Patent ID: 8363695

Claim:
A wireless communication apparatus of a direct conversion receiving scheme in which a packet is transmitted or received while performing frequency hopping for each symbol, and demodulation is started by performing carrier sensing at a beginning of the packet on a receiving side, the apparatus comprising: a plurality of receiving systems provided in accordance with a number of frequency hoppings, each of the plurality of receiving systems, setting a local oscillation frequency thereof to be fixed at a hopping frequency; and a digital baseband unit that performs carrier sensing using a predetermined number of symbols in a preamble part at the beginning of the packet, received with frequency hopping, and that performs demodulation of a payload data part after an operation from hopping pattern detection to hopping synchronization, wherein each of the receiving systems includes a variable band low-pass filter provided in a baseband portion of the receiving system, a cut-off bandwidth of the variable band low-pass filter of the receiving system being set to be a narrow bandwidth, during processing and demodulation of a portion from a preamble part to a header part.