Wireless communication apparatus
The radio communication device offers data communication with no adverse effect of EMI radiation. In response to EMI radiation detected by the radiation detector, the controller changes the normal communication mode into the avoidance communication mode. In the avoidance communication mode, the transmitter prepares a transmission packet so as to satisfy the following relational expressions: T 1 =T 0 /2/M and T 2 =T 0 /2 (where, T 0 represents the cycle of an AC power source; T 1 represents the transmission time; and T 2 represents the transmission cycle). The transmission power changer determines the transmission power by multiplying T 2 /T 1 to the transmission power in the normal communication mode. The transmission rate changer determines the transmission rate by multiplying T 2 /T 1 to the transmission rate in the normal communication mode. The transmission packet is transmitted in synchronization with the stopping time of EMI radiation detected by the timing detector.
1. A radio communication device comprising:
a receiver for receiving data;
a radiation detector for detecting electromagnetic interference (EMI) radiation from the data received by the receiver;
a timing detector for detecting a stopping time of EMI radiation;
a controller for changing a normal communication mode into an avoidance communication mode in response to EMI radiation detected by the radiation detector;
a transmitter for preparing a transmission packet in the avoidance communication mode so as to satisfy expressions of T 1 =(T 0 /2)/M and T 2 =T 0 /2 (where T 1 represents a time required for transmission; T 2 represents a cycle of transmission; T 0 represents a cycle of an AC power source; and M≧4);
a transmission power changer for determining a transmission power of the transmission packet in the avoidance communication mode by multiplying T 2 /T 1 to a transmission power in the normal communication mode; and
a transmission rate changer for determining a transmission rate of the transmission packet in the avoidance communication mode by multiplying T 2 /T 1 to a transmission rate in the normal communication mode,
wherein, the transmitter transmits the transmission packet so as to be synchronized with the stopping time of EMI radiation.
2. The radio communication device of claim 1 , wherein the radiation detector detects EMI radiation when the received data has a bit error by cycle T 0 /2, and the timing detector detects the stopping time of EMI radiation according to a timing at which the received data has no bit error.
3. The radio communication device of claim 1 , wherein the radiation detector detects EMI radiation when a received power detected by the receiver exhibits a periodic change with cycle T 0 /2 during a period with no transmission from a radio communication device as a receiver, and the timing detector detects the stopping time of EMI radiation according to a timing of decreasing the received power.
4. The radio communication device of claim 1 , wherein the controller effects control of the transmitter in a manner so as to transmit the transmission packet with transmission cycle T 3 =(T 0 /2)+T 4 , where −T 0 /2≦T 4 ≦T 0 /2), and the timing detector detects the stopping time of EMI radiation according to a response packet received by the receiver.
5. The radio communication device of claim 1 , wherein, when the radiation detector detects occurrence of a bit error in a radio communication device on the receiver side from a response packet, the controller effects control of the transmitter in a manner so as to determine a timing of a successive transmission different from transmission cycle T 2 and to transmit the transmission packet with transmission time T 1 and with transmission cycle T 2 .