A method for receiving radio frequency signals by using an access point. The access point contains a plurality of smart antennas and a processor. The method includes following steps: (a) using the plurality of smart antennas to receive first radio signals at a first time, the first radio signals including a plurality of vectors, each vector having a phase; (b) using the processor to sum up vectors having the same phase in the first radio signals received by the plurality of smart antennas respectively and to compare sums of the vectors having the same phase to find a first phase; (c) using the processor to weigh second radio signals received by the plurality of smart antennas at a second time according to the first phase and to sum up the weighed second radio signals.