Patent ID: 6480527
Filing Date: 2002-11-12
Classification: H04B

Abstract:
A code division multiple access (CDMA) demodulating method performed in a CDMA system, comprising the steps of:(a) sequentially-storing all input data, which are over-sampled by M-fold and go through a N number of paths, in a predetermined first memory, where M and N are predetermined positive integers; (b) generating PN codes for each of the N paths and storing the PN codes in a predetermined second memory; (c) generating and sequentially-storing traffic walsh codes of one period, which correspond to a processing gain L, in a predetermined third memory; (d) multiplying a complex-conjugated value with one of values stored in the first memory and one of values stored in the second memory; (e) performing a control operation for storing the PN codes in a predetermined address of the second memory and a control operation for outputting data for each of the N paths from the first, second, and third memories; (f) multiplying the resultant value of the step (d) with the traffic walsh codes of a corresponding path of data stored in the third memory; (g) cumulatively summing the resultant value of the step (f) L times for each of the N multi-paths to be processed, where L corresponds to the processing gain; (h) complex-conjugating the result value of the step (d) by cumulatively adding the resultant value of the step (d) X times for each of the N multi-paths to be processed, where X corresponds to the data bit number of the walsh codes; (i) obtaining a number (N) of data by inputting the resultant value of the step (f) and the resultant value of the step (h) and multiplying the resultant value of the step (f) with the resultant value of the step (h); (j) sequentially-obtaining a number (N) of values by sequentially-inputting the number (N) of data obtained in the step (i) and taking only real values; (k) cumulatively summing the data obtained in the step (i) N times; and (l) deciding bit values based on logic values identified by identifying the logic values of the result of the step (k).