Patent ID: 7394799

Claim:
A method for using smart antennas in a frequency division duplex (FDD) wireless communication system, comprising: using an independent transmitting smart antenna array and an independent receiving smart antenna array, feeder cables, radio frequency transmitters/radio frequency receivers, and a common baseband signal processor in downlink radio frequency transmitting and uplink radio frequency receiving, respectively; obtaining estimated values of signal direction-of-arrival (DOA) from an uplink receiving signal to determine the direction of a main path of the uplink receiving signal; and obtaining an expected downlink transmitting beam form according to the direction of the main path of the uplink receiving signal, wherein obtaining estimated values of signal DOA from an uplink receiving signal to determine the direction of a main path of the uplink receiving signal further comprises: demodulating and de-spreading N digital signals of an uplink receiving signal by N receiving signal preprocessors, wherein said digital signals are coming from the receiving smart antenna array and the radio frequency receivers; making the DOA estimate for each digital signal by a receiving beam former, respectively; combining every digital signal to perform receiving beam forming, and getting the direction of the main path of the uplink receiving signal; and sending the DOA estimate value of the main path to the downlink transmitting link, and recovering the combined digital signal to original N receiving digital signals in a post-processor.