Communication apparatus

A communication apparatus capable of connecting to one of a plurality of relay apparatuses that relays wireless communications, the communication apparatus comprising:

• an identification-data storage unit that stores therein first device identification data for identifying a first relay apparatus to which the communication apparatus is currently being connected, the first device identification data being unique to the first relay apparatus;
• a transmitting unit that transmits a request message that requests connectable relay apparatuses to return a response message;
• a receiving unit that receives response messages from the connectable relay apparatuses, each response message including individual device identification data of a relay apparatus that transmitted the request message;
• a determining unit that determines whether received response message includes individual device identification data that matches with the first device identification data stored in the identification-data storage unit;
• a connection requesting unit that requests, if no received response message includes the individual device identification data that matches with the first device identification data stored in the identification-data storage unit, a second relay apparatus from among relay apparatuses identified by second device identification data that is included in any of the received response messages to make a connection with the communication apparatus;
• and
• a radio-wave-intensity detecting unit that detects an intensity of a radio wave at which each response message is received, wherein
• the connection requesting unit requests, if the response message including the individual device identification data that matches with the first device identification data stored in the identification-data storage unit is received at an intensity weaker than a first threshold, the second relay apparatus identified by the second device identification data included in any of the received response messages to make the connection with the communication apparatus, and
• if the response message including the individual device identification data that matches with the first device identification data stored in the identification-data storage unit is received at an intensity stronger than the first threshold, the connection requesting unit maintains the connection with the first relay apparatus that is connected with the communication apparatus.

A communication apparatus capable of connecting to one of a plurality of relay apparatuses that relays wireless communications, the communication apparatus comprising:

• an identification-data storage unit that stores therein first device identification data for identifying a first relay apparatus to which the communication apparatus is currently being connected, the first device identification data being unique to the first relay apparatus;
• a transmitting unit that transmits a request message that requests connectable relay apparatuses to return a response message;
• a receiving unit that receives response messages from the connectable relay apparatuses, each response message including individual device identification data of a relay apparatus that transmitted the request message;
• a determining unit that determines whether received response message includes individual device identification data that matches with the first device identification data stored in the identification-data storage unit;
• a connection requesting unit that requests, if no received response message includes the individual device identification data that matches with the first device identification data stored in the identification-data storage unit, a second relay apparatus from among relay apparatuses identified by second device identification data that is included in any of the received response messages to make a connection with the communication apparatus;
• an intensity/noise detecting unit that detects an intensity of a radio wave at which each response message is received, and an intensity of noise;
• and
• a calculating unit that calculates a signal-to-noise ratio indicative of a ratio of the intensity of the radio wave to the intensity of noise, wherein
• the connection requesting unit requests, if the signal-to-noise ratio that is calculated from the intensity of the radio wave at which the response message including the individual device identification data that matches with the first device identification data stored in the identification-data storage unit is received is smaller than a second threshold, the second relay apparatus identified by the second device identification data included in any of the received response messages to make the connection with the communication apparatus, and
• if the signal-to-noise ratio that is calculated from the intensity of the radio wave at which the response message including the individual device identification data that matches with the first device identification data stored in the identification-data storage unit is received is greater than the second threshold, the connection requesting unit maintains the connection with the first relay apparatus that is connected with the communication apparatus.

A communication apparatus capable of connecting to one of a plurality of relay apparatuses that relays wireless communications, the communication apparatus comprising:

• an identification-data storage unit that stores therein first device identification data for identifying a first relay apparatus to which the communication apparatus is currently being connected, the first device identification data being unique to the first relay apparatus;
• a transmitting unit that transmits a request message that requests connectable relay apparatuses to return a response message;
• a receiving unit that receives response messages from the connectable relay apparatuses, each response message including individual device identification data of a relay apparatus that transmitted the request message;
• a determining unit that determines whether received response message includes individual device identification data that matches with the first device identification data stored in the identification-data storage unit;
• a connection requesting unit that requests, if no received response message includes the individual device identification data that matches with the first device identification data stored in the identification-data storage unit, a second relay apparatus from among relay apparatuses identified by second device identification data that is included in any of the received response messages to make a connection with the communication apparatus;
• and
• a quality detecting unit that detects a signal quality of a radio wave at which each response message is received, wherein
• the connection requesting unit requests, if the response message including the individual device identification data that matches with the first device identification data stored in the identification-data storage unit is received at a signal quality weaker than a third threshold, the second relay apparatus identified by the second device identification data included in any of the received response messages to make the connection with the communication apparatus, and
• if the response message including the individual device identification data that matches with the first device identification data stored in the identification-data storage unit is received at a signal quality stronger than the third threshold, the connection requesting unit maintains the connection with the first relay apparatus that is connected with the communication apparatus.

A non-transitory computer-readable storage medium storing computer-readable instructions thereon, which, when executed by a computer, cause the computer to perform a method for a communication apparatus capable of connecting to one of a plurality of relay apparatuses that relays wireless communications, the method comprising:

• storing, in the communication apparatus, first device identification data for identifying a first relay apparatus to which the communication apparatus is currently being connected, the first device identification data being unique to the first relay apparatus;
• transmitting a request message that requests connectable relay apparatuses to return a response message;
• receiving response messages from the connectable relay apparatuses, each response message including individual device identification data of a relay apparatus that transmitted the request message;
• determining whether received response message includes individual device identification data that matches with the stored first device identification data;
• requesting, if no received response message includes the individual device identification data that matches with the stored first device identification data, a second relay apparatus from among relay apparatuses identified by second device identification data that is included in any of the received response messages to make a connection with the communication apparatus;
• and
• if a received response message includes the individual device identification data that matches with the first device identification data stored in the identification-data storage unit, maintaining the connection with the first relay apparatus that is connected with the communication apparatus.