The invention relates to the technical field of mobile communication, and discloses a DFT
algorithm for a ZC sequence in a PRACH channel of a LTE
system. The DFT
algorithm comprises the following process of: inputting a parameter k into an ROM1, and reading an output parameter k' of the ROM1; inputting a parameter u into an ROM2, and reading an output parameter u' of the ROM2; subtracting Nzc-1 from a value A obtained by adding k' with u' to obtain a parameter B; inputting A and B into a first selector, outputting a result according to a
control signal, and inputting the result into an ROM3; reading output data of the ROM3, adding the output data with k to obtain a value C, and subtracting Nzc from the value C to obtain a parameter D; inputting C and D into a second selector, and according to a
control signal, obtaining an output result of the second selector; adding a value E obtained after dividing the output result of the second selector by 2 and carrying out
rounding with (with reference to the specification) to obtain a parameter F, inputting E and F into a third selector, taking a result G obtained by carrying out mod2
processing on the output result of the second selector as a
control signal, and outputting a p value of a
rotation factor index; and according to the p value, obtaining a DFT
algorithm result of the ZC sequence. According to the scheme, the solving process of the p value is low in storage capacity, and the algorithm is simple.