Patent ID: 6085104
Filing Date: 2000-07-04
Classification: H04B

Abstract:
In a wideband wireless code division multiple access (CDMA) communication system including a plurality of base stations transmitting information to a plurality of mobile stations formatted in a plurality of channels including a pilot channel spread with a code and a traffic channel with time multiplexed data symbols spread with code, the communications from a base station to a mobile station being propagated along at least one transmission path, with a corresponding path delay, a method for combining received communications from a plurality of transmission paths comprising the steps of:a) identifying each transmission path of the received communications and despreading the coded pilot channel;b) estimating a time delay associated with each identified transmission path and generating a despreading code, which is synchronized with the received communications to despread the pilot channel;c) routing the received communications of each transmission path in parallel; variably adjusting the delay of each parallel routed communication, compensating for the timing differences between transmission paths, whereby all path delays are made equal, wherein the delay of each transmission path is adjusted in response to the delay estimated for each identified transmission path and in response to synchronizing the despreading code; andd) summing the plurality of communications with compensated path delays variably adjusted before they are despread whereby the communications from a plurality of transmission paths are combined to improve the signal to noise ratio of the communications, including combining the traffic channel data symbols before they are despread.