP. The AP  20 B responds to the AP  20 A to acknowledge the request, then the AP  20 A assigns the roles of initiator AP and cooperator AP as agreed. In this embodiment, the AP  20 A is assigned to be the initiator AP and the AP  20 B is assigned to be the cooperator AP. In other embodiments, the AP  20 A may be assigned to be the cooperator AP while the AP  20 B may be assigned to be the initiator AP. In this embodiment, both the request and response for assigning roles are based on the User Datagram Protocol (UDP). 
         [0027]    In step S 403 , the identification generating module  205  randomly generates identification codes for the initiator AP  20 A, and requests for assessment of communication channels between the initiator AP  20 A and the cooperator AP  20 B. In this embodiment, the initiator AP  20 A requests the cooperator AP  20 B to assess channels, the cooperator AP  20 B then responds to the initiator AP  20 A to acknowledge the request. Both the request to assess channels and the response are based on the Transmission Control Protocol (TCP). 
         [0028]    In step S 405 , the channel quality evaluation module  207  evaluates quality of the available communication channels and generates corresponding evaluation results. In this embodiment, the initiator AP  20 A and the cooperator AP  20 B both evaluate the available communication channels, and respectively generate evaluation results comprising communication channels with different transmission qualities. In this embodiment, the evaluation result of the initiator AP  20 A is stored in the channel information storing module  201 , the evaluation result of the cooperator AP  20 B is stored in the channel information storing module  211 ′. 
         [0029]    In step S 407 , the channel quality evaluation module  207  selects a channel with the best quality based on the channel evaluation results of the initiator AP  20 A and cooperator AP  20 B. In this embodiment, the initiator AP  20 A requests the cooperator AP  20 B to provide the evaluation result thereof, the cooperator AP  20 B responds to the request and transmits the evaluation results thereof to the initiator AP  20 A, then the initiator AP  20 A selects the channel with the best quality. 
         [0030]    In step S 409 , the initiator AP  20 A and the cooperator AP  20 B switch to the selected channel at a specified time. In this embodiment, the initiator AP  20 A requests the cooperator AP  20 B to switch from the current communication channel to the selected channel at a specified time. The cooperator AP  20 B responds to the initiator AP  20 A to acknowledge the request. The initiator AP  20 A and the cooperator AP  20 B then switch to the selected channel at the specified time. In this embodiment, the request for switching channel, which includes the selected channel along with the time specified by the initiator AP  20 A, and the response from the cooperator AP  20 B are also based on the TCP. 
         [0031]      FIG. 5  is a detailed description of the method of  FIG. 4 . 
         [0032]    In step S 501 , An AP  20 A transmits a role assigning request to another AP  20 B. In this embodiment, the role assigning request is generated via the role assigning module  203  and transmitted to the AP  20 B via the transceiving module  201 . The role assigning request, which includes the request for assigning the AP  20 A to be the initiator AP and assigning the AP  20 B to be the cooperator AP, is a UDP packet. 
         [0033]    In step S 503 , the AP  20 B transmits a role assigning response to the AP  20 A to acknowledge the role assigning request. In this embodiment, the AP  20 B receives the role assigning request via the transceiving module  201 ′, generates the role assigning response via the role assigning module  203 ′, and then transmits the role assigning request response to the AP  20 A via the transceiving module  201 ′ to acknowledge the role assigning request. The role assigning response is also a UDP packet. 
         [0034]    In step S 505 , the initiator AP  20 A transmits a channel assessing request to the cooperator AP  20 B. In this embodiment, the channel assessing request includes the identification codes of the initiator AP  20 A, which are generated by the initiator AP  20 A via the identification code generating module  205  and transmitted to the cooperator AP  20 B via the transceiving module  201 . The channel assessing request is a TCP packet. 
         [0035]    In step S 507 , The cooperator AP  20 B transmits a channel assessing response to the initiator AP  20 A to acknowledge the channel assessing request. In this embodiment, the channel assessing response includes the identification codes of the cooperator AP  20 B, which are generated by the cooperator AP  20 B via the identification code generating module  205 ′ and transmitted to the initiator AP  20 A via the transceiving module  201 ′. The channel assessing response is also a TCP packet. 
         [0036]    In step S 509 , the channel quality evaluation module  207  of the initiator AP  20 A evaluates the quality of the available communication channels then generates an evaluation result comprising communication channels with different transmission qualities, which will be stored in the channel information storing module  211 . 
         [0037]    In step S 511 , in this embodiment, the channel quality evaluation module  207 ′ of the initiator AP  20 B evaluates the quality of the available communication channels then generates an evaluation result comprising communication channels with different transmission qualities, which will be stored in the channel information storing module  211 ′. 
         [0038]    In step S 513 , the initiator AP  20 A transmits a channel cooperation request to the cooperator AP  20 B. In this embodiment, the channel cooperation request is generated via the channel quality evaluation module  207  and transmitted to the cooperator AP  20 B via the transceiving module  201  to request the cooperator AP  20 B transmit the evaluation result thereof. In this embodiment, the channel cooperation request is a TCP packet. 
         [0039]    In step S 515 , the cooperator AP  20 B transmits a channel cooperation response to the initiator AP  20 A to acknowledge the channel cooperation request. In this embodiment, the channel cooperation response, which includes the evaluation result of the cooperator AP  20 B, is generated via the channel quality evaluation module  207 ′ and transmitted to the initiator AP  20 A via the transceiving module  201 ′. In this embodiment, the channel selection response is also a TCP packet. 
         [0040]    In step S 517 , the initiator AP  20 A selects a channel with the best quality. In this embodiment, the channel quality evaluation module  209  selects the channel with the best quality based on the evaluation results thereof and the response from the cooperator AP  20 B. 
         [0041]    In step S 519 , the initiator AP  20 A transmits a channel switching request to the cooperator AP  20 B for switching from the current communication channel to the channel with the best quality. In this embodiment, the channel switching module  209  generates the channel switching request based on the selected channel. The channel switching request, which includes the channel with the best quality and a specified time for switching to the channel, is also a TCP packet. 
         [0042]    In step S 521 , the cooperator AP  20 B transmits a channel switching response to the initiator AP  20 A to acknowledge the channel switching request. In this embodiment, the channel switching response, which is generated via the channel switching module  209 ′ and transmitted to the initiator AP  20 A via the transceiving module  201 ′, is also a TCP packet. 
         [0043]    In step S 523 , the initiator AP  20 A and the cooperator AP  20 B switch to the channel with the best quality at the specified time. 
         [0044]    In step S 525 , the initiator AP  20 A transmits a greeting to the cooperator AP  20 B via the switched channel. In this embodiment, the greeting, such as a hello message, is generated via the channel quality evaluation module  207  and transmitted to the cooperator AP  20 B via the transceiving module  201 . 
         [0045]    In step S 527 , the cooperator AP  20 B responds with a greeting to the initiator AP  20 A via the switched channel. In this embodiment, the greeting, such as a hello message, is generated via the channel quality evaluation module  207 ′ and transmitted to the initiator AP  20 A via the transceiving module  201 ′. 
         [0046]    In any of the above-described exemplary embodiments, the APs  20 A and  20 B can automatically switch wireless communication channels therebetween. 
         [0047]    Although the features and elements of the present invention are described in the exemplary embodiment in particular combinations, each feature or element can be used alone or in various within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.